negative cambered rear ends

[CamaroAJ]

do any of you guys run a negative cambered rear diff? i have been thinking about the rear diff i want to get for my car. since the car will see more street time than track time will it hurt anything other than tire wear? the car will get pounded on autocrossing about 12 times a year and as many track days as i can get too so i am more concerned about handling than tire wear. anyone with some experance with this one?

edit: this will be on a '69 camaro with a 3-link. thinking about -.5* with a little bit of toe in.

[Bryce]

With out a full floater designed to be cambered it will load the bearings and wear them out faster. Nascar does what you are talking about.

[Bulletpruf]

Doing the same thing on my Javelin. Looks like 1 deg. of negative camber on the back is about right for a street/track car. Any more than that and you've got to worry about excessive tire wear on the inside.

Folks at Speedway Engineering seem to be the best out there if you want a full floater 9" built to order. Their cambered rears are about $250 more than the non-cambered.
Scott

[BADDRIDE II]

4948749486
49485
I brag about THE GMR every chance I get. I purchased a Fabricated Housing Full Floater Rear from Jason at THE GMR and have never seen anything like it. I shopped ALL other full floater manufacturers and nothing was as specifically designed for AutoX/track/daily driving like the GMR kit. If you will be running high horsepower and big brakes than GMR's kit is for you. It is a lot more pricier than all others.........but you get a lot more. I think anyone looking to purchase a Full Floater rear should check them out before purchasing a Floater setup. TheGMR.com or contact Jason at [email protected]

[BADDRIDE II]

49488

This is some nice stuff! The drive plate is 35 spline and drives on a smooth shank area on the 17-4 stainless wheel studs (unlike others that drive on the wheel stud threads.....which is against everything we have been taught about shear points!) VERY STRONG!

[TheJDMan]

Speedway Engineering, Moser, Howes and others have been supplying floating rear ends for NASCAR and other sportsman class racing for over 25 years. Any of these manufacturers can supply a 9" floating hub rear end with negitive camber settings for not a lot of money. NASCAR and sportsman racing put the same if not more stress on hub components as any track day or autocross.

[BADDRIDE II]

Speedway Engineering, Moser, Howes and others have been supplying floating rear ends for NASCAR and other sportsman class racing for over 25 years. Any of these manufacturers can supply a 9" floating hub rear end with negitive camber settings for not a lot of money. NASCAR and sportsman racing put the same if not more stress on hub components as any track day or autocross.

Maybe so, but I would not run those "circle track" drive plates on anything with real horsepower and a sticky tire......if the light duty "circle track" 24 spline driveplate does'nt strip out first.....surely the studs will shear since these "circle track" driveplates drive on the thread of the stud (can we say big no no). You are also limited to smaller rotor sizes as well since NASCAR/etc. do not run Big Brakes. I have seen a few one off steel rotor adaptors made in attempt to run larger rotors on these "circle track" kits.....but I do not like all that additional rotational weight eating up hp and throwing entire wheel assembly out of balance. I am sure the "circle track" kits are fine on lighter duty applications, but for the modern day High HP muscle car that may dump the clutch with large sticky tires at the track or even a nice patch of concrete....I would recommend NEWER TECHNOLOGY......lets be realistic, the first gen small block chevy is great too and has been around a long time.....but now the LSX is available! :twothumbs Check out pic of 24 spline circle track drive plate below.

49720

[HarleyR]

Maybe so, but I would not run those "circle track" drive plates on anything with real horsepower and a sticky tire......if the light duty "circle track" 24 spline driveplate does'nt strip out first.....surely the studs will shear since these "circle track" driveplates drive on the thread of the stud (can we say big no no). You are also limited to smaller rotor sizes as well since NASCAR/etc. do not run Big Brakes. I have seen a few one off steel rotor adaptors made in attempt to run larger rotors on these "circle track" kits.....but I do not like all that additional rotational weight eating up hp and throwing entire wheel assembly out of balance. I am sure the "circle track" kits are fine on lighter duty applications, but for the modern day High HP muscle car that may dump the clutch with large sticky tires at the track or even a nice patch of concrete....I would recommend NEWER TECHNOLOGY......lets be realistic, the first gen small block chevy is great too and has been around a long time.....but now the LSX is available! :twothumbs Check out pic of 24 spline circle track drive plate below.

49720

How many miles were on the driveplate pictured? These things do wear out....and eventually need replacing.You would have to be a complete moron to not purchase the correct wheel studs so insure the plate does not ride on the threads.Dont ignore the fact that people do not always purchase the right parts for their application... Just because it says NASCAR does not mean its able to handle everything, most circletrack sportsman cars are under 500 hp and very rarely do drag strip launches...A grandnational style driveplate like speedway engineering sells handle 900RWHP 3500 pound cups cars on ovals and road courses every sunday.... although they do happen, failures are very rare(I've been doing it for over ten years and have never had an axle failure) You would also have to have serous problems to have something out of balance.... perhaps a rotor thats not mounted to the hat correctly..or if its a floating set up a tolerance issue.. Im not sure how much more rear brake you would need... 11-12 inch rear rotors seem to work well...

[BADDRIDE II]

How many miles were on the driveplate pictured? These things do wear out....and eventually need replacing.You would have to be a complete moron to not purchase the correct wheel studs so insure the plate does not ride on the threads.Dont ignore the fact that people do not always purchase the right parts for their application... Just because it says NASCAR does not mean its able to handle everything, most circletrack sportsman cars are under 500 hp and very rarely do drag strip launches...A grandnational style driveplate like speedway engineering sells handle 900RWHP 3500 pound cups cars on ovals and road courses every sunday.... although they do happen, failures are very rare(I've been doing it for over ten years and have never had an axle failure) You would also have to have serous problems to have something out of balance.... perhaps a rotor thats not mounted to the hat correctly..or if its a floating set up a tolerance issue.. Im not sure how much more rear brake you would need... 11-12 inch rear rotors seem to work well...

Not sure exactly how many miles, but definitely one too many wouldn’t you agree! Does not sound like it is a surprise to you that these 24 spline CIRCLE TRACK drive plates fail? You are not the first to step up on PT.com and testify to this weakness. As for your testament of these 24 spline CIRCLE TRACK drive plates wearing out….it would not surprise me since there are only 24 splines….had it been 35, this would not be a consumable…...:spank2:

I like that you agree with me on the drive plate needing to ride/thrust on a designated shank area on the wheel studs vs. on the wheel stud thread itself…..but you act as if no one does this? First off I can think of a few people that follow these “Floater Threads” pretty closely that may take offense to your “Moron” comment, since that is what they purchased with their CIRCLE TRACK kits . And you cannot blame them, since even these CIRCLE TRACK kit distributors even showcase them on their sites with this type design and include in their kits (which may be fine for CIRCLE TRACK…but NOT DRAG or High HP PRO TOUR.

As for speedways drive plates handling 900RWHP in 3500# cars……until these drive plates NO longer experience REGULAR failures…..I do not agree that they can handle it, nor are they a PRO TOUR car in comparison. I would have to go out on a limb and say that anyone that would run a 24 spline on 900HP is the (word you said above). Here is a good question for you, call MOSER/STRANGE/MARK WILLIAMS/THE GMR and tell them that you are running 900 RWHP in a 3500# sticky tired car, and simply ask what spline would be desirable for axle/carrier spline out of 28/31/33/35/40…….they WILL tell you that 35+ splines would be needed. Now as for the circle track 24 spline, when a 35 spline is offered…..that is a NO brainer! 35 spline is superior and will handle the abuse. How many DRAG floater kits run 24 spline drive plates……..the answer is ZERO! Why do you think? Exactly, they do not hold up.

As for brake size…this is your strongest argument….yes 11-12” rotors could be adequate? But again a lot of the most serious of PRO TOUR cars will not run these as they look small in the larger wheels. So again, another reason these kits are not PRO TOUR. And do you really want to defend a steel rotor adaptor vs. an aluminum one? Wow, sometimes I think people just want to be argumentative. No hard feelings either way :cheers:

[HarleyR]

Im not saying the 31/24 set up is gospel.. but its a lot more durable than you give credit.. every cup car you see on TV every sunday is running a 31/24 set up... I wouldnt go as far as saying that the failures are regular.. like i said Ive never had an issue with a 31/24 set up... If you feel that strongly about it call Hendrick Motorsports Gibbs and Roush and tell them they all wrong...because you called them all morons... Im not sure if your saying a PT car harder on parts than a cup car or not... I cant imagine a parking lot cone race,weekend track day or a few miles on the power tour destroying parts... in such a regular fashion...not saying it does not happen cause ive seen some pretty crazy stuff... A larger set up would be a great plan and the stuff you pictured looks nice... Im not a fan of Wilwood but you have a solid set up... Where did the picture of the driveplate come from? were the driveplate splines straigh on the axle? on a cambered rear end when they should have crowned axles.. this causes wear rather quickly

[BADDRIDE II]

Im not saying the 31/24 set up is gospel.. but its a lot more durable than you give credit.. every cup car you see on TV every sunday is running a 31/24 set up... I wouldnt go as far as saying that the failures are regular.. like i said Ive never had an issue with a 31/24 set up... If you feel that strongly about it call Hendrick Motorsports Gibbs and Roush and tell them they all wrong...because you called them all morons... Im not sure if your saying a PT car harder on parts than a cup car or not... I cant imagine a parking lot cone race,weekend track day or a few miles on the power tour destroying parts... in such a regular fashion...not saying it does not happen cause ive seen some pretty crazy stuff... A larger set up would be a great plan and the stuff you pictured looks nice... Im not a fan of Wilwood but you have a solid set up... Where did the picture of the driveplate come from? were the driveplate splines straigh on the axle? on a cambered rear end when they should have crowned axles.. this causes wear rather quickly

Sorry, but not feeling like giving credit to a flawed system that should have been replaced years ago. As for calling your respected sources (Hendrick/Gibbs/Roush) , I’m not thinking they are even remotely interested in debating this…but if you would like to arrange, and they accept, I would have NO problem discussing a component for component breakdown of the GMR kit and am sure at the end, they ALL will conclude too, that this GMR kit IS best suited for PT type application over the CIRCLE TRACK offerings. These guys are well respected for a reason and I am sure they would recognize quality when they see it. I doubt they will be as argumentative as their supporters. Good racers, respect good parts.

When one of us “little guys” ever experiences a problem/failure with a part on one of our cars, it is safe to say we remove the part and replace it with something that works (especially when one is offered “over the counter”). I believe it is just old school stubbornness that keeps this weak link around….not to mention the politics of getting all classes to approve and improve. If you/anyone want to SETTLE for this 31/24 setup and risk the LIKELY event you will strip a drive plate/break an axle/hub body…then you can SETTLE for old technology designed for CIRCLE TRACK and ruin your weekend and most likely your car as well.

To compare THE GMR floater kit to any CIRCLE TRACK kit would be like comparing an alligator to a lizard! :razz:

Yes I would most definitely say that a serious PRO TOUR car is MUCH more brutal on a set of hubs/drive plates than Roundy Round. A CIRCLE TRACK 24 spline drive plate was NEVER intended for 500-600-700+ HP that would be constantly dumping the clutch and is why these failures occur (now some will want to chime in on the lack of traction argument, but if you know how to set up your car for weekend track days with even just a drag radial you WILL and can hook) with sticky tires….even if it is just now and then that you will visit the straight track or even just dump the clutch for kicks….do you really want to say a prayer each time you get a wild hair….no thanks…I will go with a system designed specifically for BOTH hard cornering, AND clutch dumping impact as well as the added bonus of larger rotors.

The GMR has incorporated the best of CIRCLE TRACK, OFFROAD & DRAG Full Floaters to create one incredible, affordable, application specific kit. To date, the only arguments to my recommendation of The GMR kit, are from supporters of others kits that are designed for CIRCLE TRACK, known to fail, and are cheaper…..are we listening to ourselves people? I rest my case. :smoke:

[andrewb70]

Let's not hi-jack this thread. Clearly there are different ways to address the hub arrangement.

Andrew

[BADDRIDE II]

Let's not hi-jack this thread. Clearly there are different ways to address the hub arrangement.

Andrew

You are right, I got caught up in the moment!:rolleyes:

[funcars]

Experience with cambered rear - 1.5 degree neg on both sides with superspeedway rear hubs, stock car products crowned axles and coated hardened drive plates. I have not had any issues with drive plate wear or axle spline problems. I also have a non-cambered rear same set up that I ran longer and no problems there either. Tire wear isn't as good on a large camber rear. .75 to 1.0 range is probably better for a more street oriented car. I used to have a mainly street V6 Alfa with a .75 cambered rear DeDion solid rear and it did not chew up tires any faster than a flat rear, but it worked noticeably better on the track and was able to use a bigger rear anti-roll bar.

Good luck with your choice

[BADDRIDE II]

Hey funcars, great info on your experience with cambered rears. I am curious as to how much HP/TRQ at rear wheels you ran on this 1.5 degree setup with crowned axle? Is this the steel hub with larger 5" on 5" bolt pattern? Any pictures?

[ace_xp2]

Cambered rear ends can turn that camber into toe in or out depending on how the suspension is designed. Making sure the rear end maintains an acceptable position under pitch and heave becomes more important. Though it seems crowned axles worked well for funcars (is that a street ride funcars?) Cone and winters make ball drive ends (they look like cv joints with a splined center).
Cone even makes one in 35 spline, for those times when you make more than 900hp at the slicks you always use while apparently driving harder than a grand national racer (those guys are basically loafing along out there though). But it's a truck setup so I think the smallest they do is 5x5.5.
http://www.coneindustries.com/partsgallery.php#
Winters Closed Tube Catalog (http://www.google.ca/url?sa=t&rct=j&q=winters%20ball%20bearing%20drive%20hub&source=web&cd=10&sqi=2&ved=0CGYQFjAJ&url=http%3A%2F%2Fwww.wintersperformance.com%2FWint ers%25202011%2520Closed%2520Tube%2520Catalog.pdf&ctbs=search%3Fhl%3Den%26q%3D&ei=IBShTon1CpPWiALw3piMAQ&usg=AFQjCNEcQK9RSFrEuo4-_i-G6FbbSGo1dg&cad=rja)
Warning, the Winters catalog is a 12mb pdf link.

[BADDRIDE II]

Cambered rear ends can turn that camber into toe in or out depending on how the suspension is designed. Making sure the rear end maintains an acceptable position under pitch and heave becomes more important. Though it seems crowned axles worked well for funcars (is that a street ride funcars?) Cone and winters make ball drive ends (they look like cv joints with a splined center).
Cone even makes one in 35 spline, for those times when you make more than 900hp at the slicks you always use while apparently driving harder than a grand national racer (those guys are basically loafing along out there though). But it's a truck setup so I think the smallest they do is 5x5.5.
http://www.coneindustries.com/partsgallery.php#
Winters Closed Tube Catalog (http://www.google.ca/url?sa=t&rct=j&q=winters%20ball%20bearing%20drive%20hub&source=web&cd=10&sqi=2&ved=0CGYQFjAJ&url=http%3A%2F%2Fwww.wintersperformance.com%2FWint ers%25202011%2520Closed%2520Tube%2520Catalog.pdf&ctbs=search%3Fhl%3Den%26q%3D&ei=IBShTon1CpPWiALw3piMAQ&usg=AFQjCNEcQK9RSFrEuo4-_i-G6FbbSGo1dg&cad=rja)
Warning, the Winters catalog is a 12mb pdf link.

I agree ace xp2, suspension has everything to do with how successful or un-successful a cambered rear will be, especially on a street car that is driven regularly. The least amount of pinion angle change from original cambered setting at ride height, the better.

I personally do not think that a cambered rear is desirable for a car that will be driven primarily on the street or long distances, with occasional weekend type track events.

Although the crowned axles are the way to go in a cambered rear,you are at even GREATER risk of shearing/stripping the drive plate and or axle splines since the spline engagement (amount of spline meshing surface ) between the drive plate and axle spline is far less than that of a Zero cambered rear with straight axle/spline. So in my opinion for a PRO TOUR (all around car), a Zero camber rear would be the best choice for strength and all around drivability/longevity due to the GREATLY compromised spline engagement on cambered/crowned rears/axles. As you all know, the 24 spline drive plate is already questionable with even full spline engagement……add a crowned axle with less spline engagement and you are asking for problems.

If you are building a track only type car, than by all means take full advantage of a cambered rear, but be prepared to replace both driveplate and axles approx. every thousand miles like cup cars do, as these parts are generally worn, and or are known to fail soon, and are not worth the risk of failure in future.

So not only would I never run a 24 spline drive plate on a 500+hp PRO TOUR car with manual transmission & sticky tires (at track or street), definitely do not run a crowned axle that is even weaker!

Now as for the CV type drive plate, it is not applicable toa typical PRO TOUR car…..not only is the bolt circle and stud size not applicable……the hub bore on the wheel would be huge…..like a truck….oh that’s right,it is for a truck……….:slap:

[andrewb70]

You guys should all check out this build thread:

https://www.pro-touring.com/showthread.php?67239-The-unorthodox-budget-Firebird-%28-74%29

That guy is building a de dion rear suspension set-up. He build the axle and is using a Ford Cobra 8.8" center section. The axle mounts Cobra spindles which can be adjusted for toe and camber. Neat set-up!

Andrew

[BADDRIDE II]

That is a very unique build! I hadnt seen this. Obviously has the issues associated with "cambered" floater rears worked out with that design. And given that he will only experience 1.5+- suspension travel....his camber/toe will remain as set through entire suspension travel. Cool how he can add shims for toe adjustment too. Very talented fabricator!

[ace_xp2]

Glad you're picking up what I'm putting down... Though I should mention that the winters set up is also a ball drive, and not made for a truck B.C.

[funcars]

I do meet the requirements of sticky tires, manual trans and over 500 hp, but have had my drivetrain live. I've run only new dry lube coated hardened SCP 4140 lightened drive plates and solid core crowned axles (and keep the splines greased every so often). I use a full tight 31 spline black gold torque sensing differential and set up my axles carefully to avoid binding the differential splines. It chatters a bit on street but works great on the track. The one thing I don't do is drag race. Hubs are steel superspeedway 5x5 with 5/8 studs and the bearings are big.

BADRIDE -you posted the drive plate failure picture from the website you recommended. Was that a hardened 4140 drive plate or an aluminum one? What experience do you have with crowned axles, cambered rears and failures?

Thanks

[BADDRIDE II]

I do meet the requirements of sticky tires, manual trans and over 500 hp, but have had my drivetrain live. I've run only new dry lube coated hardened SCP 4140 lightened drive plates and solid core crowned axles (and keep the splines greased every so often). I use a full tight 31 spline black gold torque sensing differential and set up my axles carefully to avoid binding the differential splines. It chatters a bit on street but works great on the track. The one thing I don't do is drag race. Hubs are steel superspeedway 5x5 with 5/8 studs and the bearings are big.

BADRIDE -you posted the drive plate failure picture from the website you recommended. Was that a hardened 4140 drive plate or an aluminum one? What experience do you have with crowned axles, cambered rears and failures?

Thanks


Sorry, but you do not meet requirements in my book if you do not "drag"…a well-rounded PRO TOUR car will see ¼ mile time (even if minimal) which will certainly kill that drive plate/axle spline with crowned axles. Given that you run a 5 on 5 hub with 5/8” studs your system will not be a favorite of PRO TOUR either. Let’s take a poll of how many PRO TOUR guys run a 5 on 5 WITH 5/8” studs? This is PT.com and not CT.com right?

Yes, failed DP was a hardened 4140 and was even on a Zero cambered/non-crowned axle. I have never personally run a crowned axle since I donot build cars only for track and minimal street use, as this design IS meant for….and given all the downsides of cambered/crowned rears/axles on a High HP street cars, I personally see NO longevity in this system and is NOT ideal for PRO TOUR (cars that actually drive long distances/race courses/AND drag race at track & street). I am very familiar with these crowned axles though and is why I will not run on the street. I have spoken with Frank over at Speedway quite a bit on this subject and this is NOT ideal for street driven vehicles due to rapid component wear…..they are known as “consumables” in the CT world. But since you must know, I do however have over 20 years experience with MANY high HP muscle cars, and would consider myself very experienced when it comes to what makes a rear-end hold up to high HP on BOTH street & track…….it has never been 31 spline carriers and would NEVER be a 24 spline axle.

As for Winters CV set-up………still is a 31 spline on carrier side of axle…..remember, Higher HP PRO TOUR cars do not get push starts….:smoke:

[ace_xp2]

Mosers old site rated their 31 spline at 7000lb/ft of torque. Now assuming you're building a pro touring car, and not a pro street one, you'll probably have a 3.0 at most first gear and a rear in the 3.55 range. That means you could make more than 700lb/ft of torque (700*3.0*3.55*.9(.9 is trans/pumpkin efficiency)) and not exceed the rating of one axle. So with the kind of table top torque graph we all want that would give you over 850hp at 6500rpm (700*6500/5252). These are just back of napkin calcs, but that's already a lot more power than most people here are running.

[BADDRIDE II]

First pic.....straight spline for ZERO cambered rears (you will get full spline engagement/meshing surface into drive plate)....IDEAL for street use with Higher HP

50449



Second pic.....crowned spline for cambered applications (you will NOT have full spline engagement/meshing surface)....NOT IDEAL for street use with Higher HP

50450

People should know if determining whether to run a cambered rear, that it is a FACT that you will have less spline engagement/meshing surface were axle enters drive plate, greatly reducing strength.


People should also understand that the cambered rears whether straight spline or crowned will enter the Drive Plate crooked (at whatever angle camber is set at), thus why a crowned spline is almost mandatory to even work. Picture trying to install your driveshaft….if it is not nearly perfectly straight while installing….you feel resistance and your natural intention is to get straight so it indexes freely. Well a cambered rear snout makes your axle spline index into the drive plate crooked, and will never align straight, thus always wanting to be at a bind and wearing away at axle and drive plate. The only way to minimize this spline “bind” was to basically crown the splines, but doing this you greatly compromise thread engagement/meshing surface at this key area. Now just for the record….the drive plate end is not the only area that suffers….the carrier side axle spline/carrier also suffers from this “bind” as well.

Let’s also think about this: if cambered rears with crowned axles are not an issue and are the fix all like some have expressed…..then why would the circle track industry work on and offer the” CV style” drive plate? That is right……they do revolve in “bind” and thus wear out parts prematurely….that is a FACT
So even should you choose a CT floater kit with 24 spline……I would not recommend (given the FACTS) that you run camber or crowned axles if it will be street driven on a regular basis or you WILL wear out these known “consumables”. :smoke:

[ace_xp2]

Wow, don't run solid lifters! You do know that the nice thing about floaters is how easy it is to swap those very parts right?

[HarleyR]

The first picture looks to be the carrier end of thpe axle...those splines are usually straight

[BADDRIDE II]

Wow, don't run solid lifters! You do know that the nice thing about floaters is how easy it is to swap those very parts right?

It is good to see you do not dispute the FACTS. And YES these parts are easily replaced, I suppose you are right as long as you are fully sponsored so these replacement costs are taken care of, AND carry extra ones along with tools in the trunk of your car should this happen outside the convenience of your garage/track with pit crew to lend a hand?

[BADDRIDE II]

The first picture looks to be the carrier end of thpe axle...those splines are usually straight

You are right Harley....but picture sufficed for concept. Good eye.

[ace_xp2]

Actually, I disputed the "facts" in the post above yours,check again. Didn't realise it took a pit crew to operate a jack and a set of wrenches. And the nice thing about wear is it has a curious correlation to the odometer...
Oh, and I'd have a fair bit of cash for replacement parts if I had, say, an extra $1800 laying around for some reason,

[BADDRIDE II]

Actually, I disputed the "facts" in the post above yours,check again. Didn't realise it took a pit crew to operate a jack and a set of wrenches. And the nice thing about wear is it has a curious correlation to the odometer...
Oh, and I'd have a fair bit of cash for replacement parts if I had, say, an extra $1800 laying around for some reason,

Hey guys do not take so personal. All I am doing is pointing out the FACTS. It is up to each one of us to make the final choice of what is best suited for our cars/application.

I think I have pointed out some very valid FACTS that one should consider when going with a cambered rear or crowned axles. I would bet it would be safe to say that a lot of people on this site do not even know what a crowned axle is, thus why we have these forums to inform and share FACTS (usually). Since the post title is “negative cambered rearends”……and we ARE on PT.com and NOT CT.com, I simply was pointing out the downsides since this entire site is about multi-purpose cars that track as well as are driven on the street in long distances.

If you are building a PT style car that will be primarily track….than by all means…run camber/toe/solid lifters/jet packs/whatever…..

[vintageracer]

NASCAR driveline parts only have to last 520 miles or less in one weekend of use. The expectation of any PT guy is that his parts will last significantly longer than 520 miles and one weekend. Don't confuse true race parts with combination street, track and strip use parts used in a PT car.

[ace_xp2]

FACTS
And what of the reference to hp vs. spline count? While we don't know what the ball side of the ball drive would put up with, there's fair indication that good 31 spline axle can take up to 700lb/ft with pro-tour style gearing.
I somehow doubt it's a fact that a push start can exceed that kind of force.

[BADDRIDE II]

And what of the reference to hp vs. spline count? While we don't know what the ball side of the ball drive would put up with, there's fair indication that good 31 spline axle can take up to 700lb/ft with pro-tour style gearing.
I somehow doubt it's a fact that a push start can exceed that kind of force.

I think you need to read over again...you are missing the point. Do not take so personal.

[HarleyR]

You are right Harley....but picture sufficed for concept. Good eye.

The picture is only one thing of many I have found wrong in your posts..you have opted to enter your personal opinion rather than real facts..my personal favorite was who yoi claimed that a pro tour street car exerts more stress and force on compotes than a purpose built race car..

[BADDRIDE II]

NASCAR driveline parts only have to last 520 miles or less in one weekend of use. The expectation of any PT guy is that his parts will last significantly longer than 520 miles and one weekend. Don't confuse true race parts with combination street, track and strip use parts used in a PT car.

Well put.....some people are trying to defend products that are intended for track type use only (and very effective for the most part). But these same parts that handle (for the most part 900hp) will not last on even a 500hp street car for 10's of thousands of miles. Just not gonna happen.

[BADDRIDE II]

The picture is only one thing of many I have found wrong in your posts..you have opted to enter your personal opinion rather than real facts..my personal favorite was who yoi claimed that a pro tour street car exerts more stress and force on compotes than a purpose built race car..

Feel free to correct publically what you feel is wrong....waiting?

[BADDRIDE II]

Hey guys (you know who you are).....any comments on the post above regarding spline engagement?

[ace_xp2]

As for Winters CV set-up………still is a 31 spline on carrier side of axle…..remember, Higher HP PRO TOUR cars do not get push starts….:smoke:

Mosers old site rated their 31 spline at 7000lb/ft of torque. Now assuming you're building a pro touring car, and not a pro street one, you'll probably have a 3.0 at most first gear and a rear in the 3.55 range. That means you could make more than 700lb/ft of torque (700*3.0*3.55*.9(.9 is trans/pumpkin efficiency)) and not exceed the rating of one axle. So with the kind of table top torque graph we all want that would give you over 850hp at 6500rpm (700*6500/5252). These are just back of napkin calcs, but that's already a lot more power than most people here are running.
I'm pretty sure I'm reading this right, is this not what was stated? Only one of those things appear to approah facts...

[BADDRIDE II]

Hey Guys,

So let me get your defense straight, I have been taking notes along the way.

(1) 5”on 5”or 5.5”x 5.5” is more suited for PT than 4.5”or4.75”
(2) Narrow bearing spread is more desirable than wider
(3) Steel hub body better suited for PT than Aluminum
(4) 5/8” wheel stud is better suited for PT than ½”
(5) 24 spline drive plate is stronger than 35 spline drive plate
(6) 31 spline carrier spline is stronger than 35 spline carrier
(7) Smaller rotor is more desirable in PT than larger
(8) You would rather keep replacement parts in the trunk, along with floor jack/wrenches and don’t forget allens and large nut socket, so that when your odometer tells you to, you can replace them?
(9) Oh, and that less spline engagement/meshing surface is a good thing
(10) Per a napkin calculation...31 spline axle with 24 splines on other end will take 700ft lbs from a launching High HP car without concearn.
(11)

I left (11) blank for more stuff you guys may come up with.

[HarleyR]

Feelings alert ......like I have stated before... the set up you apparently spent alot of money on is bad ass..I never claimed that a 31/24 set up was stronger...you dont have to be a mechanical engineer to arrive at that conclusion..im simply staying that people have had great results with a 31/24 set ...you make it sound as if your wheel will pass you when yourmakimg laps around a parking lot crusing or simply riding down the highway when a person owns and maintains a high performance vehicle some parts replacement is to be expected ..

[ace_xp2]

Hey Guys,

So let me get your defense straight, I have been taking notes along the way.
(10) Per a napkin calculation...31 spline axle with 24 splines on other end will take 700ft lbs from a launching High HP car without concearn.

Interesting, I'm pretty sure you were talking about the winters CV:

As for Winters CV set-up………still is a 31 spline on carrier side of axle…..remember, Higher HP PRO TOUR cars do not get push starts….:smoke:
Who's not reading the thread again? And if any of those other variables don't meet engineering concerns than they should be upgraded. But it would be nice if some actual, even if only superficial, engineering were done to ascertain when they actually need to be upgraded. Then you could find yourself with as much as an extra, lets say, 1800 dollars to drop on other parts of the car.

[Bryce]

I am a mechanical engineer for an aerospace company. I like equations and real numbers.

Whenever I design something I design it for its intended use.

If we are designing a car to be a pt car and we want to get the last 10% out of the handling then we have consumable parts. If you are not braking then its too heavy. not many parts are engineered to last a lifetime. Certain things wear out.

Lets turn this thread into an engineering design thread!

What bearing spread do we need? This depends on Wheel/tire combo, expected lateral G force and CG height.
What bolt circle is required? When we are launching hard with slicks and 2000hp we would expect to see 5/8" studs and even a 5 x 5.5 bolt circle. Most $1000 wheels are available with custom bolt circles and stud sizes.
What diameter bearing is required? This we again depend on the load on these bearings. My car weighs 2700 pounds 1250 on the back axle. My car would require a different bearing than a 4000lb chevelle with 1800 pounds on the rear axle
What hub material is required? This depends on the design. Not everything made from aluminum is stronger and lighter than steel.
Spline count? This depends on car weight, tire size, engine torque, gear ratio and how much torque can you get to the ground.
Rotor size that is a different subject. The largest brake required to lock up the tire at race speed and prevent heat soak. Anything bigger would be extra weight and would be only for the cool factor.

When we talk PT cars most are street and not looking for the last ten percent that a full floater or a camber rear end may give them. The guys really racing their cars and going to check every part for wear and tear before and after every track day.

[BADDRIDE II]

Hey Bryce, that is all great info and do not mean any disrespect.....but it does not take a mechanical engineering degree to figure that out (although I bet makes easier).....I have no degree, and common sense allowed me to ask all the same questions you outlined before I purchased the kit I did.

As an aerospace mechanical engineer, perhaps it is hard to relate with the small private business that has to suffice as many cars as possible into one design. You see, it would not be possible to break down each and everybody’s needs into different kits based on all the different factors, it just is not cost prohibitive.....so in the name of efficiency and cost effectiveness, one would come up with a design that would suffice/survive all. Now would we produce a kit for a 2000# car? Nooooo….we would make sure it would hold up under a 5000# tanker so that you could cover everybody.

I have followed your build and I respect your work, that is why it would be hard for me to believe that if you had to design a floater kit for the PRO TOUR market, that you would not have come up with something very similar (although would not be exact since you need more than a degree and CAD skills to have a true winner – no substitute for plain old experience to come up with best end product).

Why not maximize bearing spread (downside?)….why not produce a 35 spline drive plate since it is same cost to do as a 24 (downside?) Why not use aluminum to save weight (downside?) Why not offer the option of running larger rotors (downside?) Knowing that most people want a 4.5”or 4.75” bolt center with ½” studs…..would you really bank on the fact that everybody is going to just order custom wheels with large hub bores and truck type bolt patterns and stud sizes? A small business has to produce and sell a product that will retrofit the masses.

I also think you are a little off on your 10% theory. Why would you design a part that is lacking by 10%? That is ridiculous (what parts do you design at your work-is this standard practice to make parts at 90% of what is required)? So if you push your car 100%....will it fail? I prefer a part that is intended to last, again….in the real world (non aerospace backed) try selling a part with that pitch line….”We engineer our parts 10% below par, as to not make your part too heavy!” Wow that’s good stuff. Funny enough, the kit I purchased is lighter than a comparable semi-floater and if you could run calcs would find it is overkill. So looks like a well-engineered part can be 100% strong and light

[funcars]

I am an engineer myself (BSME and MSEE), and for fun I design and fab my own suspension components just like lots of other guys do. I agree - it would be great to get some real tech/data and learn more from an engneering perspectiive. It is so hard to find any real data for drivetrain part testing.

[Bryce]

Hey Bryce, that is all great info and do not mean any disrespect.....but it does not take a mechanical engineering degree to figure that out (although I bet makes easier).....I have no degree, and common sense allowed me to ask all the same questions you outlined before I purchased the kit I did. There is a difference between asking and answering. I am trying to lead this thread to answer those questions.


As an aerospace mechanical engineer, perhaps it is hard to relate with the small private business that has to suffice as many cars as possible into one design. I can relate to a small business. I design and build all my own stuff.


You see, it would not be possible to break down each and everybody’s needs into different kits based on all the different factors, it just is not cost prohibitive.....so in the name of efficiency and cost effectiveness, one would come up with a design that would suffice/survive all. Now would we produce a kit for a 2000# car? Nooooo….we would make sure it would hold up under a 5000# tanker so that you could cover everybody. Yes, but the parts for the 5000lb car would be to heavy or too costly for the 2000lb car.




I have followed your build and I respect your work, that is why it would be hard for me to believe that if you had to design a floater kit for the PRO TOUR market, that you would not have come up with something very similar (although would not be exact since you need more than a degree and CAD skills to have a true winner – no substitute for plain old experience to come up with best end product). Thanks! I would design a part for a specific application. I would lean towards the side of race rather than street. I am building my car as light as possible. A degree and CAD skills can go a long ways, IF you know how to use the tools. Experience is great but if you cannot calculate the loads on the parts you are using you have no idea what strength the parts have or need to be.


Why not maximize bearing spread (downside?)….why not produce a 35 spline drive plate since it is same cost to do as a 24 (downside?) Weight, not all cars need 35 spline axles. The 24 spline drive plates may work great for certain people and specific applications.


Why not use aluminum to save weight (downside?) Aluminum is not the end all best material. So your opinion on aluminum is not accurate. Again it depends on the design of the part.


Why not offer the option of running larger rotors (downside?) To restate my previous post; The largest brake required to lock up the tire at race speed and prevent heat soak. Anything bigger would be extra weight and would be only for the cool factor or looks. The biggest brakes are cool but the correct size brakes are engineered.


Knowing that most people want a 4.5”or 4.75” bolt center with ½” studs…..would you really bank on the fact that everybody is going to just order custom wheels with large hub bores and truck type bolt patterns and stud sizes? Again i will restate my previous post. A 1000 horsepower car should consider stepping up to 5/8" studs and a larger bolt circle, expecially if they are thinking about drag racing!


A small business has to produce and sell a product that will retrofit the masses. True that is why there are multiple companies making floaters! Jason makes a great floater.



I also think you are a little off on your 10% theory. Why would you design a part that is lacking by 10%? That is ridiculous (what parts do you design at your work-is this standard practice to make parts at 90% of what is required)? So if you push your car 100%....will it fail? I prefer a part that is intended to last, again….in the real world (non aerospace backed) try selling a part with that pitch line….”We engineer our parts 10% below par, as to not make your part too heavy!” Wow that’s good stuff. Funny enough, the kit I purchased is lighter than a comparable semi-floater and if you could run calcs would find it is overkill. So looks like a well-engineered part can be 100% strong and light
You miss understood my post. I am saying that most people that build protouring cars are looking to have a sporty street car and are not looking to push their car to the limits. If you reach that limit and need to bring your car up to the next level or the last 10% you might consider a floater or a cambered rear end.

[Bryce]

I am an engineer myself (BSME and MSEE), and for fun I design and fab my own suspension components just like lots of other guys do. I agree - it would be great to get some real tech/data and learn more from an engneering perspectiive. It is so hard to find any real data for drivetrain part testing. Same here! I am a test and design engineer I wish I could use my tools at work to test suspension components.

[BADDRIDE II]

I give.

[BADDRIDE II]

I really was going to “give”…… but that was assuming that the engineers that were so quick to critique were going to add pertinent, scientific, “real numbers” info that would help folks with the title posted. Well….still nothing.

Since I do not hold an engineering degree, I rely on real world personal experience, and good old info from the manufacturers who sell the products (who have already ran the calcs, and have recommended limitations based on calcs & experience)…..in this first case, the subject of concern (and sticking with the subject posted) would be pros/cons of cambered rears, and one question would be the 31/24 FLOATER AXLE.

Perhaps one of these engineers could start by telling us just how much axle/spline strength is lost when running crowned spline axle vs. straight when contemplating a cambered rear or not?…..clearly, by decreasing actual meshing surface on the splines of the axle, the crowned spline holding power would be weaker and not able to hold to the same hp/trq as the fully engaged straight spline (as outlined in above thread), so let’s put your skills to work and start off slowly. Tell us just how much strength is lost? You DO agree strength is lost, right…….and you did want to “turn it into an engineering thread”.

Next we should move on to how much hp/trq this 31/ 24 spline axle/drive plate can take (on paper/CAD using real numbers), then we can compare what you come up with to my “real world experience” with a 31 spline axle…...I can tell you that in a 66 Nova that weighed just under 2900lbs with a pump gas 355sbc (with 505hp/480trq), Powerglide w/brake, 9” 4200 stall, 26”od x 8.5” tread on ground MT street slick. I broke axles two separate times before finally swapping to the larger 35 spline/larger axle o.d.

I will be curious as to how accurate your findings are in comparison to what really happens (two different times) when around 500hp/trq hook up on 2900# car coming out of the hole at around 4000rpm on 31 spline axles (god forbid I had 24 spline driveplates)? Lets keep in mind that at 4000rpm I was still slightly under my peak hp/trq.

So you do not go off in a whole different direction, please stay focused on the questions at hand knowing that I realize that a 31/24 spline CT kit would most likely be adequate on a 375hp lightweight car like yours. If you will take note…I always refer to HIGH HP applications.

Thanks in advance for all this “real number info”. Should be interesting to see if it compares to real world type documented cases.

Oh and I have one more question because I am very curious as to something I may not be familiar with. Are CIRCLE TRACK 31 splines like “super duper 31 splines”? Or are they the same 31 spline as regular semi-floater axles would use? Because NONE of the axle manufacturers I called (and explained the car was a 3000# 650hp clutch dumping monster that would see occasional 1/4mile time as well as primarily built for Auto-X/Track) even remotely tried to sell me a 31 spline. They immediately told me the 35 spline would be the recommendation

[andrewb70]

Mr. Badride II (it sure would be nice to know names)

Let it go. Nobody is bashing your beloved GMR.

Bryce is absolutely correct in that, ideally, every part on a race car needs to be built to smallest margin above breakage as possible. Anything else is extra weight and potentially more drag in the driveline, which ultimately means a slower car.

Look at Formula 1 cars. They make crazy power, yet have tiny little axles. They are made to handle whatever power is required and not much more. Every little piece has a purpose and is built specifically for that purpose.

Let's get back to the original post which was cambered rear ends, not hubs.

Andrew

[BADDRIDE II]

No problem on letting hubs go...but if you read my last response I am simply asking for crowned axle info...that is on subject.

Do you mind letting Bryce answer since he offered his expertise?

[andrewb70]

No problem on letting hubs go...but if you read my last response I am simply asking for crowned axle info...that is on subject.

Do you mind letting Bryce answer since he offered his expertise?

Bryce can answer if he wishes although I think it will be rather pointless. You have your mind all made up and have all the answers, so what's the point?

Andrew

[BADDRIDE II]

Bryce can answer if he wishes although I think it will be rather pointless. You have your mind all made up and have all the answers, so what's the point?

Andrew

Thank you all mighty one...do you care to dispute my offered info of crowned axle splines are weaker....I gotta hear this!

[JEFFTATE]

Thank you all mighty one...do you care to dispute my offered info of crowned axle splines are weaker....I gotta hear this!

Not everyone wants to argue , or get the last word in , or debate .

Let's turn this thread into constructive information , not a debate .
Or let it go ..

[BADDRIDE II]

Not everyone wants to argue , or get the last word in , or debate .

Let's turn this thread into constructive information , not a debate .
Or let it go ..

Last time I checked....I WAS adding constructive info that pertained to the original post......it only turned into a debate when a few select others wanted to continually argue my given info....so point your finger in the right direction. :wasntme:

[andrewb70]

Last time I checked....I WAS adding constructive info that pertained to the original post......it only turned into a debate when a few select others wanted to continually argue my given info....so point your finger in the right direction. :wasntme:

You act as if what you say is 100% true for every possible situation. Your problem is that you cannot stand being challenged and you must always have the last word. Let it go...

Andrew

[JEFFTATE]

Last time I checked....I WAS adding constructive info that pertained to the original post......it only turned into a debate when a few select others wanted to continually argue my given info....so point your finger in the right direction. :wasntme:

I'm pointing the finger at you because you have argued with every person in this thread .

You have great information , and GMR makes a great product , but you come across as argumentative , and you talk down to people .
Why don't you communicate in a nicer way ?

[andrewb70]

Civil discourse regarding cambered rear ends and various hub solutions may now resume.

For the record, this situation has been under discussion by several moderators since last night, and a joint decision was made to ban Mr. BaddRide II for 7 days, since this was not his first incident.

Andrew

[Bryce]

WOW, I dont sign on for a few days and see we have had a few changes in the direction I was hoping this thread would go. To not cause anymore issues I will add info only pertaining to cambered rear ends.

If someone wants to run a cambered rear end they probably are not interested in drag racing (a cambered axle will reduce the tire footprint during straight line acceleration) and dropping the clutch at 5500rpm may not be in the game plan for the track days.
Obviously an axle designed for a cambered rear end will not be as strong as a straight splined axle. See my previous statement, the use of a cambered rear end will be used in a very specific vehicle, someone who wants a little more cornering capability.

A protouring car with a 200 treadware tire is never going to hook up like a drag car with a drag slick. When the tire spins first you are less likely to break a driveline piece.

[andrewb70]

WOW, I dont sign on for a few days and see we have had a few changes in the direction I was hoping this thread would go. To not cause anymore issues I will add info only pertaining to cambered rear ends.

If someone wants to run a cambered rear end they probably are not interested in drag racing (a cambered axle will reduce the tire footprint during straight line acceleration) and dropping the clutch at 5500rpm may not be in the game plan for the track days.
Obviously an axle designed for a cambered rear end will not be as strong as a straight splined axle. See my previous statement, the use of a cambered rear end will be used in a very specific vehicle, someone who wants a little more cornering capability.

A protouring car with a 200 treadware tire is never going to hook up like a drag car with a drag slick. When the tire spins first you are less likely to break a driveline piece.

Excellent points.

Andrew

[HarleyR]

Sorry fellas....I guess im the one that poured the first cup of gas on the fire

[go-fish]

Sorry fellas....I guess im the one that poured the first cup of gas on the fire

OK, he's gone. You can let it go too.

I've been following the thread and would like to know if there were ever any OEM cars that had adjustability or a cambered rear end. If so, what kind of suspension did they use. I ask this because I would assume it would be the most long lasting, given that this was replicated in a similar weight car.

I see a lot of Miata's running around with cambered rear ends on the street and was wondering if the parts they use have big brothers that would survive in our heavier cars?

[Bryce]

IRS (miata) cars and a dedion tube rear suspension could have had camber adjustments.

[go-fish]

That explains it. So any IRS can have adjustments? Like the Heidts?

[Bryce]

Johnny,

Yes an IRS should have camber adjustments.