HotRods to Hell truck Arm Suspension

[novanutcase]

Just got back from Hotrods from Hell and Steve is claiming his rear end solution is the best. Anyone want to tell me why this is not true? He says he has the exhaust issue sorted out.

[Steve1968LS2]

It's a good system but NO system is perfect.. they all have compromises. I wonder how they did the exhaust. The guy I know with one had to dump it out the side (was cool though).

[sinned]

I wouldn't give a nickel of my money to any vendor who flat out claimed that their product was the best. I would also challenge Steve to show how he came to that conclusion, he won’t be able to.



While the truck-arm system is an improvement both over the C4L of the early "A" bodies and the conventional leaf spring, it is not "the best". The Satchell link, 3-link, and T/A arrangements properly designed and installed all offer all the advantages of the truck arm with none of the deficiencies with the exception of perhaps packaging (which is also an ailment of Steve’s truck-arm system). Don't ever buy the "well Nascar uses it" argument, they use lots of stuff as a requirement of the rules that make one scratch their head and wonder why.

[novanutcase]

But up until now no one has told me why it is bad. What are the technical aspects that make it not as good as say IRS. 4 link would be great but I don't have the time to be adjusting and readjusting to optimize it. Also, since 99% of the driving I will be doing is on the street I need to have a solution that is a set it and forget it type of solution.

[Kenova]

From what I've read, most who use it are pleased with the results. It's not on my list of preffered suspensions for my Nova because of the necessary floor mods. The rear seat foot wells have to be raised a few inches.
Ken

[67SSDan]

I'd be interested in to know the same thing. I'm really hot and heavy on this setup (I don't know why... maybe it was the NASCAR argument)... I must admit that the AirBar has my eye too.

[67SSDan]

Oh... BTW, I'd be willing to bet the exhaust solution was with those spintech mufflers. It seems like I remember them talking about working with those guys on some sort of solution. I also thought I remembered them saying there was a way to run it out the back without using the spin tech pipes... I didn't ask for much of an explaination at the time though.

[sinned]

No one has implied that the truck-arm system is "bad”, not just that are better options. The truck-arm system has an incredibly high sprung/unsprung weight disadvantage as well as relying on the two arms to bind to work... I think it is ironic that Steve very proudly proclaims that the truck-arm system never binds yet that is how it attains the roll stiffness that makes it a good system, you would think the "expert" in that design would be aware of how it works.

There is actually quite a bit already discussed about this same topic, you just haven’t looked for it.

[67SSDan]

Yeah... it seems like a lot of the vendor specific stuff always turns into a big "these people who are selling these things don't know what they're talking about" flame wars... which is all well and good... but I just want to know if the average joe is ever going to notice the difference between any of these systems...

Sorry to hijack your thread novanutcase

[sinned]

Yes, the average driver will definitely notice a difference in driving characteristics of the separate systems. Now if the question is will one handle better than another in an everyday driving environment, then the answer is probably not. If you have the ability to push a vehicle to the point of differentiating attributes of different designs in your daily life I want to move there....the LEO around here wouldn't allow it.

[novanutcase]

67ss

[novanutcase]

67SSdan - DO NOT EVEN WORRY ABOUT THIS! I welcome the input from those that are more in the know than me. This way when I make my decision I won't regret it and I can do it right the FIRST time. I am really leaning towards an IRS system at this point. I figure that if every car manufacturer on the planet uses IRS for their rear suspension then from both a safety and performance standpoint it seems that this would be the way to go. Also, since the only thing moving on the rear is the A arms, the brakes and the wheels and not the entire rear it would seem that I would have better contact patch on the other side along with a quicker response in terms of getting the bouncing tire back on the road!

[Damn True]

That sort of suspension configuration does have some benefits. It is extremely stable at high speeds as a result of the mounting location of the arms (there's a bunch of math to support that but it would take me days to type it) and it does a great job at dealing with sustained lateral loads like 1/2 mile long left handers. But because it depends on the arms themselves to provide a sort of torsion/anti roll function it does not deal with rapid transitions as well as some other configurations.

There simply is no "perfect" solution. Every suspension configuration has positive and negative aspects. I'd be leery of any retailer that fails to recognize and educate a potential customer as to the shortcomings of his product.

[gchandler]

Novanutcase, I was the fellow down having lunch with Steve when you dropped in.

Just to keep the correct information out there, the Nova kits only require floor modifications on the second generation cars. The "shoebox" Novas do not require floor modifications. So if you have a pre-68 Nova you will not need to make floor modifications.

As for the rear exit exhaust you can use any sort of muffler that you would like. The system that was developed has an x-pipe configuration.

http://www.hotrodstohell.net/truckarm/truckarm_camaro/f_body_truckarm.htm

I do not work for Hotrods to Hell, but I am quite familiar with their products and I did build the website.

And to reply to Damn True: You are certainly correct about the long arms. They make a truckarm car very hard to keep up with in the long, high speed turns. I know of one porsche owner out there that is still trying to figure out why he was unable to lose a 40 year old black and silver missle crossing from La Canada to Palmdale. Boy was that guy suprised. :)

[gchandler]

I think that it bears to mention in the time that I worked at Hotrods to Hell we turned out cars with 3-links, 4 links (convergent upper arms as well as parallel with panhard), IRS, Torque Arms, leaf springs, satchel link, and torque tube. All the cars that came out of that shop were made to work the best for what they were. Exaggeration tends to find its way into relayed statements so I will not comment further on that.

It important to note that the truckarm kits are different for each car. A camaro has much different needs then a chevelle and there are significant differences in the design and composition of each of the kits. There is a reason that it has taken more then a decade to get from the first kits for late 30's coupes to the kits for camaros and novas.

An extensive amount of research and development was done for each kit. Often for the initial research HTH actually went out and acquired a test mule to build and drive around for anywhere from several months to literally years.

At this point in time there are literally hundreds of truckarm equipped hot rods driving around. I personally built over 125 shipping crates in my short time with HTH, and the volume has only increased since then.

Both of my truckarmed cars are 100% street. I do not go to the track other then LACR for the occasional jaunt down the old 1320. I consider my cars to be no compromise street cars. I want them to be as comfortable and easy to drive as possible. To me a street car is the kind of vehicle that you wouldn't hesitate to let you 18 year old sister drive, or your girlfriend to take when she is late for work and her car will not start. They type of car that can take a speedbump or unexpected dip in the road without becoming completely unsettled.

That being said, I also want a car that I don't have to be 3 miles ahead of just to do some spirited driving. It needs to react in a linear and predictable fashion. I think that many of the discussions that take place on the intranet often look at the world of automotive design through a narrow lense. A suspension system has to address many unknowns. For me personally, truckarm has allowed me to survive my own driving habits for this long, it must have something going for it.

[67SSDan]

Hey Dennis, Come to East Tennessee for the PForge pro-touring event and we'll show you around! :)

gchandler - Do you know of anyone who has done a truck-arm with AirRide's bags?

[67SSDan]

Oh yeah, and by the way... for any noobs out there (like myself), Popular Hotrodding Magazine did an awesome article this month on the differente rear-suspension setups out there. http://popularhotrodding.com/tech/0604_rear_suspension_guide/ Subsequently though... I'm no farther along at deciding what I want simply because there are so many cool things out there.

Also, thanks gchandler for the "I own it, and here's what I think about it" comments... even if you did used to work for them ;)

[gchandler]

Cars have been done with airbags. While I was at the shop we did a 1964 Lincoln Continental for Pharrell Williams that had airbags and truckarm. That was one beautiful car.

[whytry]

Do you have any pics of that car? I am hoping to get my hands on a 64 too!!! Black primer and 22's and air....


Besides the point. had to ask though...

I was looking at the truckarm and bags for my Camaro as well as the AirBar setup, I like both for the ability to easily swap out the bags for springs or coilovers.... So I can cruise it low, and then swap the air out and hit the track... Plus for me atleast I can get some testing done with both and see what works best for me. From what I can tell both kits cost about the same uninstalled....

[67SSDan]

Is that a good setup for a mostly street driven application you think? I was thinking of doing all the DSE front stuff and then the HTH rear stuff... but using the AirRide gear to make the ride nice and easy to adjust. I wouldn't have even considered this a couple years ago... but this whole G/28 thing has me scratching my head.

Coil-overs may still be the answer... I just haven't decided yet.

[whytry]

I think so, I have been using bags for 5 years now, but they were in a 1/2 Chevy truck and a 2 door 2 wheel drive Tahoe, and the Camaro had full air up front and helper bags in rear for years, but now looking at redoing the rear the correct way.. Was on a tight budget then (College)....

[67SSDan]

What are you comparing when you say that it looks to be about the same price, coil-overs and an airbag setup? Or HTH vs AirBar? I'm thinking that adding the AirBags to the HTH and DSE setups will drive the price up... but hell I was originally planning on doing the whole Wayne Due thing... so I'll probably still come out cheaper.

Interesting stuff. With the way the G/28 articles are reading... you might not need to switch out the bags for the coil-overs. Depending on how crazy you want to get on the track I guess.

[796spdbu]

Can you run coilovers with the truckarms.Id like to try them in my 72'malibu.

[67SSDan]

Yeah, I think so... isn't that right gchandler?

Also, how much does this thing weigh anyway? Everyone always talks about it like it weighs a ton.

[sinned]

I don't have the number in front of me but the arms themselves are in the neighborhood of 50lbs/ea, plus all the PHB bracing, crossmembers, and brackets.

[67SSDan]

How does that stackup against any other system? Or something like that AirBar system?

[sinned]

Well all of my links including the PHB and brackets don't weight over 40 pounds so it is quite a bit heavier. I'll bet the shipping weight of the complete HTH truck-arm kit is at least 200 lbs.

[gchandler]

First, Dennis does not have an HTH kit, nor does he have HTH Truckarms.

HTH makes its own Truckarms. They do not buy them from another supplier, nor do they use GM units. A significant amount of design and testing went into the development of arms suited for each application.

Kit weight differs by application.

A large amount of the weight is sprung weight, low in the vehicle.

The front crossmember is at the center of gravity and serves to stiffen the chassis significantly compared to stock on all applications.

The panhard crossmember is built to handle the massive loads that are placed on the unit.

Both the panhard crossmember and the truckarm crossmember have been stress tested under the most extreme conditions in a real world application.

The panhard weighs around 5 lbs, 1/2 unsprung.

The arms weigh around 25lbs, also 1/2 unsprung.

The total shipping weight for a camaro kit including, shocks, springs, screw jacks, floor pans and the wood crate that contains it is around 165 lbs.

The total kit weight is comparable to a stock multi-leaf setup.

The 1969 camaro that HTH built for Formula D with an iron big block, floater, m22, 22 gallon fuel cell and all steel body weighed just over 2850lbs.

Coilovers can be used, but I personally prefer the seperate spring and shock. I feel that it gives me a better selection for each part. I have tried both.

[Matt@RFR]

How does that stackup against any other system?

Our kit is 115lbs total, including the rear end and all fasteners. The rear end is 52lbs empty. It's roughly 13lbs unsprung weight not including the rear end, brakes or shocks, since that seems to be the norm.

[novanutcase]

G, Yes I do remember you. Wish I would have had more time to talk to you. I guess in my application I won't be driving as hard as Steve so I am still unconvinced as to why the truck arm is better than the IRS I have in mind. I know that Steve mentioned a bind point somewher in the travel but isn't that the principals upon which the truck arm works? Also, if truck arms truly improved performance that much why does detroit and practically every other car maker on the planet use IRS as their choice for a rear suspension? I would imagine that it is in, at least part, due to the safety and performance that they can get from it. What I want to know is why Truck Arm is better than IRS other than price?(by the way, the price steve quoted me is pretty much the same as an entire IRS system!)

[Mean 69]

The truck arm setup is better than an IRS, or any other setup out there, because the company that is trying to sell the system to you says so. There is no question that there are many positive attributes to the setup, but there are also some pretty significant drawbacks in relative terms also, many of which are covered here but glossed over as being completely insignificant. Unfortunately, not every company is forthright about disclosing the "dark side" of their setups.

IRS systems, when designed properly, are very, very good setups. Because the wheels move independent, and the the design that makes this possible, there are some neat things that a stick axle can't do, such as ride over road irregularities with one wheel while not upsetting the other, gaining negative camber in roll to help contact patch in hard cornering, etc. The problem is, there aren't a whole lot of good IRS setups out there, and further, it's pretty hard to adapt the better ones to a muscle car, especially for the average enthusiast. One other very significant "drawback" relative to stick axle cars is the limited amount of anti-squat that can be attained from the systems, and this is pure physics. With a heavy muscle car, that has lots of torque (sound familiar, like 99% of the muscle cars on the road?!), getting an appreciable amount of anti-squat can be very important, especially in drag race applications, or road race where planting the tires hard is critical. Given a clean sheet of paper, and liberty with packaging, etc, I'd state that the overwhelming majority of suspension designers would choose an IRS any day of the week, and twice on Sundays. Those that wouldn't are the ones that aren't capable of understanding the systems, and are unable to design such a setup, or have such a vested interest in their own existing design that they refuse to accept the inherent benefits.

So back to the stick axle argument and why there are so many more options on the aftermarket (including ours). Compromise. Period. Every, every, every suspension system is a compromise, and anyone that tells you differently is either clueless, or trying to take your money. The benfits of a stick axle arrangement in a muscle car are the ability to take advantage of the relatively high unsprung weight of the axle assembly to generate good amounts of anti-squat. Stick axles can be made very, very strong. Due to the design of the early muscle cars, adapting a different type of stick axle suspension (three link, T/A, four link, etc) is usually a lot easier than adapting a IRS deal. Tuning a stick axles is a ton easier than an IRS for the lay-person. And of course, and not insignificant, economics. Stick axles are virtually always less expensive to develop than IRS setups just because of the fewer number of parts, the large market of available components, etc.

It is tough for the consumer to sort through all of this stuff, especially because there are so many strong opinions out there. For the truck arms, the folks that run them generally like them from what I gather and seem to be extremely loyal to them. The folks that don't run them, hate them. For the ten millionth time, NASCAR requires them in the rules, and the argument is that these cars haul booty, which they do. And for the ten millionth time, every single race team would switch to a different system if given the choice. It doesn't mean that the setups are crap, nor that they don't work, but it certainly doesn't imply that they are the "best" suspension systems on the market as some folks would have one believe. Here's an exercise: watch the NASCAR events that run on road courses, and then watch a different race, such as a Grand Am race on the same course and pay attention to how the cars deal with the turns, such as the chicanes. The NASCAR cars bounce over the curbs on two wheels every time they hit one, and the other cars.... don't.


I know that Steve mentioned a bind point somewher in the travel but isn't that the principals upon which the truck arm works?

Yes. Or rather, torsional bending, but there is inherent bind in the forward bushing attachments that is there by design.

Whatever you end up using, have fun with the car. It's a great hobby.

Mark

[67SSDan]

Yeah, I think the quote from PHR was something like; the running joke in NASCAR is that the cars are basically a 1967 truck with an aerobody kit.

Interesting stuff there Mean 69. Which company are you with, and what setups would you prefer to the truck-arm?

I had also looked into the independent rear setups as well, but decided against it for a few reasons... the first being price to get one going on a 1st gen. Secondly, every 1st gen I've ever seen with one always looks to me like it sits too low in the back (? maybe that's just my imagination). I've also been told in the past that for the average person, a race between a stick rear and a indi rear would simply come down to who had the bigger b@ll$. (again.. not sure how true it is... I've only ever driven an indi rear car twice... and I must admit... I did feel like a pro... but it could have just been the corvette demons trying to get me to ditch the camaros)

[Mean 69]

Which company are you with, and what setups would you prefer to the truck-arm?


It'd be distasteful for me, as a competitor, to recommend a specific alternative on this thread, but we clearly have our own opinion. If you read the PHR article again, and note my name in my signature below, you can connect the dots as to who I am with.

Mark

[Damn True]

All the major players provide viable alternatives. Regardless if you go with a Wayne Due IRS, HTH Truck-Arm, GW or Hotchkiss leafs, DSE 4link or leafs or Lateral Dynamics 3-link you will have a very nice rear suspension system that works WAAAAAY better than stock.

Each of them has specific features that serve different benefits to the end user. What should drive your decision is what the realistic intent of the car will be, and which systems features will best serve that use.

Nobody is slamming the HTH system. It's a great product as are the above mentioned products. But like all the above it has certain things it does very well, and others in which there are comprimises.

[Steve1968LS2]

Yeah, I think the quote from PHR was something like; the running joke in NASCAR is that the cars are basically a 1967 truck with an aerobody kit.


Just be clear is was a joke said by a NASCAR suspension mechanic.. He said "the running joke around the pits is that NASCAR's are basically 1967 trucks with headers and an aerokit" Or something like that, it was pretty funny when he said it.

He also said the truckarm is very tuneable for the highspeed ovals that they run on and they can really dial the car in good. However, how many of us drive on high speed ovals?

I think the truckarm deal is good in certain situations and not so good in others. I do know that if I bought one it would be from Hotrods to Hell. The argument that it must be the best since NASCAR uses them is like arguing that the V8 must be better than the V10 since F1 has mandated that cars now run V8.. it's not "better" just the rule.

[67SSDan]

Mark... very well said, and I certainly respect your ethics. That being said... check your email.

So, looking at all these systems... for the average joe with little to no knowledge on these things... how realistic is it that we'll be able to properly tune one of these setups, and which setup requires the least amount of tuning right out of the box to get it "close".

[67SSDan]

Err.... how bout PM instead of email.

[deak350]

I just wanted to say that I enjoy my truck arm set-up and it has a great ride and great feed back. However I haven't autocrossed or driven on the open track yet. I would recommend it if you want a relatively simple rear end modification. Here are some old photos of my set-up and exhaust. The x-pipe is about 5"-6" off the ground.


https://www.pro-touring.com/forum/showthread.php?t=10896

[novanutcase]

well.....it seems that after all the discussion I've pretty much made up my mind. What I've been able to surmise from all the posts is that the truck arm, although good, is used mainly for its all around set it and forget it properties and the fact that an IRS is expensive and hard to set up in the constraints of original car. Thankfully, in my situation I think I will have Wayne Due bend me a frame and adapt an IRS to it. this way the packaging issues will be a non-issue for me. As far as tuning it, I will have to consult with him and others but I'm sure Wayne has a pretty good idea as to how it should go for my application (Mainly street!). Thanks for all the input guys!:1st:

[Madspeed]

You should do a search on rear end suspensions
I have been sniffing this site for over 3 months to decide what I want.
Its gonna Be a 3 link or T arm setup
these dudes on this site are actually Friggin Sickningly knowlagable fellas ( id allmost like to say rocket scientists) =)

Ill bet ya a good amount of money if you should read read read youl find out that you will do somthing else besides a truck arm =)

thats all Im gonna say about that =)

Gl Ken F

[Beige]

Remember when doing searches, not to get caught up in the discussion and post on a thread that has been dead for months.

[novanutcase]

LOL......DEAD???!!!??? Didn't you see the flames on the main board:rotfl: