View Full Version : Spindle design
HellPhish89
05-12-2017, 06:08 PM
Semi-seriously thinking of building a set as no one makes the things to fit the third gen f-bodies for anything other than drag racing which aren't streetable. the features I believe it should have are:
- bolt on steering arm. The other option is a sort of mortise and tenon joint that would be welded. I feel that would provide a certain degree of safety should a weld fail.
- use of modern hubs (maybe)
- 1.5 to 2 inch drop possibly more
- modular brake caliper mounting
If you were to come up with your own: what details or features would you add to it? From improvements in geometry to material/weight.
Discuss?
WOLF1732
05-13-2017, 09:37 AM
There is a few more questions.
What ball joints ?
Why bolt on steering arms ?
What Hubs? what material?
Make sure you use large bearings as the stock stuff just won't cut it.
What is the weight of the car/ on the front end.
What are you going to do on the tie rods, for bump steer? , stock taper units or rod ends ?
Fabricated sheetmetal or milled billet ?
4130-4340 or alum?
Yukon Cornelius
05-13-2017, 01:53 PM
I was thinking of this as well. Was thinking about making a pattern out of hardwood to send to a foundry to be cast. I still like our spindle design and not the modern sealed hub. On ffrax.com I see a lot more failures of the sealed hub on 4th gens than 3rd gens.
andrewb70
05-13-2017, 05:09 PM
Spindles need to be forged. Cast is not appropriate since a spindle is probably the most stressed suspension part.
Andrew
HellPhish89
05-13-2017, 05:26 PM
There is a few more questions.
What ball joints ?
Why bolt on steering arms ?
What Hubs? what material?
Make sure you use large bearings as the stock stuff just won't cut it.
What is the weight of the car/ on the front end.
What are you going to do on the tie rods, for bump steer? , stock taper units or rod ends ?
Fabricated sheetmetal or milled billet ?
4130-4340 or alum?
Stock ball joints
Ease of change and a sort of copy of the 1st gen Camaro pieces. Not married to the idea.
C6 hubs like SKF.
3300/~1750
Idea (at this point) is to preserve stock geometry but allow for use of more readily available rack and pinion units.
Fabricated from plate. Right now I am unsure of which steel to use. Quite a few alloys that would work well. Strut mount and ball joint mount would be stick welded into slots in the main body. Main body would be up to .5" thick.
There are other reasons for wanting the sealed bearing hub
Yukon Cornelius
05-14-2017, 06:18 AM
Spindles need to be forged. Cast is not appropriate since a spindle is probably the most stressed suspension part.
Andrew
I guess that would lead me to a fabricated billet spindle with bolt on steering arm then. I have a lathe and bridgeport in my home shop.
WOLF1732
05-14-2017, 09:37 AM
No spindles don't need to be forged.Forged is just how you make a million cheap. Fabricated or billet works just fine. When I was a PRI last year there are LOTS of aftermarket spindles out there that you can buy and skip the built thing, where other people have worked out all the issues for you, for real cheap money. My 2-cents is customs spindles in todays market is when you can't buy what you want or you are so outside the normal you "must " built to get correct function or ya just want too cause you can.
Twentyover
05-14-2017, 11:22 AM
Think I'd be talking to someone like Coleman for a fabricated spindle
HellPhish89
05-14-2017, 01:16 PM
Think I'd be talking to someone like Coleman for a fabricated spindle
The problem is that they nor anyone else makes a spindle that is safe for street driving for the third gen.
andrewb70
05-14-2017, 01:22 PM
No spindles don't need to be forged.Forged is just how you make a million cheap. Fabricated or billet works just fine. When I was a PRI last year there are LOTS of aftermarket spindles out there that you can buy and skip the built thing, where other people have worked out all the issues for you, for real cheap money. My 2-cents is customs spindles in todays market is when you can't buy what you want or you are so outside the normal you "must " built to get correct function or ya just want too cause you can.
PRI is for race cars. Are you building a pure race car or a car that also needs to live on the street? The build parameters are very different. I would never use a non-forged spindle on a car that sees street duty.
Andrew
HellPhish89
05-14-2017, 05:09 PM
PRI is for race cars. Are you building a pure race car or a car that also needs to live on the street? The build parameters are very different. I would never use a non-forged spindle on a car that sees street duty.
Andrew
needs to live on the street. This also wouldnt be an issue if someone made spindles for the third gen Fbodies..haha. Fabricated spindles can do just fine. This was a spindle Racecraft offered at one point:
140255
Yukon Cornelius
05-14-2017, 05:56 PM
I can't figure out why they stopped offering their Road Race spindle.
BonzoHansen
05-14-2017, 06:38 PM
So then are you losing the whole strut suspension?
Stock 3rd gen knuckles are cast, not forged. The pin that the wheel bearings/wheels go onto are forged and pressed into the knuckle.
Bob.
Formula364
05-16-2017, 08:32 AM
That's my spindle and pic above. Happy to have them!
Kore3 makes an aluminum hub with Set3 bearings - plenty strong.
Rack and Pinion is difficult due to engine placement vs k-member. The rear passenger seats pushed the firewall and engine forward vs Corvettes, which led to the front steering spindle. No doubt someone has done it, though. I'm not convinced with solutions, to date.
Someone on FRRAX had the factory blueprints of the stock spindle. You might search there. In the suspension forum - search "blueprint".
3rd Gens are very capable handling platforms out of the box, and fun to drive (though under-powered in stock trim). It's the SAI and scrub issues with wider meats. Even though one goes wider, it doesn't mean that you are using all the available contact patch, and tire wear is exacerbated (some might not care if it's a track car). IMO, a 275 is a good street tire. Unfortunately, my spindle limits me to a 245. With the drop spindle, improved front RC, lower unsprung wheel assembly, and full use of contact patch; I like to think I'm even/competitive with the 275. Anything above 275 and it's not close.
I'm a traditional 4 square guy, but I am considering a 275 out back. I might be able to fit an 8.5" wheel up front and run 255/275. That's not terribly bad. That's, when I finally get to ordering wheels.
In the meantime, it's good to let the aftermarket make advances and watch.
Formula364
05-17-2017, 06:51 AM
140332
Here is a small pic of the stock spindle blueprint.
HellPhish89
05-24-2017, 04:03 PM
anyone happen to have the angles for the strut mount?
Formula, I found the thread. He was selling prints of it..lol.
Mean 69
08-25-2017, 08:50 AM
Pulling this thread back up - what is the specific problem you are trying to solve? I am not very familiar with the 3rd gen Camaro platform but a friend was asking about a similar item. Are you looking to preserve the factory brake package, or would late model Corvette packages be an option?
As far as forged or not - any stressed component needs to be appropriately engineered - which means one needs to understand the actual requirements, not guess at them. Too often in this hobby you see folks making thing bigger and heavier than they need to be, which is typically a case of copying someone else's idea, and then making it bigger because it "must" be good enough that way. Then the third guy comes along, and so on. It takes more than a mill and plasma cutter to make the parts "right."
Cheers,
Mark
The hard part of engineering something like this is determining the forces at play. It won't take much to be strong enough, but stiff enough takes more material in the right places. With the factory print, or part, you can reverse engineer it, to determine the loads it can take, and then design to the same loads, or a percentage higher.
You could use a new unit bearing, to eliminate the spindle pin, and its machining/design.
Have the main body cut out of plate.
LBJ can mount to the steering arm, which bolts on, and stut mount can bolt on (see http://www.colemanracing.com/Assets/file/Custom_Spindle_Chart.pdf for and example)
Cdh84Z28
08-26-2017, 05:15 AM
Set of 7075 T6 spindles are already in the works.
Mean 69
08-28-2017, 08:42 AM
"The hard part of engineering something like this is determining the forces at play. It won't take much to be strong enough, but stiff enough takes more material in the right places. With the factory print, or part, you can reverse engineer it, to determine the loads it can take, and then design to the same loads, or a percentage higher."
This is largely true, but consider also that the factory pieces have somewhat different design and performance requirements, relative to a very high performance application. Further, today's street radials are better than probably all but the best race tires, and today's track tires are WAY better than those of even 20 years ago. So cornering forces go up well beyond what the factory was using as a design input, on the flip side the OEM's need to insure an appropriate safety factor - and cheap manufacture, so they usually go stronger than basic needs. But you are right, starting with a fundamental engineering analysis - free body diagram to understand all of the forces and moments in all driving conditions - is the very first part you should start with.
In general, 7075 is an excellent material choice for small production runs of such parts, as long as the part is designed correctly.
Cdh84Z28
08-28-2017, 09:19 AM
If it would let me post a picture, there is a prototype cut already.
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