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Summary of Bump Steer Adjustments:
I thought this might be a good time to summarize the necessary bump steer adjustments for each of the 3 different caster settings.
I was able to get the bump under .010", within 1" of ride height, up or down, at 2, 4 and 6* caster.
Duplicate my settings below, and you should get similar results.
You do not even have to double check it with a bump gauge, unless you just want to.
Each car should be pretty close.
2* Degree Caster:
To run 2* Caster you need a lot of tie rod end drop.
The easiest way is to use a 1.0" or 0.7" thick bump block, as well as a bump stud from Howe or Van Steel.
If you have a 0.7" thick bump block, use a .33" shim on the bump stud.
If you have a 1.0" thick bump block, use a .03" shim on the bump stud.
Both of those settings should give you the red curve above, or really close if your car varies.
That is if you have stock ride height.
If you lower the car, say 1.0", try an additional .07" shim to get the orange curve above.
That will shift the center of the curve up one inch. Bump studs from Van Steel or Howe. Tapered fit.
Prototype wood 0.70" bump block. These bump blocks require drilling the steering arm for bolts, require a shorter tie rod, cause the bump response to have a strong curve, and make it sensitive to ride height. But they work. 1.0" and 1.25" thick bump blocks are or were commercially available. From sources like Van Steel, VBP, Duntov and Guldstrand.
Bump block and bump stud installed.
4* Degree Caster:
If you max out the caster in your steering arms, you might be able to get 4*.
You will need a 0.70" thick bump block.
And a bump stud, with .16" of shims.
That should give you the red curve above.
If you lower the car 1.0", try an additional .07" shim, just as in the 2* version.
That should shift the center of the curve up 1 inch.
Alternate 4* Method:
If you want to get rid of the curve, and have a linear bump response, you need to get rid of the bump block.
Then you would need a very long bump stud, longer than is currently available.
You could use a long 5/8" dia bolt, use that as your bump stud, and lower the heim joint 1.69" below the steering arm.
The linear nature of the curve means the ride height of the car does not matter. This is my prototype long bump stud, just for measuring purposes. If you torqued it tight, with loctitie, etc. It will work.
I like this result so much I am going to contact several suppliers or machine shops, and see if I can a bump stud this size made.
6* Degree Caster:
A 6* Caster setting almost lowers the steering arm down to the perfect height.
Add a bump stud, with a full 0.70" of shims, and you get the blue curve above.
It is very good. It goes to +.10 & -.11" bump.
If I get the longer stud manufactured, the purple line is achievable, with .75" of shims, and .004" bump.
Bonus this curve is so linear that ride height has no effect.
This is the bump stud with .70" of shims.
I used regular nuts top & bottom instead of the lock nuts, just for testing.
Last edited by leigh1322; Feb 23, 2026 at 11:09 PM.
This weeks update:
I have been in touch with several manufacturers and machine shops.
Trying to produce a couple of parts moving forward.
I have some interest, I'll keep you posted.
In the meantime I am quantifying the adjustments needed at several different alignment settings.
The adjustments even vary right and left side...grrr...
But they are working out.
Sample:
They all worked out just fine. All under .010" bump steer. With minor stud height tweaks.
Leigh - Thousand THANK YOU’s ! ! !
I have been shooting the parts-cannon at a poor handling problem.
I knew that building a bump-steer tool might give me some direction?
Leigh, You have Actually done the time consuming research and
then presented multiple situations, changes and effects in a very precise
format, while backing Your research with photos graphs etc.
Over my years of reading content of contributing CF Members a few
“GREATS” have risen to the to the “ToP” -
Leigh You have joined ranks with the BEST, Again Thank YOU.
I will be able to put an adjustment chart together once the parts are made. You will not even need a bump steer gauge.
Breaking News!
Parts are being designed!
Dan at Van Steel has agreed to work with me on developing these two parts to make this work.
He already makes some outstanding products and is more than willing to add to his selection, based on my testing results.
*****5 Stars for a great Corvette Vendor!*****
The currently available bump studs allow for fine adjustment of the tie rod end height. But it needs to be lengthened some more. He has the CAD program, and the skill in house to get that done. Just look at his recent high end aluminum front suspension offerings. His current bump studs are made to his specifications, in chrome moly, and he has the CAD design in house. He has agreed to design a new one a little longer for more adjustment range.
Plus he already has aluminum steering arms made for his recently added C7 bearing/aluminum hub conversion kits. He has the ability to make an arm for the stock hubs, which will replace the stock forged arm, with the increased drop we think is effective. Having some of the rod end drop handled by the steering arm, means less has to be handled by the bump stud. So the bump stud can be shorter and everything will flex less.
The tie rod joint is currently 1.25" below the arm. It needs to drop as far as 2" with some alignment settings. That is about 0.75" more than stock. Basically the two of us think splitting that drop 50/50 between a new arm, and the bump stud, makes the entire system less flex prone.
Awesome Leigh.
Thanks so much for going through all this!
I’ve been waiting until you finished up with your research before I installed the Van Steel bumpsteer kit I already have.
Now it’s just down to Dan getting the design done and parts available.
I’m excited.
Once the parts are available, I’ll need to talk with Dan about how to set them up with their upper and lower tubular A Arms.
Very nice follow-up, Leigh. I agree, Van Steel is a top notch organization and they build quality products. I worked with Dan when I bought the aluminum spindles, and as I get closer to finishing my project I will get with him to see if he can build a couple of custom parts for me. Again, great work.
This pic shows three different versions of the tie rod end.
The stock tie rod end on the right drops the joint 1.25" and has a .560" dia forged shaft. This .560" shaft is roughly 1.0"-1.25" long.
The currently available bump stud in the middle, can drop the joint 1.60", and has a 5/8" dia shaft where the bump shims go (not shown). But it still has the .560" dia taper shaft where it goes thru the steering arm. I assume this taper joint is the weak point now. It lowers the joint 0.35" over the stock tie rod, for 28% more length, and 28% more force on the stud. Van Steel makes these in Cr-Mo. And it is thicker. But the current bump stud only works some of the time, by itself.
The hardware store bolt on the left, has the 2.0" drop we need, to cover all the possible alignment settings. But it needs to look like the bump stud in the middle. It will be 60% longer than the stock tie rod end. And it would put a lot more force on the .560" weak point, where it enters the steering arm. I would prefer not to have to run the heim joint that low on the bump stud, with that much leverage.
This pic shows the large 2.0" drop required to get near zero bump steer. It also shows why I would prefer for a new steering arm to handle half of the required drop. Then the bump stud does not have to be nearly as long, and everything should be stronger, flex less, and be safer. Van Steel makes their bump stud out of Chrome Moly, and the new longer one will be also, so that material is tougher than a stock forged steel tie rod end.
The new dropped steering arm will run the cost up, but safe is better than sorry. I really do not think normal steering forces are the issue .How much force do you apply to a steering wheel, like 7# maybe. With the 20:1 steering ratio that is only 140# at the tie rod end. The issue is sudden jarring from pothole impacts. The less drop you can run on the bump stud, the stronger it is.
Some caster alignment settings may not need the dropped steering arm at all. But using it, if possible, would still make the system stronger.
Last edited by leigh1322; Mar 10, 2026 at 12:31 PM.
Do you happen to have a photo with the end positions compared to a stock wheel/tire setup? How close do the steering arms get to the debris on the ground, or the edge of the tire? I think the .7" drop, with the double-bolted wedge-shaped adapter is a great solution for many of us.
As for aluminum steering arms, there's a reason that GM chose steel for that piece. Likely forged steel. Hopefully VanSteel can prove me wrong. There are other examples of aluminum arms for other cars. https://www.trzmotorsports.com/produ...steering-arms/
Leigh, I took a look at the Van Steel steering arm made for their OEM replacement spindle (not the one for the C7 bearings), and compared that steering arm to the OEM piece. That steering arm, geometry wise, comes very close to achieving what you are looking for. It drops the tie rod end about 1" and preserves the tie rod length. Unfortunately, in its current configuration it will not bolt to the OEM spindle because of the "spine" on the back side of the spindle between the two arm mounting bolts. A redesign of the area between the bolt holes to clear the spine would be fairly simple. I would like to see a little more material around the tie rod pin hole for strength. Here are a couple of photos showing the amount of drop.
Do you happen to have a photo with the end positions compared to a stock wheel/tire setup? How close do the steering arms get to the debris on the ground, or the edge of the tire? I think the .7" drop, with the double-bolted wedge-shaped adapter is a great solution for many of us.
As for aluminum steering arms, there's a reason that GM chose steel for that piece. Likely forged steel. Hopefully VanSteel can prove me wrong. There are other examples of aluminum arms for other cars. https://www.trzmotorsports.com/produ...steering-arms/
GM has been using aluminum uprights and steering arms on Corvettes since 1984. I use aluminum steering arms on my race cars with big slicks with no issues, although I usually have the steering arms made from 7075 aluminum. What Leigh is trying to avoid by not using the bump steer blocks is that they shorten the tie rod length with adverse bump steer effects. Here is a photo of a stock C-3 spindle and steering arm installed in a 15" rally wheel to give you an idea of ground clearance. The photo with the aluminum steering arm shows what lowering the tie rod mounting point about one inch looks like. Leigh is on the right track.
I will be able to put an adjustment chart together once the parts are made. You will not even need a bump steer gauge.
Breaking News!
Parts are being designed!
Dan at Van Steel has agreed to work with me on developing these two parts to make this work.
He already makes some outstanding products and is more than willing to add to his selection, based on my testing results.
*****5 Stars for a great Corvette Vendor!*****
The currently available bump studs allow for fine adjustment of the tie rod end height. But it needs to be lengthened some more. He has the CAD program, and the skill in house to get that done. Just look at his recent high end aluminum front suspension offerings. His current bump studs are made to his specifications, in chrome moly, and he has the CAD design in house. He has agreed to design a new one a little longer for more adjustment range.
Plus he already has aluminum steering arms made for his recently added C7 bearing/aluminum hub conversion kits. He has the ability to make an arm for the stock hubs, which will replace the stock forged arm, with the increased drop we think is effective. Having some of the rod end drop handled by the steering arm, means less has to be handled by the bump stud. So the bump stud can be shorter and everything will flex less.
The tie rod joint is currently 1.25" below the arm. It needs to drop as far as 2" with some alignment settings. That is about 0.75" more than stock. Basically the two of us think splitting that drop 50/50 between a new arm, and the bump stud, makes the entire system less flex prone.
The research stage is done.
This is the product design stage.
Next is prototype part production.
After that is cost analysis, then production.
Keep your fingers crossed for good luck!
More news as it develops!
I am ready to buy!!! If Van Steel needs another R&D car count me in! Been wanting aluminum steering arms for a while now and no one makes them for stock spindles. The car is lowered 2” and already has spherical tie rod ends. The car’s steering system is manual with all solid joints. Very looking forward to this!
As for aluminum steering arms, there's a reason that GM chose steel for that piece. Likely forged steel. Hopefully VanSteel can prove me wrong. There are other examples of aluminum arms for other cars. https://www.trzmotorsports.com/produ...steering-arms/
I think C4 and later front suspension components are forged aluminum. Which, I think, is stronger than cast aluminum. Not sure where billet aluminum figures in for shock, impact strength and longevity. Sort of like the usage of aluminum connecting rods in race cars, can't use those for street-driven cars that rack up some mileage.
just my 2 cents, kibbitzing from the peanut gallery.
Do you happen to have a photo with the end positions compared to a stock wheel/tire setup? How close do the steering arms get to the debris on the ground, or the edge of the tire? I think the .7" drop, with the double-bolted wedge-shaped adapter is a great solution for many of us.
As for aluminum steering arms, there's a reason that GM chose steel for that piece. Likely forged steel. Hopefully VanSteel can prove me wrong. There are other examples of aluminum arms for other cars. https://www.trzmotorsports.com/produ...steering-arms/
Yes I did.
C3 15" ralley wheel with 245/60-15 tires.
Bump (bolt) has the full 2" drop required.
Looks like plenty of room to me.
I can easily get a finger or so in there, Although I did not measure it.
The rod end is only .75" lower than stock, so it is not a lot.
I would guess the same clearance as OEM.
Well, to say I’m disappointed is an understatement. I went and purchased longer bolts with 1.5” aluminum bushings and the bolt hits the tires… This is with 18x9.5 with 5.04 backspace…
I guess there was a reason why blocks to mount on the steering arms
where developed for this…
Well, to say I’m disappointed is an understatement. I went and purchased longer bolts with 1.5” aluminum bushings and the bolt hits the tires… This is with 18x9.5 with 5.04 backspace…
I guess there was a reason why blocks to mount on the steering arms
where developed for this…
Thanks! That was my real concern. I have the same size wheels (though with 4.75" backspace with the spacers I have. So despite the shortened tie rods, the offset solution will likely work better for a lot of folks, including me.
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