I recently switched from BMR a-arms back to my Spohn tubular a-arms with spring perches. I also have the SSBC 1LE front brakes with the 1LE spindles. The car is an 88 Camaro with a 2.8L. I have the quick ratio steering gear and the springs were replaced with stock MOOG parts a couple years ago. Since the switch back to the Spohn a-arms my right tire have been rubbing the heck out of the inner fender well on the backside. Whenever I turn to the right when parking it rubs and rubs and I cannot figure out why. When I had the BMR a-arms it rubbed a tiny bit but now it is excessive. I thought maybe the suspension had to settle or something but I don't think the rub will go away on its own. What I cannot figure out is why it would rub when everything I have is stock in design except the a-arm. The wheels I have are in the photo attached to this post. Does anyone have some suggestions? My mechanic who also has a third gen thought maybe the hub on the rotors SSBC sent with their kit was not large enough. Meaning it was not pushing the wheel far enough out from the car. Any help is always appreciated, thanks guys.

 

Well i'm running a 275/40/17 front, but mine rub on both sides excessively. Spohn's a-arms are to blame. I think others have stated this.

Plenty of people have tucked 275/40 under the front but this looks like i'm going to have to do a lot more trimming.

 

I have the 245/50/16 tires up front. I was wondering if the a-arms were to blame or not. For some reason I wanted to blame the alignment. Maybe I will just have to find some stock a-arms to solve the problem.

 

Would maybe running a 225/50 help? Using this calculator http://www.miata.net/garage/tirecalc.html the diameter shrinks by about 0.7" which would help. I don't know what handling issues I would encounter with 245/50 in back and 225/50 up front.

 

What if you use spacers?

 

I have the same problem. I thought it was the alingment at first but I believe it is because of the spohn a arms. Ive had to file my gfx a little and push the fender liner back a little. The problem as well is the spohn a arms have no steering stops. Im going to fab up a stop and put it on the arms and see if I can fix or limit how much the tire rubs. My tires rub on both the outside edge in the fender and then turn the other way rubs on the inside edge on the sway bar.

 

Has anyone done a direct stock Aarm -> spohn Aarm -> Stock Aarm swap to verify 100% that these things are the cause?

I just email Spohn and got back a useless response

"We do not change any geometry on the k-member or the a-arms."

when obviously something has changed. My stock 16x8s needed a slight
clearance after the Aarms, but I just found out my racing rims (17x9.5s) won't
turn past 75% and the new vette rims (18x9s) with SPD spacers won't turn
past 50%.

With my stock rims and wheels turned straight, I have 2" gap in the back, and 4" in the front. Seems like a geometry change to me...

 

When I contacted spohn I also got a useless response saying they were not aware of any issues with there aarms and that I should notch the rear bolt hole to gain the added clearance to keap the tires from rubbing. I dont want to do that. I think I am going to get rid of the spohn ones and get the ones from UMI.

 

When I took my car into my mechanic he said the tire and wheel was mounted too far outboard of the car. Then it occured to me maybe it is the rotor. The rotor hub could be too thick which then pushes the wheel and tire further out. I cannot confirm this is the problem yet until I get my rotors next week from my parts guy at the Chevy dealer. He ordered me some ACDelco performance rotors that are slotted and drilled. I'll see if the rotor is made differently than the one I got from Stainless Steel Brakes in their 1LE brake package I have. It is possible that different manufacturers of rotors don't give us the correct measurements in the hub. Don't be too quick to judge Spohn and other manufacturers yet. I had BMR a-arms too and they rubbed just not as severely as my Spohn. Stay tuned.

 

Well it was a guess but rotors did not affect the tires rubbing. I took my car back to the place I got my tires and the guy there said my problem was most likely the incorrect caster. When I originally got the tires it was 4.1 degrees and now it is about 3 degrees. The specification for the caster on the IROC is 5 degrees positive caster. So for some reason nobody has the tool needed to set the caster and camber right on our cars. The guy told me to bring the car back next week when their one mechanic who works on Camaros knows how to set it right. I do know one thing when my caster was closer to 5 there was less rub. Does anyone else know if their caster is off?

 

Well I took it back to the alignment shop and the closest they could get was 3.4 degrees on the left and 3.1 on the right. Does anyone know if the IROC had more caster adjustment built into it? I am going to try another shop because I know I have had the caster at 4.1 degrees before from other shops.

 

So I took my car to the Chevrolet dealer. For some reason everywhere I go they tell me that the wheels and tires are not the right size. I tell them sure they are not right for a Sport Coupe which I have but they are for the IROC. So the guy doing the alignment says that he has to slot the caster adjustment holes so he can get more caster out of it. Has anyone ever heard of this? I am going to have him do it tomorrow but it just seems odd. The caster specs for the IROC and Sport Coupe were relatively the same.

 

Not exactly what your asking but I have those same 16 x 8" wheels on my 82 and my car is lowered 2". The tires do not rub at all and I have never had any issues.

My guess is either something is bent or something is off. Have you measured the wheel offset to make sure you do not have a rear wheel on the front? My wheels are marked front and rear.

 

Well I have the stock springs for the 1988 Sport Coupe in there. The wheels I have are marked front and back. I also had the wheels refinished by a company called Transwheel which did excellent work. They made sure the wheels were straight and they refinished them for me. The tie rods, idler arm, relay rod, a-arms, and upper strut mounts have all been replaced. Everything on the front suspension has been replaced. I have the 1LE brakes along with the 1LE modified spindle from Stainless Steel Brake Company. I honestly think I am running into people who do not know how to align the car. I keep all my alignment sheets and in the past people could do it so I am not sure why they cannot do it now with a 16" wheel. I might just end up doing it at home.

 

Well that is one of your issues right there. The 1LE brakes push the wheels out about a 1/2". I am not sure why only one side is rubbing but I know Cadillac did a thread on his 1LE brake change over and his wheels started to rub after the conversion.

 

[Edit: I'm eating crow... After the suspension settled, the geometry was all exactly the same..]

 

Thanks for that info. I will have to contact spohn about mine as well. Since I bought over a year and a half I dont think they will refund mine so I will most likely be buying the umi a arms and putting my spohn a arms on ebay.

 

whats you final outcome? Where the spohn a arms the problem or something else? If you put the stock a arms against the spohn ones is there any differences?

 

In my case, the spohn a-arms and stock ones were the same..

I measured my EdMiller C4-HD brakes against a Baer 13' track kit, and it was 1/8" more outboard. Given additional 3/8" thickness of the 13" HD rotor, and mounted on 1LE hubs, I think I'm just stacking tolerances.

 

Hmm ok with the spohn a arms on my car the wheels definetly look like the wheels sit farther back in the wheel well. I also have the ls1 big brake upgrade kit on the car as well.