Hi guys,

Currently, the car has rotated struts to get more negative camber (-2.8) up front since factory (max is -1.4 or something) setting does'nt give enough unless you use the 7mm shims. I was trying to get the Kussmaul settings actually. Decided to do the rotated option because it gives more negative to play with even though I never went more than 2.8. Everytime I talked to a different mechanics who work on GT3s, I get different answers. Some say I should never rotate the struts as it changes the geometry of the suspension and adding shim is the only way. What do you guys think? Is rotating the struts ever an alternative way to get more negative camber from the factory? When I read the following post, it looks like it is.

https://rennlist.com/forums/showpost...78&postcount=7

Wondering whether anyone here has gone with adding the shims option more than the rotating the struts. So far, I have no problem with the handing of the car (even thought I'm still on stock suspension at 40k miles ). With slightly toe-out front, the car grabs the corners like no other. The turn-in is absolutely amazing. But, curious if I put the top of the struts back to where it was and adding shims instead will make things even better.

Happy Thanksgiving!

Ken

 

I have 2 X 3mm shims with -2.5 front camber; stock suspension with minimal toe in. Turns in very nicely and the tire temps and wear indicate that this camber is correct for an MPSC on 9" rim. I did not try to rotate the strut as I was under the impression that it gives too much camber. The tire rubs the inner fender liner slightly at full lock.

 

Ken, they are adjustable strut tops for a reason. With that said, the optimal way is both rotate AND shims to maintain caster settings across the adjustment. I had mine rotated and shimmed to -3.8 up front.

 

Ken you have done it right. If you use only the shims, you end up increasing caster so much that the tires will rub on the fender liner at even 2.5 degrees negative. Which is not good.

Better is to rotate the strut which gives about neg 2.0 degrees negative with the top adjusters in the minimum (least negative) position. If you simply slide the top inwards you'll get more negative camber, but caster will be too low around 7 degrees, which is way out of spec and promotes understeer.

At that point you have two choices, rotate the struts to get neg 2 (ish) and use shims for the rest and get your caster in spec in the process, or, use the alternate hole in the lower A arm to increase the caster. Note that using the alternate hole will increase the caster but there is no fine control, it will be what it will be. The shims allow far greater finesse which is why everyone I know has done it the way you did.

Best,

 

That makes sense if you're going for more than -2.5 camber (like for slicks) to do both. I don't have my alignment specs in front of me but I'm pretty sure that my casteris right around 8 deg. What does rotating the strut one position do to the caster?

 

Ken, rotating the struts is fine.

I just rotated the camber plates on the GT3 RS, because I was rubbing the 265 tires on the fender liners. No more rubbing, after I rotated the camber plates, I have 7mm shims, with the strut fully outboard at a 10mm lower front ride height, I get -2.7 camber (all I need).

Rotating the camber plates allows to run wider wheels and tires, while it reduces caster, you can gain caster adding shims. If you don't rotate the camber plates and add shims, you end up with a lot of caster (good) and a lot of rubbing on the fender liners (not good).

 

Thanks a lot for posting guys. Very useful infos. Never thought of how caster is gain mostly with adding the shims but reduced after the strut is rotated. Dell's crazy with -3.8 front! May be that's why the tires won't last more than 2-3 events for you baller.

Thanks Bob. I believe mine is set at least negative camber after rotating the strut, which is -2.8ish, so assuming my caster is still within proper spec relate to the camber as I don't have any rubbing issues yet. Then again, my fronts are R888 245s so I'll see whether there's any rubbings when I go up the size. Like you mentioned above, there's still a room to push the top inwards and get even more negative. But, that won't happen until I get the shims and/or bigger tires.

One mechanic was telling me that rotating struts is not an option and adding shims or aftermarket suspension with camber adjustable plates are the only way so I was a bit confused.

Interesting set up. Never tried toe-ins before. Turn in is definitely better with toe-out for me. Very last few events, I've been trying to make myself turn in lot later and harder into a corners and still car has no push or (little) drama. It's amazing. Sometime I get 3 wheel actions.

 

I just had my strut rotated to go from 1.8 to 2.5 The only issue is it took my Caster down from 8 to 7.7 and 7.4

The shop I used said that was the best he could get the caster with the camber at exactly 2.5 since they are not adjustable.

My only concern is the RF caster at 7.4. The spec is 8° ± 30' so I am a little unsure about this setup.

Before the alignment I had 7.9 and 8.3.

What would need to be done to bump the Caster up a bit without changing the camber? Would I need new adjustable links?