Rubbing

OEM 2005 LGT 17x7, +53 with 225x45/17 Hoosier A6.

Tarmac 1's and adjustable rear arms at -1.0* camber (in the rear obviously)

 

After this weekends' autox on a road course when I was switching back to street tires, I noticed a little bit of rubbing in the rear on what looks like, or what I think is, the rear trailing arm.

 

I've run these on a normal autox course before and never noticed any rubbing so I think it was the extra speed through longer sustained turns that may have deflected the tires enough to rub again the arms.

 

So the question now is... if I get new wheels, I obviously want to get ones with a lower offset. How far do I go though? Would +48 be enough or... what's next after that, would +43 be a better choice.

+48 for any wheel up to 8.5" wide. with the wheel mounted on the car, how much clearance is ther between the tire and the arm in question?

Hmm. I'll have to check later. It's late and I'd have to remount the wheel and measure it. If I drive it up a ramp, will that affect the measured clearance between the tire and arm? Jacking it up probably would right since the unloads that corner?

as long as the car is sitting ont he wheel and not jacked up, it should be fine. did the rubbing show on the arm or on the tire?

I first noticed it when I saw that a small portion of the arm was polished and not grimy like the rest. Then when I looked at the tire, the inside shoulder also had a polished look to it, different from the rest of it (and the fronts sets)

I took some rough measurements.

 

Prodrive P7 17x7 +52 mounted with 225/45/17 Dunlop Z1 Star Specs - about 15mm between the tire and the trailing arm. (No rubbing)

 

OEM 05 LGT 17x7 +53 mounted with 225/45/17 Hoosier A6 - about 5-7mm of space between the tire and trailing arm. (Rubbed during the autox on the road course)

that interesting. 7mm is alot. i dont see the tire flexing that much totake 7mm of space. i could be wrong though. easiest fix is a 5mm spacer, essentially making the +53 rim a +48 rim. the better mor expensive solution is to buy a +48 tim that is 8" wide to stretch the tire alittle more and stop it from flexing.

What do you think would happen if I went to a 225/40/17? Although, I do have to admit that I've been looking at 17x8 and 245/40/17 tires again ~_~

well you have tires already, so i wouldnt get new tires untill you wear the current ones out. id just get new 8" wide or wider rims and put the hoosiers on them. that will solve any rub issues ince the 225/45/17 tires are more at home on a 8" wide rim. once they wear out, you buy 245/40/17 r-comps on since you can now accommodate them on the 8"+ wide rims. 225/40/17 is too short of a sidewall, but it could be beneficial if its just for autox. it would br good on the street though.

 

I may have an elegant solution for you about getting 17x8 rims. pm me.