judd944

Right before I put my 86 away for the winter I has a few issues with rubbing on the rear tires. when I would go over RR tracks, or get on the gas when coming out of a dip the tires would rub. so much that it chopped off some rubber from the outside of the tire where it would impact the fender. I am running 17" turbo twists, 9" in the rear. (255's). I was going to remove the shocks from the 85.5 parts car I have and see if those are still good. can I fix this by getting a shock with a higher "b" value?
that last sentence was for all you engineers, I am in a vibrations class right now. I am such a nerd.

ninefiveone

Shocks won't really solve your problem. The fender lips are contacting the tires and while stiffer spring rate or shocks will prevent your wheels from reaching that point of travel, that's just a bandaid. Probably a slight difference in offset with your 17" rims. You can grind down the lip or roll them if you have the right equipment/technique.

ErichCS

What about a narrower tire for the rear...like a 245 instead of a 255? That solved a similar issue on my 924S when it was rubbing.
Goodluck!

-Erich

judd944

I will try to roll my rear fender this spring, the rear tires have quite abit of life left in them.

Dave

Maybe...
You might want to have your local tire place take a look, make sure that damage won't come back to haunt you.

xsboost90

i had jjjr come over one day before a cruise and we fixed his rubbing problem on his early car. The main area for the tire to contact is in the front of the wheel well, because of the way the rear arms swing forward. I put a rubber block on the outside of the wheelwell and tapped the lip inwards with a rubber mallet, till the lip was folded over flat. Hasnt rubbed since.

judd944

good Idea XS, thanks.

t1tec

225/55-16 = Section Width(mm)/Aspect Ratio(%) - Wheel Diameter(inches)


Section Width

The first number in a tire size specification is the Section Width (SW). SW is the width of the tire measured from sidewall-to-sidewall at its widest point, ON A GIVEN RIM WIDTH. SW is NOT the tread width. SW changes approx. 5mm for every 0.5" change in rim width. Our example tire has a SW of 225mm on a 6" wide rim. A 6" rim is what most tire manufactures spec a 225/55 tire with. If this tire were mounted on a 7" wide rim, the section width would increase to 235mm (10mm more), since we've increased the rim width by 1".


Aspect Ratio

The second number is the Aspect Ratio (AR). The AR is the sidewall height expressed as a percentage of the SW. Therefore our example tire is 225mm X 0.55, or 124mm. This is measured from the inside of the bead edge to the outside surface of the tread. Some tire manufacturers refer to this as the Section Height.


Wheel Diameter

The last number is the wheel diameter, expressed in inches. No further explanation needed here.


judd you must change you Aspect Ratio to get the desired result. It is possible to go up rim sizes and adjust your tire size to remain within factory specs.