Rubbing Issues

[dluxxx]

So Heres the info about my car. I have my car lowered on Bilstein B14 PSS coilovers. My wheel/tire combo is 20x9 et 35 w/ Conti 245/35. I raised my car to where there is no visible gap, rolled and pulled my fenders. I am still rubbing in the rear. I believe the place where it is rubbing is where the rear bumper meets the rear quarter panel. I wanted to grind down where the two body panels meet but of course there is a screw there keeping it together. Is there any other ways i can stop the rubbing? Will changing tire size work maybe down to a 235? Just getting tired of slowing down for bumps and what not. Thanks.

[SinCityA6]

A 35 offset with 9" wheel is aggressive. You have a couple of options:
1. Dropping to a 235 tire would make it narrower but I fear that you will be running far to much stretch on a 9" wide wheel. Plus, unless you upped the aspect ratio (35 to 40) you will lose ride quality because of the decreased sidewall.
2. Dial in some negative camber (if you don't have it already). Max available is -2.5.


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[3.0T]

If the problem is only when you go over bumps, you could see if Bilstein offers a higher spring rate for the rear.

Or drill a new hole to set back the mounting point where you want to grind.


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[ichi d]

I rub also with pretty much the same setup except my et is 37. On turns if I hit a bump the fronts will rub slightly and as for the rears it's only when I hit a big dip.

[dluxxx]

If the problem is only when you go over bumps, you could see if Bilstein offers a higher spring rate for the rear.

Or drill a new hole to set back the mounting point where you want to grind.


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Thats a good idea. What is weird is that I didnt rub as much with my ST setup. I wonder if the ST coils have a higher spring rate than the bilsteins?

I rub also with pretty much the same setup except my et is 37. On turns if I hit a bump the fronts will rub slightly and as for the rears it's only when I hit a big dip.

The front rub used to happen to me but then i remember either grinding something down in the front to stop the rubbing or rolling it. It totally got rid of the rubbing and my front is a lil lower in the front.

[ichi d]

I see. Ya my fenders are not rolled at all. Maybe I'll give it a try. How do u like the billstien? I was going to go with those coils but the wait was like 6m so I ended up going with h&r.

[dluxxx]

Ok so my buddies brought up a good point. If I were to up the tires to 255/30 that would actually bring down the circumference of my wheel/tire setup. Lower circumference meaning my wheels will tuck in earlier essentially clearing the bumper. Does that sounds right?

[SinCityA6]

Ok so my buddies brought up a good point. If I were to up the tires to 255/30 that would actually bring down the circumference of my wheel/tire setup. Lower circumference meaning my wheels will tuck in earlier essentially clearing the bumper. Does that sounds right?

That does not sound right to me. If you up the tire size 245 to 255, you are going wider; but if you don't account for the aspect ratio (30 in your example) you could be making the overall circumference larger. The aspect ration is the width of the sidewall calculated as a percentage of the width of the tire; 30% of 255mm. So if you increase the width of the tire and don't adjust DOWN the aspect ratio, you overall circumference gets larger; 30% of 255 (76.5) is greater than 30% of 245 (73.5)


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[dluxxx]

That does not sound right to me. If you up the tire size 245 to 255, you are going wider; but if you don't account for the aspect ratio (30 in your example) you could be making the overall circumference larger. The aspect ration is the width of the sidewall calculated as a percentage of the width of the tire; 30% of 255mm. So if you increase the width of the tire and don't adjust DOWN the aspect ratio, you overall circumference gets larger; 30% of 255 (76.5) is greater than 30% of 245 (73.5)


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So I actually found a website https://tiresize.com/calculator/

I tested out their thinking and so If i switch from my current setup of 245/35 to 255/30 the circumference will decrease by 3% from 84in to 81.7in. Thats 2.3in difference. So now looking at this website it might work. I want to find some test wheels on craigslist to see if works before i commit do doing this change

[seanentrust]

It seems like in order to run 20s you have to run a 30 series which makes me nervous.

[SinCityA6]

So I actually found a website https://tiresize.com/calculator/

I tested out their thinking and so If i switch from my current setup of 245/35 to 255/30 the circumference will decrease by 3% from 84in to 81.7in. Thats 2.3in difference. So now looking at this website it might work. I want to find some test wheels on craigslist to see if works before i commit do doing this change

So I am an idiot. I was assuming that you were going from a 245/30 to a 255/30; duh! If I would have looked at your original post, I would have seen that you were running a 245/35 tire. Sorry for muddying the waters.

[ichi d]

a tire shop was telling me the same thing to go with 30 series tires instead of 35 with 20s. either that or he said raise it. lol