# Tires Rub on Launches



## SpdKilz (Nov 27, 2009)

Im running a 275 tire on a 17" summit star wheel with 6.00" of backspacing....exactly what i measured, and what the tech departmentat summit told me would work. When I launch my car the tires rub pretty bad on both sides....Fenders have been rolled three times.....still can roll more though. When launched the car squats alot, and would tuck the 275 on a stock wheel, over half way down the sidewall.....

Would Drag Bags be the solution to stiffen up my car to keep it from squatting to much?

All help will be greatly appreciatied!!


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## danfigg (Sep 27, 2009)

*re*

Are the rims 8 inches wide. Also I think you need more than 6 inches of BS more closer to seven inches. I would guess 6.50 or 6.75 of BS so figure out your measurement by how much space you have on the inside closest to the inner quarter I think you need 3/4 of an inch then measure to the inside of the fender lip. You want the tire at least 1/2 inch inside of the edge of the quarter panel. Most likely you will not find a rim that will meet these measurements since pontiac didnt give our rims the correct backspace. If you look at the tire you will see that it sits just under the quarterpanel. It should sit inside the quarter not under it. So if you have the wrong Offset or backspace your rim and tire will sit to far outside the rear quarter hence forth tire rib. If anyone has the correct measurements please post it. I also had this problem with a set of 15 inch rims I put slicks on. Now I have a set of 94 S-10 4X4 rims that have 6.75 inches of back space and with the stock S-10 tire which was like a 255-75-15 (A hugh tire) it tucked in nicely with no rub----danfigg ----I think it is 171.45mm of BS------------6.75 X 25.4=177.45-----Someone please correct me if im wrong:confused inches X 25.4 converts inches into mm


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## svede1212 (Nov 1, 2005)

danfigg said:


> Are the rims 8 inches wide. Also I think you need more than 6 inches of BS more closer to seven inches. I would guess 6.50 or 6.75 of BS so figure out your measurement by how much space you have on the inside closest to the inner quarter I think you need 3/4 of an inch then measure to the inside of the fender lip. You want the tire at least 1/2 inch inside of the edge of the quarter panel. Most likely you will not find a rim that will meet these measurements since pontiac didnt give our rims the correct backspace. If you look at the tire you will see that it sits just under the quarterpanel. It should sit inside the quarter not under it. So if you have the wrong Offset or backspace your rim and tire will sit to far outside the rear quarter hence forth tire rib. If anyone has the correct measurements please post it. I also had this problem with a set of 15 inch rims I put slicks on. Now I have a set of 94 S-10 4X4 rims that have 6.75 inches of back space and with the stock S-10 tire which was like a 255-75-15 (A *huge* tire) it tucked in nicely with no rub----danfigg ----I think it is 171.45mm of BS------------6.75 X 25.4=177.45-----Someone please correct me if im wrong:confused inches X 25.4 converts inches into mm


I think you have it (except I think you meant the highlighted word). I'll bet he has too narrow of a rim too. 275s would need at least a 9-9 1/2" rim to not bulge the sides in addition to the back spacing issue. As I've stated many times also it depends a lot on *what brand* of tire as they all run different actual widths. Drag bags are a hack fix to a mismatched wheel but it may be the only real solution to the problem if the OP wants to stay with that tire/wheel combo. It will look like a 60s throwback with the rake and ride like a buckboard but. . .


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## 6QTS11OZ (Mar 27, 2005)

As stated above, the section width changes between different tire brands. Not saying that you are but some people get hung up on having the look of a wider tire. That's cool but wider doesn't necessarily mean better performance. One thing you can do is take your wheels to a reputable wheel shop and see if they can "safely" remove a few millimeters from you wheels. That's what I did. I had 3 mms removed from my rear wheels for $35 a wheel.


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## GM4life (Mar 18, 2007)

Section width is the approx. width of the tire.

And yes drag bags will help the car from squatting.


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## SpdKilz (Nov 27, 2009)

The tires are nitto 555R's They dont actually bulge much at all since nittos section width is smaller than most. The rim measured approx. 8.4" wide and 17.2" tall. the tires are actually even with the lip of the fender as of right now. the car actually sqauts a little much for me, some squat is good, to much is bad....but i think the shocks could have something to do with it. You can actually watch the car squat and raise back up when pulling the car into reverse or drive....Theres not any good tire shops around here. Im in Northern AL. The only thing around here is a few machine shops that probably could handle it.... I'll try and get some pics of the car and where the wheels are on the fender and post them. Quite possibly even a launch pic.. Thanks for the info guys!


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## Rukee (Feb 8, 2007)

GM4life said:


> Section width is the approx. width of the tire.
> *
> And yes drag bags will help the car from squatting.*


:agree


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## SpdKilz (Nov 27, 2009)

Drag bags are ordered and will be here tomorrow. Ive gotten most of the rub out by rolling the fenders again. With the help of a soft mallet.... Decided to jack the front of the car up on the front corners to see where the fender was still rubbing....gave me a great idea and got 98.9% of it by doing that.....Thanks for the help though guys....any other suggestions will be appreciated though!! 

Thanks,
Tyler


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## Rukee (Feb 8, 2007)

SpdKilz said:


> Drag bags are ordered and will be here tomorrow. Ive gotten most of the rub out by rolling the fenders again. With the help of a soft mallet.... Decided to jack the front of the car up on the front corners to see where the fender was still rubbing....gave me a great idea and got 98.9% of it by doing that.....Thanks for the help though guys....*any other suggestions will be appreciated though!! *
> 
> Thanks,
> Tyler


Tell your fat friends to get out of the car before you do any racing.


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## 87GN06GTO07IRL (Aug 10, 2009)

Silly question but your not on stock springs and shocks are you? If so get to work.


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## SpdKilz (Nov 27, 2009)

The fat friends get left far behind when i head to the track...or when we go racing period... As for stock springs and shock, yes theyre still stock. I cant quite afford adjustable shocks yet..... Installed drag bags lastnight, fixed problem, launches better, no california rake either, and rides better IMO


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## 87GN06GTO07IRL (Aug 10, 2009)

Next step get rid of the stock shocks and springs. That's the problem.


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## SpdKilz (Nov 27, 2009)

Which springs would be some of the best ones for the money? I havent looked into springs that far... shocks on the other hand i have. QA1 Adjustables are waiting to be paid for right now. Ive ordered them and theyre on the special oprder shelf at work right now. I've just got to get the dough to afford them....


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## svede1212 (Nov 1, 2005)

06gtoin216 said:


> Next step get rid of the stock shocks and springs. That's the problem.


You do know you have a sig... :rofl:


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## 87GN06GTO07IRL (Aug 10, 2009)

SpdKilz said:


> Which springs would be some of the best ones for the money?


All the major players in the Gto spring market have excellent products. I'm a fan of King because i like stiff springs but Lovelle and Pedders are wise choices too. There are other brands with cheaper springs but not much feed back on them.


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## 6QTS11OZ (Mar 27, 2005)

svede1212 said:


> You do know you have a sig... :rofl:


:lol: Damn that's funny. I wouldn't have noticed that if you didn't point it out. I guess *06gtoin216* got tired of that special man closet he was in. :rofl:


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## Poncho Dan (Jun 30, 2009)

When I had the car up in the air to install my LC-1, I rotated the tires as well, and found out that I'm a new member to the Strut Rub and Spring Sag clubs.  It wouldn't even come close to passing the pencil test.

Rear springs are an easy (and hopefully cheap) fix. Its the front stuff I'm worried about, because it'll probably end up by being more than just one or two parts that'll need replacing...


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## svede1212 (Nov 1, 2005)

Poncho Dan said:


> When I had the car up in the air to install my LC-1, I rotated the tires as well, and found out that I'm a new member to the Strut Rub and Spring Sag clubs.  It wouldn't even come close to passing the pencil test.
> 
> Rear springs are an easy (and hopefully cheap) fix. Its the front stuff I'm worried about, because it'll probably end up by being more than just one or two parts that'll need replacing...


Strut rub isn't the springs but usually the rubber strut mount bushing on top of the strut assembly


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## Lautinjr (Mar 27, 2010)

has anyone seen a GTO bagged or a Air bag kit for one?


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## danfigg (Sep 27, 2009)

*re*

I will be figuring out an air shock set up simular to the coil over set up some had made awhile back. Just waiting for the warranty to wear out. I must have searched the Monroe shock listing a million times and will come up with something---Danfigg


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## 87GN06GTO07IRL (Aug 10, 2009)

6QTS11OZ said:


> :lol: Damn that's funny. I wouldn't have noticed that if you didn't point it out. I guess *06gtoin216* got tired of that special man closet he was in. :rofl:


:rofl: (i lack cool smilies)


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## 6QTS11OZ (Mar 27, 2005)

06gtoin216 said:


> :rofl: (i lack cool smilies)


I don't want you to feel left out bruh. 

ø Smileys - Free Smileys | Forum Smileys | Smiley Icons | Smiley Emoticons | My Smiley ø

Mysmilies.com - Welcome


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## Poncho Dan (Jun 30, 2009)

svede1212 said:


> Strut rub isn't the springs but usually the rubber strut mount bushing on top of the strut assembly


Yah, that'd be the problem... mine are collapsed. It doesn't look like a entire weekend's project to replace, either.

Last time I replaced/pulled shocks it was not a pleasant experience, since I had to disconnect the tie rod ends. :willy:
Then later I found the swaybar had broke at one of the bushings. :lol:


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## Lautinjr (Mar 27, 2010)

danfigg said:


> I will be figuring out an air shock set up simular to the coil over set up some had made awhile back. Just waiting for the warranty to wear out. I must have searched the Monroe shock listing a million times and will come up with something---Danfigg


I just looked at the rear shock set up and i believe the Camaro/Firebird 4th gen shocks should bolt right up to the GTO and it's available as a Air shock. A employee of mine has a forth Gen I'll see if I can get the GTO and Camaro up in the air together and take some measurements extended and depressed. Also there is another GM vehicle that used the same mounting set up for the rear shocks but a different length I can't remember the type now i'll have to do some research. I wonder if air shocks would help my wheel hop.


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## danfigg (Sep 27, 2009)

*re*

Cool our GTO use a wierd shock they are 27 inches tall and 15.600 compressed there travel is 11 inches + and the upper mounts and lower mounts are also wierd not many cars even come close so finding something to interchange is near to impossible. That is why I want to make bracket to bolt up and shock using the bolts off the fuel tank like the guy that made the coil over shocks. I plan on just finding a shock (Monroe) that will bolt in and then the reg shock cross references to air shock, helper shocks and also what ever other shock that will cross references to the Monroe shock.---_Danfigg


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