Widest Tire On Stock Rims

[turbo buicks]

ive heard that on a stock 7" wide GN rim that a 275 tire can be mounted but you should not road race on it. what about this size on a street car? same problems? please give me the biggest size and profile tire that can be SAFELY run on a street GN w/stock 7" wide rims.

thanks

 

[John Larkin]

I have 275/60s and they are about as big as I can stand. Look great, but they definitely are bulged since the stock rim is narrow. If I ever come up with an extra $200 I want to throw into them, I should have the rims widened to 8 - 8.5. For this size tire, aluminum drums were a must for me since I had some rubbing while cornering with the cast iron drums. Slight but the extra 1/8" thickness of the aluminum drum eliminated it.

 

[charlloots]

i have 275 50 bfg drag radials you need quarter inch wheel
spaces. they look really fat . if you race alot i would look for a
8.5 in rim.
charlloots
we4

 

[Snorman]

I'm going to run a 235-60/15 on my car.
The problem with running a 275 is that you pinch in the edges because he wheel is too narrow. You end up with no more tire/tread on the ground than if you ran a properly sized, smaller tire. The offsetting factor is if you run low enough tire pressure to distort the sidewall to the point that the entire tread is on the ground, but that somewhat defeats the purpose of a radial tire or DR.
I do think a set of 275-50/15's on a 15x10 wheel would be a very nice setup.
S.

 

[charlloots]

i agree with you but the tire does fit it also leaves anice even
patch. that is why if he is gonna race he should look for a 8.5 in
rim. the 235 60 fits very nice and is agreat daily driver

charlloots
we4

 

[UNGN]

You can't "Road Race" with a 275 tire on back for two reasons:

1. The Huge tire out back causes a ton of understeer,and the car wants to go straight instead of turning. A huge rear swaybar helps a lot, but the front tires will still roll over and scream in pain.

2. They will rub the frame when using stock sized wheels (15X7 with 3.75 - 4.0 BS) when you are conerning hard. Enough that on fast on ramps I can see tire smoke in my rear view mirror

275/60's on T-wheels with no spacers work great if you don't try to push the envelop on every on ramp. 275/50's rub a little more (wider section and tread) and can limit mph at the track (I couldn't go over 114 with mine)

If you don't want or need drag radials and want a good tire size in back for regular radials, 255/60 would allow for better handling and less rub.

 

[tim87tr]

Originally posted by charlloots
the 235 60 fits very nice and is agreat daily driver
charlloots
we4

The 235 looks near stock and with a drag radial, it can be used at the track also to get traction. Especially if you don't go the track too much, the drag radial is good for the daily driver to be used on occasion at the track. The BFGs DRs have a wrinkle wall side that behave like a slick at the track, a good dual purpose setup. If you plan to put a lot of miles on the car, the drag radial will definitely not last very long.

The 275s really stand out, so the 235s are more of a sleeper on the street. Something to consider, instead of spending $200 on changing those rims, you can just pick up an extra set of rims cheaply. I'm picking up an extra set of T rims tomorrow and plan on mounting 28x9 slicks or 275/60R15s BFG DRs on them for the track use. But, if you don't run a drag radial on the street and the car is running good and has good valve springs, you will fry the tires at the top of first .

EDIT: I see you are road racing, not drag racing......I'll just leave this for when you want to drag race

 

[Dan Thompson]

I don't road race, but I do drive the car to work about once a week on the freeways.

I don't race at the track, but sometimes I get into one on the streets.

I did have some rubbing on the DS when going hard on the freeway, but I put the smallest spacer I could get on that side and I don't have the problem anymore.

There is a picture of the tires/rims on my website, click the pictures to enlarge.