View Full Version : Need fresh set of eyes on tire fit isssue


scott747driver
Apr 14th, 07, 10:43 AM
Hi Guys:

I need a fresh set of eyes on this issue. I have read many of the posts dealing with tire fit. Specifically, BFG Radial TA 275 60 r15 on a 68 camaro (multi leaf springs, no tubs) with American Racing Torque Thrust D. (following are Summit racing numbers ) part # are-1055861 8.5" rim width, 3.75" backspacing, 15" rim. I have these wheels and tires on the back of my car.

The posts I have seen do not indicate any rubbing problems with these wheels and tires. Is this with the 3.75" BS wheel? On my car the chrome trim was slicing into the outer tread whenever I pulled into my sloped driveway, or when I make a tight turn.

To compensate for this problem I installed a lift kit.This solved the problem but I don't like the look of the shackles and the tail end of the car sits up too high on top of the fact that weight transfer during launch at the drag strip has been affected.

I had thought this was the maximum BS available on this model wheel. On the American Racing website there is another size available. Model number 1056861. This wheel has an 8"rim 16" diameter and 4" BS.

So, this other rim is 1/2" narrower, 16" diameter vs 15" but with a bit more offset.

Now to the point. I am considering ordering the 16" rim and putting the 275 60 15s on them.. Does anyone think this would bring the tire deep enough into the wheel well so I can remove the lift kit and not have any rubbing issues? the 1/4" difference does not sound like a lot. Or am I just spinning my wheels? :D

Any opinions would be greatly appreciated.

Thanks,

Scott

JimM
Apr 14th, 07, 11:28 AM
3.75" bs on an 8.5" wheel is no where near enough. the tire will stick out too far, and get into the outer opening lip on bumps.

To get the tire inside the wheelwell, you need at least 4 1/2" bs on an 8" rim, closer to 5" on an 8.5"

Hopefully this was a typo, but note that you CANNOT put a 15" tire on a 16" rim!

scott747driver
Apr 14th, 07, 11:56 AM
Thanks for the reply Jim. I guess this means that the Torque Thrust d's were a poorly thought out purchase. I guess I will have to select another style that will provide the required backspacing and sell the TTD's. Quick question though, 4.5-5" BS will not cause any clearance problems with the inside portion of the wheel (shock absorber etc.) will it?

Thanks again,

Scott

DOUG G
Apr 14th, 07, 12:09 PM
15 x 8's with 4.5"bs is about as perfect as you can get without being a custom made wheel.

If you measure a stock 68 wheelwell you'll find 6" from inner wheelwell to wheel mounting flange and 5" from the lip to the wheel mounting surface.

scott747driver
Apr 14th, 07, 12:20 PM
Thanks Doug. I'm browsing through the summit catalog now trying to find a different wheel style . Sure did like the look of the TTD's though.

Scott

JimM
Apr 14th, 07, 12:52 PM
as you tuck in that 15" wheel, clearance to the inner fender and to the lower shock eye will become an issue.

Do some measuring with what's on there now and calculate where it will be. The shock eye tucks inside the rim nicely with a 17" wheel, but not a 15"

scott747driver
Apr 14th, 07, 12:54 PM
Thanks Jim. Got to try and not screw it up a second time.

Scott

madmax87
Apr 15th, 07, 12:48 PM
I had the same wheel on my 69 and also was going to get the 16" because of the added BS. That 8.5" just sticks out a little too far for me. I was only running 255

http://i55.photobucket.com/albums/g136/Caman355/MVC-017F.jpg

scott747driver
Apr 16th, 07, 07:56 AM
Thanks Dennis:
Re: Jims reply, The 16 or 17 " rim with the 4.5 " BS seems like the way to go. Only thing is I have two sets of new 15" tires (MT ET streets and bfg radial TA's.
So I'm in a bit of a bind as to which way to go, stick with what I have or sell the wheels and tires and start over. Hate to risk buying the 4.5" BS 15" wheels and finding I have clearance problems.

Anyone out there tried a 15" wheel with 4.5" BS?

Scott