You Guys With Fat Tires . . .

There's been a lot of discussion here lately about tire & wheels sizes for these cars.
My question is for all you guys running wide tires on the back (and still running leaf-springs):

How close are your tires' sidewalls to the leaf-springs? When you have time, if you'd take a measurement, I'd be interested to know (along with the tire sizes you're running).

I'm just curious of what the "sweet spot" for maximum tire width is between the body and the leaf-spring. The rest is just a matter of calculating the wheel backspacing so that the tire sits where it needs to.

 

275/45-17. they have about 1/2 inch of space between them and the leaf spring. when i started autocrossing i noticed rub marks on the spring from the tire. it took extreem corning loads to make that happen. i dont have the wheel back spacing available right now.

 

255/60-15 BFG T/A...15x8 w/4.5 backspace..gave me about 5/16 clearance to leaf...a little close,but the car isn't being built for twists and turns...4.25 backspacing would have been perfect...the BFG is a wide tire 10.2" section width versus
Cooper 255/60-15 has a 9.73" section width...the bump stop will need some grinder lovin on the tab that may try to eat your inner sidewall

 

275/60/15s...raised white letters to the inside and no rubbing...some motorXing)

 

Cooper 255/60/15 4.5 back space. I had .25 of clearance so I added a .25 spacer for a little wiggle room... Also removed bump stops...

 

I find it interesting that all of our cars seem to be able to take different sized max tires. I ran 245/60-15 no probs. Went up to 255/60 and cannot get my pinkie finger between springs and tire, and the fenders rubbed on hard takeoffs (not rubbed...cut into the tire sidewall). These were both BFG T/As. I have rolled the fenders since. There is no way I could get a 275 on the back of mine.

Here is the space I have left with 255s installed.



And attached photo of the sidewalls after a few launches.

 

Scooper,
Tire brands run different section widths for the same numeric sizing. BFGs run fat in their given sizes. I have 265/50/15 Coopers on mine, and a 245/60/15 BFG is less than 1/2" narrower. Strictly speaking, that should be more.

By the way guys .... I have a new job, and after 30 years I am back in the TIRE BUSINESS. I am a commercial account rep (not my official title, which is a bit confusing) for American Tire Distributors ... the biggest wholesaler in the country. We stock over 20 brands, all the majors. Neat job, very happy! I have a lot of catching up to do... lots of changes over the years.

 

So, based on Jeff's response, you cannot just ask "How big?" as much as "How big in Brand X?" will fit...

 

width of rim has a lot to do with it also...

 

Yes, the width of the rim does make a big difference. I am trying to decide whether I am going to use my 15" rims that I have restored or buy new 17" rims.

Can you guys (bryant, JoeB,Frank, Mavgrab302, scooper and Captain) chime in and tell us what width your rims are please?

 

Rim is a 15x8 with 4.5" backspace...haven't mounted them yet due to bump stop...I will run a1/4" spacer until I get the 9" in

 

15X8 with 4.5 BS also.

 

I had 15x 8 with 4½ backspacing with 255 60 r 15 tires and I would only rub in the fender well when I tried to slide the rear end.

 

Don't you have a 9-inch rear (or maybe I'm thinking of someone else)?
When you have time, maybe you could take a measurement between the leaf and tire sidewall. 'Just curious.

We all know about wheel backspace. I'm just wondering what the ideal (or absolutely necessary) space is between tire & leaf-spring, and tire & body.

 

8" rear