Biggest Drag tires

Old man · 07-05-2009

What is the biggest drag tire people have fit in a Fox without cutting? Will a 28 inch tall 11.2 section width tire fit??

My son said he had 28x10 slicks, and I used to run M&H 26x10 slicks and could pull the front wheels. Section width of the 26 inch tall tires I ran was 11.1.

I have to run a bias ply tire with slick compound because I have a stick and it just ignites the drag radials I have when I shock the tires.

(I know moderators might want to move this to tires and wheels, but I really want the opinions of people who have seriously drag raced. )

Tom

**RLG34750** · 07-05-2009

Quote:

Originally Posted by Old man

What is the biggest drag tire people have fit in a Fox without cutting? Will a 28 inch tall 11.2 section width tire fit??

My son said he had 28x10 slicks, and I used to run M&H 26x10 slicks and could pull the front wheels. Section width of the 26 inch tall tires I ran was 11.1.

I have to run a bias ply tire with slick compound because I have a stick and it just ignites the drag radials I have when I shock the tires.

(I know moderators might want to move this to tires and wheels, but I really want the opinions of people who have seriously drag raced. )

Tom

No worry Tom your thread will stay right where it is........

You should be able to squeeze a 28" tire under the car you may have to roll the the fender......

A lot with regard to the width you use (IE 10.5w) will be based on the back spacing of the wheels.....

blueracecar · 07-05-2009

i am running 28x10.5s under my 89 gt with a 5.5" backspace on a 15x8 wheel. about to go to 15x10 with 6.5" b.s. i did have to take a hammer to the inside of the wheel well in a couple of spots. or you could put wheel spacers on it.

Old man · 07-05-2009

Quote:

Originally Posted by blueracecar

i am running 28x10.5s under my 89 gt with a 5.5" backspace on a 15x8 wheel. about to go to 15x10 with 6.5" b.s. i did have to take a hammer to the inside of the wheel well in a couple of spots. or you could put wheel spacers on it.

Great info! What wheels?

I want a stock look. (It is my "theme".) I have Pony rims now, 16 inch 4 lug. I have 31 spline axles and a Cobra posi, but before I install the final gear I want the tires on the car.

If I go to a 15 inch wheel I'll have a much better tire selection. I'm looking at something around 27 tall and close to 10 inch tread with soft sidewalls.

If I stay with a Pony wheel I'll be stuck with 7" rim width but that will pull the sidewalls in and reduce section width a bit. It severely limits tire selection.

What rims did you use? Do your tires hit real hard off the line??

Thanks, Tom

**RLG34750** · 07-05-2009

take a look at these

i'm running a 26x15x10.5 with a 9" wheel 6.25 BS

Bogart Racing Wheels

Old man · 07-06-2009

Quote:

Originally Posted by RLG34750

take a look at these

i'm running a 26x15x10.5 with a 9" wheel 6.25 BS

Bogart Racing Wheels

Great Reggie. 10.5 x 26 M&H slicks (10" tread, 11.1 inch sidewall) were always the biggest tire I tried to run and they never rubbed. I'd like to try taller if I could for a longer footprint.

Does the 6.25 BS center the tire OK in the available space, or would you move it if you could do it over??

Thanks, Tom

**RLG34750** · 07-06-2009

Quote:

Originally Posted by Old man

Great Reggie. 10.5 x 26 M&H slicks (10" tread, 11.1 inch sidewall) were always the biggest tire I tried to run and they never rubbed. I'd like to try taller if I could for a longer footprint.

Does the 6.25 BS center the tire OK in the available space, or would you move it if you could do it over??

Thanks, Tom

The 6.25 BS has work fine for me perfectly happy with the tire location.....

Just an FYI i have friend with a 93 notch that we have run a 28" tire on all was need was to roll the inner fender slightly....

Old man · 07-06-2009

Check me out on this.

The factory wheel is 6.25 BS and 7" width. The bead surface to outer edge is about .75 inch (just guessing).

The theoretical center line (tCL) of a 7" width wheel is 7/2+ .75 = 4.25 inches of backspace. Since Ford uses a 6.25 BS it moves the tire inward by 6.25-4.25 inches = 2 inches.

Blueracecar uses a 5.5BS on a 8" wide wheel. The tCL of an 8 inch wheel is 8/2+.75= 4.75 inches backspace. Since he has 5.5 BS it offsets his tires inward by 5.5-4.75= .75 inches. (He has moved his tires outward by 1.25 inches from stock.) Does that sound correct?

Reggie has a 6.25 BS on a 9" bead width rim. Assuming the .75" difference between bead width and outer edge location that a 9" wheel would have a tCL of 5.25 inches. Since Reggie's wheel is at 6.25 BS he has 6.25-5.25= 1 inch inward offset of tire centerlines. Reggie's tire centerlines should be about 1" out from Ford's original CL, 1/4 inch more than Blueracecar.

Does this sound correct?

It looks like Blueracecar wants to go to a 6.5BS on a 10" wide bead width. tCL would be 5.75 inches. So the 6.5" BS would give him 6.5-5.75=.75 inch tire center movement toward the middle of the car.

It looks like both of you want about 1" of actual tire center movement in, instead of the 2" that I estimate Ford used.

Does this all make sense????

Blueracecar had to roll the inner wall in, as did Reggie, so I probably want to move my tire CL out about an inch from what the factory rim used. That would keep the exact tire CL he has right now.

Does this all make sense??

I can get a 8" 5.5 offset from Summit in a Summit wheel. This will be identical to Blueracecar and .25 inch off from Reggie's spacing. It will mover the tire center OUTWARD about 1/4 inch from what Reggie has now.

Otherwise I have to go with a Weld Wheel. Then I have more offset choices.

Did I make any mistakes?? Why hasn't anyone ever documented this to help people pick wheels??

Tom

**RLG34750** · 07-06-2009

Why to much math for me....

But in theory you are correct......

If you talk to the people at bogart they pretty much have documented everything....

Old man · 07-06-2009

Thanks Reggie,

I just picked up 8 inch wide wheels with 5.5 inch backspace and 27-10.50x15 ET streets (soft sidewalls).

I got a deal I could not refuse on new stuff.

This should move my tire spacing just slightly out from yours Reggie. I could not find anything else within driving distance so I got what I could get that looked like it was ballpark and stayed conservative on tire size.

I'm going to run the tires without tubes and see what happens. I hear people do that now.

Appreciate the help.

Tom

**RLG34750** · 07-07-2009

Quote:

Originally Posted by Old man

Thanks Reggie,

I just picked up 8 inch wide wheels with 5.5 inch backspace and 27-10.50x15 ET streets (soft sidewalls).

I got a deal I could not refuse on new stuff.

This should move my tire spacing just slightly out from yours Reggie. I could not find anything else within driving distance so I got what I could get that looked like it was ballpark and stayed conservative on tire size.

I'm going to run the tires without tubes and see what happens. I hear people do that now.

Appreciate the help.

Tom

you can run them without tubes ......

But if you get the squirmy feeling on the big end you may want to put tubes in

Thats what PLstang recommended i do......

with the ET streets you will be fine......

Old man · 07-07-2009

I was all wrong about my thinking of spacing. I was overcomplicating it.

It is really pretty simple. The back space sets the distance from the rim's edge to the wheel well at the INSIDE of the wheel well.

The correct Ford back space is about 4- 7/8" . This sets the distance from the innermost part of the rim lip to the inner fender well. Very simple.

As we increase the back space number the wheel moves towards the inner fender. As we decrease it, it moves out towards the brake drum surface.

The wheel width sets the location of the outer edges from the inner point that was set by backspace.

Going from a 4-7/8 (4.875) back space stock pony wheel to a 5.5 inch back space Summit mag moved my inner wheel lip in by 5/8th of an inch.

Because I went 1 inch wider on the wheel I moved the tire center line out 1/2 inch from the rim width change. The tire center always moves 1/2 of the rim width change.

I could have stood to move the tire in another 1/2 inch if I took the quad shocks off. That would have taken a 6 inch back spacing instead of 5.5 inch. Right now they are in place but reversed. I would have had better fit with a 7" rim instead of 8" rim because the outer tire edge would have come back in using a narrower rim.

The tightest spot without hammering anything using 27x10.50 - 15 tires is the outer fender lip. It is very close but workable with a little cutting and bending. Either a 5.5 back space with a 7 inch rim or a 6 inch back space with an 8 inch rim would be a bit better, but I am very near optimum.

This is less complex than my earlier statement.

Tom

lilorange79 · 07-09-2009

well fudge! I had my heart set on a set of Mickey Thompson S/S Indy Profile in a N-50. They are 28" tall and 11.8 tread width and 14.1 section width......I was hoping to go a 6.5 offset and remove the inner lip on the fender completely.... then shoehorn them in there........
Mini tubs and relocate springs?????????
It would sure look bad and help eliminate the serious traction problem I have.

**RLG34750** · 07-10-2009

Quote:

Originally Posted by lilorange79

well fudge! I had my heart set on a set of Mickey Thompson S/S Indy Profile in a N-50. They are 28" tall and 11.8 tread width and 14.1 section width......I was hoping to go a 6.5 offset and remove the inner lip on the fender completely.... then shoehorn them in there........
Mini tubs and relocate springs?????????
It would sure look bad and help eliminate the serious traction problem I have.

Real men don't need more than 10.5.....