Ford Mustang Forums banner

1 - 10 of 10 Posts

·
Registered
Joined
·
10,294 Posts
Discussion Starter #1
I am currently running a Posi Unit in my dirt track car.

Usually we set the rear up with a bigger tire on the RR and a smaller tire on the LR to give it stagger to make the car turn left.

Usually I just weld the spider gears to lock the rear. But this year I decided to run a posi unit. I am running the same size tire on all 4 corners (255/60/15).
I am just currious as to if it will hurt the posi unit to run a 235/60/15 on the LR and a 255/60/15 on the RR?
 

·
Registered
Joined
·
239 Posts
I am currently running a Posi Unit in my dirt track car.

Usually we set the rear up with a bigger tire on the RR and a smaller tire on the LR to give it stagger to make the car turn left.

Usually I just weld the spider gears to lock the rear. But this year I decided to run a posi unit. I am running the same size tire on all 4 corners (255/60/15).
I am just currious as to if it will hurt the posi unit to run a 235/60/15 on the LR and a 255/60/15 on the RR?
Realistically no
 

·
Registered
Joined
·
3,013 Posts
Dont understand the "Realistically no"...
How would it not burn up the clutches, with contstantly running different rpms to each end?

IMOHO its a bad idea. I wouldnt even run a spare tire (if I got a flat)that wasnt the same diameter as the other side.
 

·
Registered
Joined
·
739 Posts
It will..... When the rotating of the two wheels is different, the clutches are being "used".

That's the way it is. I agree with drudis 100%
 

·
Registered
Joined
·
1,421 Posts
For that matter running a continuous circle in one direction is going to wear the clutches whether you have the same size tires or not. Running the stagger you suggested might equal out or offset some of that wear.
 

·
Registered
Joined
·
529 Posts
An inportant fact is he is running on DIRT! The tires will spin long before the clutches slip. The amount of stagger you need to run varies depending on the banking of the track, if any, the radius of the turns, your driving style.

I would try at least two different size tires on the outside wheel or the inside wheel and compare the differences in how the car handles.

When I ran a car on a local oval track, but on pavement, not dirt, we ran huge stagger. But this track you never went straight, it was that small.
 

·
Registered
Joined
·
1,421 Posts
I't ain't like the clutches are that expensive or hard to change. Run it however it handles the best and if they burn up in 1 or 2 races you'll know you need to go back to the welded spiders.

Hell I ran a welded dif in my FWD Mini back in the 70s and used it for autocross. Damn thing would break your arm if you let off the gas in a turn but as long as you had the power down it was like power steering. Worked out fine since you needed to keep the front wheels pulling in the turns anyways.
 

·
Registered
Joined
·
239 Posts
My point was it probably wont matter with what he is doing. Id run it, see what happens. Whats the worst thing you do, burn up the clutches?? Id weld it personally.
 
1 - 10 of 10 Posts
Top