Expert: Dan Liddy - 5/18/2005

Question
Hello  I am building a car to run at the local dirt track. It is a half mile oval slightly banked.[may be flattened out for this season].I plan to run v8 auto.[350 turbo] and right now have 3:73's. What is the optimum tire size that I should use?  Thanks   Gary

Answer
Hi Gary:

Most tracks have tire rules, and some even have spec tires for some classes.  You didn't tell me ir you're runing a dirt late model or a super mod or what, but I'd say a 24" diameter at whatever width they will allow , should get you in the ballpark.   Certainly that will give you a tall enough final drive ratio to get down the longer straight.  If you then find that you are running out of revs early, I'd be inclined to change the gear ratio before I added any more tire.  Tires have rolling resistance and it makes a BIG difference.  It takes a lot less power to turn a ring and pinion than it does a big tire.

That's about all I can offer, perhaps you could snoop around the pits some before making any final decisions.  That's usually the best practice.  And I have learned that your best sources of info are usually your competitors, cuz they want to see you run up there with them.

Good luck

Dan Liddy
Sarasota, Florida