I'm currently running BFG All-Terrain LT 305/70/R16 on some Center-Line 16" rims. I think the rims are 10" wide. The rear gearing is the stock 3.5x, the trans a non lock-up A518.

With these tires my best in the quarter is 13.90.

My current set of tires are a bit on the thin side with one somewhat egg shaped.

Would there be any benefit to slightly altering the tires OD?

For example: The current tires are about 33" in diameter. Going to a 275 would be 31.2" (with the tread width shrinking about an inch).


I'm using the Miata.net Tire Size Calculator http://www.miata.net/garage/tirecalc.html to help better visualize what things might look like.


Would I be correct in considering a dyno sheet to help the cyphering?




Based on the above, my HP starts rolling off at 100mph (I've got another print-out that shows the actual engine RPMs . . .. somewhere).


What'chawl reckon?

 

with 3.54 gears i would look at something between 31 and 33 inches. wider tires are worse on mileage, period. but to me a tall skinny tire looks goofy so you have to give and take a little. im running 35x12.50's and am going smaller with my next set because towing with them isnt fun up mountains but power might not be a problem for me in the near future hopefully.