% of difference in speedo with 315's?

[Elijah]

What number do I multiply the indicated speed by when running 315's. Could've sworn I just read it somewhere. Couldn't find it in a search. Thanks.

 

[Uncle Ben]

What gears?

 

[nakman]

Check out the calculators here: http://pitbulltires.com/calculate.php

If you're still running the stock t-case gear, I think you'd be about 12% high? So speedo*1.12=actual.. someone will no doubt correct me if I'm wrong.

 

[TroutRunner]

Assuming you have stock gears and no speedo correction.

Going to 315's will be about 11-12 percent change.

Easy way to calculate what you are going is to move the decimal one space to the left and add it to your speed. Thsi is actually 10% difference.

60.0 on the speedo is 6 (move the decimal to the left one space) + 60 = 66 mph

25.0 on the speedo is 2.5+25=27.5 mph.

Only a 10% fix but....GEEZ....How much math can you do while driving anyway.

TR

 

[Elijah]

I was thinking it was 12 percent, wasn't sure. It's stock gearing. Thanks.

 

[ginericLC]

At 71mph indicated I'm doing 80mph. This is with Toyo MTs in the 315. When I had the 315 BFGs It was like 73mph that was 80mph. I'm running stock gears. At 20mph I'm at about 21mph. 45mph is 52 if I recall correctly.

 

[landtank]

original tire 32"
new tire 35"

35/32=1.09375

so a 9.375% change in speed.

but those are rough numbers and the actual tire diameters are slightly off but you get the idea.