http://www.gordon-glasgow.org/tirecalc.html
or, use this handy tire revs per mile calculator:
Calculating tire size
- mikel
- Posts: 57793
- Joined: Tue Jan 16, 2007 1:17 pm
- Location: DiabloSport World Headquarters
- Contact:
Calculating tire size
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- Tire_Conversion_Revs.xls
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Mike Litsch
DiabloSport Brand Manager
Diablo Tech support by phone:
561-908-0040
M-F 8:00 AM to 5:00 PM EST
tech@diablosport.com
DiabloSport Brand Manager
Diablo Tech support by phone:
561-908-0040
M-F 8:00 AM to 5:00 PM EST
tech@diablosport.com
RE: Calculating tire size
I run staggered tire sizes; I assume I should use the tire size info from my rear tires for this calculation...am I correct?
Thanks,
-Chris
Thanks,
-Chris
RE: Calculating tire size
Yes, the rear tires are the ones you use.
Certified Advanced EFI Calibrators for Ford, GM and DCX/Jeep Vehicles.
http://www.tpctuning.com
http://www.tpctuning.com
- Gointopless
- Posts: 11
- Joined: Fri Mar 04, 2011 11:46 pm
RE: Calculating tire size
There are all kinds of apps for smart phones too..
These calculations will get you in the ballpark. However, it has been my experience that your speedometer will be off by about 5 mph @ 80mph. I used my GPS to help me fine tune the value for the revs per mile in the tune. I ended up having to use a value of 880 revs per mile for a set of 275/40 R18 wheels. If you run this through your calculations it will tell you that you should be running 756 for the revs per mile.
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- Posts: 4
- Joined: Tue Oct 07, 2014 1:23 pm
Re: Calculating tire size
I'm trying to do the tire Change on my truck and was wondering do I put in the revs per mile in the tire circumference? I'm running a 35x12.50x20.
Re: Calculating tire size
sup bruh ,im tried to recalibrate my speedo but it asked for diameter and mine says is 100.25 for a set of 275/55/20 lowest value is 500 what im doing wrong