Suspension, Brakes, Tires & Wheels Talk about your suspension, tires, wheels and brakes within.

tire size/ milage question?

Thread Tools
 
Search this Thread
 
Old Nov 9, 2008 | 07:27 PM
  #11  
conceptualpolymer's Avatar
HCF Member
Joined: Sep 2005
Posts: 906
From:
Default

You are absolutely correct. According to my calculations, your OEM tires are 22.65" in diameter and have a circumference of 71.16", so for every mile, each one turns 890.4 revolutions. With the larger tires and wheels, that many revolutions will get you 1.025 miles instead of 1 mile. Multiply that by the number of miles you've driven and then divide the answer by the number of gallons of gas you've used and the answer will be your gas mileage.
 
Old Nov 9, 2008 | 07:57 PM
  #12  
sfazngiants's Avatar
HCF Member
Joined: Oct 2007
Posts: 3,199
From: NorCal
Default

^ is it possible if you can help me with finding the number to multiply with my number of miles. my cars stock size is 185 65 14 and i am currently running 195 60 14. its not a big difference but i just want to get a more accurate MPG
 
Old Nov 9, 2008 | 08:10 PM
  #13  
trustdestruction's Avatar
Moderator
Joined: May 2007
Posts: 11,417
From: FL
Default

Originally Posted by sfazngiants
^ is it possible if you can help me with finding the number to multiply with my number of miles. my cars stock size is 185 65 14 and i am currently running 195 60 14. its not a big difference but i just want to get a more accurate MPG
when you fill up and do your calculation, multiply the miles on the trip count by .989 (or .99 will work just as good)
you are actually only traveling 98.9% of what your trip count says
 
Old Nov 9, 2008 | 08:55 PM
  #14  
sfazngiants's Avatar
HCF Member
Joined: Oct 2007
Posts: 3,199
From: NorCal
Default

thanks
 

Last edited by sfazngiants; Nov 9, 2008 at 09:06 PM.
Old Nov 10, 2008 | 01:56 PM
  #15  
conceptualpolymer's Avatar
HCF Member
Joined: Sep 2005
Posts: 906
From:
Default

Originally Posted by trustdestruction
when you fill up and do your calculation, multiply the miles on the trip count by .989 (or .99 will work just as good)
you are actually only traveling 98.9% of what your trip count says
This is correct. I will type in the calculations a bit later.
 
Old Nov 10, 2008 | 07:41 PM
  #16  
conceptualpolymer's Avatar
HCF Member
Joined: Sep 2005
Posts: 906
From:
Default Tire size calcs

First, calculate tire diameter:

185 x .65 x 2 x (14 x 25.4) = 596.1 millimeters, so 596.1/25.4 = 23.47 inches diameter

195 x .60 x 2 x (14 x 25.4) = 589.6 millimeters, so 589.6/25.4 = 23.21 inches diameter

The first tire will travel 73.73 inches (23.47 x pi) for every revolution, whereas the second tire will travel 72.92 inches.

If your car calculates distance based upon the OEM (first) tires' revolutions, the second tire's distance will be 23.21/23.47 of the actual distance, or .989 x the actual distance in miles.

If you had larger tires than OEM, then your multiplier would be greater than 1, as is the case with the original poster.
 
Old Dec 7, 2008 | 08:43 AM
  #17  
winkosmosis's Avatar
Junior Member
Joined: Dec 2008
Posts: 5
Default

That 2% difference is not even worth thinking about. But also, the sizes of tires are not that precise, so the new tire could very well be 2% smaller, or 5% bigger.
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
apoplectic1
Header, Intake, & Exhaust
4
Apr 9, 2010 08:09 PM
addiction2bass
General Civic Talk
13
Aug 22, 2008 06:42 PM
davidb123
Engine & Internal
3
Sep 13, 2007 08:25 AM
Turbo99SI
Suspension, Brakes, Tires & Wheels
1
Oct 6, 2006 11:21 PM
rpinoh1
Suspension, Brakes, Tires & Wheels
8
Feb 13, 2006 02:12 PM




All times are GMT -8. The time now is 12:47 AM.