Volvo RWD 120-130 Forum

INDEX FOR 1/2026(CURRENT) INDEX FOR 2/2003 120-130 INDEX

[<<]  [>>]


 VIEW    REPLY TO THIS MESSAGE    PRINT   SAVE 

Tire Question... 120-130

I may be doing my math wrong (I was good at it a long time ago in school, now it makes my head hurt!), but I get different numbers:
165/65/15 = 860 revolutions per mile
205/60/15 = 817 revs per mile
205/65/15 = 791 revs per mile

If I understand it right, the second number is the aspect of the tire expressed as a percentage of the tire width, so I multipied the first number by the second (as a percentage), converted from metric to english, multiplied by two ("top" and "bottom" of the tire) and added that to 15" to get the diameter of the wheel and tire, multiply by pi for the circumference, then diveded 63,360 by each circumference to get the revs per mile.

As I said, I might be making a big error somewhere.... but if I'm lucky, it seems like the bigger diameter I'll have with the new tires will just about compensate for the almost 10% error my speedo and odo seem to have! Or wait, will it make the error now 20%...? Nah, I think it's the former.
Tom
NYC






THREADED THREADED EXPANDED FLAT PRINT ALL
MESSAGES IN THIS THREAD

New Tire Question... [120-130]
posted by  someone claiming to be honeychrome  on Thu Sep 8 08:09 CST 2005 >


<< < > >>



©Jarrod Stenberg 1997-2022. All material except where indicated.


All participants agree to these terms.

Brickboard.com is not affiliated with nor sponsored by AB Volvo, Volvo Car Corporation, Volvo Cars of North America, Inc. or Ford Motor Company. Brickboard.com is a Volvo owner/enthusiast site, similar to a club, and does not intend to pose as an official Volvo site. The official Volvo site can be found here.