Question about Revs/mile

[KU Ned]

I have a 2003 330i ZHP with the following Michelin Pilot Sports:

Front - 225/40-18 Revs/mile=821
Rear - 255/35-18 Revs/mile=824

I have a set of AT Italia 17X8 wheels that I want to use for Auto X and Track events. I plan to put on 235/40-17 Kuhmo Ecsta V700's. The Revs/mile for the Kuhmo's is 855. What effect will this have on the car?

Also, I have a three 225/45-17 V700's. Two are in really good condition. I want to use two of them on the front and order two 235-40's for the rear. When the fronts wear out I will replace them with 235's. Any thoughts?

[AF]

Ned,

try entering this into this tire calculator . . . it might help you out . . .

http://www.miata.net/garage/tirecalc.html

[Nick325xiT 5spd]

It means that you will have imperceptably lower gearing.

[KU Ned]

Originally posted by AF330i
Ned,

try entering this into this tire calculator . . . it might help you out . . .

http://www.miata.net/garage/tirecalc.html


Great site Thank you!!!

It says my speedo will be 2.5% off when the speedo says 60 I will be doing 58.5 mph.

[Gary@Tirerack]

Right, these are not large difference in 'real' feel and handling. All work fine and are popular choices for R compund tires.

[·clyde·]

Originally posted by KU Ned
It says my speedo will be 2.5% off when the speedo says 60 I will be doing 58.5 mph.

Don't worry about it. It is well known that BMW speedos are overly optimistic to begin with.

There have been threads about this here and on other boards. Car and Driver had an article about speedos in general about a year ago.

Car and Driver Speedometer Article (http://caranddriver.com/article.asp?section_id=4&article_id=1906&page_number=1)

Summary of Results (http://caranddriver.com/article.asp?section_id=4&article_id=1907&page_number=1) (check out how the BMWs tested comapre to the other makes)

[Ashe too]

the actual measurements for a particular tire can be found on the tirerack website by clicking on "specs" on the page describing a particular tire or by finding the specs on the manufacturers website. for example, compare the diameter of any two same size tires on these two charts:

Bridgestone RE750
http://www.tirerack.com/tires/Spec.jsp?make=Bridgestone&model=Potenza+RE750

Yokahama AVS ES100
http://www.tirerack.com/tires/Spec.jsp?make=Yokohama&model=AVS+ES100