I just got a set of 15 inch stock phone dial type rims and want to put 205/55/15 tires on. this will replace my stock 17 inch s lite runflats. Will this work and will this change my speedo readings or affect my flat sensors?

 

might change your speedo to read high marginally, and will probably set off your tire monitor. Just hold the button for 5+ seconds to reset it.

 

175/65/15 is 23.9 OD

205/55 is 23.9 OD

205/45/17 is a 24.2 OD

thats a 1% change!

Alex

 

Here's a program that will convert speed variations due to different tire sizes. :smile:

 

Here is another excellent tire size/speedo calculator:

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

 

The MINI speedo reads optimistic from the factory (as a matter of fact, BMW has been rated worst for having their speedos read faster than the speed you're actually going) so I think putting 15s on would at the very most either set it right or make it slightly pessimistic.