Speedo readings with 17 alloys

[madmerv]

Quick question. Does speedo need re calibrated with bigger wheels than standard ?

[code-]

Different diamater wheels = speedo wrong

Or, more wrong then it allready is, most cars show too much.

[Ziggy]

Depends on the overall diameter - ie what size tyres you fit...

[320Touring]

try this link dude and dial the info in

standard on 15"BBs is 205/55/r15 all round iirc

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

it'll give you an idea of how far teh speedo will be out...

[Zayyan]

Or, more wrong then it allready is, most cars show too much.

If the speedo is over-reading, with bigger wheels surely it'd be less wrong?

If you can, borrowing a sat nav (GPS) system is an easy way of telling for certain how far it's out, and then you can calibrate it - I think I remember someone typing up a thread explaining exactly how to do this a few months ago

[madmerv]

Been busy at work, thanks for the replies and the link. Will see how i get on. Cheers folks.