VH tyre size for 15 inch rims?

[NOMADTRAV]

Hi i am a little embarassed to ask but my speedo is reading about 18km/h over at 100km/h so thought tyre size may be the issue. The rear tyres are 205/60R15
these were on the car when i brought it last month. I was wondering if these were right?

[vb_commie]

Speedo gear Calculator
This will help you to an extent. You will need to know what colour driven and drive speedo gears are though which isnt too hard (atleast not on my Trimatic).
You can buy replacement gears to get the right combo from Rare Spares or any good auto trans workshop should have a selection.

Mine was about 9km/h under at 100km/h, until recently when I manged to get it near perfect by just changing the small driven gear.

[NOMADTRAV]

Thanks mate that sounds good i was thinking i'd be up for new tyres.