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Technical => Drivetrain Tech => Topic started by: jncocowboyx on September 17, 2010, 12:33:36 PM

Title: what size rear tires to correct speedometer...
Post by: jncocowboyx on September 17, 2010, 12:33:36 PM
I have 17" Rims, 3.55 gears, and a 22 tooth speedily gear. Anyone know the equation to get the speedo as close to accurate as possible using tire sizes?  Wanna get it close enough so the cruise control will work properly.
Title: what size rear tires to correct speedometer...
Post by: BogusSVO on September 17, 2010, 03:02:21 PM
well then you just need to keep the same size overall OD of the stock tire

so if you had a 225/60/15 the od would be..25.6 inches
so for a 17 you would have to run a 245/45/17 and that is a OD of 25.7

you can play around with tire sizes and gears here..http://www.accuautoparts.com/calculatorfin.jsp

 the crusie is vac operated, so the tire size will not matter, but it will mess with your speedo
Title: what size rear tires to correct speedometer...
Post by: Aerocoupe on September 17, 2010, 05:32:57 PM
Speedo driven (the one on the end of the speedo cable to transmission adapter) and drive (the one on the output shaft of the transmission) gear calculator:

http://www.sccoa.com/faq/speedgr.html

Darren