 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
Car Forum / Ford / Ford Mustang / February 200616" vs 17" Wheels and Tires
Group: 1996 Mustang GT Convertible. Had factory 16" wheels and tires. Bought a set of the factory 17" GT/Cobra 10 spoke wheels and added new tires. Will the difference between the 16" versus the 17" wheels cause a difference in the speedometer? Appears to be a 5-6mph difference (e.g. shows doing 80, only really doing 74-75). How would one go about getting something like this re-calibrated? Thank you! gjt > Group: > [quoted text clipped - 8 lines] > Thank you! > gjt As you know, wheel size has no effect on speedometer accuracy. Tire size? Well, that is another matter. What size did you start with, and what size do you have now? If you used the same tires on your new wheels, your speedometer will be WAY off. Use this calculator to compare your old tires w/ new ones: http://www.miata.net/garage/tirecalc.html and you will be able to calculate the PERCENTAGE difference (it won't be the same # of mph everywhere on the speedo). Rob Not sure about 'stangs but in Jeeps we just buy a new speedometer drive gear. Also called a pinion speedometer drive gear. It's calibrated to your tire size and gear ratio. IE: I had 33" tires and 4.10' gears in my Wrangler so I needed a 32 (guess) tooth pinion speeedomete drive gear. HTH Carl >> Group: >> [quoted text clipped - 22 lines] > > Rob > Not sure about 'stangs but in Jeeps we just buy a new speedometer drive > gear. Also called a pinion speedometer drive gear. It's calibrated to your [quoted text clipped - 17 lines] > >> Thank you! > >> gjt A programming from a stealership or one of those programmers used in OBD2 vehicles will do the job. You could do the old 1+ method, I think it went something like this, for every inch increase in rim diameter you add 10 to the width and subtract 10 from the aspect ratio. Example, take a stock 16 inch rim with 225 by 60 tires. i.e. R16 x 225 x 60. To go to a 17 inch rim but still maintain the same overall diameter you would replace your tires with R17 x 235 x 50's. This gives you a wider, lower profile tire with the approximate same overall diameter as the ones you just replaced, note the operative term wider, your fender wells need to have enough room to accommodate the new tire. Everybody feel free to jump in here if I got this wrong > > Not sure about 'stangs but in Jeeps we just buy a new speedometer drive > > gear. Also called a pinion speedometer drive gear. It's calibrated to your [quoted text clipped - 20 lines] > A programming from a stealership or one of those programmers used in > OBD2 vehicles will do the job. That's weird. It sound like the new tires/wheels combination is a smaller diameter? Fred 89 LX Appears to be a 5-6mph difference (e.g. shows doing > > >> 80, only really doing 74-75). > You could do the old 1+ method, I think it went something like this, for > every inch increase in rim diameter you add 10 to the width and subtract [quoted text clipped - 40 lines] >> A programming from a stealership or one of those programmers used in >> OBD2 vehicles will do the job. There is a site that has the calculations done for you, it gives you the percentage between your stock wheel/tire combo and what you are thinking of putting on. It even gives you the speedpmeter reading at 60mph and what you are actually going. the site is Miata Tire size calculator. Just type it into Google and go from there You are offsetting having a larger diameter rim by using a tire with a narrower side wall. If placed side by side the new lower profile tire on the larger rim should stand almost as tall as the original tires. > That's weird. It sound like the new tires/wheels combination is a smaller > diameter? [quoted text clipped - 48 lines] > >> A programming from a stealership or one of those programmers used in > >> OBD2 vehicles will do the job. |
Reply to this Message |
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2008 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.