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Buying new rims?

2K views 10 replies 6 participants last post by  GE3G 
#1 ·
Hey everybody I just have a quick question.... Im planning on buying new rims and I am considering 20s... I just wanna no if i need to re tune my car cause ill be going with a larger rim... I curently have the 19" Brembo wheels.. Will my speedo be affected?
 
#5 ·
If your running a 255-40-19, any 20 inch tire you choose that is taller will have a very minimal change on your speedo, not enough to worry about imo. 285-30-20 would be the same height I believe, but I would never do a 30 profile unless I had zero wheel gap. 35 profile looks great with 20's.
 
#8 · (Edited by Moderator)
Tire Size Comparison
Specification Sidewall Radius Diameter Circumference Revs/Mile Difference 255/40-19 4.0in 13.5in 27.0in 84.9in 746 0.0% 275/35-19 3.8in 13.3in 26.6in 83.5in 759 -1.7%
Back to the Calculator

You want the tire size to match your stock 27" tire as close as possible. And 4/10 of an inch is not close.



You can change the settings in your tuner yourself if you have one providing your tuner left those options open. Not all do.
 
#10 ·
My nitto invos are a full inch taller than my stock tires, and the revolution difference was a 746 vs 739. I saw zero difference in my speedo. You can't go by the tire calculators. Certain tires have softer side walls and they flex when driven, which increases the rev per mile.
 
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