Tire and Rim Size increase
#1
06-27-2005, 01:09 PM
Join Date: Sep 2001
Location: Long Island, NY
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Tire and Rim Size increase
All,
I am changing from 16" tires and rims to 20" tires and rims.
When I drive now, will I be going faster or slower than what my spedo says?
Is there anyway to calculate in my mind what the percentage is? IE: at 70mph on the spedo I am actually going 10% faster?
I am changing from 16" tires and rims to 20" tires and rims.
When I drive now, will I be going faster or slower than what my spedo says?
Is there anyway to calculate in my mind what the percentage is? IE: at 70mph on the spedo I am actually going 10% faster?
#2
06-27-2005, 01:53 PM
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Try this site:
http://www.miata.net/garage/tirecalc.html
Type in the numbers, old tires & new, and you'll get a percentage difference which will equate to your speedometer error.
Larger tires will turn slower that smaller tires, so you'll be traveling a little faster than what the speedo says.
You can correct for this error with a programmer for your truck. And the programmer will give you all the power increases of a chip as well.
http://www.miata.net/garage/tirecalc.html
Type in the numbers, old tires & new, and you'll get a percentage difference which will equate to your speedometer error.
Larger tires will turn slower that smaller tires, so you'll be traveling a little faster than what the speedo says.
You can correct for this error with a programmer for your truck. And the programmer will give you all the power increases of a chip as well.
#3
06-27-2005, 04:46 PM
Rim size has nothing to do with it. It's the height of the tire. What size tires did you go with and what was the OEM size. If the new tires are taller, your speedo will register slower than you are actually traveling. If the new tires are shorter, your speedo will register faster than you are actually going.