If you put s lower profile tire in the 20" u may able to keep everything running normal. If you can do that, like me, u will not have any speeds issues. N, our trucks can withstand a bigger rim. Anything over 24"s, will cause ur tranny to west out too soon. Without a gear swap to a lower gear. Hope that helps.

 

I have the original 20's that CAME WITH my truck and my speedo is off the same as the poster above. 65 on the speedo is about 67 on GPS. My speedo is about 1.75mph low. Take it for what it's worth I guess.

 

Bolt pattern is totally BS...I bought some used 20"s balloon type mags for my 2009 and fit real nice, I also bought some FALKEN tire to fit my 20" and the diameter is the perfect size as the origianl 17"s go to the site below and punch in the size you want and see.

http://www.miata.net/garage/tirecalc.html

 

If ur overall diameter is the same with both wheel/tire combo's, then u shouldn't any problems.

 

talked to tire discounters about the rim situation and those damn sensors. he said that i would have to get the sensors flashed to match my truck, and they are $100 a piece so for a set of mopar twenty's just went from free to at least $400. not to mention they don't carry copper tires rally looking hard at the zeon ltz 33'' is a good start

 

Quote:

Originally Posted by RawRam2006

If you put s lower profile tire in the 20" u may able to keep everything running normal. If you can do that, like me, u will not have any speeds issues. N, our trucks can withstand a bigger rim. Anything over 24"s, will cause ur tranny to west out too soon. Without a gear swap to a lower gear. Hope that helps.

So, If I don't want to tow a lot and I drive a lot of highway with my ST.. changing 31.6" tires to 33" tires would be good. The change in the gear ratio would go from 3.55 to 3.40, hence the lower RPMs and highway mileage. Does this sound right? Also, alternatively the benefit from a SLT/Sport w/3.55 gears changing from 33" tires to 31.6" tires = 3.71 gear ratio. Does anyone know if the SLT/Sport to ST difference is just in the computer or are there physical differences in the driveline to warrant bigger stock tires?

 

arent the sensors in the stems? just swap the stems.

 

you have to take the tire off to remove the stems i thought of that but you still have to get the stems flashed to match the new rim so you still have to make a trip to the dealer. both my buddy and i don't have the time to do that. if it could be as simple as letting all the air out and peeling the tire back to get to the stem i would do it but trying to get the tire back on and filling it back with air i don't know if i could do that...