Swapping from 20" to 19" or 18" wheels

[AustinTrkJunkie]

Considering selling the comp package wheels and getting something else, but there's obviously a difference in diameter if I go smaller (18 or 19). Not to mention a smaller diameter will rack up the miles faster unless the the car knows it's running smaller wheels/tires. So what's the process to re-code the ECU to take into account a new/smaller wheel set up?

[M BE4ST]

I would imagine if u go from a 20 down to a 19 u will run a bigger side wall say from a 30 to a 35 so I don't think there would be much of a difference between overal wheel diameter but I could be wrong.

[x.shell]

You'd should try to keep the overall diameter (wheel diameter+tire sidewall height) the same as your Comp wheels/tires. No coding needed.

[M3SQRD]

As others have already stated, you'll use 19" and 18" tires with taller sidewalls so the overall diameter stays (about) the same as the 20" tires.

[AustinTrkJunkie]

The thing is when I stand my track 18" track wheels (APEX 18x10 and 18x11 running 275 and 305 rubber) next to the OE wheels, they are about 3/4" shorter than the 666's, so I know there'll be a difference in diameter, that's why think I'll need coding. May not sound like much, but it will add more "miles" since the overall diameter is smaller...

[mcvaughan]

No coding required.

[Fugazii]

I think the car self adapts to the new size I could be wrong though.

[AustinTrkJunkie]

Originally Posted by Fugazii

I think the car self adapts to the new size I could be wrong though.

Was thinking on this, since it has sensors for wheel spin perhaps it is able to adapt. I'll ask my SA at the next visit for an oil change!

[gatorfast]

If you are running stock tire sizes the total diameter should be extremely close between the 18-20' setups. You can do the math to calculate the total diameter for yourself and compare.

[Justin.AutoTalent]

Originally Posted by Fugazii

I think the car self adapts to the new size I could be wrong though.

^ pretty much.

I've had a few different wheel sets - 19" & 20".

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