So heres the deal. I have 17 inch wheels (255/65 tires) on my truck and thinking about putting the 18 inch FX4 wheels on. My question is, has anybody done this yet and if so how far off was your speed. Can the dealer fix the speedo? Thanks.....

 

I just replaced my 17" with the 18" wheels a couple of weeks ago. The dealership changed the wheel/tire size in the computer so the speeometer is still accurate. Total cost: $35 plus tax.

 

I have changed my FX4 from 17" to 18". This link shows what changing sizes does to the speedometer - not much difference.

http://www.csgnetwork.com/speedocalibcalc.html

 

brown1275, thanks for the cool link

 

I'll be playing with this thing all day now.

 

You know when I called my dealer and ask them, they told me no way they could change it. And by putting on the bigger tires could change the shift points in the transmission and tear it up. Second dealer told me "no problem". What gives?

 

was there any follow up to this question? Or anyone know the answer?

I am getting ready to put on 315/70/17 - and need to know if i have to have it reprogrammed.

 

What dealer charged you $35? Mine is in shop right now, and they want to charge me $70

Thanks!

 

Got mine done a couple of weeks ago cost me $42.80