matt852

I was wondering since I have 32's on instead of the factory really small street tires that are available on the barbones, I don't have my old tires anymore so I don't know the correct tire size they were, I just know that they were the smallest tires that came with the X, how much of a mileage difference is there? I think the stock tires were a 225 size
Say in 1 mile with the old tires looks like something like this


compared with the Rubi tires which is about 32 inches in diameter.

Should my dealer flash my computer for free since it would be basically re flashing a stock rubicon for the odometer?

matt852

NVM
http://www.miata.net/garage/tirecalc.html
according to that 225 vs a 255 my odometer is 10% off

So when I'm at 50 mph odometer reading I'm actually doing 55 mph, at 40 mph im really doing 44 mph, is this correct? At 60 mph I'm really going 66 mph.

Fuzz 40

I did the same thing you did. Your milage will be off roughly 10% so you have the right idea. 40 becomes 44, 50 to 55, so on. Also note that your fuel economy will be off by 10% as well if you are wondering why your MPG is low, other than being a Jeep of course.

blw

That explains why my mpg is so low compared to others on this site! I had the rubi wheels and tires put on a stock jeep, too! I doubt the dealer did anything to the computer. Does this mean my warranty lasts longer as my odometer will read low?

Rusman161

Don't bother at the dealership with flashing because they can only select from 4 tire sizes and 32's are not one of the choices for your jeep unless it's a rubicon. They can get it close, but it's still off and they'll still try to charge you $110 for it. This happened to me last week. They gave me this whole spill how the regular jeep isnt a rubicon and cannot handle 32s! I could not believe the words coming out of this guys mouth. He said by putting oversized tires on my jeep I'm risking excessive wear to me entire suspension and drivetrain. I laughed out loud and told him he lost his talking priviliges. Since when are 32's considered oversized tires??? The solution on my service ticket said " get an aftermarket programmer" I asked if that would void my warranty and the lady next to him said not if the programmer only does tire size. She said the computer had a tattle tale system on it and if it shows any engine or transmission config change that my warranty would be voided.

Fuzz 40

Yup, you got to add about 10% to your MPG as well then you are looking at a more realistic number. Your warranty will last longer as long as you put your older tires back on or leave them on and hope your dealer can't put two and two together. If they realize the tire size is incorrect I am sure they will claim you have voided the warranty.

Orangeav

Get an AEV Procal, you can change tire size, adjust for new gears, set DRL's and other things as well. It's just about $150.00 too.

Red Wings

If the first picture is your Jeep with the original tires then you don't have the smallest tire and they are the same size as the Rubicon tire.

Deere_Jeep

Agree... If for some reason you have a larger tire get the AEV procal, about a $150, worth the price of a speeding ticket, plus you get the shift points back too.

BLK08JK

I've heard the dealership can only flash up to 32" but never heard they can't unless it's a Rubicon? Isn't the optional tire for an X or Sport a 32"?

What are the 4 sizes the dealer can flash then (for an X)? Or is it less than 4?