Hello all going from the stock 255 75r17 on 2016 JKU Willy's with Automatic to 285/70r17 (aka 33s) . I have my tires in and will be puitting wheel spacers on (when I owned a TJ said I would never use them), still waiting on my Flashcal though.

My question is if I get tires installed and drive for a couple days before i reprogram with such a small change in tire diameter am I risking limp mode?

Thanks

PS I did a search on this didn't find anything this specfic.

 

I ran 33's for years with no issues.

 

I ran 275/70r18s for three years w/o issue.

 

I ran 33s for about a year and a half with no issues.

 

You don't have to program for tire size, but your speedo and any computer generated data like fuel economy will be off. It will not put you in limp mode.

 

Thanks all for the fast responses.

 

Unless there are some other settings you want to fix with a programmer, you might consider just saving your money for now. with 35s, speedos are off about 5mph up around 70mph.....so with 33s would think you're only talking 3pm diff in the speedo. May or may not be enough of a difference for you to plunk down $150 or more to correct.

 

You don't have to use spacers if you add a thin washer under each steering stop-bolt. The tiny increase in turn radius isn't noticeable. Ball joints will likely last much longer -- almost 100K on my stock ones and the play measured with a dial indicator is well within spec.