Tire size and gearing question

[SCKOMS]

Greetings all. I have a 2021 2 dr Sport S and am looking to install bigger tires. I have the Crystal Granite wheels, which are 17x7.5.

This is my first Jeep, so my knowledge base is very limited....bear with me.

I know that the easy route is to source a set of Rubicon take-offs that will provide a 32.7" diameter; I think I'd like to go a little bigger, though.

It's also my understanding that going to 35" diameter can cause performance issues and requires some rear axle gearing modifications.

If I go with 285/75/17 tires on my stock wheels, I will get 33.8" overall diameter. Will this require any rear axle gear ratio mods?

With the bigger tires, either 33's or 34's do I need to add some reinforcement to the tailgate to support the additional weight? If so, what are my options?

Thanks in advance

Sponsored

 

[Kreepin1]

This answer assumes this is a daily driver with an automatic.

I totally agree with your choice of tire size. The same width as on a Rubicon but a little taller. Your axles bring the tires in 3/4" compared to a Rubicon. If they rub I suggest turning the steering stops out a little until they don't rub. Two doors can give up a little turning radius.

The weight is OK for the factory spare mount. The key is to have the rubber snubbers keep the tire secure and not flopping around but also not stress the tailgate a lot when tightened down. I don't know if there is a difference in the rubber snubbers between Sport and Rubicon models, just pay attention when mounting the spare.

Hard to say on gearing. You will definitely notice a difference in acceleration and braking, also from what I've read you won't see much use from 8th gear. Only you can decide if it's acceptable. If you had off road plans I would definitely suggest looking for a set of Rubicon axles. Still might not be a bad long term plan if you can swing it.

 

[Stuckinthesand]

You can run 35’s on a sport s as a daily and wheel it. I have a 19 sport s with 35’s. I don’t see 8th gear as often as stock but I still do see it. Usually on a straight flat ground with no headwind. Even without 8th I average 19-20mpg highway and 16-17 city. I wheel anything rated a blue trail and below. I do have the M220 rear with the LSD.

 

[RatherDashing]

You can run 35’s on a sport s as a daily and wheel it. I have a 19 sport s with 35’s. I don’t see 8th gear as often as stock but I still do see it. Usually on a straight flat ground with no headwind. Even without 8th I average 19-20mpg highway and 16-17 city. I wheel anything rated a blue trail and below. I do have the M220 rear with the LSD.

What lift do you have?

 

[Stuckinthesand]

What lift do you have?

Rough country 2.5” spacer lift. Bought the correct size shocks though as I wasn’t thrilled with using shock extensions. No issues wheeling it with what I do. Now if I did anything rated black or above I’d definitely go with a legit spring lift.

 

[Headbarcode]

Assuming you have the 8-speed auto, you should be fine with 35's on your factory gearing. You'd never just regear the rear axle. It's $2000+ for parts and labor to regear both axles, which would be money better put towards a set of rubi axles from someone upgrading theirs.

You'll definitely want to reprogram the Jeep for the new tire size. Again, assuming you have the auto trans. It's a learning unit that requires accurate inputs in order for it to optimize its shift points and perform at its best. The Tazer is a popular reprogrammer, but if you don't care about its feature list, there's other more cost effective options like the Flashcal.

Sponsored