34s

[Wheelin98TJ]

Personally to keep it enjoyable as a daily driver, I would not recommend over a 285/70R17 or 33” with the stock 3.73 gearing. Going taller and heavier will kill your acceleration and fuel economy. My Sport S is quite enjoyable as a daily driver with 265/70R17.

I have no problems with acceleration or MPG with 35s and 3.73. Dash says 18.6 MPG.

My problem is not getting in 8th gear very often.

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[Bjeepz]

I had 34’s (285/75r17) on my 2020 Overland with 3.73’s, it drove great! Go for it!!

 

[Sigz]

Personally to keep it enjoyable as a daily driver, I would not recommend over a 285/70R17 or 33” with the stock 3.73 gearing. Going taller and heavier will kill your acceleration and fuel economy. My Sport S is quite enjoyable as a daily driver with 265/70R17.

I understand the concept of larger tires with a lower gear ratio - but this statement is very individualized.

People need to remember when upgrading to 35s or a larger tire with 3.73 gearing:

- Where are you located? Mountains? Flat land? Sea level? Etc

- What Brand tire, and what size of 35s? 35x11.5 or 35x12.5, etc

- What WEIGHT of the 35inch tire?

- Are people correcting speedometer / shift points with apps such as TAZR / JSCAN?

- What time of year are people upgrading tires.... Summer blend of fuel or winter blend?

My Falken At3w SL 285/70/17 were 54# to my current 35x12.5x17 Toyo's which are 59# and I have seen literally no change in fuel economy (in fact I believe I'm a smigey better). I still get into 8th gear on the interstate - and yes sure, it may not hold as long with elevation changes in the road - but it has not caused the drive to be unfriendly.

Over Memorial day weekend, we drove from Madison WI to the UP of Michigan and averaged 20mpg overall.

With that said - if someone upgraded to a 35inch tire that is like 84#'s (like new Falken AT4w) then yes... a re-gear is probably a good idea.

 

[rhaney02]

Looks great! What lift was that?

Thanks. I went simple with that one with just a TeraFlex 2" leveling kit. Loved that JKU, daily drove it for over 7 years total until it was traded for my current JT.

 

[Brucewillys]

Hey all, I just bought a 2025 Gladiator Nighthawk. This is my 8th jeep, but first one in 14 years. In the past I owned CJs, YJs, and a TJ. They were never daily drivers except when I was a kid. Now it’s going to be my daily driver, I’m thinking 34s with a 1.5 terraflex kit. Any advice on this?

thanks in advance!!

Do it! I've run Nitto Trail grapplers for 3 summers and one winter. They're a great size.

 

[SamJ3]

Regarding the gearing, my personal experience says you'll be good. I replaced my factory tires with 35's and am running 3.73 gears and an 8 speed automatic transmission. Tire size was recalibrated with a Tazer. The shifting felt a little wonky at first, but once the transmission reprogrammed itself all felt fine. Fuel economy and road manners seems unaffected.

As others have said, 8th gear is not always selected at highway speeds - but I do have to wonder if anyone gave that attention before their tire swap. Note that both 7th and 8th are overdrive gears, and the engine RPMs at highest speeds are rather modest. In practice, the only noticeable driving differences will be under full throttle acceleration from a stand still, and low gear pulling torque. (For the low gear climbs and pulls, for me, that is what 4LO is for.)

Bottom line: recalibrate the tire size and let (or force) the transmission relearn (before worrying about regearing).

 

[capejeep17]

Went with the 34s happy with the results.

 

[Wheelin98TJ]

Went with the 34s happy with the results.

Nice, looks great!

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