35" tires and 8th gear

[GlacierGladiator]

I have 35" tires on my JT and recently recalibrated the tires with my Tazer JL mini. The other day I drove about 2.5 hours on the freeway and noticed that it rarely shifted into 8th gear. Usually only if I was on a slight decline. Is this normal for adding 35" tires or is there gear changes I can make with the Tazer to alter shift points?
New to tazer and don't want to go messing with gear ratios if I don't know what I'm doing.
Any input/ help would be appreciated.

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[tbaker]

I put 35 inch tires on my gladiator rubicon and it doesn’t like 8th gear only when i am going down a slight decline even driving on a flat road if there is a slight change in the road it will down shift to 7th gear it likes 7th gear better with the 35 inch tires I have saw people regearing there gladiator and posting about it on YouTube

 

[Deleted member 24880]

Mine has hardly seen 8th gear since adding my 35s. I look at it as my last truck with 35s only had 5 gears so it’s all good. Hanging around 15mpg with a mix of town and highway driving. 11mpg with last truck on 35s.

 

[Trippin01]

I have an 8th gear? with the auto tranny? wow! that is cool, I'm gonna have to figure out how to use it now.

Maybe in 4 low ????????????????

 

[canyonrat]

I also see 8th gear on slight descents or more, running 315/70r17. Thats ok, I think of it like riding a bike and the truck can't "coast" downhill so one extra tall gear is a good reserve.

Also one of multiple reasons I did not want to go to 37's or taller.

 

[Blisskiss]

Good to know. Just regear if you dont plan on going 37s. Get your 8th gear back, get your powah! And no a regear is done physically in the drivetrain/axle housing or whatever.l, not digitally, although you do need to recalibrate the computer / speedometer.

 

[DylanR]

I am running 37’s and have zero issues getting to 8th gear. Obviously a little more difficult than say with 33’s. I have 4:10 gears. If you have the 3:73 then yes I could see where there would be way more complications...

 

[ShadowsPapa]

Mine only hits 8th on the flat or with no wind, spends a lot of time in 7th so this is no surprise.
Granted mine is an Overland with a higher ratio but larger tires result in a higher end ratio as well so........ if a wind or the local hills mean I don't see 8th until I get to more level interstate and 70 mph speeds, anything larger would mean even less time for 8th gear.
Yesterday with the wind, even at 65-70 on I35 I hit 8th maybe a couple of times for a mile or so, most of the time was in 7th at 70 mph.

 

[GlacierGladiator]

I am running 37’s and have zero issues getting to 8th gear. Obviously a little more difficult than say with 33’s. I have 4:10 gears. If you have the 3:73 then yes I could see where there would be way more complications...

I have a Rubicon so I'm surprised to see you hit 8th gear with 37's. Maybe you live somewhere really flat? I run in 7th gear 65+ mph at 2500rpm's and it still never makes it into 8th gear.

 

[DylanR]

I have a Rubicon so I'm surprised to see you hit 8th gear with 37's. Maybe you live somewhere really flat? I run in 7th gear 65+ mph at 2500rpm's and it still never makes it into 8th gear.

You having a rubicon vs my max tow makes no difference... they have the same gear ratio. the max tow would even have the advantage for running a bigger tire. Little better cooling... and not as heavy bumpers etc. (stock) if you want to get real technical.
I live in TN elevation is around 1500... I see a little bit of everything when it comes to driving conditions.
Of course 8th is only ever really seen on a flat road or maybe slight incline. You would never see 8th with stock wheels and tires going up a significant grade to begin with.

 

[ShadowsPapa]

You having a rubicon vs my max tow makes no difference... they have the same gear ratio. the max tow would even have the advantage for running a bigger tire. Little better cooling... and not as heavy bumpers etc. (stock) if you want to get real technical.
I live in TN elevation is around 1500... I see a little bit of everything when it comes to driving conditions.
Of course 8th is only ever really seen on a flat road or maybe slight incline. You would never see 8th with stock wheels and tires going up a significant grade to begin with.

Max tow and tow package have the same cooling - same alternator, should be the same wattage fans as I recall.
"HD cooling"
As long as there is a towing package, it should have the same.

Are the base Rubicon bumpers really heavier than the Sport or Overland bumper? If so - by very much?

The Rubicon is about 400 pounds heavier - some of that in the axles, some in the sway bar disconnect, and a few other fun things.

 

[DylanR]

@ShadowsPapa
The max tow package and the tow package are not the same thing.

 

[ShadowsPapa]

@ShadowsPapa
The max tow package and the tow package are not the same thing.

Uh, I KNOW that very well, but they have the same cooling setup. They are the same exact alternator and that larger alternator was included to handle the larger fans.
Tow vs. max tow differences is in the axles and springs for the most part.
I have the exact same alternator under the hood as anyone with max tow.

 

[Renegade]

I’m going to start a petition for Jeep to remove 8th gear in Wrangler transmissions. That way people will stop worrying whether their Jeep uses 8th gear. The transmission is programmed to change gears sufficiently to move the Jeep down the road at the speed requested by the driver. As long as that happens with reasonable efficiency, it doesn’t need to use every gear.

 

[Blisskiss]

Even on flat you will lose time in 8th gear, seconds, because certain gears maybe 2-7 arent turning as efficiently because of the number of teeth on the gears arent perfect for the vehicle weight and rotational mass. As soon as you change even 2" of tire size, youll lose efficiency. Its simple, its there. If you know you want 35" tires for a long time then install 4.88s, or 4.56.

Its important to keep your vehicle performing better than stock when building it up, don't throw an imbalance on your beast

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