Regearing a 2010 JKUR

[ccfdcal]

I have a 2010 JKUR which I just put AEV's 3.5" lift on. I'm currently running the stock Rubi wheels and tires until my wallet plumps up a bit. I also tow a Sierra4x4trailer with a RTT when I go camping. I'm planning on upgrading the tires to 35's in a couple weeks. I hear a lot about changing gears to overcome the bigger tires and helping out when towing. I've also heard many opinions about just adding a chip and improving the exhaust system. I'm looking for advice on the subject. I'm leaning towards regearing, I'm just not sure what would be the appropriate gearing for my set up.

 

[CCFD170]

Just put a Hemi in it!!

 

[Bigjerm]

Auto or manual? If Auto I would say 5.13's and manual I would say maybe 4.88's but with the trailer maybe just 5.13's as well. How often do you tow?

 

[Rovertrader]

I am running the AEV 3.5 w/ 37's and 5.13s and am well pleased, auto by the way.

 

[ccfdcal]

I've got the Auto transmission

 

[ccfdcal]

I am running the AEV 3.5 w/ 37's and 5.13s and am well pleased, auto by the way.

What type of mileage do you get with that combo? Do you notice any loss off the top end, say at around 80?

 

[JIMBO]

:sombrero: You have a Rubi, so my advice would be have a good suspension shop install YUKON (ALL NEW)/w rebuild kits--5.38 gears--

I also tow a 1000 lb trailer and with my '08 JKUR, that weighs 5200 lbs--UNLOADED-I've had on-road/off-road pure happyness and a new jeep with good mileage/power/immediate throttle response and that coupled /w aux cooling system, my auto stays 150° freeway travel and never gets over 210° off-road-hills/rocks-etc

The single most beneficial mod I've made to this jeep in three 1/2 years (51 mods)-

If you're gonna run anything over 33" in diameter--use 5.38s--I wouldn't consider any ratio below 5.13s, my mileage went up from 15.2 (4.10 gears) to 17 mpg and almost 16mpg towing the trailer-

:costumed-smiley-007:wings: JIMBO

 

[jeep-N-montero]

:sombrero: You have a Rubi, so my advice would be have a good suspension shop install YUKON (ALL NEW)/w rebuild kits--5.38 gears--

I also tow a 1000 lb trailer and with my '08 JKUR, that weighs 5200 lbs--UNLOADED-I've had on-road/off-road pure happyness and a new jeep with good mileage/power/immediate throttle response and that coupled /w aux cooling system, my auto stays 150° freeway travel and never gets over 210° off-road-hills/rocks-etc

The single most beneficial mod I've made to this jeep in three 1/2 years (51 mods)-

If you're gonna run anything over 33" in diameter--use 5.38s--I wouldn't consider any ratio below 5.13s, my mileage went up from 15.2 (4.10 gears) to 17 mpg and almost 16mpg towing the trailer-

:costumed-smiley-007:wings: JIMBO

I would think a drivetrain shop would be more accommodating than a suspension shop....

 

[JIMBO]

:sombrero: Actually a race shop is probaby the best, but

You have to find any shop with a good rep--this is a major mod to the suspension -

I would think a drivetrain shop would be more accommodating than a suspension shop....

You should find a shop-have them buy the gears and take care of the whole deal-and they can take care of any warranty problems-

I had mine done by a race shop in Reno--no problemo

:costumed-smiley-007:wings: JIMBO

 

[mvbeggs]

Jeep Regearing and Gas Mileage

..I also tow a 1000 lb trailer and with my '08 JKUR, that weighs 5200 lbs--UNLOADED-....
The single most beneficial mod I've made to this jeep in three 1/2 years (51 mods)-

If you're gonna run anything over 33" in diameter--use 5.38s--I wouldn't consider any ratio below 5.13s, my mileage went up from 15.2 (4.10 gears) to 17 mpg and almost 16mpg towing the trailer-

:costumed-smiley-007:wings: JIMBO

Wow! Increase weight, add larger tires, regear AND gas mileage improves?! That hasn't been my experience.

My Jeep has also gained some weight from the mods....probably north of 6,000lbs. My Jeep started out as a 2011 JKUR. I was getting about 15 mpg before the mods. After adding bumpers, sliders, axles, regearing to 5.13, adding heavy beadlocks and 37" tires...and using an AEV Procal to recalibrate the speedometer/odometer...I was in the 13mpg range unloaded and not towing. Loaded and towing the trailer on a 3300 mile trip, I averaged about 11mpg. This was all with the original 3.8l. In this configuration, the Jeep did fine on the flats. Running through Montrose and Vail passes in Colorado was a different story. Even geared 5.13 the Jeep struggled to maintain 45mph up these grades while loaded and towing the trailer.

Running 80mph down the highway in the above configuration yielded about 2400 rpm , If I recall correctly.

Good luck with the build.

 

[JIMBO]

:sombrero: Heh Heh, sorry, but no JKUR ever weighed 2011 lbs--the stock weight without gas is 4350lbs and I've had mine weighed at a Nevada certified "CAT" station 5150lbs/w full tank of gas-

Wow! Increase weight, add larger tires, regear AND gas mileage improves?! That hasn't been my experience.

My Jeep has also gained some weight from the mods....probably north of 6,000lbs. My Jeep started out as a 2011 JKUR. I was getting about 15 mpg before the mods. After adding bumpers, sliders, axles, regearing to 5.13, adding heavy beadlocks and 37" tires...and using an AEV Procal to recalibrate the speedometer/odometer...I was in the 13mpg range unloaded and not towing. Loaded and towing the trailer on a 3300 mile trip, I averaged about 11mpg. This was all with the original 3.8l. In this configuration, the Jeep did fine on the flats. Running through Montrose and Vail passes in Colorado was a different story. Even geared 5.13 the Jeep struggled to maintain 45mph up these grades while loaded and towing the trailer.

Running 80mph down the highway in the above configuration yielded about 2400 rpm , If I recall correctly.

Good luck with the build.

And the reason my mileage has improved is because the 3.8L v6 NEEDS to cruise at 2200/2500 rpm for effeciency and When I cruise at 60mph/2250 rpm, the mileage has been calculated at 17.2 mpg---now at 70mph it turns 2600 rpm and nets 16mpg--towing with trailer on level freeway at 2250 rpm/O/D, she nets 14.9 mpg--

When my JKUR is loaded for camping/fishing/trailer the GVW weight is approx. 6600lbs and climbing long hills in the Sierras, it's no problem staying at 60 mph in 3rd gear (2700rpm)

:costumed-smiley-007:wings: JIMBO

 

[bdr529]

Wow Jimbo, your JK must have been built on a good day. My experience has been more in line with mvbeggs. Mine has pretty similar specs: JKUR, auto, 5.38s, steel bumpers and skid plates, and even on the best days of interstate cruising unloaded (no trailer) @70mph, I'm lucky to get much over 14 mpg.

To the OP, do the gears, you won't regret it. As Jimbo and others have said, go with either 5.13 or 5.38.

 

[JIMBO]

:sombrero: It's pretty hard to judge driving techniques, but we're all a little different and

Wow Jimbo, your JK must have been built on a good day. My experience has been more in line with mvbeggs. Mine has pretty similar specs: JKUR, auto, 5.38s, steel bumpers and skid plates, and even on the best days of interstate cruising unloaded (no trailer) @70mph, I'm lucky to get much over 14 mpg.

To the OP, do the gears, you won't regret it. As Jimbo and others have said, go with either 5.13 or 5.38.

I've got witnessed refill/mileage receipts on trips from the Ca. Bay Area to Reno Nevada and back the same way--223 miles/loaded JKUR/15.2 mpg Union 76-- 87 oct-

One of the MINOR mileage saviors is my dual auto aux cooling system that keeps the auto op temp at 150°/70mph, that and my front under bumper/pan/auto skid plates can add up to aerodynamic effeciency !

And, on trips I run my Hankook MTs at 37 psi, also my trailer is almost the same track as my jeep and when towing--is actually drafting behind the jeep

Actually, when breaking in my new YUKONS (5.38s) and driving like a Granmothers/Grandmother-I recorded 19 mpg.60 miles/level freeway/60mph/UNLOADED JKUR-(5150lbs)-

Ain't jeepin great ?

:costumed-smiley-007:wings: JIMBO

 

[Rovertrader]

I to am getting 17-18 mpg consistently.However, I cannot comment on going 80, as I haven't. On the other hand I built a bit different this time- stock shorty front bumper, factory rear bumper w/ AEV tire carrier, and running A/Ts, as well as AEV programer. Nice and quiet, smooth, and decent mileage- and I have a small roof rack- well, here is mine:



The garage shot is most recent, but the jest of it is to keep the weight low!! I replaced the cable with rope, got rid of the KM2s, etc. I do have HD axles, lockers, etc but nothing adding weight that isn't a must...

 

[Main Line Overland]

Rovertrader, I like the look of your rig. You can't beat the color matched steel wheel look :sombrero:.