stretch-bsn
Well-Known Member
- First Name
- Chris
- Joined
- Sep 25, 2024
- Threads
- 77
- Messages
- 794
- Reaction score
- 1,464
- Location
- Northern VA
- Vehicle(s)
- 2018 JLU
- Thread starter
- #1
Let me make a few qualifications.
This is my first Jeep
I’ve owned it for a little over a year. In that time I’ve put about 30,000 miles on it including a trip to Moab and several off roading trips. Mostly east coast.
I’m making my observations after only one week of driving on these new tires. I’m specifically doing it at one week because I can still recall the feeling of the old vs the new and if I get 3-6 months down the road I know myself and I won’t recall the little things. So I’m doing it now.
This is just my experience and what I found from my research. First I’ll give my Jeeps “stats”:
2018 JLU Sport S
JLU wrangler sport s 2018
3.6L engine
8 speed automatic trans
3.73 gears
392 Dana 44 axles with cast knuckles and lockers front and rear
2.5” lift rubicon XR with tereflx spacer up front to level
Skyjacker m95 shocks
BFG KO2 37/12.5/17
Go Rhino frame mount rock sliders
Steel front bumper for high clearance
12000 lbs winch
Smittybilt steel fenders
Front and rear rough country differential skid plates
Granite crystal metallic gray
Milage- 76,605
I bought my JLU used
When I bought it it had an AEV spacer lift and the aftermarket wheels it has today along with a set of 315 70 17 Falkin wildpeak AT3 tires. The stock axles were still on it with stock 3.45 gears.
I bought 392 rubicon axles with the 3.73 gears (don’t get me started on why I got the 3.73 it was a mess but it’s what I have). Good thing out of this was the cast C’s instead of aluminum, beefed up brakes, and now I have front/rear lockers.
I didn’t notice any gain or loss with this gearing combo compared to the 3.45 gears.
Fast forward and I can’t leave well enough alone.
My Falkins are 73+ lbs tires at a load range E (315 70R17 - ground to top tire real size 33.5”)
Current new KO2’s are 64+ (almost 65) lbs tires in a load range C (37 12.5 R17 - ground to top of tire real size 35.5”) I specifically chose the KO2’s because of the weight and height (they run smaller than typical 37’s from what I’ve read).
I am aware I’m undergeared for either set up.
My personal experience after a week of being on these 37’s.
I have not driven a Jeep with stock gearing and stick tire size…only the stock gearing and the Falkins.
From my experience is these are awesome lol. I think it mainly has to do with the load rating of the tire. My old Falkins were stout…great tire but stiff as all get out. These KO2’s in load range C seem to float and provide much more cushion than the Falkins. The ride is so much smoother.
I do sit up a little taller and I like that. The 12.5 seem slightly more narrow but I think that’s an illusion because of the added height of the tire.
I drive roughly 110 miles a day for work (round trip) some city some highways and my MPG’s have not changed (still getting about 18mpg). My rpm’s and gears have not changed (I do see 8th gear but it’s more common than not the transmission hunts between 7-8 on the highway and hills it’s at 5-6).
I’ve been monitoring transmission and oil temps and nothing has shifted there either.
Losing 8-9lbs per corner of the Jeep has compensated for the size to a degree. From what I understand there is till more rolling resistance, even with the weight loss, but I personally can’t feel or notice it.
That being said I have not taken it off road yet and I understand that may be a different story/experience. I will update when I’ve had a chance to do some off roading.
I will most likely still to easy and moderate trails.
I also do still plan to regear but I’m not in a rush (12 months give or take)
Just figured I’d share my experience. I know so many people on here have different experiences. Some from actual experience and some keyboard warriors who run the calculations and will swear on their mother that everything will explode if you don’t do it right.
Happy wheeling everyone!
This is my first Jeep
I’ve owned it for a little over a year. In that time I’ve put about 30,000 miles on it including a trip to Moab and several off roading trips. Mostly east coast.
I’m making my observations after only one week of driving on these new tires. I’m specifically doing it at one week because I can still recall the feeling of the old vs the new and if I get 3-6 months down the road I know myself and I won’t recall the little things. So I’m doing it now.
This is just my experience and what I found from my research. First I’ll give my Jeeps “stats”:
2018 JLU Sport S
JLU wrangler sport s 2018
3.6L engine
8 speed automatic trans
3.73 gears
392 Dana 44 axles with cast knuckles and lockers front and rear
2.5” lift rubicon XR with tereflx spacer up front to level
Skyjacker m95 shocks
BFG KO2 37/12.5/17
Go Rhino frame mount rock sliders
Steel front bumper for high clearance
12000 lbs winch
Smittybilt steel fenders
Front and rear rough country differential skid plates
Granite crystal metallic gray
Milage- 76,605
I bought my JLU used
When I bought it it had an AEV spacer lift and the aftermarket wheels it has today along with a set of 315 70 17 Falkin wildpeak AT3 tires. The stock axles were still on it with stock 3.45 gears.
I bought 392 rubicon axles with the 3.73 gears (don’t get me started on why I got the 3.73 it was a mess but it’s what I have). Good thing out of this was the cast C’s instead of aluminum, beefed up brakes, and now I have front/rear lockers.
I didn’t notice any gain or loss with this gearing combo compared to the 3.45 gears.
Fast forward and I can’t leave well enough alone.
My Falkins are 73+ lbs tires at a load range E (315 70R17 - ground to top tire real size 33.5”)
Current new KO2’s are 64+ (almost 65) lbs tires in a load range C (37 12.5 R17 - ground to top of tire real size 35.5”) I specifically chose the KO2’s because of the weight and height (they run smaller than typical 37’s from what I’ve read).
I am aware I’m undergeared for either set up.
My personal experience after a week of being on these 37’s.
I have not driven a Jeep with stock gearing and stick tire size…only the stock gearing and the Falkins.
From my experience is these are awesome lol. I think it mainly has to do with the load rating of the tire. My old Falkins were stout…great tire but stiff as all get out. These KO2’s in load range C seem to float and provide much more cushion than the Falkins. The ride is so much smoother.
I do sit up a little taller and I like that. The 12.5 seem slightly more narrow but I think that’s an illusion because of the added height of the tire.
I drive roughly 110 miles a day for work (round trip) some city some highways and my MPG’s have not changed (still getting about 18mpg). My rpm’s and gears have not changed (I do see 8th gear but it’s more common than not the transmission hunts between 7-8 on the highway and hills it’s at 5-6).
I’ve been monitoring transmission and oil temps and nothing has shifted there either.
Losing 8-9lbs per corner of the Jeep has compensated for the size to a degree. From what I understand there is till more rolling resistance, even with the weight loss, but I personally can’t feel or notice it.
That being said I have not taken it off road yet and I understand that may be a different story/experience. I will update when I’ve had a chance to do some off roading.
I will most likely still to easy and moderate trails.
I also do still plan to regear but I’m not in a rush (12 months give or take)
Just figured I’d share my experience. I know so many people on here have different experiences. Some from actual experience and some keyboard warriors who run the calculations and will swear on their mother that everything will explode if you don’t do it right.
Happy wheeling everyone!
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