Re-gearing for 35's

[Mjw85]

I’m at looking to re-gear my 99 Tj with a 4.0 5 speed and 35s. I do about 80 percent highway. This isn’t a daily driver just mainly for the weekends. What gearing would be best for my application? I was leaning towards 4.88 but just wanted some opinions
Thank you.

 

[L J]

4.88s for the flatlands
5.13s if you encounter hills and mountains

 

[RINC]

I’m at looking to re-gear my 99 Tj with a 4.0 5 speed and 35s. I do about 80 percent highway. This isn’t a daily driver just mainly for the weekends. What gearing would be best for my application? I was leaning towards 4.88 but just wanted some opinions
Thank you.

I followed the path of others in my area and went 5.13 gears on my Dana 30 front and swapped in Dana 44 rear. My '04 has the 4.0L, NV3500 5-speed. Revolutions R&P's, Shafts and Eaton E-Lockers.

 

[NPhopper]

I’m at looking to re-gear my 99 Tj with a 4.0 5 speed and 35s. I do about 80 percent highway. This isn’t a daily driver just mainly for the weekends. What gearing would be best for my application? I was leaning towards 4.88 but just wanted some opinions
Thank you.

I put in 5.13 and i did not regret it at all after driving 2000 plus miles and national park hopping. So ik one thing and 5.13 is great if you ecounter a lot of mountians and different environments. There was not a single situation where i said i wish i went with 4.88.

 

[machoheadgames]

5.13.

 

[inkedrose]

I'm on 35s with 5.13 in the Rockies, 5speed manual. Can do speed limit up hill... no Jeep is getting anywhere fast.

 

[Jerry Bransford]

I’m at looking to re-gear my 99 Tj with a 4.0 5 speed and 35s. I do about 80 percent highway. This isn’t a daily driver just mainly for the weekends. What gearing would be best for my application? I was leaning towards 4.88 but just wanted some opinions
Thank you.

I had that exact same combination, 35's and 5-speed manual, on my previous TJ and 4.88 was absolutely the right choice for it. I loved its onroad and offroad performance and its highway rpms were ideal. 2700-2750 rpms at 70 mph which was perfect. I would have hated life if I had undergeared it with 4.56 as a few suggested. I'm glad I listened to more experienced types who told me to go with 4.88.

 

[Grant Lasson]

I took out 5.13s primarily because the PO installed them incorrectly (ring gear teeth were breaking off). I switched to 4.56 because it brought the jeep back to close to stock. 4.56 has worked fine (not that I also have the 4:1 transfer case reduction for crawling situations).

On the freeway, I'm often in 4th gear running around 3K RPM. Very comfortable there. 5th gear can get you to 75+ MPH which is about as fast as I care to drive the jeep. Non-freeway driving is often done in 3rd gear and it has a wide enough effective range that it works well.

I'm sure 4.88 would be great. In my case, I don't consider 4.56 to have been a mistake.

 

[Jerry Bransford]

I took out 5.13s primarily because the PO installed them incorrectly (ring gear teeth were breaking off). I switched to 4.56 because it brought the jeep back to close to stock.

The problem with gearing to return to stock rpms is they don't work for larger diameter tires that require more power to turn. The bigger the tire the more rpms are needed to maintain the same power the factory set for it.

 

[DougyintheBushies]

What ratio do y’all recommend with 4.0,35s & nsg370 6speed

 

[Jerry Bransford]

What ratio do y’all recommend with 4.0,35s & nsg370 6speed

Some will say 4.56 due to its very slightly lower 6th gear ratio but I'd still choose 4.88 for 35's. 'Tis better to be slightly overgeared than slightly undergeared.

 

[L J]

What ratio do y’all recommend with 4.0,35s & nsg370 6speed

I'm running 4.0/35/NSG370/5.13. I turn ~3000 rpm at 70 mph. It works for me due to my local geography and the fact that my LJ is a fun vehicle not a daily driver. Some who are more RPM-averse wouldn't like it. 4.88s are better suited for most guys running a 4.0/35s/NSG370 set up. I wouldn't consider 4.56s.

 

[machoheadgames]

The problem with gearing to return to stock rpms is they don't work for larger diameter tires that require more power to turn. The bigger the tire the more rpms are needed to maintain the same power the factory set for it.

Never really understood this. Given the same tire size, 4.88 with the 6 speed is lower than 5.13 and the 5 speed. With the logic is 4.88/6-speed, the 5-speed should have 5.13s.

 

[Jerry Bransford]

Not when 4.88 is perfect for 35s. You just get very slightly higher rpms with the 6-speed due to its very slightly lower 6th gear ratio.

 

[machoheadgames]

Not when 4.88 is perfect for 35s. You just get very slightly higher rpms with the 6-speed due to its very slightly lower 6th gear ratio.

But on 5.13 with the 5 speed you get lower rpm with the same size tire on 4.88 with the 6 speed. The 5 speed has a worse gear spread, so why shouldn’t the 5 speed get 5.13 by your gearing logic?

 

[Akitadog]

I have 4.88 w/ NSG370-6spd and I'm quite pleased with it on the road, off road and in the rocks w/ 5.1 case.

 

[Jerry Bransford]

But on 5.13 with the 5 speed you get lower rpm with the same size tire on 4.88 with the 6 speed. The 5 speed has a worse gear spread, so why shouldn’t the 5 speed get 5.13 by your gearing logic?

If 5.13 is your choice for the 5-speed go for it.

 

[John Cooper]

I PM'd back and forth with @Jerry Bransford on this a while, I am still up in the air on tire size(I have 33's now) if I decide to stay on 33's I will probably go 4.88 due to living in mountainous terrain. That plus I feel it would help Sport offroad!!!!

 

[JMT]

I PM'd back and forth with @Jerry Bransford on this a while, I am still up in the air on tire size(I have 33's now) if I decide to stay on 33's I will probably go 4.88 due to living in mountainous terrain. That plus I feel it would help Sport offroad!!!!

If you are up in the air on final tire size, you’ll be going bigger.

 

[John Cooper]

If you are up in the air on final tire size, you’ll be going bigger.

Maybe, I have run 33's and 35's in the past, while it was on a CJ I honestly couldn't tell any difference. Now it Gateway would come back out with the Q78 15 Buckshot (9.50 x 36) I would be running that for sure!!!!!! Then I would go with 5.13 gears.