For those on 35s who have re-geared

[j.o.y.ride]

I know, endless gearing threads here, this one is a little more specific. I also know there's charts galore, but I want to hear real world experience.

Highly unlikely I will ever tow, and unlikely to go to 37.

Most of my driving is highway at speeds of 75-80. I am interested to know what people who a) have 35s and b) have either 4.56 or 4.88 are turning for RPMs and gears at those speeds.

While 3.73 doesn't like those speeds too much, I am thinking 4.88 may be too far the other direction and it will be spinning quite high RPM.

If I can get 3,000 rpm to be 85ish I will be good. The charts at 70 say 4.56 is 2544 and 4.88 is 2723, so am thinking by 80 I will be spinning out of 4.88s

What's everyone's experience been?

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[Tufelhundin]

Not sure what charts your using, I’m currently running 315/70-17’s with 4.56 and I took the below picture for another member yesterday.

 

[j.o.y.ride]

Not sure what charts your using, I’m currently running 315/70-17’s with 4.56 and I took the below picture for another member yesterday.

70 @2100 sounds good, better than the charts. Maybe even 4.88 territory then. Assume this is 8th?

 

[Jeeperjamie]

I got 4.10 gears in mine and I'm on 315 70 17 BFG ko2s and I don't see 3,000 RPMs at 80. I'll try to get a video later of my commute on I-85 but here's a video up to 75mph and I was under 2100, haven't regeared

 

[j.o.y.ride]

I got 4.10 gears in mine and I'm on 315 70 17 BFG ko2s and I don't see 3,000 RPMs at 80. I'll try to get a video later of my commute on I-85 but here's a video up to 75mph and I was under 2100, haven't regeared

But what gear?

 

[Jeeperjamie]

Here's another one. I normally stay at 7th to 8th gear as l stay under 85, never really been above that fast but maybe once, don't really have the need to. I'll shoot a better one when a get a opportunity.

 

[brianinca]

Didn't regear, 75 MPH corrected with 315/70R17's is 2000 rpm. Ironically, that's the same engine rpm as my 93 Wrangler 5 spd with 33's and 3.54 gears.

The fastest we've driven or that I've seen my wife drive was 98. Cruise control will disengage above a certain engine RPM, I haven't had it happen often enough to know what that is.

4.10's seem plenty for 35's, H2's did fine with 35's and only a 4 spd and a 6L with 4.10's from the factory. With all the gears we have in the JT, do you need to go to 4.56's?

Edit to add: that chart must be for the JK's 6 spd.

I know, endless gearing threads here, this one is a little more specific. I also know there's charts galore, but I want to hear real world experience.

Highly unlikely I will ever tow, and unlikely to go to 37.

Most of my driving is highway at speeds of 75-80. I am interested to know what people who a) have 35s and b) have either 4.56 or 4.88 are turning for RPMs and gears at those speeds.

While 3.73 doesn't like those speeds too much, I am thinking 4.88 may be too far the other direction and it will be spinning quite high RPM.

If I can get 3,000 rpm to be 85ish I will be good. The charts at 70 say 4.56 is 2544 and 4.88 is 2723, so am thinking by 80 I will be spinning out of 4.88s

What's everyone's experience been?

 

[RiverMtnBeach]

Happy with 4.10s and 315/70R17, and I tow 4K-5.5K lbs regularly. On stock 265/75 was almost comically short on gearing. 1st gear was almost useless, now it seems just right. The 8-speed is amazingly flexible. I wouldn’t invest in a regear to 4.88 unless running 37s, and didn’t want to run load range E tires, so 35 is a good compromise.

 

[Tufelhundin]

If I had 4.10’s I truly believe i would have not re-geared. I would have certainly saved that money.

 

[smlobx]

Happy with 4.10s and 315/70R17, and I tow 4K-5.5K lbs regularly. On stock 265/75 was almost comically short on gearing. 1st gear was almost useless, now it seems just right. The 8-speed is amazingly flexible. I wouldn’t invest in a regear to 4.88 unless running 37s, and didn’t want to run load range E tires, so 35 is a good compromise.

I am reading this thread because I’m wondering if there are negative side effects going to 315/70R17 with the 4.10 gears but from your comment there doesn’t appear to be any. What tire brand are you running as they are all a bit different in circumference?
Thanks.

 

[j.o.y.ride]

If I had 4.10’s I truly believe i would have not re-geared. I would have certainly saved that money.

I maybe would have kept 4.10, not sure, but I know it would have made the decision harder for sure. But I am also going to be adding some ARB air lockers at the same time.

Here's another one. I normally stay at 7th to 8th gear as l stay under 85, never really been above that fast but maybe once, don't really have the need to. I'll shoot a better one when a get a opportunity.

Ok well if you are normally 7th to 8th on 4.10 then I suspect I would be comfortably into 8th. And probably spinning high on 4.88.

 

[j.o.y.ride]

Didn't regear, 75 MPH corrected with 315/70R17's is 2000 rpm. Ironically, that's the same engine rpm as my 93 Wrangler 5 spd with 33's and 3.54 gears.

The fastest we've driven or that I've seen my wife drive was 98. Cruise control will disengage above a certain engine RPM, I haven't had it happen often enough to know what that is.

4.10's seem plenty for 35's, H2's did fine with 35's and only a 4 spd and a 6L with 4.10's from the factory. With all the gears we have in the JT, do you need to go to 4.56's?

Edit to add: that chart must be for the JK's 6 spd.

It may be a JK chart.

Do we need it? No, I drive everywhere just fine as it is. But, all the gears aren't being used as often as they should be. It drives more like a 6.5 speed most of the time.

 

[RiverMtnBeach]

I am reading this thread because I’m wondering if there are negative side effects going to 315/70R17 with the 4.10 gears but from your comment there doesn’t appear to be any. What tire brand are you running as they are all a bit different in circumference?
Thanks.

BFG KO2’s - make sure to get the load “C” versions, not “E”. Way too stiff, and every shop tries to sell you “E” (more money). As for down-side, you can definitely feel it’s slower from a stop, but recalibration for the bigger tires seemed to adjust the shift points just enough to compensate. Still more than adequate power to tow at hwy speeds even over passes, just a little buzzy keeping the revs up. Also expect to lose about 2-3 MPGs average daily driving, but towing is almost identical. Like everything, it’s a compromise. ?

 

[PresidentGod]

Plug in the numbers for your JT HERE . Put in actual tire height for more accurate results.
You can arrange grimmjeeper’s calculator for any set up you have and compare it to any set up you may get. Using his site I was able to determine that the best set up for me, on 35x10.50r17 Kenda Klever R/Ts measuring 34.4 inches was to go with 4.56 gears. Installing 4.10 gears would yield almost the exact rpm profile as stock 3.73 with my Kendas.
My JT is a 6spd manual and I wanted to adjust the rpm profile in each gear so I went a notch beyond (lower than, higher numerically) the stock rpm profile (245/75r17&3.73 gears = 35x10.5r17&4.11 gears so I went to 4.56). If you’re driving an automatic your variable gearing would probably be fine at 4.10, especially if you don’t live in a mountainous area or tow anything.
Anyway, I hope that calculator helps you with your decision!

 

[-miko-]

It may be a JK chart.

Do we need it? No, I drive everywhere just fine as it is. But, all the gears aren't being used as often as they should be. It drives more like a 6.5 speed most of the time.

Do you have an auto or manual? Wrestling with the 4.56 vs. 4.88 debate but with a manual transmission so these real world examples are helpful.

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