Feedback/experience on 4.10s with 37s

[MarineHawk]

I actually did the math on it in that post. 37s on a Rubi are basically the same as 33s on a sport. The 8 speed is very well thought out in it's ratios.

I went from stock 33s tires to 35s on my LTR. I had the dealer reprogram, so that my speedo and odo are correct. I can't say for certain, but it seems to have lowered my shift points. Does anyone know for sure whether dealer reprogramming lowers the shift points to account for the larger tires?

Or does some other reprogrammer (Razor or whatever) do that? If so, doesn't that moot the issue?

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[Oscar Indy]

I went from stock 33s tires to 35s on my LTR. I had the dealer reprogram, so that my speedo and odo are correct. I can't say for certain, but it seems to have lowered my shift points. Does anyone know for sure whether dealer reprogramming lowers the shift points to account for the larger tires?

Or does some other reprogrammer (Razor or whatever) do that? If so, doesn't that moot the issue?

Not how it works. Shift points are based on many factors and speed being one of them. Correct tire size in the computer let's it calculate shifts more accurately. It doesn't change shift points as those are a combination of variables.

 

[MarineHawk]

Not how it works. Shift points are based on many factors and speed being one of them. Correct tire size in the computer let's it calculate shifts more accurately. It doesn't change shift points as those are a combination of variables.

Thanks for the info. It's a bit of a shame that Jeep doesn't have something like the "Tow/Haul" setting I had with my GMs. It lowers the shift points. For those running 37s, you could just hit that button on start-up--kind of like how I hit the Engine Start-Stop disable button on my Gladi as soon as I hit the start button.

 

[Oscar Indy]

Thanks for the info. It's a bit of a shame that Jeep doesn't have something like the "Tow/Haul" setting I had with my GMs. It lowers the shift points. For those running 37s, you could just hit that button on start-up--kind of like how I hit the Engine Start-Stop disable button on my Gladi as soon as I hit the start button.

Actually it raises the shift points and increases shift pressure. Keeping you in the lower gear longer for more torque.

 

[MarineHawk]

Actually it raises the shift points and increases shift pressure. Keeping you in the lower gear longer for more torque.

Yeah, that's what I meant to write, but my mind is playing opposite day.

 

[Alabama Mud Machine]

So, from what I've gathered in this thread...

Overall, if you mostly drive on roads under 65 MPH, the 37's are going to be fine with the stock 4.10's, correct?

And if you do a lot of highway driving, 4.56 minimums are recommended to retain factory performance with the stock 33's...

Most of my driving is under 65 MPH...So, I'll probably just leave the stock 4.10's in there for now when I order my 37's.

 

[Bacon]

I haven’t really noticed a difference in back of the seat feel. It’s still fun to drive; not scientific, I know. The real test is when I have to tow my 6500# camper.

 

[Phljeeper]

Any updates from those with 37s and 4.10s? Anyone tow with that setup? I have 35s and 4.10s currently and it does great, but really want the bigger tires.

 

[Bacon]

I haven’t really noticed a difference in back of the seat feel. It’s still fun to drive; not scientific, I know. The real test is when I have to tow my 6500# camper.

If I may quote myself.....so I did tow my camper and spent a lot of time in low gears and high RPM on hills. I’m really considering 4.88, for towing, but 4.10 is fine for every day driving.

 

[Alabama Mud Machine]

Any updates from those with 37s and 4.10s? Anyone tow with that setup? I have 35s and 4.10s currently and it does great, but really want the bigger tires.

So far almost 3,000 miles on 37’s with stock 4.10 gears, and It’s not bad at all once you reprogram the ECM for the 37’s with the Tazer JL Mini, and It’s even better if you add the iDrive throttle control unit I go the mix.

Granted, my fuel mileage and low-end power could definitely improve, but I’ll save up enough for the 4.88 swap one day.

 

[Alabama Mud Machine]

If I may quote myself.....so I did tow my camper and spent a lot of time in low gears and high RPM on hills. I’m really considering 4.88, for towing, but 4.10 is fine for every day driving.

I agree with this assessment.

 

[Benbean66]

I agree with this assessment.

Reading this makes me more confident that my decision to go with 35's rather than 37's would be wiser at the moment. Maybe I'll save up enough for when the 35's wear out, I can go with 37's, 4:88's and lockers. I just hope they (the 35's) don't look too small with the 3.5 Game Changer lift that is on its way.

 

[Alabama Mud Machine]

Reading this makes me more confident that my decision to go with 35's rather than 37's would be wiser at the moment. Maybe I'll save up enough for when the 35's wear out, I can go with 37's, 4:88's and lockers. I just hope they (the 35's) don't look too small with the 3.5 Game Changer lift that is on its way.

Don’t worry, they will.

 

[Bacon]

If you've ever looked at 37s, you will regret buying 35s. I went through this on my JKR 2dr with 33s and 35s and vowed not to make the same mistake ever again.

Buy once, cry once.

 

[wvyankee2]

If I may quote myself.....so I did tow my camper and spent a lot of time in low gears and high RPM on hills. I’m really considering 4.88, for towing, but 4.10 is fine for every day driving.

I have 35" Falkens and 488 gears. Towing 4000 pounds through the hills of WV ( as high as 3600 feet ) I was down to 4th in the Auto, @ 4800 RPM to hold 60MPH. Can't imagine how bad it would have been with 410's, or pulling 6500#.

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