4.88 or 5.29 gears

Running KDMax Pro, 5.29s, 285/75/16 KO2s, automatic. Speedo reports 65mph, GPS reports 68mph at 2200 rpm. 75mph = 2500 rpm-ish.

This has been an extremely helpful thread. Thanks for all the good info. I was afraid I may be over revving on long trips when I'm cruising at 65-70 for a couple hours or more at 2200-2400 rpm constantly. I went with 5.29s so I'd be geared for anything in the future, towing, 35s, etc. The truck is an absolute beast off road, especially in 4Lo, but definitely gave up the 80+ highway speeds with the 33s unless its revving pretty high. 6th gear was rare with stock gears, now I'm in 6th gear regularly. I almost had buyers remorse gearing so high but I know in the end the truck is ready for anything now and I just don't need to do 80+mph. At least I know I won't be getting any speeding tickets in this truck.

@Taco X that calculator is awesome and spot on. I wish I'd seen it before hand just for informational reasons. Thanks for sharing it.

Everything @ClassyTacos mentioned is spot on and great feedback too. I've had the same experience with obstacles and the 5.29s.

 

Actually mine is an automatic. But thank you for the info

 

I'm also in an automatic.

 

My bad I thought you said it was manual.

 

I have a ‘17 with 255/85/16’s which are 33’s and with my 5.29’s it’s 2400 rpm at 70. Roughly 2150 at 65.

Not a single gear hunting episode since install two months ago. Looking forward to first tow next month.

Should’ve done it long ago!

 

I always find the gearing discussion interesting.

I have 5.29 with 32” no lift just levelled. 73000k on a 2020 OR. Only 16000k with stock gearing. Driven the complete Alaska highway (ALCAN for the yanks) 7 times with 5.29 and another 4 times to the Yukon only. My experience says. No worse on fuel than the one time I drove the Alaska highway with stock gears. I get better fuel range in the city with 5.29 than with stock. I noticed that right from day one the fuel economy in the city. I will say I don’t do bumper to bumper traffic very often. Got the best fuel economy this last trip with a fully loaded box with a smart cap top 4 32” tires in the back and two hockey bags of gear in the back. Not to mention a Thule box on the top loaded as well. Let’s say truck was loaded.

my two cents. If you can’t handle it, please don’t slap me for my words

 

I run 4.88 with e rated 33's. Love it! ECGS.com did my regear, I had options for either 4.88 or 5.29. It was suggested 4.88 considering my setup and the amount of highway driving I do.

 

Mid Atlantic doesn't have 80 Mph speed limits like I 25 from CO to WY and I did just fine towing 3500# at 60 - 65 (last week). You think RV's drive that fast on the road? I lived in Richmond for years and made more than a few trips up to Philly and NY and yes, the drivers are aggressive but they move over as long as you keep to the slower lanes of travel. I 80 across Nebraska and I 25 North with wind gusts above 40 Mph are a lot for a 3.5 V6 to keep up with but I did just fine. Semi drivers are professionals and know how to avoid RVs and light pickups with travel trailers. It is the city driving idiots that don't think ahead or have a care for who is behind them that you have to worry about. I give a wide birth to those people and city driving is the most stressful when I'm towing.

OP - FWIW I am planning on 5.29s with 285 70 17s since I tow 95% of the time. I don't think there is a wrong answer between 4.88/5.29, just trade-offs which most others have done a good job of pointing out.

 

I have 5.29s with 285/75-17s. It is too low for good gas mileage and high speeds. It will do 80mph super easy and can cruise there, but its sucking gas like crazy. I would do the 4.88 if you are going no larger in tire size than mine. I plan to go up a size eventually, so I am not too disappointed in these gears. Otherwise, I wish I would have done the 4.88. At least until I go into 4LO. It is quite capable down there...

 

I have armor, topper, bumpers, winch, tire carrier, etc.. I get the power loss for sure, but I would still go 4.88 if I were to do it again WITHOUT the plan to go bigger on the tires.

 

Don't forget towing. A lower gear ratio helps move heat from the upstream drivetrain into the diff. This applies to offroading as well.

A head wind, or even side wind, will tank your mpg anyway, so why not save the engine and transmission some strain?

That being said, the 4.88 seems like a good option as well if you are unladen and concerned with mpg at high speed.

Your crawl ratios aren't too far off, but if you go into moderately rough terrain, being closer to 50 is much better
Crawl ratio:
4.88: 45
5.29: 49

 

I have to admit - my brain hurts. There is no easy answer to which gearing to go to for some applications. I find the one common that makes sense is the AT owners going to 4.88's to get rid of the shift hunting for everyday driving (minimalist off-road use).

I am leaning towards the 5.29 while still running 32's with some added weight on my rig (a lot more when camping), I have a MT but I tow a 4300lb off-road camper and live at altitude in Colorado. I do not drive interstate very often so when I do I will have to just accept the less mpg efficiency running without the trailer. I am not sure the 4.88 will get me where I want - power to climb both on the highway and off-road pulling the camper. When I picked up the camper in Boise last June I had problems with every mtn pass especially on I-70 where I had to downshift and could only get to 45mph where semi's were passing me.

At one time I was looking for a turbo mod but the 3.5L actually has the guts it just isn't geared properly due to Toyota meeting EPA requirements in the US for the majority of the market.

I am interested in more information on the "tune" options and if anyone has found that to be helpful after the re-gear? With these vehicles being so computer managed now does the re-tune help.

 

For your case it's a no brainer, 5.29. I'm skeptical of the tunes. Don't they usually just increase hp? Even if you got some more torque is it even significant compared to multiplying torque with gears?

 

James, I to am skeptical of the 'tune' idea but I have read where some - not in my application - have found a re-tune to help. Definitely not on my priority list of things to get done and the more I read about the 'tune' options I am leaning more-and-more away from that idea.

Thanks for responding and your PO confirming the route I am taking, like I said previously my brain hurts with all the data and different applications in these threads. I (personally) think if I went with the 4.88 I would be disappointed and out some significant money - it isn't like an easy or cheap flip if you go the wrong direction. I do have the 5.29's on order and will respond to this thread once installed and broken in to what I experience. Hopefully that will help some that have an MT in trying to decide which direction to go. Thanks

 

Update after a couple long highway trips:
The 5.29 gearing gives a lot more power on the low end, just when I go into the next gear. I had to adjust my shifting to shift earlier, and my gas mileage improved slightly from my last post, but is still not much different from stock 4.30 gearing with 33" tires. The truck feels really light now maintaining speed and accelerating (I do also have the OVTune).

On highway, there is nothing I can do to improve gas mileage except keep closer to 70mph. So a GPS reading of 80mph is where the RPMs hit 3k, which is pretty high for the truck on flat ground. I don't exactly remember the RPMs at 70mph, but think they're around 2.5K. I used to be able to pull about 18 to 20mpg on flat ground at highway speeds around 75mph, but now I'm more like 14-18mpg. I think the happy highway RPMs for the best MPGs on the truck is about 2k, but you'll have no acceleration power.

Moral of the story, it's probably better to stick to 4.88s with 33s from most people. The advantage for me was more 1st gear capability and having more usable gears in the 25-50 mph range (I was basically only 2nd and 3rd at that speed with stock 4.30 if I wanted to accelerate at all, and with 5.29, it's 2nd-5th). I'm happy with my 1st gear now on nightmare-inducing San Francisco hill starts in the Offroad (no hill hold).

 

on 5.29's and 285/75/16 (33's) here's the some real world RPM info i'm spinning.

65mph @ 2120RPM 6th gear
75mph @ 2435RPM 6th gear
80mph @2600RPM 6th gear

I do enjoy the truck and my truck is pretty maxxed out so the 5.29's help a lot. Absolute best mpg I ever got on 5.29's was about 16.5mpg.

 

Sorry but something seems off about these numbers to me. The the best mpg you've seen is 16.5? Is that the computer mpg? Are you towing?

I regeared my Xterra to a very similar ratio (taking the transmission into account) and it has 285/75/16 Duratracs, a 4.0 v6, lifted 3", and I get better mpg than that...

I will eat my hat if and when I get my truck if the mpg drops 5mpg and can barely manage the mpg of a one ton truck





A side note on rpm, I would give the tire brand and pressure for people to find it useful. Your tire is likely a 32" if measured vertically under load. Some 285s are taller.

 

Nothing off. these were number i recorded driving down the highway on cruise control. My speedo is corrected with a hypertech and accurate speeds to GPS. I'm running pretty heavy Cooper ST Maxx 285/75/16's they measure at 32.9" on their website. I was running around 35psi all 4 corners. I looked again and my actual best MPG was 16.91 That is corrected number and was from the CA bay area to south lake Tahoe and back. up highway 50 and home. about a 250mi trip. During this trip I'd estimate my vehicle had around 600lbs of total added weight between steel sliders, aluminum skid plates, full size spare, larger battery, tonneu cover, bed mat and gear. Vehicle is lifted about 2 inches on all 4 corners and tuned with OVtune 2.0 during this MPG test.

Since then my vehicle is very loaded down with a FWC swift. MPG has decreased even more, but to be expected. I bet without my camper and lighter tires i could see MPG numbers closer to 17.5 on long highway trips.

I'll upload some pics of my truck around the time when I hit this best mpg of 16.91 mpg. around town where I live it's very hilly and i have a work commute of about 16 miles round trip where i'd get only around 14.5 mpg even trying to drive extremely conservatively. These are just my numbers, i'm sure others may differ.

 

OP, Your truck looks cool af. Anyway, tuning in west Texas I’ve read @mZiggy being the most mentioned in TW.

 

What is the weight compared to stock?

4.88's aren't a bad option if you know you'll be sticking with that tire size, but if you're adding weight to what's already a heavier than stock vehicle then I'd add up that weight accurately and make the call. A hunting trip can get heavy fast, and you may be regretting your gear choice if you're not geared appropriately. Take people make comments about 5.29s with a grain of salt, they likely have never driven on them with 33s and are basing their opinions of preconceptions.

I wouldn't be getting too caught up in MPG from gears either, the biggest improvement is in drivability and less strain on the engine. People will absolutely see shift's in mileage, but they're usually so small that it'll take many years to pay off the job. Weight, rotational wheel/tire mass and to a lesser degree aero play a much bigger role than gears will.