Nitro gears: 4.88 or 5.29? (1 Viewer)

[80t0ylc]

I am stepping up to Black Rhino 17” wheels and Yokohama New MTs in 35”. I am heavy fully loaded. Would it be better to do 4.88 or 5.29 I like to drive at and average speed of 70 mph on hwy. comments suggestions???

Concerning 35" tires, all the comments to go with 4.88 are obviously owners with light loads or not towing. I was warned by @gearinstalls.com (when upgrading) that many owners he installed 4.88's in had got back to him wishing they'd gone with the 5.29's. If speed and light loads are all you'll do, 4.88 will probably work. I run 315/75/16 with 5.29's and at 65 mph my tach reads 2750-2800. 70 mph is about 3k. My'94 is fully armored and I tow a squaredrop off road trailer. 5.29's are the better choice for 35's off road for power. About the only negative thing that I've heard about 5.29's is the pinion is at the minimum for strength due to the smaller number of teeth needed for the gear ratio (smaller gear has less "beef" for structural strength). There has been breakage reported in extreme events, so care with your right foot would be advised. If you're getting into your diffs like I was, to install e-lockers, it's the perfect time to do it. But if you're not opening up your diffs, you might consider changing your gearing in your transfer case (center diff) instead. This page on Cruiser Outfitters website is an excellent choice for parts for T/C. You'll need to do some scrolling to get there and I would talk to them for their advice for your best satisfation, if you choose to go that way. Look for the Land Cruiser Transfer Case Low Range Gear Sets section about 2/3rds of the way down.

 

[SmokingRocks]

So I hear what your saying ^ but not sure I agree.

ive been running stock gears at altitude since 2015 on 35’s. Many over the pass trips (11,000ft) towing and not towing, always been able to hold 65mph+ at the toughest parts

now I’m about to put my 4.88’s in because I’ve wanted to for a long time. But if the rig has been fine on 4.10’s hauling its 7k lbs ass around at altitude 4.88’s should be just fine.

I also have the transfer case gear. Which I think is absolutely necessary regardless of your diff gearing. Really gives you best of both worlds.

 

[bnh032]

$100 for a plug and play speedometer correction and the shift point issues disappear

This works on a 92’ HDJ81?

 

[MoJ]

This works on a 92’ HDJ81?

I would think so but you should ask Yellowbox or see if it’s mentioned on their website.

 

[eurorom]

4.88 for 35’s is appropriate. I have 5.29 for 37” tires and it works for daily driving and mountains. 5.29 with 35’s will be 3,000+rpm going down highway.

I just did some testing today, on stock gears and 35"s I am at 2900 rpm with out the Overdrive engaged at 70mph . So what is the benefit on changing gears if I only want to keep my speed up?

 

[OffRoadScott]

Do you at any time plan on doing the underdrive/overdrive gears in the transfer case? If you do I would recommend staying with the factory gears or if you are thinking about stepping up to 37s since they are the new 35.

If you do the transfer case high range gears it will essentially feel like you do 4.56 gears with just the transfer case done, if you install 4.56 gears in the 3rds with the high range gears you are essentially at 5.016, 4.56 x 1.10 yields the 5.016

"These gears offer a 10% underdrive in high range, equivalent to converting axle gears from the 4.10 to 4.56 gears without having to do ring & pinion work." from Cruiser TEQ website

Transfer case gear

In the past there have been posts about 5.29 sheering the gears due to the lack of metal, I am sure the ones that did grenade were being abused pretty good. So if that is the case a 4.56 would be better due to more material on the ring, you can also have the ring/pinon polished.

 

[philip g]

Do you at any time plan on doing the underdrive/overdrive gears in the transfer case? If you do I would recommend staying with the factory gears or if you are thinking about stepping up to 37s since they are the new 35.

If you do the transfer case high range gears it will essentially feel like you do 4.56 gears with just the transfer case done, if you install 4.56 gears in the 3rds with the high range gears you are essentially at 5.016, 4.56 x 1.10 yields the 5.016

"These gears offer a 10% underdrive in high range, equivalent to converting axle gears from the 4.10 to 4.56 gears without having to do ring & pinion work." from Cruiser TEQ website

Transfer case gear

In the past there have been posts about 5.29 sheering the gears due to the lack of metal, I am sure the ones that did grenade were being abused pretty good. So if that is the case a 4.56 would be better due to more material on the ring, you can also have the ring/pinon polished.

How fortuitous this has come up. I've been thinking about my path forward.

With the factory gears and a 10% underdrive set, could a guy run 35's? Seems like 4.56 is a little high. I'm at altitude in Colorado so it sounds like I could use a bit lower gearing than stock even on stock size tires? Maybe I should do the u/d gears then go to 33" and see how I like it?

Edits: typos

 

[OffRoadScott]

How fortuitous this has come up. I've been thinking about my path forward.

With the factory gears and a 10% underdrive set, could a guy run 35's? Seems like 4.56 is a little high. I'm at altitude in Colorado so it sounds like I could use aittme lower gearing that stock even on stock size tires?

You should be fine. A friend of mine has 4.88 with 37s and it is heavy and it feels great driving his 80.

My 80 with stock 4.10 and 315 (34.6) tires is always looking for gears and I am in the gas more to keep it up to speed.

Depending on the actual tire you are planning on going with IE 315/75-16 or a 35x11.5x17 you are looking at an overall size increase of 10-12% in tire size.

Using the gear ratio calculator on tiresize.com Gear Ratio Calculator going from the stock 275/70-16 to a 315/75-16 it says you will need to run at least a 4.56 to get back to equivalent factory ratio.

 

[philip g]

You should be fine. A friend of mine has 4.88 with 37s and it is heavy and it feels great driving his 80.

My 80 with stock 4.10 and 315 (34.6) tires is always looking for gears and I am in the gas more to keep it up to speed.

Depending on the actual tire you are planning on going with IE 315/75-16 or a 35x11.5x17 you are looking at an overall size increase of 10-12% in tire size.

Using the gear ratio calculator on tiresize.com Gear Ratio Calculator going from the stock 275/70-16 to a 315/75-16 it says you will need to run at least a 4.56 to get back to equivalent factory ratio.

Thanks for the input. Gearing decisions are always vexing.

 

[Squeegee]

After going through it. I try to just think of it as what gearing puts me in the power band at my desired highway speed, for the biggest tire I’d want. 4.88s for 35s is great, it’s happy in the power band at 80. But now that I’m wanting to go to 37s I’m now thinking about the under drive gears or regearing to 5.29. I’d be nice if I just geared it to the hilt and was done the first time.

 

[Marco Lau]

i am running 37s and 488 for the past few years and just had my TC re-gear - high and low range underdrive and gone part time. No more front vibes going above 70 and now my MPG has improved since i no longer need to drop down to 3rd. on slight inclines. I am just shy of 3k @ 70mph
on Dirt, i can stay on 4Lo on Drive and it will walk over any obstacles without kicking down to 3rd or 2nd..

 

[richmondbob]

I would not do 5.29's with 35's if you plan to do much freeway driving. RPMs will be much higher than you want for just cruising. One other thing to consider is that the shift points change if you have gears that aren't matched to the tire size. 4.56 gears are the closest match for 35's. I have 4.88's with 35's and it drove well but the shift points and speedo were off. If you think you might possibly step up to 37's at some point, 4.88's are a perfect match for 37's. I get 37's just over a year ago and the truck feels even better than it did with the 35's and guess what? Shift points and speedo are accurate again.

If your 80 will primarily be a trail rig, then 5.29s might be ok. Personally, I'd do 4.88's and if you felt like you wanted something lower for the trails, then get the low range t-case gear upgrade.

I went with 4.88s since I'd done the same in my Jeep YJ on 35s (also an inline 6). Just as with the Jeep, going 4.88s was preferable for my driving preferences and location. That said, you're right on the shift points and speedo for anyone else reading this. Shift points haven't been much of an issue since it's mostly just above sea-level and flat around here. Speedo being off is the one I pay attention to since over 50 MPH is where it reads less accurately.

$100 for a plug and play speedometer correction and the shift point issues disappear

Good reminder. Looked up Yellowbox and will likely order (Official home page of the Yellow Box Speedo Recalibrator - https://www.yellr.com/).

So I hear what your saying ^ but not sure I agree.

ive been running stock gears at altitude since 2015 on 35’s. Many over the pass trips (11,000ft) towing and not towing, always been able to hold 65mph+ at the toughest parts

now I’m about to put my 4.88’s in because I’ve wanted to for a long time. But if the rig has been fine on 4.10’s hauling its 7k lbs ass around at altitude 4.88’s should be just fine.

I also have the transfer case gear. Which I think is absolutely necessary regardless of your diff gearing. Really gives you best of both worlds.

What transfer case gear did you go with? I'm looking to lower the RPMs at highway speeds. Running about 2,600-2,900 RPMs at 65-70 MPH. Doesn't help that the Yukon gears scream like a bloody banshee. Nitro Gears installed at a different shop may be on the horizon.

 

[SmokingRocks]

I have the trail gear 3.11 low range gear, it's been great. I did not change my high range though.

 

[LC4LIFE]

I am running 35's with the 10% underdrive in the transfer case netting me basically 4.56's. It drives great all over Colorado until I hook up the trailer, then I want gears and forced induction

The low-range underdrive is simply awesome too.

 

[stokesdead]

I went with 4.88s with e lockers riding on 315's and I am very satisfied with the ride. I do occasionally pull a couple large 4wheelers on a 14' single axle and it does well. I doubt I will ever step up to 37's but if I do I think I still have a bit of gearing left in the 4.88's to pull it off.

 

[COYS]

I run 315/75/16 with 5.29's and at 65 mph my tach reads 2750-2800. 70 mph is about 3k.

That sounds miserable for any USA road trip. You're getting smoked by semi-trucks on the regular. The hwy NVH would wear anyone down.

Toyota got it right with the stock gearing and tires. Quality AT/MT 37s and 4.88s is the sweet spot imho.

 

[Squeegee]

That sounds miserable for any USA road trip. You're getting smoked by semi-trucks on the regular. The hwy NVH would wear anyone down.

Toyota got it right with the stock gearing and tires. Quality AT/MT 37s and 4.88s is the sweet spot imho.

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I think that sounds great It’s right in the middle of the power and at 75. I feel like mine needs more gearing. 80s are way to slow

 

[COYS]

I think that sounds great It’s right in the middle of the power and at 75. I feel like mine needs more gearing. 80s are way to slow

What power? Make up your mind. jk

If you don't wanna get buzzed by semis, you need to be pushing at least 75mph to which you're going to be in excess of 3K RPM when veering outside of stock ratios. That's a shtty driving experience in my book. I had 35s on 4.88s. Never felt right and I'd sell my dialed in 80 than go back to it.

Mine keeps up great with modern day traffic.

 

[80t0ylc]

What power? Make up your mind. jk

If you don't wanna get buzzed by semis, you need to be pushing at least 75mph to which you're going to be in excess of 3K RPM when veering outside of stock ratios. That's a shtty driving experience in my book. I had 35s on 4.88s. Never felt right and I'd sell my dialed in 80 than go back to it.

Mine keeps up great with modern day traffic.

Some people don't spend that much time on freeways - by choice. My gearing choice is more for other things which by your previous posts - you just wouldn't understand. Anyway, yes towing my trailer and on hills in general - I'm an easy target to pass. But my 80 is running sweet IMHO. Not too many pass me when I'm in my X5, on any road.

 

[COYS]

Some people don't spend that much time on freeways - by choice. My gearing choice is more for other things which by your previous posts - you just wouldn't understand. Anyway, yes towing my trailer and on hills in general - I'm an easy target to pass. But my 80 is running sweet IMHO. Not too many pass me when I'm in my X5, on any road.

And by choice, if I had to tow, an 80 wouldn't be it.