Going big, 4.88 or 5.29 gears

[FJnAK]

Well, I just went out and ordered my lift and tires, J springs L shocks and spacers, I will probably order a 1" body lift also. I had some money left so I ordered 37x14 Super Swamper Iroks. Now I'm wondering if I can get by running them with stock gears for a few months (off road only) until I can get gears. I need to know if 4.88 or 5.29 are the right gears. I have some 35" BFG All Terrains for street use. What do you all run for gearing with large tires?

 

[MTNRAT]

4.88 will bring you back to about stock. 5.29 will give lower for offroad and better towing.

 

[Nay]

5.29 is a no brainer unless you will also have a crawler.

 

[Skim]

Whoz got a crawler ?

 

[Nay]

Whoz got a crawler ?

Marks (from Oz). Requires some serious mods, though, to make it fit.

 

[PKP80]

5.29 is a no brainer unless you will also have a crawler.

IF you plan on going bigger that 37's and not doing a lot of highway in the mean time in the truck I would go 5.29.

If the idea is to throw on the 37's for the trail and run around town on the 35's daily then you want to go 4.88.

Marks (from Oz). Requires some serious mods, though, to make it fit.

All you really NEED is a body lift and some patience....take the money out of the equation and it's a cinch. I'll show you just how easy it is if you'd care to donate the crawl box$$$

 

[FJnAK]

Are there any problems with 5.29's being weak?
I'm going to be running 35's most of the time, but when its off road it will be lots of hills and mud. I'm leaning toward 5.29's just for the extra Ummph.

 

[Nay]

Are there any problems with 5.29's being weak?
I'm going to be running 35's most of the time, but when its off road it will be lots of hills and mud. I'm leaning toward 5.29's just for the extra Ummph.

Slee has said on a number of occasions he hasn't seen issues with 5.29's in the 80. It's always kind of a strange issue to me to think the next step up in gears is suddenly going to put yourself at great risk of blowing your ring and pinion. If you leave yourself undergeared and have to compensate for throttle you are much more likely to shock load the system and bust something. Breakage rarely happens in a slow and controlled environment unless it is a failure based on years of stress, and that's more like an axle issue than a R&P issue.

To put it another way, all the data I've ever seen suggests your birf is going to go long before your R&P whether you are on 4.88 or 5.29.

To gauge 5.29's on your 35's for highway use, turn off overdrive with your stock 4.10's and you'll get a good sense of 5.29's. Think in the range of 3,000 RPM @ 70 mph. If you need to drive faster, which seems pretty contrary to a build for 37's, then 4.88's are the choice.

 

[sleeoffroad]

Slee has said on a number of occasions he hasn't seen issues with 5.29's in the 80. It's always kind of a strange issue to me to think the next step up in gears is suddenly going to put yourself at great risk of blowing your ring and pinion. If you leave yourself undergeared and have to compensate for throttle you are much more likely to shock load the system and bust something. Breakage rarely happens in a slow and controlled environment unless it is a failure based on years of stress, and that's more like an axle issue than a R&P issue.

There is another part of this ring and pinion issue that gets overlooked a lot and could be the cause for people not comparing apples to apples when speaking about R&P on different vehicles.

The 80 has very little to no axle wrap. Leaf sprung trucks do. I believe axle wrap is what causes a lot of breakages on pinions on Toyota diffs. People then extrapolate that the 5.29 is weak in a Toyota application, and they compare pickups and 4Runners to 80's.

i have broken Toyota Genuine OE 4.88's in the front - reason backing up with lockers on trying to pull a old guy's van out of a snow drift.

I now broke 5.29 gears in the Shortbus - Why? backing up pulling a Tacoma with a broken input shaft up a ledge.

See that common part, me being stupid or helpfull, take your pick

 

[jon@svwbarchitects.c]

I would put the 5.29 in it will make off road nicer with little impact on the road. As for crawler boxes, Slee sales the Mark's box, Advanced Adapters is working on one and Marlin is trying to fit into the schedule.

 

[SR.GRINGO]

I run 4.88's with 35's. I thought running 37's would put you back to stock? Anyhow for me the cruiser is much faster off the line now. The fastest I ever run is 80--hardly ever--the cruiser is turning around 3k. 70 is much more comfy. As far as climbing she has plenty of oomph.......trust me

 

[Nay]

I run 4.88's with 35's. I thought running 37's would put you back to stock? Anyhow for me the cruiser is much faster off the line now. The fastest I ever run is 80--hardly ever--the cruiser is turning around 3k. 70 is much more comfy. As far as climbing she has plenty of oomph.......trust me

Good point about spring wrap - another check in favor of the 80 front end design that helps offset the "issue" of limited flex.

4.88's are the "back to stock" ratio for 35's, but nothing goes back to stock when you are running 37's. I figure if you really need 37's, i.e. 35's are too small, then crawl ratio gearing is one of the absolute most important factors in your build.

We talk all day long about lockers this and lockers that...low gearing is, IMO, equally if not more important. Or perhaps better said, you really can't maximize one without the other. I have to rely heavily on my lockers to wheel with 35's and 4.10's at my elevation. Which is ok, but hardly optimal.

I'd love to have 5.29's and some sort of low range reduction. My rig runs wonderfully @ 3,000 RPM @ 70 mph. Perfectly in the power band. Waiting to see what Slee/Marlin/AA have coming to market before making any decisions on regearing the diffs, but it will be 5.29 if I do it.

 

[FJnAK]

I'm still leaning toward the 5.29's, I will be running a lot of mud with a true 37" tire. I only run the highway for 8 miles each way to work and back, and even then I don't go above 70 mph. I'm thinking about leaving the Swampers on for the Summer, so the lower gears would be better.

 

[alkaline747trio]

I'd go 5.29s, everyone needs to slow down anyways.

 

[Skim]

I have 315s now and plan to go to 4.88s.

If I was considering 37s (and I am) I'd go 5.29s.

Who needs to go past 70 MPH on 37s anyway.

 

[Letsgomoreplaces]

5.29 and 37's

I would go 5.29 w/ 37's. You probably wont be able to do it until may though. over 70 mph wont be a prob. just dont pull people out in reverse like Christo.

 

[Dusty]

skim makes a good point. 37's will never ballance well and most wont be going past 60mph on tires that size. but tcase gears would still be better cause if im dd the truck the 37's will be for wheeling only.

 

[Taz]

I've had 37's with the 5.29s for over a year now and it works great...even at 85 on the freeway I drove it to Moab last year from So Cal and had no regrets!
As far as the 5.29s being weeker I think Christo's experiences tell alot. I would do it again even if (when) I do break them.