Problems With Re-gearing (1 Viewer)

[nicopodaca]

So my 87 Hilux straight axle, 22R, 5-speed, is on a 3 inch lift with 33x12.50.15 mud terrains. I still have the stock 4.10 gears in the axles. I wanna re-gear to pick up the power I lost with the tires. I've been doing research and I need 4.88 gears to bring it back to "stock" feel. If I can I'd like to take the plunge to 5.29 gears. I talked to one of my local 4x4 mechanics and he said that if I go to 5.29's and even 4.88's that I'll run a high risk of breaking axle shafts. Is this true? I'm fairly mechanically inclined but no too much, so explain in detail. Thanks!

 

[Mudder]

You're more likely to break them by going to larger tires then regearing.

 

[nicopodaca]

You're more likely to break them by going to larger tires then regearing.

So then would the combination of the tires and lower gear ratio just make for trouble?

 

[Mudder]

nah, I know kids with 5.29's and 39.5's and they seem to just break gears. If you're careful on the skinny pedal when off roading you'll be fine.

 

[Toast]

Low gearing isn't going to cause you to break axles. Like mudder said, larger tires will do that but 33s? Forget it! Your not going to break anything as long as your nice when off road. Gearing alters the speed and torque at which your axle spins. Going off your mechanics logic, you would you break axles with 5.29s and 28s but not 4.10s with 33s. It's the large tire that the axle has to try and turn that puts stress on it. A good friend of mine runs 33x12.5s with 5.29s, highly recommended. He's never had an issue and wheels his runner fairly hard with stock axles.

 

[SimplyTanner]

I ran my stock 4.10 gears for years of VERY HARD wheeling with 33s and then 36s. I eventually swapped to 5.29s and I wonder how I went so many years on 4.10s! Somehow I have NEVER broken my stock '83 axles . Just like Mudder and Toast said... It's all about driving wisely and being nice to your junk! Everytime I've seen a birf or axle break it's due to poor driving. Hard on the gas and stuffed into a rock.

 

[Kris]

I understand where your mechanic is coming from. From a conceptual standpoint, by re-gearing, you are gaining a mechanical advantage and will be placing a slighting larger load on axles and running gear. However, your only other option would be to increase the power of your engine - which, in my opinion, would be more harmful to running gear than running a lower gear ratio. That or sell your truck and get a car.

This is completely excluding the fact that your clutch will thank you with every shift once you replace your gears.

As said previously, there are people running much more powerful engines, with lower gears (think dual x-fers) and much larger tires.

I had an 87 x-cab with 33's and it was a DOG! I was seriously considering re-gearing around the time I sold it.

Short-story-long, don't worry about it.

 

[Mudder]

Here's the other way to look at it. If thing were able to break more easily then why did Toyota use 4.88's in some of their vehicles?

 

[RufusTheDufus]

I'm considering re-gearing my 84 Hilux. I never plan to run larger than 33s. Is a 4.88 the optimum from other's experience?

I'm considering going to a high pinion front diff at the same time. (out of a later Land Cruiser). I wonder if the drive shaft length changes going from stock to high pinion? I suppose a quick search would help.

 

[pappy]

I'm considering re-gearing my 84 Hilux. I never plan to run larger than 33s. Is a 4.88 the optimum from other's experience?

I'm considering going to a high pinion front diff at the same time. (out of a later Land Cruiser). I wonder if the drive shaft length changes going from stock to high pinion? I suppose a quick search would help.

I've run 4.88 with 33's, and currently run 4.56 with 33's. It all comes down to personal preference. With the 4.88 I found the highway rpm way too high. My engine is stronger than stock, so I can get by with the 4.56 gearing. Plus, I have a R151F with the lower first gear that makes it easier at stop lights.

 

[Kris]

There are all kinds of gear ratio calculators on the internet. Find one that asks what ring and pinion ratio you wish to run, what transmission/transfercase ratio and what size tire and solves for what rpm your motor will have to turn at a given speed or vice versa; depending on what you want to know.

This will be able to show you your crawl ratio/speed (1st gear + 4-low) as well as a highway ratio/speed (5th gear + 2-high).

 

[Mudder]

Here's my favourite one to use
Ring & Pinion | Marlin Crawler, Inc.

 

[KLF]

I run 285/75R16 Duratracs which the specs say are 33.1", and 4.88 gears, and it's perfect. I checked both my speedo and odometer with an app on my phone just the other day and I was actually surprised how close it was. I drove about 60 miles, and it was only off by 0.3 miles, which is within 0.5%, not bad at all.

I put a hi-pinion FZJ-80 e-locker in my '84 and the stock driveshaft was fine (with OME springs). When I did the SAS on my '87 and moved the axle over, I did have the driveshaft lengthened just a little, but that was because I have the axle mounted ~1.25" forward to keep the tire from hitting the back of the fender.

 

[Toast]

I've run 4.88 with 33's, and currently run 4.56 with 33's. It all comes down to personal preference. With the 4.88 I found the highway rpm way too high. My engine is stronger than stock, so I can get by with the 4.56 gearing. Plus, I have a R151F with the lower first gear that makes it easier at stop lights.

Pappy, I currently have 4.56 with 31's but thinking of going to 33's. How do you like your current gear to tire ratio? Also about how many ponies are you pushing out of your 22re?

 

[pappy]

No idea how much power my engine makes. It is certainly better than the stock engines I've driven. As far as the gearing, try it. I ran 4.10 and 32" tires for over a decade. I didn't regear until I went to 33's.

 

[RufusTheDufus]

The hard part (for me at least) about the gearing calculators is that they don't really tell you how much torque the engine needs to produce to be able to sustain a particular speed. At the moment the normally aspirated 2L in my Hilux, with 33s can maintain 65 MPH on flat ground with no headwind. The slightest headwind or incline and I'm downshifting.

I think maybe I should look at the calculators from a perspective of RPM drop/difference between gears at a particular speed The RPM drop from 4th to 5th gear moves the engine out of its peak torque range to I have to carry 4th for longer than normal to be able to use 5th and then only on flat ground.

 

[MatS]

I don't have any flat ground around me and in my Hilux with the 2L. I've running 33s also but 12.5s instead of your skinnys, speedo on the highway is comfortable at 100km/h but that's without correction, I'm more comfortable running the truck at 80km/h for a long period. Stock gears at 4.56, just all depends on what RPM you feel comfortable running. I agree with you though the 4th to 5th gear is a steep jump although I've never looked into the actual numbers because... it just is what it is haha.

 

[RufusTheDufus]

The stock gear is a 4.56? I'll have to check mine.

 

[Mudder]

Toyota's did come stock with 4.56's. Had a set in my 89 22re with auto trans and 31's.

 

[ntsqd]

FWIW my '84 came to me with 4.88's (& 31's, go figure.... ). I run 33-10.50's on it. Speedo is uncorrected and my GPS says it's really close to correct up to as fast as I will ever want to go in the truck. I've never felt like I needed 5.29's, but I don't do extreme rock crawling. I have, on occasion, wished for more low range, but not often enough to actually finish the remotely shifted Marlin Crawler & put it in the truck.

Just had to replace the rear diff, barely got it broken in, only ~100,000 miles on it! Would have gone a lot further I'd guess, but the RR wheel bearing Brinnelled the mating surface on the axle and the resulting wobble caused the side 'gear' in the Detroit to eat into the case bushing, which put metal thru the whole housing.