Tire size for my 1995 diesel 5 sp LC 80 (1 Viewer)

[NuchatlitzRod]

I'm new on the forum and just purchased a diesel 5 sp 80 series (LHD). It has 31's on it with a 2" OME lift. I know 33's should fit easily and maybe even 35's but if I go with 35's should I consider changing gearing in the transfer case or differential. If none of this makes sense that's what someone told me I should do, I'm not much of a gear head. Does anyone know if the gearing in a diesel with a manual transmission is different than in an automatic?

 

[scottryana]

What is your intended purpose? Are you going to take it off-road where you would likely want lower gears? Are you just driving it to the mall? Are you going to load it heavy or pull a trailer?

90% of people could get away with 33's and stock gears.

 

[baldilocks]

Welcome to mud. Any time we post tech questions it’s good to also include year of the vehicle and any other pertinent details that will help other members lead you in the correct direction and don’t forget the mandatory pic or two of your rig. We like pictures.

This subject was being discussed in another thread yesterday and the day before with questions by a member in Europe who owns an HdJ with 1hd-t and R-151. He said his gear ratio is 3.73 so I would assume yours is as well. You can find this info on the sticker in the drivers door jam I believe. Be ready to read many opinions on how to gear your 80 for a given tire size. This is why it is important for you to be clear on what your end goal is for your vehicles use and perfomance needs.

 

[NuchatlitzRod]

What is your intended purpose? Are you going to take it off-road where you would likely want lower gears? Are you just driving it to the mall? Are you going to load it heavy or pull a trailer?

90% of people could get away with 33's and stock gears.

I will using the vehicle almost entirely for off-roading, mostly in Washington and British Columbia to explore and fish. Most of the roads will be active or retired logging roads and some of them can get a little hairy. Washouts and slides are frequent.

It will be loaded up heavy but I won't be pulling a trailer but I do have a boat that I would occasionly trailer but on decent roads.
I agree that the 33's will likely be all I need but 35's do look awesome. I wondered about compromising with 295 x 75 x 16's, don't see much about that size of tires being discussed.

 

[leonard_nemoy]

Considering where and how you plan on using the rig than I would recommend a regear.

 

[MUDZLLA]

Check your axle code. I think HDJ-81s are 4:10... You can use stock gears and run 35's if its an automatic, but you'll prematurely wear out clutches with your 5spd standard.

 

[mudgudgeon]

I will using the vehicle almost entirely for off-roading, mostly in Washington and British Columbia to explore and fish. Most of the roads will be active or retired logging roads and some of them can get a little hairy. Washouts and slides are frequent.

It will be loaded up heavy but I won't be pulling a trailer but I do have a boat that I would occasionly trailer but on decent roads.
I agree that the 33's will likely be all I need but 35's do look awesome. I wondered about compromising with 295 x 75 x 16's, don't see much about that size of tires being discussed.

35s will fit with your lift.

You're splitting hairs going for 295s.

In Australia they aren't a common size, so replacing a damaged tire can be problematic. Don't know if that's true where you are going to be travelling.

I've had a hdj81 5 speed, and had 35s on it. With standard gearing, crawling over rocky trail in steep country can be hard on the clutch.
The hdj81 5 speed has a high first gear ratio. That combined with 35" tires reduces the torque at the wheels.
On road, the gearing is fine. Off-road, low speed crawling, you've often not got any turbo boost, and the engine can lack power and torque. This means you will be needing to work the clutch to navigate obstacles.

I'd say definitely re- gear if you go over 33" tires size.
Do some searching and read up about re-gearing transfer case with low range reduction gears

 

[NuchatlitzRod]

35s will fit with your lift.

You're splitting hairs going for 295s.

In Australia they aren't a common size, so replacing a damaged tire can be problematic. Don't know if that's true where you are going to be travelling.

I've had a hdj81 5 speed, and had 35s on it. With standard gearing, crawling over rocky trail in steep country can be hard on the clutch.
The hdj81 5 speed has a high first gear ratio. That combined with 35" tires reduces the torque at the wheels.
On road, the gearing is fine. Off-road, low speed crawling, you've often not got any turbo boost, and the engine can lack power and torque. This means you will be needing to work the clutch to navigate obstacles.

I'd say definitely re- gear if you go over 33" tires size.
Do some searching and read up about re-gearing transfer case with low range reduction gears

Thanks for all that information. Looks like I have a little homework to do. I think I made my decision for the near future at least. I will go with 33's as I need to drive the truck from Texas to Washington state next month. I'll spend a few weeks doing that and exploring some of the great off road venues along the way. I must say you guys have been great and this website and forum is very helpful

 

[mudgudgeon]

Thanks for all that information. Looks like I have a little homework to do. I think I made my decision for the near future at least. I will go with 33's as I need to drive the truck from Texas to Washington state next month. I'll spend a few weeks doing that and exploring some of the great off road venues along the way. I must say you guys have been great and this website and forum is very helpful

33s will take you a load of places in a locked cruiser.

I think 2" lift, 33s, and lockers is the sweet spot for these rigs
Good road manners
Stable off-road
Gearing is ok as is
Should be no driveline issue
No clearance issues

Will need ( but can get away without)
caster correction
Sway bar extensions
Brake line extensions

 

[baldilocks]

33s will take you a load of places in a locked cruiser.

I think 2" lift, 33s, and lockers is the sweet spot for these rigs
Good road manners
Stable off-road
Gearing is ok as is
Should be no driveline issue
No clearance issues

Will need ( but can get away without)
caster correction
Sway bar extensions
Brake line extensions

Some say this about 35’s and some about 37’s. We all have our comfort zone. As a resident of WA State like the OP, I have run many miles of retired, old logging roads in the Gifford Pinchot Nat’l forest. They get very grown in with fallen trees across the track and sometime big ones. Bigger obstacles require bigger equipment. 37’s

 

[gilmorneau]

You might first want to confirm which ratio axles you currently have. Look at the VIN tag on the firewall in the engine compartment. There will be codes on there for axle ratio. If you have differential locks, it’ll likely be K294 (4.100), K304 (3.727), or K374 (3.583). Open diffs would be the same but end in a 2 instead of 4. Diesel 80’s were available with all these options.

With 4.100 axles, I wouldn’t go any smaller than 32-33” tires. With 3.583 axles, I wouldn’t go any larger than that. You can interpolate from there depending on what you have and your tire preference.

 

[scottryana]

deleted

 

[ozarkmud]

There's a lot of drawbacks to bigger tires. If you're doing a lot of gravel roads, you might prefer the ride of 31"s to 35"s.

They look nice though, and clearly even the 37" can have some serious uses. But road manners will suffer, along with mileage.

As for the diesel and gearing, I have no personal experience. But taller tires do get you a faster crawl speed, but I know from experience can be bad.

 

[mudgudgeon]

Some say this about 35’s and some about 37’s. We all have our comfort zone. As a resident of WA State like the OP, I have run many miles of retired, old logging roads in the Gifford Pinchot Nat’l forest. They get very grown in with fallen trees across the track and sometime big ones. Bigger obstacles require bigger equipment. 37’sView attachment 3297544View attachment 3297545View attachment 3297547

I guess so. Everything can be subjective.

The further you stay from factory specs, the more the original performance and handling are altered.

 

[DivByZero]

Some say this about 35’s and some about 37’s. We all have our comfort zone. As a resident of WA State like the OP, I have run many miles of retired, old logging roads in the Gifford Pinchot Nat’l forest. They get very grown in with fallen trees across the track and sometime big ones. Bigger obstacles require bigger equipment. 37’sView attachment 3297544View attachment 3297545View attachment 3297547

Damn, not too many trees like that around here! I've gotta say though, that's where I'd break out the chainsaw and use the winch to drag the cut piece out of the way.

Or if you're bored/drunk/borrowing someone else's car, build a ramp and dukes of hazzard it?

 

[baldilocks]

Damn, not too many trees like that around here! I've gotta say though, that's where I'd break out the chainsaw and use the winch to drag the cut piece out of the way.

Or if you're bored/drunk/borrowing someone else's car, build a ramp and dukes of hazzard it?

I always have the chain saw with me when I go up there but that log was too big for my MS250. Was quicker to winch over it.

 

[NuchatlitzRod]

I always have the chain saw with me when I go up there but that log was too big for my MS250. Was quicker to winch over it.

Yeah, chain saw and winch definitely come in handy up here in the NW when off road. Not sure I'd have the guts to crawl over that large fir.

Thanks for the info on gearing and axle ratios

 

[baldilocks]

Yeah, chain saw and winch definitely come in handy up here in the NW when off road. Not sure I'd have the guts to crawl over that large fir.

Thanks for the info on gearing and axle ratios

Although your stated purpose for your 80 is mostly off-road, which is mine also, you will travel many more miles of paved road getting to your off road routes than you will travel off road. I have begrudgingly kept this in mind as my rig has evolved over the years in an attempt to strike a balance.