Builds 1996 HZJ75 Land Cruiser Pickup (1 Viewer)

[Broski]

I'm thinking that the bigger tires ( rubber overdrive ) would work really well with the Lockers that you are planing to install.
And if you don't have to buy those gears that money can go to buying the the new tires, and I'm sure you can sell your current ones

I can remember trying to explane to my wife that I needed to replace my new 35s for 37s because the guys on 37s were digging 37" hole at every obstacle and making it hard for me on 35s

 

[Will Van]

I'm thinking that the bigger tires ( rubber overdrive ) would work really well with the Lockers that you are planing to install.
And if you don't have to buy those gears that money can go to buying the the new tires, and I'm sure you can sell your current ones

I can remember trying to explane to my wife that I needed to replace my new 35s for 37s because the guys on 37s were digging 37" hole at every obstacle and making it hard for me on 35s

Except I already have the 3.7 gears. They’re paid for. I may need some inexpensive install components, but after that, it’s just my sweat-equity. Lockers and tires can wait.


Either way, I need to wrap up my A/C and interior work and just drive the truck!

 

[shafferandy]

Yes, you do! Summer is here!

 

[FJBen]

All tires have a recommended rim width for install. Most shops don’t care. They’ll put whatever size tire on whatever size wheel you have, assuming it will actually fit.

But the national tire shops are more picky due to liability.

For example, my OEM Toyota steel wheels are 16” diameter x 6” width. The recommended rim width range on a 255/85/16 BGF Mud Terrain is 6.5” to 8” rim width. The majority of tire shops wouldn’t blink an eye, they would just install the 255 tire on the 6” wide wheel.

However, it is likely that Discount Tire (or Costco, or NTB, or whatever national chain) would refuse to install the 255, because the tire width is 1/2” out of spec. Silly, I know.

But again, I didn’t want to be stranded in a situation where I needed a replacement tire mounted on my 6” wide wheels, and the only available shop was a national chain that refused because it was outside of spec.

So I went with the 235/85/16 tires because they are much more common and cheaper (and the recommended rim width range is within spec at 6” to 7.5”).

None of this really matters though, because I have a brand new set of 235/85/16 tires on my truck right now. And my wife would murder me if I showed up with a set of new tires.

I have discount tire rotate and deal with my 255/85/16 all the time. They just repaired a nail in my tire, pulled it off, patched and mounted again, zero questions asked.

I find if you have a cool vehicle, they tend to not worry at all especially something as small as that. Now if you were mounting a big ol 12.50 they might not do that.

 

[Will Van]

I have discount tire rotate and deal with my 255/85/16 all the time. They just repaired a nail in my tire, pulled it off, patched and mounted again, zero questions asked.

I find if you have a cool vehicle, they tend to not worry at all especially something as small as that. Now if you were mounting a big ol 12.50 they might not do that.

Yes, some locations don’t care. And some locations are sticklers about it.

I didn’t want to be at the mercy of the manager on duty.

 

[FJ73Texas]

I have discount tire rotate and deal with my 255/85/16 all the time. They just repaired a nail in my tire, pulled it off, patched and mounted again, zero questions asked.

I find if you have a cool vehicle, they tend to not worry at all especially something as small as that. Now if you were mounting a big ol 12.50 they might not do that.

Like I said....it depends on the manager (in the case of DTC) and also how strict the district and regional manager is but 255 isn't a wild and crazy combo in the case of the OP of this thread. I am not keeping up on what is currently allowed and is not either since I don't work in the retail tire replacement market anymore and haven't for a long time.

Trust me...I saw some crazy requests during my time there we clearly had to say no to.

 

[roma042987]

I've regretted every 3.70 gear install I have done. I think it has been three now. I have 255 85 16s on my 12ht powered fj60 and it's not great with the 3.70s. problem is that the 3.70s are freshly rebuilt cable locked axles so I'm not going to regear now. I'll just step down to the 235's you currently have. I have the same wheels also. I like what you've done to your truck and as you can see I'm a fan of the beige Saudi spec cruisers

 

[Broski]

I've regretted every 3.70 gear install I have done. I think it has been three now. I have 255 85 16s on my 12ht powered fj60 and it's not great with the 3.70s. problem is that the 3.70s are freshly rebuilt cable locked axles so I'm not going to regear now. I'll just step down to the 235's you currently have. I have the same wheels also. I like what you've done to your truck and as you can see I'm a fan of the beige Saudi spec cruisers

View attachment 3028438View attachment 3028445

Wow that's a super cool cruiser in the second pic!!! looks to new to be state side ? I want !!!

Sorry for the Hi Jack !!!

 

[Will Van]

I like what you've done to your truck and as you can see I'm a fan of the beige Saudi spec cruisers

Thank you, Roma. I followed your Tucker build and you do outstanding work. The compliment means a lot.


And that 70 series is a beauty!

I've regretted every 3.70 gear install I have done. I think it has been three now. I have 255 85 16s on my 12ht powered fj60 and it's not great with the 3.70s.

Good intel. I'm vacillating on what to do with the tires/gears. But the truck is nearly unbearable to drive on the highway right now with the 4:1 t-case, 235/85/16 tires, and 4.11 diff gears.

problem is that the 3.70s are freshly rebuilt cable locked axles so I'm not going to regear now. I'll just step down to the 235's you currently have.

Wanna just trade? My 235 tires are brand new.

 

[coldtaco]

Why do you say your Ute is unbearable on the hwy? I have 4:11 gears and 235/85/16, @ 65mph rpm’s are at around 2500rpm. I don’t have the HZ but seems like there are plenty of happy HZ drivers with the same setup as yours What speed are you trying to drive? Or what exactly is unbearable? Sorry for my confusion/ignorance

 

[Will Van]

Why do you say your Ute is unbearable on the hwy? I have 4:11 gears and 235/85/16, @ 65mph rpm’s are at around 2500rpm. I don’t have the HZ but seems like there are plenty of happy HZ drivers with the same setup as yours What speed are you trying to drive? Or what exactly is unbearable? Sorry for my confusion/ignorance

It just feels like the engine is screaming. But I should probably hook up a tach before I start making (false) claims.

 

[RHINO]

Everybody in this thread seems to keep missing that he has a 4:1 tcase gearset, which is a 10% underdrive , which makes his 4:11 almost a 4:56

 

[Honger]

Everybody in this thread seems to keep missing that he has a 4:1 tcase gearset, which is a 10% underdrive , which makes his 4:11 almost a 4:56

I'm not missing that fact...

But what I keep not getting is that negating the 4:1 xfer with 3.7 diffs seems redundant. Did you want lower gearing, or not? Do you want a crawler or a cruiser?
Or am I missing some way that changing diffs doesn't uniformly negate the xfer regear?

 

[FJBen]

Everybody in this thread seems to keep missing that he has a 4:1 tcase gearset, which is a 10% underdrive , which makes his 4:11 almost a 4:56

He is probably running around 2700 -2750 rpms with that 10% under drive. 235's usually only measure out in real world to 31.5.

 

[FJBen]

I'm not missing that fact...

But what I keep not getting is that negating the 4:1 xfer with 3.7 diffs seems redundant. Did you want lower gearing, or not? Do you want a crawler or a cruiser?
Or am I missing some way that changing diffs doesn't uniformly negate the xfer regear?

It changes your crawl ratio. However the under drive complicates things little.

H55f x low range x diffs

4.85 x 4. x 4.11 = 79.7:1 crawl ratio
4.85 x 4. x 3.75 = 72.5:1 crawl ratio

Stock:
4.85 x 1.99 x 4.11 = 29.5:1

So the low range isn't a big difference at all between 3.7's and 4.11s. It's a huge difference over stock. That said the under drive makes that diesel rev higher. Most people I believe get the 4 to 1 tcase to help with bigger tires and more crawl control. The 10% helps overcoming the extra unsprung tire weight, diameter.

So if he already has the 3.7's he really isn't losing any noticeable crawl ratio and it is helping the on road performance by dropping those RPM's. With my 255/85r16's I'm running 2350 at 65mph.

 

[RHINO]

I'm not missing that fact...

But what I keep not getting is that negating the 4:1 xfer with 3.7 diffs seems redundant. Did you want lower gearing, or not? Do you want a crawler or a cruiser?
Or am I missing some way that changing diffs doesn't uniformly negate the xfer regear?

4:1 isn't really all that crazy a low range, what he will end up with is slightly lower low range, and slightly taller hi range than Toyota equipped the rig with from the factory.

That's the beauty of the gearset, best of both.

 

[Honger]

It changes your crawl ratio. However the under drive complicates things little.

H55f x low range x diffs

4.85 x 4. x 4.11 = 79.7:1 crawl ratio
4.85 x 4. x 3.75 = 72.5:1 crawl ratio

Stock:
4.85 x 1.99 x 4.11 = 29.5:1

So the low range isn't a big difference at all between 3.7's and 4.11s. It's a huge difference over stock. That said the under drive makes that diesel rev higher. Most people I believe get the 4 to 1 tcase to help with bigger tires and more crawl control. The 10% helps overcoming the extra unsprung tire weight, diameter.

So if he already has the 3.7's he really isn't losing any noticeable crawl ratio and it is helping the on road performance by dropping those RPM's. With my 255/85r16's I'm running 2350 at 65mph.

So it changes your low range xfer and puts an under drive on your high range? But at different ratios?

 

[RHINO]

Yup,,,, 50% low range and 10% high range

I was gonna do that on mine but wanted a deeper underdrive in high range

So I went 4:88 on mine and am happy

 

[Will Van]

But what I keep not getting is that negating the 4:1 xfer with 3.7 diffs seems redundant. Did you want lower gearing, or not? Do you want a crawler or a cruiser?
Or am I missing some way that changing diffs doesn't uniformly negate the xfer regear?

So it changes your low range xfer and puts an under drive on your high range? But at different ratios?

Apologies, I should have explained to everyone more thoroughly.

The original transfer case on my truck was 1:1 High and 2:1 Low. That’s a fairly puny gear ratio for Low range gearing in the t-case.

So I swapped to the 4:1 t-case gears. This effectively doubles (200%) my low speed crawling ability when the t-case is in Low.

But it comes at cost. The 4:1 gears also alter the High ratio of the t-case to 1.1:1 (10% underdrive). This 10% underdrive arguably exacerbates a truck that perhaps wasn’t geared tall enough (in High) to begin with. So my engine is turning very high RPMs on the highway in 5th gear.

By swapping to 3.7 diff gears, I am effectively going back to 1:1 in High for the t-case (the difference between 4.11 and 3.7 diff gears is about 10%). And I’m only sacrificing 10% in Low (and we just doubled low to 4:1, so a 10% loss is no big deal).

As @RHINO mentioned above, after the 4:1 t-case and 3.7 diff gears, I get a better final drive ratio in both scenarios: I get a lower crawl ratio than stock in 1st gear Low t-case AND I get a better highway ratio than stock in 5th gear High t-case.

I will post more hard ratio data later, when I am back at my desk.

 

[svsisu]

Some numbers that I've already sent to Will. I have 4.11 diffs, 4:1 tcase gears and 35" tires. At 66/67 mph I'm turning 2500 RPMs, 70 is about 2600. I would actually prefer the 3.70 gears and be able to run smaller tires at lower/or sameRPMs, but I have too many other fish to fry, so I'll keep what I have for now. Too bad I didn't buy 2 sets of 35" kenda's when they were $130 each. Any one checked the price of 35" rubber overdrives recently

This thread is turning on, got more action than a drum bite at the point!