As the title says, what is in your experiences maximum tyre size before you had to change rations in diffs or tranfer case for HJ60 with 2H engine?
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Maximum tyre size before considering diff ratios changing?
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I have 35's, and 4.11's, with an H41 (4.85 first gear). This works fine. But for my driving, it worked better with 33's. The key is what kind of driving you do. I have a lot of driving in the mountains...lots of long climbs...and with 35's I'm just out side the powerband, where with 33's I was able to manage these passes fine w/out shifting to 3rd. My point being...talk to peeps who have similar needs to what you have, and decide accordingly. Gearing is expensive. Gearing that works for all conditions means wide ratio's...which means expensive. Do you have a 4 speed or 5 speed tranny? Are you willing/able to limit your top speed to whatever your gearing determines? What low gear ratio do you need for the conditions you typically encounter?
...and, I sure wish I had a 2H instead of a 2F.
...and, I sure wish I had a 2H instead of a 2F.
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Well said! After exploring a bit more, I'm leaning towards 33 as well. It's not just gearing, there are clearance / rubbing issues for me. Much bigger investment for 35s than 33s. So far what I heard, shouldn't have problems with standard 5 speed gearbox and 33s.
I have 32x11.5x15 right now and they cope with a heavily loaded HJ-60 on mountain roads.
Have a set 255/85/16 wich are comparable with 33'' and they make the truck a bit slower.
On the other hand, with low road speeds the 255 makes you shift a little less between the first 3 gears
I don't want to go any bigger then those two with standard gearing.
Have a set 255/85/16 wich are comparable with 33'' and they make the truck a bit slower.
On the other hand, with low road speeds the 255 makes you shift a little less between the first 3 gears
I don't want to go any bigger then those two with standard gearing.
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I have a HJ60 with the automatic transmission, 4.11s and 31/10.5/15. No rub, doesn't seem to affect overall "performance" of the truck, but going bigger with that auto trans is a no-go in my case. Should switch ratio or find a manual transmission 
if nothing changes but the tire size...here is what I"ve found to be a good match.
33 inch tires = 4.11
35 inch tires = 4.56 or 4.88 depending on if you drive a lot off-road.
GAS engine.... you probally could go lighter on the gears with oil burner.
33 inch tires = 4.11
35 inch tires = 4.56 or 4.88 depending on if you drive a lot off-road.
GAS engine.... you probally could go lighter on the gears with oil burner.
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I have 37s with 4.11 with a 4bt engine and nv4500 transmission. I'm thinking of going to 3.73 so that I can get a little more speed and slightly better mpg on the highway, but mostly to lower my EGT. The engine is still torquey enough to offroad with if I re-gear. So it all just depends on what you're wanting to do and what your driving will consist of.
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murf
Lifer
I ran 33's on my 1985 FJ60 and felt it was a good trade off. I could run 65-70mph at decent rpms and still have enough spunk to idle through rough terrain. Any larger would require gears in my opinoin.
So what size tires are you running and what's your rear gear ratio?
I've got a 12ht with 3.70 gears. I run 285x75R17 tires (approx 34"). I get great fuel economy, but with a 1000 lb trailer on hills, I kinda wish I had 4:11's. I have a 5 speed, so I've had to train myself to shift down to 4th earlier. Doing 700 km legs straight, keep the 3.70's for the economy. If you are going slower in the bush, looking for torque, maybe taller tires, then you've got to go to 4:11's or lower maybe. I am still on the fence, as I eyeball a new set of ARB's, that I only want to install once! Good luck.
I should add, I've looked at t-case sets, lots of $$, but they would really be the best solution for me. Keep the economy, do a bit of math and figure out which set works best. I guess if money was less of a concern, it would be keep the taller gears, install t-case gear set for the slower going.
i have 35's and stock 60 ratio (3.73?)..... I don't really recommend it but i get good gas mileage and with a light load around town its not bad as long as you don't live near any hills, otherwise I would at least do 4.11's or lower with 35's
1911
chupacabra
Granted it's nit-picking, but FYI the stock ratio is 3.70.
no problem, i invited it.... i couldn't remember hence the ? mark.... on my way to commiting it to memory.
Marks Gearing 3.73
I have '65 FJ45 SWB w/ Marks 3.73 gearing, NV4500, Cummins 3bt which worked great with 31" tires. I then went up to 33" tires for clearance on trails and took a huge hit going up big hills and down to 22-27mpg. Added a fuel intake heater and mpg went back up to 27-31mpg.
I recently decided to go with 35" tires, 5.29 gearing and SOA conversion, as most of my driving is offroad now and not for the Expedition Rig I originally intended it for.
just have to sell my old Marks gearing and 33" tires- wish i would have went to 35's the first time, but as always these rigs are an evolution of wants..
I have '65 FJ45 SWB w/ Marks 3.73 gearing, NV4500, Cummins 3bt which worked great with 31" tires. I then went up to 33" tires for clearance on trails and took a huge hit going up big hills and down to 22-27mpg. Added a fuel intake heater and mpg went back up to 27-31mpg.
I recently decided to go with 35" tires, 5.29 gearing and SOA conversion, as most of my driving is offroad now and not for the Expedition Rig I originally intended it for.
just have to sell my old Marks gearing and 33" tires- wish i would have went to 35's the first time, but as always these rigs are an evolution of wants..
MCJakeCrim - digging through the oldies! I can add an update from this. I have gone the 3.0:1 low range gear set about 3 years ago. Its
been a worthwhile improvement especially off road. This past month I went the next step and stepped down to 4.11's in the axles.
The combination is really perfect. I ran a couple of off trail sections in 2nd and 3rd low, only using 1st low when it was really steep.
On the highway, the lower ratio makes for nicer streetability, just a bit quicker and smoother off lights and much better
coming up to hills. Still running the 285's, in fact just put the second set on.
I had to look this one up because I didn't believe it at first. I've been at this a while but every time I start to feel like a know what I'm about, someone or something humbles me.
TLC FAQ - 9.1 Axle Codes
Glad I took the time to check the data plates on 2 of my Cruisers because I not only did I discover my FJ-60 was 3.70 instead of 3.73, I now know that my HJ-61 came with factory limited slip 4.11.
1911
chupacabra
I had to look this one up because I didn't believe it at first. I've been at this a while but every time I start to feel like a know what I'm about, someone or something humbles me.
TLC FAQ - 9.1 Axle Codes
Glad I took the time to check the data plates on 2 of my Cruisers because I not only did I discover my FJ-60 was 3.70 instead of 3.73, I now know that my HJ-61 came with factory limited slip 4.11.
Most people don't know the difference, since 3.73:1 is a common ratio for American-made trucks. But it's just simple math for Land Cruiser diffs: 37 teeth on the ring gear and 10 teeth on the pinion gear, so 37/10 = 3.70
I turn 42s with 3.73s without much issue 
IT doesn't usually get mentioned, because it's not very sexy and a bit of a killjoy, but I'll bring it up...
Increasing tyre diameter reduces braking performance. When I stepped from 31's to 33's I really noticed the increased effort required to stop the vehicle in the same manner. I prefer 32's instead of 33's for that reason as well as the gearing benefits.
https://www.aamva.org/uploadedFiles...izedTiresOnAlteredHeightVehicles_Findings.pdf
at the bottom of page 8
"Maximum Deceleration
The maximum deceleration of the test vehicle ranged from 0.53g and 0.71g. The oversize tires had a significant impact on maximum deceleration at various levels of applied pedal force. With the exception of 39.5-inch tires (anomalous data), braking performance reduced 20 to 25 percent by tire/suspension configuration regardless of the amount of applied pedal force (see Table 4). It is immediately evident that the ability to stop a vehicle with oversize tires depends on the amount of pedal force that can be applied. "
Increasing tyre diameter reduces braking performance. When I stepped from 31's to 33's I really noticed the increased effort required to stop the vehicle in the same manner. I prefer 32's instead of 33's for that reason as well as the gearing benefits.
https://www.aamva.org/uploadedFiles...izedTiresOnAlteredHeightVehicles_Findings.pdf
at the bottom of page 8
"Maximum Deceleration
The maximum deceleration of the test vehicle ranged from 0.53g and 0.71g. The oversize tires had a significant impact on maximum deceleration at various levels of applied pedal force. With the exception of 39.5-inch tires (anomalous data), braking performance reduced 20 to 25 percent by tire/suspension configuration regardless of the amount of applied pedal force (see Table 4). It is immediately evident that the ability to stop a vehicle with oversize tires depends on the amount of pedal force that can be applied. "
