H42, 32" inch tires, 3.73 gears, engine RPM questions

[Bryan062087]

I've got an fj62 which I'm considering converting to manual.

Would an H42, true 32" tires (32.2" in diameter), and stock fj60 gears be a good combination to run? This would be on a daily driver that I use on the highway on trips, around the city, and offroading (no hardcore rock crawling).

Would I lose too much on the low end for offroading? I'm used to the a440f and 4.11 gears with 33's.

I've heard 33's and stock fj60 gears with the 4 speed do not work that well, i.e. clutch engagement off the start is tricky etc and the gears are too "tall". Hill starts are a pain, not enough power on inclines etc, Is this true? If so, would 32's make it any different?

Thanks.

 

[NocalFJ60]

You have microsoft excel?

https://forum.ih8mud.com/60-series-wagons/240513-gear-calculator-microsoft-excel-download.html

 

[Bryan062087]

Yes, thanks. Now to try to figure out how to use it, not the brightest about gear ratios etc as you can see.

Edit: wow, that thing is amazing.


Would also like some real world input.

 

[NocalFJ60]

I drove with my 32's and 3.7 gears until I could upgrade to 4.11's. I knew I wanted to go to 33's or larger though. It is possible especially if you live somewhere relatively flat. You could always use 4L when you go off the pavement.

 

[RredFJ40]

I've driven my 60 with stock gears and 33's (actually 32.7") for two years. I don't have any problems on the road. I especially enjoy the top speed lower RPMs at any given speed. Only downside is off road it would be nice to have lower gears (but then you want REALLY low gears).

My current plan is an H41, 35's and stock gears and see how that goes - I'll have even more overdrive with the lower first to get going. Step it up to 4.11 when I go to 37's. If it doesn't work, go to 4.11 earlier.

My suggestion would be to give it a try and only change gears if you have to.

 

[Bryan062087]

I would have access to both 4.11 gears and the 3.70's in the fj60's.

With the amount of highway driving I do, I don't think I could run the h42, 235/85/16's (32"'s), and 4.11's. I like to keep the rpms between 2500-2700, and this would only give me like 60 mph. Not fast enough.

But my concern is losing all my low end gearing with 3.70's...

Has anyone thought the low in the h55f and h41 is too low in 1st gear? Wind out the engine too fast?


Didn't aussie cruisers come stock with 7.5r16's (235/85's), What transmission and gears did they get?

 

[lovetoski]

I would have access to both 4.11 gears and the 3.70's in the fj60's.

With the amount of highway driving I do, I don't think I could run the h42, 235/85/16's (32"'s), and 4.11's. I like to keep the rpms between 2500-2700, and this would only give me like 60 mph. Not fast enough.

But my concern is losing all my low end gearing with 3.70's...

Has anyone thought the low in the h55f and h41 is too low in 1st gear? Wind out the engine too fast?


Didn't aussie cruisers come stock with 7.5r16's (235/85's), What transmission and gears did they get?

I've had 33's and an h42 for 4 years. For flat to moderate hill starts it's fine. The 2F has lots of low-end grunt. I live in Seattle, and on steep hills you've got to slip the clutch a lot. I switched to 4.10's and the improvement was huge. Wish I'd done it years ago.

That said, the 3.70's do make highway cruising easier, especially if you want to go faster as you indicate. 4.10's and 33's = 55mph @ 2500 rpm. With the 3.70's, you get ~65mph at 2500 rpm. 70 mph is easy.

For what it's worth, I get 3 mpg improvement when I drop from 70 to 60 mph. That's a big percentage on a low base.

 

[Bomar]

Bryan

The manny will wake up the 3FE. I would leave the 4.11 in there until you actually drive the truck. At 2.5k to 3k rpm I feel the 3FE has a sweet spot. Gas mileage sucks at any rpm.

It is going to be a pain enough to add all the stuff for the manny trans.

I had 33's on my 87 with the 4 spd stock gears and it was all around quicker than the 3FE auto.

 

[FJ60Cam]

I've got an fj62 which I'm considering converting to manual.

Would an H42, true 32" tires (32.2" in diameter), and stock fj60 gears be a good combination to run? This would be on a daily driver that I use on the highway on trips, around the city, and offroading (no hardcore rock crawling).

Would I lose too much on the low end for offroading? I'm used to the a440f and 4.11 gears with 33's.

I've heard 33's and stock fj60 gears with the 4 speed do not work that well, i.e. clutch engagement off the start is tricky etc and the gears are too "tall". Hill starts are a pain, not enough power on inclines etc, Is this true? If so, would 32's make it any different?

Thanks.

Without going to the 5spd and keeping the 4.11s, it's a trade-off.

You can have a decent first gear, or decent highway RPMs. Pick your favorite and rock on...

Bad analogy, but do you have a family member with a 5spd car you could borrow for two weeks? Drive one week without using 1st gear, and drive the second without using 5th gear and see which you like better.

 

[Bryan062087]

I think I will try to save enough money for the 5 speed. Seems that there is too big of a trade-off with the other options.

The reason why I was considering this is that I need to rebuild my transfer case ASAP and my automatic transmission is on its way out. I didn't want to rebuild the transfer case then install it back on the auto, then have to take it apart again when my auto died 10k later. But it looks like thats the way its going to be if the 3.70's with 32's and an h42 would really be that bad as a longterm setup.

I can't do the 4.11's and h42, I drive way too much/fast on the highway. I'm used to going 80mph with my a440f and 33's.

I guess if I could find a cheap h41, that could be a possibility with 3.70's, but I doubt I'd be able find one to make it worth not getting the 5 speed.

Thanks for the input.

haha, nice avatar cameron.

 

[RredFJ40]

H41 and H42 4th gears are both 1:1. So no NEED to go to H41, you'll be the same either way. Really- speaking from experience you won't need the low first with 3.70's and 32's or 33's. Swap a post-85 H42 in and go. You'll be set for the H55 when the time comes and then you can decide whether 4.11 or 3.73 best fits your driving habits with the 5 speed.

I think I will try to save enough money for the 5 speed. Seems that there is too big of a trade-off with the other options.

The reason why I was considering this is that I need to rebuild my transfer case ASAP and my automatic transmission is on its way out. I didn't want to rebuild the transfer case then install it back on the auto, then have to take it apart again when my auto died 10k later. But it looks like thats the way its going to be if the 3.70's with 32's and an h42 would really be that bad as a longterm setup.

I can't do the 4.11's and h42, I drive way too much/fast on the highway. I'm used to going 80mph with my a440f and 33's.

I guess if I could find a cheap h41, that could be a possibility with 3.70's, but I doubt I'd be able find one to make it worth not getting the 5 speed.

Thanks for the input.

haha, nice avatar cameron.

 

[Bryan062087]

Well, I was thinking of using an h41 AND the 3.73 gears. That would give me a low first gear and tolerable highway rpms.
Would there be too big of jump between 1st and 2nd though using this set up?

 

[Bryan062087]

I've been playing around with gear ratios and crawl ratio calculators etc.

Would I not be gaining low end even switching to the h42 and the 3.70's? It looks like even this combo would have a lower first gear than with the a440f and 4.11's
Am I wrong on this?

3.555 x 2.296 x 3.73 = 30.402 (h42, fj62 transfer case)

2.95 x 2.296 x 4.11 = 27.83 (a440f, fj62 transfer case)

Now I don't understand why people are having problems with 3.7's, h42's and 33's and not the 4.11's, a440f, 33's which would be even worse? Does it have something to do with the clutch engagement etc on the manual? Not nearly as many people talk about changing the diff ratios when you move up to 33's with a440f.

 

[Cruiserdrew]

Now I don't understand why people are having problems with 3.7's, h42's and 33's and not the 4.11's, a440f, 33's which would be even worse? Does it have something to do with the clutch engagement etc on the manual? Not nearly as many people talk about changing the diff ratios when you move up to 33's with a440f.

I replied to your thread on EP.


The torque converter in an auto can magnify low end torque, and that's why the ratios don't tell the whole tale. Manuals are very different from autos in ways both good and bad, so you can't compare the first gear ratios and make an accurate comparison.

Offroad, there is no such thing as too low of a gear. On my FJ40 I have a 7:1 first gear, and even then, there are times I want a lower gear.

On road, I have BTDT with 33s and 3.70 diffs. It's Ok but not optimal. It reminds you something isn't right every time you leave a stop light. Leave a stop light uphill, and you slip the clutch a long time. that isn't good for your clutch at all. On a manual the goal is to get the clutch fully engaged as soon as possible at as low rpm as possible after a start. The auto never gets fully engaged until you hit 4th gear!

I think you are exactly right saving up for an H55f. For on road driving the overdrive is really nice for dropping the revs. For offroad, the 5:1 is pretty sweet as well.

 

[FJ60M1KE]

Does anyone know the exact gearing for the H42 4 speed tranny?

I am especially interested in what the 1st gear is on the H42 for comparison. I found the exact gearing for the H55f on CCOT site, they currently have the H55f listed for 2700 Robert DeNiro's. They list the transmission gearing as follows...

• 1st....4.843:1

• 2nd....2.619:1
  
  
• 3rd....1.516:1
  
  
• 4th....1.000:1
  
  
• 5th….0.845:1
  
  
• R....4.843:1

I am considering upgrading to the H55. I am currently running 265/75 - R16's with the stock 4 speed and a brand new clutch. 1st gear needs some help or that new clutch wont last very long. It is not horrible with that tire size and imo probably the best tire you could match to a 4 speed to maintain driveability in town and on the freeway, but you will have to rev up the r's just a bit before you slip it in to 1st or its going to puke out on you. I also live in a pretty flat area. My gears are the stock 3.70's and my cruiser is a late '85 (8/'85)

 

[Heckraiser]

I drove my old FJ60 with H42 and stock gears with the following tires:

31x10.5: Felt fine, like this was the original tire size (although it's actually quite a bit bigger than original)
32x11.5: Also felt fine. Struggled a little bit on hill climbs. Being as you're in TN and I'm in CO, I think you'd be just fine
33x12.5: Fine around town and on flat highway. Sucked on hill climbs (40-45mph up I-70), sucked in a head wind, low range performance started to feel noticeably compromised and the clutch took some extra abuse.

 

[1911]

Does anyone know the exact gearing for the H42 4 speed tranny?

H42:

1st 3.56:1

2nd 2.29:1

3rd 1.41:1

4th 1.00:1


H41:

1st 5.3:1

2nd 2.84:1

3rd 1.63:1

4th 1.00:1