Hj60 - 2H wheel Confusion (I know - there was too much info out there) (1 Viewer)

[togril]

Ok - I apologise in advance, having looked online for a few days including here - I am hoping someone will take pity on my whining and give me some easy answers...

Hj60, 2H, 5 speed, 2inch Lift. Australia (N.T).

I will be travelling for a few months - 99.9% ON ROAD - and if not, on "packed" dry roads.
I may need to get the vehicle Rego'd in another State - so can't go Massive (?)

I need to replace my old 31x10.5 R15's.
I will get rims and tyres - Was going to get 16" rims, for more choice. (I can even get the original split rims that came on the 60's series). Have no idea as to what width I should get though.

I want the best size applicable, for the best fuel economy I can, so wanted to go a little taller (32.## inch)?

I just don't know anymore - I just want something that works well, and gives me perhaps a drop in rev's (though have been told that larger rolling radius = more fuel used)???? Is that true on a diesel on long roads? Again - conflicting reports.

I am already driving the "poverty pack" version, so I can't really afford to trial and error - though I found the 31" small for the vehicle.

Any help appreciated, I am really bloody confused by all of this.

Regards from Darwin.

T.

 

[Sooke]

I am going through the same thing right now. If you have easy access to 16" rims that have the proper backspace for your 60 (3.5"-3.75"), you will find there will be many more tire choices available. I am personally going to a 16x7" rim so I can run 255/86/16 tires. If you are only going to run a 32" size tire you could use a narrower rim and run 235/85/16 tires. As for tire choice it sounds like your main driving will be on highway, an "All Terrain " type tire with less tread void would be suitable. I am not too sure what tire brands you have available in Aus, as I live in Canada. Good luck

 

[togril]

Yes, thanks, I think that's what they came out with.
I don't REALLY mind pizza cutters, despite the silly "narrower than truck" looks.
They are pretty common for a reason out here. Was thinking of splits for that same reason - I will be in some remote places, even on roads - and on my own, and you are right, A/T's will do me fine.
The 235's come out to be about 31.7 I think, still feels small to me. Maybe I just need to get a grip!
Any comments on the optimum tyre/fuel side of things?


T.

 

[Sooke]

If I had access to split rims, that would be my preference since I travel to some remote areas but since I don't, I carry two full size spares.

As for optimum fuel economy, I can't really comment. I am hoping to increase my economy by changing the following;
1. change rim size from 15x 8 to 16x 7
2. Change tire size from 33/12.5R15 to 255/85/16
3. Change tire from mud terrain (high void) to all terrain.

With these changes I am hoping to increase fuel economy.

There is a great post on this site outlining the benefits of a tall skinny tire. It has me sold for what I use my truck for.

 

[cruisermatt]

285/75/16, skinny is good for road manners.

 

[togril]

I found a few threads and a "white paper" on the pros and cons for skinnys, thanks sooke.
I will be definitely going that way after reading them, and might actually go for exactly what you are looking at.
Need to find out if they are good for splits, and wether I want splits after watching a few explode on youtube am not so sure! Ill do some research into this.
There seems to be a lot of conflicting data. Ie: they are good until you run at lower psi, on sand for example with a risk of tube creep (had this on a 29er mountain bike).
Never had to change a car tyre before, so need to work that out.

Cruisermat: thanks, Yes, they are around 32.8. I think Somewhere around 32 - 33 skinny is for me.

Thanks for helping out.

 

[Slow Left]

It sounds like the calculation that you are chasing is one that relates the diameter of the tire (tire height) to the engine rpm you cruise at (where 'cruise' means the optimal rpm for engine performance/economy). To do that, you will have to take into consideration the gear ratio of the: transmission, transfercase and differential

So cruising in 2H, for each gear you select in the transmission, there is an optimal rpm for efficiency (differential gear ratio is a known and not changeable while driving, and tire size is what you are selecting for), so once you want to choose a tire size that fits in the optimal rpm range for your Cruiser, if you drive within that rpm range, then you are getting the 'best' efficiency.

A chart like this might help you do that calculation:

http://www.4lo.com/calc/geartable.php
or
http://www.southwestpowersports.com/GEARCHANGE.HTML


I can't vouch for the accuracy of the calculations in this chart. In fact, there may be other charts out there. But at least you can see that the calculation is possible and probably helpful to get you the number you are looking for.

 

[togril]

A chart like this might help you do that calculation:

http://www.4lo.com/calc/geartable.php
or
http://www.southwestpowersports.com/GEARCHANGE.HTML


I can't vouch for the accuracy of the calculations in this chart. In fact, there may be other charts out there. But at least you can see that the calculation i

Those were very interesting and informative - would never have looked them up.
Thanks.
It is also making me realise I probably under-rpm a lot in my driving, especially changing up.

Having said that - writing the words "2H Power band" into google made me laugh.

I have 4.11:1 diffs. So It's interesting to see where the 32/33's lie approximately.

 

[Slow Left]

OK, so 4.11:1 diffs, and I think the 5th gear of the H55 is 1:1 or slightly under 1:1 (you should be able to find the ratios for all the transmission gears), then you'll need to know the gear ratio for the transfer case in high 2.

Anyway, run those numbers together using the equation for 'gear ratio', then use that calculated number and compare it with the ideal rpms for the 2H, and voila, those are the tire heights most appropriate for efficiency.

Then for tire width, the narrower the tire, the smaller the surface area in contact with the pavement, the lower the resistance so the better 'efficiency' (but the poorer the grip). But since you aren't going to be driving Formula 1 races...

I'm also looking into tall and skinny tires, but unfortunately, here in the States, it is hard to find 31x9.5 r15 ... the all terrain treads all come in 31x10.5 r15 and there is only one tire mold in 31x9.5 r15 and it is a mud terrain...

 

[togril]

ok - can't find the ratio for Transfer in H2wd - so assume it is 1:1
I also put in a arbitrary RPM at 2000 - still trying to find an "optimum RPM" for the 2H:
max torque around 2000, max Power around 3500 -

Anyway -

I plugged it all in and got the following:

Which is a neat way of looking at it - thanks!

 

[Slow Left]

Looks good! You should be able to find those numbers. Maybe post in the 'Diesel' section, someone over there who is more familiar with the 2H will probably have those numbers easy.

Cheers!

 

[togril]

I'll find out the optimum rpm and transfer high2wd numbers, and if I come up with anything good I'll post back.
Thanks slowleft/sooke/cruisermat for making this such a good and educational post for me.


T.

 

[Sooke]

This turned out to be a great post and learning opportunity. Thanks to all

 

[togril]

This turned out to be a great post and learning opportunity. Thanks to all

I'm back......
What offset (if any) are you intending to go with on your 16x7's ?
I found some hefty 750 r16's today, that could suit me, though I don't know if they will fit on a 7. Maybe a 6...oh well nearly there.

Thanks
T.

 

[Sooke]

Optimum back space would be 3.5", keeping the stance as stock as possible without the use of spacers. You could probably get away with a 4" back space with a 16" wheel without TRE rubbing. If you google back spacing and offset, you can look at a chart that correlates the two different measurements according to rim width.

 

[Sooke]

I believe the OEM 70 series steelies part number 42601-60262-03 which is a 16x6" wheel came with a 3.75" back space. Someone correct me please if I am wrong.

 

[phoenix60]

I'm running 33.5 10.5 R 15. looking to go to 16' rims as well. I'm going to keep them skinny though. 33 is wayyy better than 31 for me. You may want to turbo that 2H though if you went bigger and wider (12.5). Not a lot of pickup starting out with that engine.

 

[Spudman]

Hey Togril

Another Aussie and we're so close too. Are you heading this way, we'll have to catch up for a coffee or so

You got the 2nd best vehicle for travelling around Aus and the fuel economy will be good if you drive to the conditions.

Now the big argument splits V steelies, splits are good because with a simple tyre changing kit you can change them anywhere, they are easy to get hold of if you damage one or lose the split and all tyre outlets in the small country towns will stock them. The bad things with them, if you do a lot of desert driving sand and dust gets in between the rim and the tube and eventually will blow the tube, you normally only get around 15-20000 Km's out of a tyre and they are expensive for what they are.

Now I run Kumho's KL71 on my 200 series and so far they are an awesome tyre, they go for around $360 a corner, I have 265x75x17 depending on where you buy them.

Also the best rims for your truck are 16 inch sunraisers you can pick them fairly cheap at any wreckers like Palmerston 4x4 etc.

As for split rims exploding I've only ever seen it happen when the split was not secure properly, this actually happened to me whilst driving across the centre of Australia, I never actually found the split so they've certainly got some punch if they let go.

As long as you have 6 of either one you should be right.

Spudman

 

[togril]

Yes, i'm probably going for the 16 sunnies. There are some v.cheap koh,s locally at $40 per rim sell out but they are 16x8, and I wanted skinnier like a 16x7 or less even. Especially as they had some 750r16 tyres with the chalk still on for a bargain as well. (I DO drive an hj 60 for a reason!). They ARE skinny though.

Well, you know I might be heading that way in a month or so, I'll keep in touch on that one!

Thanks.
T.

 

[cruisermatt]

Actually I really want to see what 255/85r16 on 16x7s with a two inch lift looks like, so do that.

If you don't mind