rim offset, tyre dimensions HJ61

Submitted: Sunday, May 15, 2005 at 17:58
ThreadID: 23004 Views:5972 Replies:1 FollowUps:2
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Hi there,
I got second hand landcruiser (grey import from Japan) and just realised that the spare wheel is different than the main wheels. SO, I ended up with 4 alloy wheels, on which I could read the following:
Bradley IX
8JJx15
offset -25
PCD 139.7
The tyres are BFG A/T 32x11.5R15

The spare wheel is srteel:
T15x7-JJ
DOT 2 88

the fitted tyre is Desert Dueler (unused) 31x10.5R15.

Now, I went through many many posts on the web to find out wjat would all that mean and concluded that I should not mix these wheels (i.e. use the spare only at low speed in emergencies). HOwever, them I went and actually measured the tyres/wheels....

It turned out that all the wheels are about the same overall diameter!!!30 inches!!(not 32 as BFG should be-pressure in the tyres is 36PSI). The rim offset on the main aheels does not make sense-I measure PLUS 21mm... On the spare, it is +22mm, which would mean that I could actually use the spare wheel (the width of the spare tyre is different than for BFG's)....

Going to BFG's web-site, the overall diameter for this size is atated as 32" -this simply cannot be the case, the tyre on my truck is less than half-worn and 5cm is missing to make up to the stated 32".

I would appreciate an advice what to do (we are going to Kimberley this June and would like to buy another spare wheel):

a) use the existing wheels and get another with BFG tyre and stated offset of -25mm, would such wheels be available? the ones on the truck I found only in Japan. Alternative would be to get a spare tyre and beadbreaker or tyrepliers...

b) Buy an altogether new set of 5 wheels. What kind of price I would be expected to pay for steel wheels ? IF the wheel offset on the available wheels is not -25mm (or whatever it really is), should anything on the suspension/steering be changed?
I suspect that this offset is needed to enable fitting of wide 11.5" tyres...

I am sorry for going on for this long, I ma VERY frustrated with all the mess. I am not even sure what is the legal diameter of the tyre for this truck...

thanks,

Joseph

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Reply By: Tim HJ61 (WA) - Sunday, May 15, 2005 at 23:18

Sunday, May 15, 2005 at 23:18
Hi Figtree,

I have the same truck, bought mine over a year ago now, and also had different tyres/rims on the road wheels and the spare. Must be a little trick they play on us. Actually I suspect the spare is probably the original.

You are fortunate your road tyres are serviceable. I thought mine were but when I took them to get balanced, closer inspection revealed age cracking so I had to replace them.

My solution was to revert to 31x10.5 all round as the expense of five 32x11.5 was too much for my wallet. However I also could not get the truck into the garage with new 32 or 33 inch tyres on. Yours may measure the same now, but comparing new to new, they will be different. Also look for some web sites that compare rolling distance per rotation to show the difference.

I suggest it would be a shame to get rid of your alloys, in fact don't, you'll regret it later. the weight difference is huge.

If the steel rim fits the hub, then it will be okay. If you are worried about different rolling diameter, put it on the front if have a flat as you are likely to have a rear LSD and should not put different tyres on the back. This is a hassle if you get a flat on the rear. If you have one odd ball, unless you have reasons of cost or others like I had, then why worry and simply replace the odd ball to match the others. Sell the current spare tyre off it's rim.

Why not buy two new 32x11.5 and put them on the back. Put one on the spare rim, and keep the other as a bare spare for your trip to the Kimberley. Buy a R&R Beadbreaker so you can fit this tyre to any rim if you need to, and it will save the weight of a 6th rim, and also save the Olympian strength needed to put a full wheel on the roof rack.

I understand 31x10.5 is the standard tyre size for the HJ61 Sahara. The original Japanese owners always put the fancy wider wheels on to trick them up. Mine has 8.5 road rims (6 inch spare) which is about the maximum width for a 31x10.5 to hang on to. If you have not already done so, make sure your spare fits your front hubs and turns both ways without knocking. It should be fine, and really is the best way to get things clearer in your head and not too overwhelmed with technicalities.

All the best, and enjoy your truck.

Tim
AnswerID: 111395

Follow Up By: figtree - Monday, May 16, 2005 at 14:11

Monday, May 16, 2005 at 14:11
Thank you for advice, TIm,

I was also thinking along the same lines, however.... the 32x11.5 does not fit on 15x7 rim, so I would have to get a new rim. The problem is, this brand seems to be sold only in Japan and it is about $700 there... I am not sure if it is OK to use another brand wheel with the same specs. (i.e. rim width, diameter and offser)-it would be impossible to get the one with the same mass, though and this may give hard time to the diffs when accelerating.

Anyway, maybe we should just geat a spare tyre and beadbreaker / tyre repair kit.

By the way, what is the difference in price for 32x11.5 and 31x10.5 BFG's?

Joseph
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FollowupID: 367783

Follow Up By: Tim HJ61 (WA) - Monday, May 16, 2005 at 14:31

Monday, May 16, 2005 at 14:31
Hi Joseph,

I'm thinking you'd just buy a steel rim of the right size and not try to match the special rims. No one looks at it under the car :-) If all goes well, you'll never need it.

I'd be interested in other people's opinion of the different masses of the wheels, I wouldn't have thought it mattered too much - don't overthink this one!! Remember the diff, whether LSD or not, it DESIGNED to spin at different speeds such as going around corners. The lighter wheel might be easier to get spinning, but the heavier wheel would require less energy to keep it going due to inertia like a flywheel - jeez I'm gunna get flamed here - I really don't know what I'm talking about, just guessing. :-) Like I said, don't overthink this!

Don't know the price difference now, but a year ago I remember there was around $100 a tyre difference. That wasn't for BFG.

I was also thinking you might need to be a bit careful putting a too wide a tyre underneath as it is more vulnerable. People suggest keeping the spare without air so it is less likely to get ripped when stored underneath and travelling in the stony ground.

If your 32's are fine, keep them. Dropping back to 31's put my speedo 7% slow.

There are many recommendations for a second spare when travelling in the Kimberleys, just in case.

Regards
tim
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FollowupID: 367787

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