what's the largest tire for stock FJ40?

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I've got a stock FJ40 w/ factory (Mitsubishi) leaf springs and totally rust-free body with no mods or stick-on rear fender flares. What's the largest tire I can accommodate without chewing up the tires or the truck at stock height, while still being capable of reasonable offroad driving? It's currently got 30x9.5x15's and has been converted to GM front disc brakes. Obviously, the wheels will need to be upgraded accordingly, but I don't want more rubber than the steering can handle. I'd like to see some pictures of rigs that match the criteria, if anyone wants to show theirs off. thanks
 

SlapSmak

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Joined
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this is like a window to 20 years ago when this was asked every other day.
Sorry, the last "40" I had, since buying this one 4 years ago, was in 1979 when off-road radial tires were few and far between. I remember having Denman bias ply Gumbo Mudders on 10" x 15" Western Wheels, but no memory of the height or profile. I'd rather get input from people that own LC's opposed to a tire salesman. I'm told that modern radials balance and track much better than the old bias ply. We had a service (gas) station back then and one of the first computerized tire balancers on the market in the 70's. Some of these larger tires were so bad, I'd have to deflate, break the bead and turn 90 degrees on the wheel just to get the balancer up to speed without foundation-rattling vibration. Consequently, there's a lot more to know that what looks good.
 

locklaw

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They can take quite a large diameter tyre on a standard suspension, but that is if you stick with bias type/sized tyres. Biggest they will take without too much hassle are 7.50-16's if you have access to 16" splitties. These are often taller in height than a 33" yet so narrow that the steering input and wear on the steering components is not untoward.

Modern radial 7.50R16's have quite good manners, the Michelin XZL being the best of the bunch in an aggressive tread.

This is what they look like on an FJ45-

20140802_120949-1.jpg
 

flx

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Jan 4, 2019
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France
I love the XZL too :D
1629580076666.png

But they are noisy at highway speed and not very reassuring on wet roads.

For the sake of the topic, 7.50R16 with original suspension 40 years old:
1629579653991.png


7.50R16 with original suspension only 3 years old:
1629579723563.png



I think some countries also got 9.00R15 from stock to drive on sand.
 
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