Tires 'N gears

Greg_M

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Dec 27, 2021
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Vancouver Island
Was pondering tires and put together a table to summarise things. It might save someone a few button presses on their calculator so here it is. I included GM's 6L80E because I'm allowed to dream a bit. I'm sure there'd be lots of tire/gear calculators online but I haven't tried them.
Cheers, Greg
 

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rovercanus

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Apr 24, 2004
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Informative but I think most people here are running 32 and above.
I would think the 235's would be a little squirrelly on stock rims since they are 8".
I really like 255/85-16 on a D2.
I'm running 285/75-18 on my 2004 with 4:12 gears.
 

p m

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Greg_M: consider adding 1.4:1 high ratio LT230 option.

235s are fine on stock rims. If you run tall tires, keep the pressure up.
From the abyss of Discoweb wisdom - KvT was running 235/85R16s at 65 psi.
 
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Greg_M

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Dec 27, 2021
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Ok, revised to include the big boots and 1.4:1 T-box. Those 255/85/16's must rub the fender wells no?
 

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rovercanus

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Ok, revised to include the big boots and 1.4:1 T-box. Those 255/85/16's must rub the fender wells no?
Actually they didn't with the lift I had. They are 33" about. The front bumper may need to be trimmed if it's stock but my truck at least is way beyond that. If I recall, the 255's didn't even rub the radius arms but it's been a while since I had that size tire. The 285's will definitely rub the arms.
The 18" tires I am running now rub the arms and I had to trim the plastic rocker covers some since the tires will rub there when it flexes.
If I ever get around to getting sliders for this thing I may have to trim them also.

Peter, I just remember how my 255's had to stretch a bit to fit 8" rims. I can get it about higher pressure on 235's, I don't think I would want to air them down much.
 

p m

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Peter, I just remember how my 255's had to stretch a bit to fit 8" rims. I can get it about higher pressure on 235's, I don't think I would want to air them down much.
8" is indeed a wide rim, but 255 mm is 10" - should be okay.
My WAG is based on me currently running 7.50s on 6.5"-wide Wolfs. These tires definitely looked more "natural" on 5.5" Series rims, but they seem to do just fine on 6.5 - at pressures from 18 to 50 psi. I do feel the sidewalls bending in sharp turns, that's true.
 

rover rob

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Mar 29, 2016
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upstate NY
8" is indeed a wide rim, but 255 mm is 10" - should be okay.
My WAG is based on me currently running 7.50s on 6.5"-wide Wolfs. These tires definitely looked more "natural" on 5.5" Series rims, but they seem to do just fine on 6.5 - at pressures from 18 to 50 psi. I do feel the sidewalls bending in sharp turns, that's true.
i'm running 235/85s on stock wheels and had a slow leak I couldn't feel a difference until it got down to 15 psi. i'm surprised it stayed on the bead.
 

p m

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i'm running 235/85s on stock wheels and had a slow leak I couldn't feel a difference until it got down to 15 psi. i'm surprised it stayed on the bead.
Assuming you're talking about a D1 - stock wheels are 7" wide, meant to be used with 235-mm-wide tires.
BTW, the bead humps on RRC/D1 alloy wheels are pretty tall.
 
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