8 lug to 10 lug adapter or phantom 10 lug rims

[Grit dog]

No sir, none of that. There have been many many light truck type 16.5" tires with a max psi of 35-50 psi, and still to this day too. Interco tires, for example. Plus a bunch of obscure brands of tires that are focused more on farm/implement tires.

A light truck 16.5" tire is just that- a light truck tire. There's no reason a tire manufacturer couldn't produce a light truck 22.5" tire, designed to run at light truck pressures. No, I don't believe it's a good idea to run low pressures in 17.5-24.5 truck tires as they are not designed for that.

Also, I don't know where your recommendations came from, but a 16.5" light truck tire has no problem staying seated at 20 psi or less.

So you’re saying (honest question) that it’s not the flatter bead angle 15deg vs 5 deg and lack of a safety bead but the tire design, guessing too stiff, that begets the higher pressures. And if someone made a squishy-er sidewall tire in those rim sizes that they would be just fine at much lower pressures?
If that’s the case then it makes zero sense why at least 1 mfg doesn’t capitalize on that, not for 22.5s on slammed duallys but for the larger market (still not huge but much bigger) of class 3-5 trucks rolling on 19.5s that don’t want or need all that harshness and load capacity.
To your point it would be the best of both worlds for many to have some 19.5s that were say in the 3600lb cap range which would be the limit of a LT tire on the upper end of widths that would still work on 19.5 rims.
I’m guessing the NHTSA would not allow it though as one could easily put tires on a truck that are much lower than the gvw or allowable axle loads. (Although literally no different than mounting a P rated tire on a 1 ton truck now. There is no regulation that prevents the lighter tire from being mounted as they’re the same bead design)
Good discussion.
Although I’ve always been told the pressure was due to the bead angle. That’s what the whole world is lead to believe.

 

[bucket]

So you’re saying (honest question) that it’s not the flatter bead angle 15deg vs 5 deg and lack of a safety bead but the tire design, guessing too stiff, that begets the higher pressures. And if someone made a squishy-er sidewall tire in those rim sizes that they would be just fine at much lower pressures?
If that’s the case then it makes zero sense why at least 1 mfg doesn’t capitalize on that, not for 22.5s on slammed duallys but for the larger market (still not huge but much bigger) of class 3-5 trucks rolling on 19.5s that don’t want or need all that harshness and load capacity.
To your point it would be the best of both worlds for many to have some 19.5s that were say in the 3600lb cap range which would be the limit of a LT tire on the upper end of widths that would still work on 19.5 rims.
I’m guessing the NHTSA would not allow it though as one could easily put tires on a truck that are much lower than the gvw or allowable axle loads. (Although literally no different than mounting a P rated tire on a 1 ton truck now. There is no regulation that prevents the lighter tire from being mounted as they’re the same bead design)
Good discussion.
Although I’ve always been told the pressure was due to the bead angle. That’s what the whole world is lead to believe.

Correct. Just for reference, there are some sizes of Interco TSL (bias) that are a max psi of only 30. The Interco Vortrac LT (very mild AT type radial for street trucks) has a max psi of 65 for the 16.5" sizes.

You know, you just hit on something that probably explains why a manufacturer doesn't offer them for the custom truck world. I too figured that lighter 19.5's were not available because manufacturers didn't want people putting them on trucks rated for much higher capacity. But I'll bet that if a tire manufacturer offered a lighter duty, low profile 22.5" for the custom LT truck crowd, some goofball would inevitably mount a set of them on their custom Peterbilt or KW show rig.

 

[bluex]

Since yall brought up weight ratings an all help me understand this.

My dually has a max capacity of 12k lbs with a weight distribution hitch, it gcvw
is 19k. The factory specs tires on it are rated at 2680/2470. So my rear axle has a rated tire capacity of 9880 lbs.

Everyone likes to make a big deal about these wheel setups using a XL rated tire an it "not being enough for the truck" but the math dont math to me.

265/40/22 XL is 2094/1885 so my rear axle capacity now is 7540 by tires. My max payload in the bed is 2k. Trailer tounge weight is maybe 1k but I think thats over the hitch rating. I've never done/pulled a gooseneck but id imagine your pin weight still cant/shouldnt exceed the trucks payload rating.

So with all that said, what's the issue? Properly loaded its still within spec on the XL tires. I know people have had issues with tires on these but I think it's more cheap tires an not keeping an eye on the pressures. Mine are wearing good an I haven't had an issue or anything weird from it an I do/have towed up around 93-9500 with it.

 

[Grit dog]

Correct. Just for reference, there are some sizes of Interco TSL (bias) that are a max psi of only 30. The Interco Vortrac LT (very mild AT type radial for street trucks) has a max psi of 65 for the 16.5" sizes.

You know, you just hit on something that probably explains why a manufacturer doesn't offer them for the custom truck world. I too figured that lighter 19.5's were not available because manufacturers didn't want people putting them on trucks rated for much higher capacity. But I'll bet that if a tire manufacturer offered a lighter duty, low profile 22.5" for the custom LT truck crowd, some goofball would inevitably mount a set of them on their custom Peterbilt or KW show rig.

Yes.
Or just low production/sales, which is probably also a big part of my “why can’t you get a LT tire for a 19.5 rim”. Most of those rims are on working trucks with the recreational heavy hauling crowd that could use the flexibility (in more ways than one) in load capacity is very small. Then add in the dumbass factor where liability concerns steer corporations in directions that engineer things to hopefully not be harmful to the lower IQ half of the population.

 

[Grit dog]

Since yall brought up weight ratings an all help me understand this.

My dually has a max capacity of 12k lbs with a weight distribution hitch, it gcvw
is 19k. The factory specs tires on it are rated at 2680/2470. So my rear axle has a rated tire capacity of 9880 lbs.

Everyone likes to make a big deal about these wheel setups using a XL rated tire an it "not being enough for the truck" but the math dont math to me.

265/40/22 XL is 2094/1885 so my rear axle capacity now is 7540 by tires. My max payload in the bed is 2k. Trailer tounge weight is maybe 1k but I think thats over the hitch rating. I've never done/pulled a gooseneck but id imagine your pin weight still cant/shouldnt exceed the trucks payload rating.

So with all that said, what's the issue? Properly loaded its still within spec on the XL tires. I know people have had issues with tires on these but I think it's more cheap tires a not keeping an eye on the pressures. Mine are wearing good an I haven't had an issue or anything weird from it an I do/have towed up around 93-9500 with it.

Yes, you’re generally mathing right. But pursuant to the last few posts between me and @bucket, not very one can math. Hell there’s folks who think an all terrain tire isn’t for the road and 9 of 10 people don’t understand the differences in load capacity and tire size and how it relates to air volume primarily but also to width and aspect ratio. Nevermind that most also think a tire should be at its max pressure to be “right.” Doesn’t help that the govt mandated it for class 2 trucks before of the 9 out of 10 dumbass factor.
So in general, “XL tires are bad on a Hd pickup” period end of story because there’s 10 wrong combinations where it IS bad compared to the 1 who can doo the math and knows their weights.

I will offer a couple considerations if you’re choosing to go by the math and not by the norm.
1. While P/XL tires are generally softer compound than the identical tire in a LT rating, the LTs also last longer due to harder compounds and many times also have a bit greater tread depth when new. The $ per tire per mile IS in favor of under using a LT heavier rated tire in a lighter application….at the expense sometimes of a little bit of snow traction.
Also, same concept as above. While air supports the whole load effectively, a stiffer sidewall carcass (like the above 19.5 etc discussion) does add to overall stability.
That said, I’ve had the opportunity to use and abuse more light duty trucks (class 1-3) for more miles over more varied conditions, loads, terrain and weather than most people. And when I used to end up with new half ton company trucks and then be put into positions to haul more weight or tow heavier than they were rated for (new truck new tires can’t go ask the boss to buy new tires to replace new tires, because he’s in the 9 of 10 dumbass category) I would routinely air up my half ton rear XL or even P rated cheapo factory baloney skins to 55-65 psi on 40-50 psi max rated tires. It helped considerably and never popped one. I’d haul a load or trailer locally or even over the road across the state like that. HUGE improvement.

 

[bluex]

If we could just get a low pro LT it would help alot. currently the best is XL in nitro or toyo an we only have these newer heavy suvs to thank for that. If your aren't lowering it you can get AT or MT style treads in 22/24 with better ratings because that's far more popular than the lowered ones.

The look on people's faces when I tell them they have to derate the rears in a dual setup explains a lot. I have had that argument idk how many times. They understand it on an E tire because they publish it that way but think it doesn't apply to anything else