37x12.50/r18 Toyo Rt Trail Pressure

[Rbalazs]

This is the second truck I’ve had these tires on and this set, I’m noticing that the rear tires are not even wearing or making contact on the outside lugs.

I have gone down to 50 psi and still it runs on the center two lugs and I just don’t know if I should just keep dropping the pressure until it’s even contact patch or what. Of course, right now I just have a canopy on my truck and once I tow it probably flattens out and during the winter I’ll have my sled deck the snowmobiles on it and so it’ll flatten out.

I just find it crazy that at 50 psi it’s not contacting the outer lugs..

 

[gmbpilot757]

On my 285/75 RT Trails I ran 55F/50R the first year. I’ve dropped it down to 53F/48R over the last couple months. Seem to be wearing fairly decently with rotation every 5k.

 

[Rbalazs]

On my 285/75 RT Trails I ran 55F/50R the first year. I’ve dropped it down to 53F/48R over the last couple months. Seems to be wearing fairly decently with rotation every 5k.

Well, maybe I’ll drop it down some more and see. When they put them on, it was at 65 and I thought that was too high of course and so I dropped it down to 55 and it was still doing it so then I dropped it down to 50 and it’s still doing it so I’ll go down to 45 maybe and see if it does it

 

[Rbalazs]

Cold, rear is at 46 and front is at 53, I’ll keep you posted. The front obviously with the weight of the engine has a good contact patch.

 

[McE]

Page 27: https://www.toyotires.com/media/2125/application_of_load_inflation_tables_20170203.pdf

You should most likely be somewhere in the 30s in the rear if you just have a canopy back there. Load limits are per tire

Keep in mind these are load limits, not necessarily ideal pressures, but it gives you an idea of how low you can safely go at any given load.

 

[Rbalazs]

Page 27: https://www.toyotires.com/media/2125/application_of_load_inflation_tables_20170203.pdf

You should most likely be somewhere in the 30s in the rear if you just have a canopy back there. Load limits are per tire

View attachment 271771

Keep in mind these are load limits, not necessarily ideal pressures, but it gives you an idea of how low you can safely go at any given load.

Awesome. This is great info. So, obviously I’d have to hit a CAT scale to get rear axle weight with as is to be technical, but we don’t need to get that anal. I’ll just keep dropping until I’ve got a flat contact patch.

 

[JCKustoms]

I'm running the 37x13.50R20 at 52 F and 40 R (cold) and I'm getting really good even tread wear. I used a chalk line multiple times to get it correct.

This is of course not towing!

 

[TremorSS]

I run 45 front and 35 rear for my 37s and 6.7.

I’ll air it up for towing. I do believe either CJC or Carli recommend this range.

 

[ramv]

For trail, I’m a 17/15 F/R guy, maybe 20 with a diesel. You will occasionally pop a bead but the traction is worth it. With beadlocks I would recommend 12 psi with a heavy truck.

Obviously these are trail only pressures.

 

[McE]

Threads like this are a great example of why you need to be careful who you take advice from on the internet. You could inadvertently run dangerously low pressures if someone just says "I run my 37s at X psi" and you run that on a 37 with less air volume. Tire diameter alone is dangerously incomplete information for determining appropriate load pressure, but I see it on here all the time.

All else equal, different air volume requires different pressures to support the same load...a lot of guys either overlook this for some reason or don't understand. The difference is not insignificant.

For example, if you look at the load inflation tables I posted above, you'll see that a 37x12.50R20 and a 37x12.50R18 at equal pressures are two very different things. The 37x12.50R18 at 50psi can support 3,415lbs per tire, where the 37x12.50R20 at 50psi can only support 3,085lbs, and those tires seem like they are very close in overall size. The greater the difference in air volume, the greater the difference in load carrying capacity at a given pressure.

Be safe out there - ALWAYS check the load tables for your tires

 

[Najaf4life]

Have you tried the chalk test?

 

[Blade420Play🔪🏆]

Have you tried the chalk test?

That's what I ended up doing. I am at 42 all around right now. I need to do it one more time though

 

[Rbalazs]

Have you tried the chalk test?

No, but never needed yet. I can clearly see this not even touching the outside lugs. I might once we get closer to a flat contact Patch but no, I haven’t.