37s air pressure

[PL1HD1]

Any one running 37s on a HD ? If so what air pressure are you guys running ? Starting to experiment with mine to see what rides and handles the best .

 

[IrishRedFish]

Experimenting myself... Running 37 Nitto RGs on Stock AEVs. 45 in the front 35 in the rear unloaded and not towing... 45 towing my 5500lb boat. So far so good.. just annoying with the low air pressure light on the dash.

 

[GATORB8]

They keep changing it every time I rotate, but my baseline goal was 40 all around, bump 10 rear towing heavy, and that rode well. Last time Chevy rotated they put them at almost 80 psi and it rode like hammered shit until I got home and dropped it.

Gasser 37" RGs.

Load comps:

 

[AXE]

Seems really low to me! I would expect 50 psi on the low end and I'd run near max towing, whatever it says on tire sidewall, so 65-80 psi if they are load range E.

 

[GATORB8]

Seems really low to me! I would expect 50 psi on the low end and I'd run near max towing, whatever it says on tire sidewall, so 65-80 psi if they are load range E.

EDIT: Although you have the heavier Dmax, so I'd expect your front axle to be pushed up for that weight, maybe 10 psi? 10 psi should be 900-1k lbs extra for the axle (two tires).

EDIT EDIT: Also, the 37" RG E loads are maxed at 65 psi:

 

[AXE]

I've always run tires that have max 80 psi specifically because I tow heavy occasionally. Usually that's been Toyos in 295s.

I dont like flex in my sidewalls with a 9000 lb truck that sits up as tall as these do, so I like higher pressure. I wouldn't run down the road at speed unless my tires were running 55 psi unladen.

Now on my 1500, I'll run down the road at 42-45 psi unladen.

 

[GATORB8]

I've always run tires that have max 80 psi specifically because I tow heavy occasionally. Usually that's been Toyos in 295s.

I dont like flex in my sidewalls with a 9000 lb truck that sits up as tall as these do, so I like higher pressure. I wouldn't run down the road at speed unless my tires were running 55 psi unladen.

Now on my 1500, I'll run down the road at 42-45 psi unladen.

I always find tire loading pretty interesting (god I'm a dork). I know about the deltas in tire pressure within E loads, but hadn't connected it to the E1/E2 rating I see on the tire orders.

So, E1 is 80 psi, E2 is 65 psi max inflation/load. E2 doesn't really show up until you get pretty big on the couple I looked at.

Given similar load index and overall size, it appears to take more rubber (tire weight) to accomplish the load index. Here's Toyo's since you mentioned them, this is their OC RT:

Comparing the 295 and the 35x12.50 which are about as close in size as these get, the E2 35 takes 12 more pounds of rubber to accomplish 84% of the capacity of the 295 at the lower pressure.

Like anything, there are a lot of negatives that offset the positives (off road performance a "cool" looks) on larger tires. Our E2 load 37" RGs are almost 20 lbs heavier per tire to allow for the weight at a lower pressure compared to a 295 E1. I have no doubt that's costing real money at the pump.

On the Jeep side of things, everyone complains about load ratings impacting ride, but, really, my experience is that the load setting (load where you set the psi) was the equalizer. While we run D load 38s on the Jeep, it doesn't ride any worse than the factory C load 285s, we just run them 10 psi lower.