Air pressure with 37s?

[JINO]

Im on 38s, but had 37s prior.
26 psi hot on both tires.

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[Reaper-1]

I contacted a MT tech rep and gave them all my vehicle info and got this answer. So I’m going to need to do a chalk test.
“ The correct pressure for your new Baja Boss MT 37x12.50R17LT's would be 33 psi cold for normal street driving.”

Right on bro. Question though…what psi range do you air down to for trails on 37’s? I’m new to this tire size…so please don’t mind the stupid questions

 

[MntGoat]

Im at 26 pounds for road and so far have only gone down to 12 pounds, with no bead locks

 

[BDinTX]

I contacted a MT tech rep and gave them all my vehicle info and got this answer. So I’m going to need to do a chalk test.
“ The correct pressure for your new Baja Boss MT 37x12.50R17LT's would be 33 psi cold for normal street driving.”

Now that’s interesting. Same tires and when I gave them my VIN, they recommended 25 psi. Normally only go down to 28 to keep my dash light off.

On trails I try to air down to 13psi.

 

[Deleted User 38384]

Just curious what others are running for air pressure on road with 37s.


I did the chalk method and I'm down to 26 pounds front and rear. This is my first time doing the pressure this way, so curious what others are running.
My tires are
General Grabber X3 37/12.50R17 on method 105 beadlocks.

According to the tire size calculator, I was running 23 PSI as recommended by their conversion chart, but after a recent off-roading trip, I aired up to 26 PSI, and I've actually noticed a 1 MPG increase.

At 23 PSI on my 37/12.5r17 RT tires I was averaging 21 MPGs with my EcoDiesel.

Now at 26 PSI with the same tires I'm averaging 22 MPGs.

Currently it's been in the high 90s - low 100s here in North Texas. I do 80% highway driving. 20 miles to work, 20 mi home, and then on the weekends I'll do another 100 - 200 mi mostly highway driving.

I'm thinking about kicking it up to 28 PSI here shortly to see if I can get another MPG out of it.


I only have a 1.5 in lift on my Wrangler, even with the high clearance fender flares, I only air down to 10 PSI on my Icon interlock wheels. Last time I went off-roading with a group, I went down to 6 PSI, and honestly I just bottomed out on even more shit. Until I get a 3.5 in lift, I don't think I'll be going much beneath 10 PSI. That extra half an inch seems to make a difference right now.

 

[Terrymo]

Now that’s interesting. Same tires and when I gave them my VIN, they recommended 25 psi. Normally only go down to 28 to keep my dash light off.

On trails I try to air down to 13psi.

Yeah it didn’t sound right to me. I set mine to 28 because I’m defiant.

 

[Terpsmandan]

I have been running 29 and that seems too high. I used JScan to lower the TPMS threshold. Still getting 22-24 mpg on the diesel.

 

[jeepingib]

I was running 28-29 for mileage only when I was driving the Jeep 160 miles a day. But I found that they rode, and wore better around 26. Even with the garbage that Patagonia tried to say about their tires needing higher psi to avoid cupping. I just rotate more frequently.

 

[jellis4148]

27 psi cold for me.

 

[Terpsmandan]

Set them this morning to 27. Drive to work, about 25 miles and they were at 30.

 

[Left Field]

Now that’s interesting. Same tires and when I gave them my VIN, they recommended 25 psi. Normally only go down to 28 to keep my dash light off.

On trails I try to air down to 13psi.

Interesting the variation from MT tech support. I've also got the MT BB A/Ts

Now that’s interesting. Same tires and when I gave them my VIN, they recommended 25 psi. Normally only go down to 28 to keep my dash light off.

On trails I try to air down to 13psi.

Ditto on the 'interesting' regarding the different numbers from MT tech support. Suppose some of it is due to specific vehicle and tire differences, but it's not clear that's the entire answer.

I've got the MT BB A/T's in 37x12.50 load range D on a 392 with OEM wheels, loaded for travel its around 3000 lbs/axle. MT recommended 26 psi cold on the highway. I've got around 12k miles on them, rotating them at every oil change. So far the wear looks very even, no cupping, minimal noise, handling and stability are good.

On the trail I usually run around 12 psi.

LF

 

[BDinTX]

Suppose some of it is due to specific vehicle and tire differences, but it's not clear that's the entire answer.

Ya if the tire pressure recommendations were reversed it would make more sense. Mine being a diesel is heavy, but only using my VIN number would have given them factory curb weight and wouldn't have accounted for other add-ons. I weighed mine just recently and found my normal road DD weight is 5800. I may have to start filling my tires with helium...

@Terrymo When you were talking to them, did they ask more probing questions to got a better idea of your vehicles actual weight (steel skids, aftermarket bumper, winch, etc)?

 

[Terrymo]

Ya if the tire pressure recommendations were reversed it would make more sense. Mine being a diesel is heavy, but only using my VIN number would have given them factory curb weight and wouldn't have accounted for other add-ons. I weighed mine just recently and found my normal road DD weight is 5800. I may have to start filling my tires with helium...

@Terrymo When you were talking to them, did they ask more probing questions to got a better idea of your vehicles actual weight (steel skids, aftermarket bumper, winch, etc)?

No I was lazy and just emailed their tech support. They wanted the OEM info off the door jamb placard and the estimated weight. I’m sure I grosslyunderestimated with all the weight I carry. I discovered last weekend carrying 4 gallons of water is pointless if your radiator won’t hold any water for more than a couple of minutes. I think a chalk test may be my best solution. Still procrastinating on that.

 

[BDinTX]

No I was lazy and just emailed their tech support. They wanted the OEM info off the door jamb placard and the estimated weight. I’m sure I grosslyunderestimated with all the weight I carry. I discovered last weekend carrying 4 gallons of water is pointless if your radiator won’t hold any water for more than a couple of minutes. I think a chalk test may be my best solution. Still procrastinating on that.

Ok full disclosure I was emailing also. So I guess that mystery remains.

Was sorry to see that happened... Any movement on the radiator repair?

 

[Terrymo]

Ok full disclosure I was emailing also. So I guess that mystery remains.

Was sorry to see that happened... Any movement on the radiator repair?

Replaced under warranty with no backlash on the lift and tires. Allegedly block test by the dealer etc showed no damage or water intrusion to the motor. But who knows what the dealer really did. Picked it up yesterday and did an oil change and cut open the old filter. Used a magnet to check for shrapnel in the old oil. Nothing found in the oil or the pleats of the filter. Probably do another oil change in a short time to check again.

They did try to charge me $400 to remove the aftermarket bumper and winch but I explained that I had removed the two lower attachment points on the back of the grill so that was unnecessary. Pop the grill and slide it sideways or call me and I’ll be there to show your tech it can be done.

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