Offroad Tire PSI

So I wanted to start a discussion about what PSI ya'll go down to when rockcrawling. This past weekend we saw the differences between 15 lbs and 20lbs. Drastic difference.
So let's post up:
Tire size
What tire you have
Lbs of pressure
How she crawls

I'll start with mine from this past weekend. 245/75/16 Duratracs aired to 20. Didn't fair so well on the rocks. Significant tire spin.

245/70/16 general grabber 2. 12-15. Crawls awesome with limited spin (unless my lead foot hits anything).

245/70/17 Terra Grapplers. Run 20. Works good on rocks, probably could go lower but it's good enough. Plus for trips like Windrock where you're staying in town you don't have to air up to get on the road for a bit.

Ran my 265-75-16 Duratracs at 18, worked great no spin ( well unless I wanted them to :icon_lol

This is good feedback. At 20psi and a grade of 55 or more I get lots of spin

I'd think the tire composition from brand to brand, age, etc, would make this an individual one at a time decision.

Drag racers often drill holes in rim flanges and "screw" the tires on to keep em from turning on the bead. Anyone ever done this for really low pressure crawling?

Bob

right around 10-12psi
35x12.5R17
Treadwright Guarddogs

Haven't had an issue but here in Iowa I also haven't really gone to extreme.

M38 Bob said:

I'd think the tire composition from brand to brand, age, etc, would make this an individual one at a time decision.

Drag racers often drill holes in rim flanges and "screw" the tires on to keep em from turning on the bead. Anyone ever done this for really low pressure crawling?

Bob

Click to expand...

Right, that's why I was asking about the size and type of tire. Gives ya a better idea

My 02
265/75r16
guard dogs
12-15 psi
Crawls? She climbs lol.

My 06
265/75r16
Hankook dynapros atm P rated
15-18 psi
Does decent

M38 Bob said:

I'd think the tire composition from brand to brand, age, etc, would make this an individual one at a time decision.

Drag racers often drill holes in rim flanges and "screw" the tires on to keep em from turning on the bead. Anyone ever done this for really low pressure crawling?

Bob

Click to expand...

They also use inner tubes..................


If you want to drop low get beadlock wheels,really low get double beadlock wheels($450+ per wheel).




When I ran 265/75R16 MT/R's I dropped to 12psi on a 7" rim.For 265/75R16 Trxus MT's on a 7" rim I dropped to 10psi.On my 35x12.50x15 MT/R K's on a 8" rim I drop to 10psi but 6psi would work so much better but $5000 for double beadlock rims and tires is not high on my list since I'd have top jump to 17" rims/tires for double internal beadlock wheels.

HoosierJeeper said:

245/70/17 Terra Grapplers. Run 20. Works good on rocks, probably could go lower but it's good enough. Plus for trips like Windrock where you're staying in town you don't have to air up to get on the road for a bit.

Click to expand...

I think I aired down to 18psi on my Firestone Destination AT's two years ago at Windrock and that drive on the road to the far side of the mountain was squirrely - didn't do my tires any good. Probably should have stayed at 20psi like you did, HJ.

However, on the trails the Firestones did far better than I expected. Very dry conditions, mostly rock, dirt & gravel.

Bob

Maybe next time I go crawling I'll air down to 15, and monitor the wheels. I'm gonna start making mental notations until I find what works well. It also depends in the weight of our vehicle too.

TwoBobsKJ said:

I think I aired down to 18psi on my Firestone Destination AT's two years ago at Windrock and that drive on the road to the far side of the mountain was squirrely - didn't do my tires any good. Probably should have stayed at 20psi like you did, HJ.

However, on the trails the Firestones did far better than I expected. Very dry conditions, mostly rock, dirt & gravel.

Bob

Click to expand...

That time when we aired down we had left the gauge somewhere and we had to air down with a pebble and borrowed a gauge from Sarah and Louis- good first impressions :happy175:

WickedBruce said:

Maybe next time I go crawling I'll air down to 15, and monitor the wheels. I'm gonna start making mental notations until I find what works well. It also depends in the weight of our vehicle too.

Click to expand...

If your running LT tires(load range C,D,or E) and at least a AT tread design with some shoulder tread you can air down to 10psi easily if your on a narrow rim like a 265 wide tires on a 7" rim,15psi easily for a 245 on a 7" rim.




I would not recommend going lower then 18psi on a P metric tires and not to air down at all with retreads(not safe,sorry but not).

General Grabber AT2 235x85 R16
I usually go to 16 PSI for rock crawling

Mastercraft Courser AXT LT245/75/16
When hill climbing I had em at 20 psi and they were just fine, no wheel spin unless I got on her. Pretty impressed with this tire so far. Just did a 200 mile round trip to the Detroit area and back on Wednesday ran em at 33 psi cold and they heated up to around 35 psi cruising I75. Smooth and decently quiet. I know it's not rock crawling but it's something!