Is it OK to air down "P" rated tires?

[grahamfitter]

A friend of mine has a 2008 Tacoma quad cab with a 4 wheel camper. Its stock except for some air springs. Stock includes some cheesy 245/75R16 "P" rated tires.

We're planning on taking the Taco to Maine's Northern Woods this weekend to kayak a couple of interesting whitewater rivers. The roads are all dirt -- rutted and pot-holed -- and jarring with tires at street pressure. I usually air down the MTRs on my Jeep to 15 PSI and it rides like a Cadillac. Comparatively speaking, of course.

I was doing pretty much the same thing last weekend (yup ) and a local old-timer raft guide told me that, because the area has a lot of sharp blue shale, its a bad idea to air down any tires. I came across a car with two flats, possibly because of that.

So here's the big question: Should we air-down the Taco's cheesy "P" rated tires for a more comfortable ride?

Cheers,
Graham

 

[computeruser]

A little bit to take the edge off the ride, perhaps, but I'd not go crazy. I'm guessing it doesn't have the stoutest sidewalls out there...

 

[gabepari]

We rescued 5 people in an actual Cadillac, some sort of crossover SUV thing, on Racetrack Road in DV with 5, count 'em, 5 flats. They were running street pressures, the sharp rocks tore them to shreds. I think sharp rocks are going to get ya no matter what. But personally I would rather air down a little and have some chance of the side wall flexing over, away or around the rock. Just don't let the comfy ride trick you into going too speedily down the road.

Gabe

 

[Sportsman Matt]

All the P stands for is metric now. Before you had LT and P to differentiate between Light Truck and Passenger Cars. The P is sort of gone by the wayside, for all vehicles coming from the manufacturer, with the exception of Heavy Trucks, are Pxxx/xx-xx rated tires. I would look at the particular manufacturer's literature about the sidewall construction and consider if the sidewalls would be strong enough to do what you want.
BTW I bought my latest set of tires, they are marked 265/75-16, no P or LT written on them, but in the small fine print on the load and pressure label, it says Load Range E.

Good luck

 

[Redline]

Interesting. I wasn't aware that the "P" or "LT" was being officially dropped. My recently purchased LT285/75R16 tires DO have "LT" in front of the size.

All the P stands for is metric now. Before you had LT and P to differentiate between Light Truck and Passenger Cars. The P is sort of gone by the wayside, for all vehicles coming from the manufacturer, with the exception of Heavy Trucks, are Pxxx/xx-xx rated tires. I would look at the particular manufacturer's literature about the sidewall construction and consider if the sidewalls would be strong enough to do what you want.
BTW I bought my latest set of tires, they are marked 265/75-16, no P or LT written on them, but in the small fine print on the load and pressure label, it says Load Range E.

Good luck

 

[spencyg]

No idea about the tires, but I'll be offended if you don't stop by on the way through for a beer in the old port

Spence