# What Tire Pressure For 21Rs With Towmax Tires?



## Thunder Mountain (Jun 24, 2012)

Getting the Outback ready for the season. I can't find my notes telling me what tire pressure to maintain in the stock Towmax tires. When I checked the pressure the four tires varied from 41 psi to 50 psi. On the tire sidewall max pressure at max load is 65 psi. I put 54 psi in this morning to take it out for a trail run.

Most of my driving is 55 to 65 mph with some 70 mph on runs of 200 miles or less.


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## Todd&Regan (Jul 1, 2010)

Recommended tire pressure information for the stock tires is located on the Keystone information sticker on the outside left-front of your camper. For my 270BH with Towmax tires, the recommended tire pressure is 65psi.


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## Thunder Mountain (Jun 24, 2012)

double d said:


> Recommended tire pressure information for the stock tires is located on the Keystone information sticker on the outside left-front of your camper. For my 270BH with Towmax tires, the recommended tire pressure is 65psi.


Sticker only says 65 psi at maximum payload just like the sidewall of the tire. I've never run tires at max psi. Just wonder what people are airing up their tires in the real world.


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## CamperAndy (Aug 26, 2004)

The load carrying capability of the tires is in direct relationship to the tire pressure.

Run them at MAXIMUM at all times. This increases the tire load capability to its rated max and improves sidewall stiffness. It also reduces tire heat and rolling resistance. Don't look at trailer tires the way you would the tires on your car.


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## KTMRacer (Jun 28, 2010)

I agree with camper andy.

Unlike car/truck tires where the inflation pressure is determined by the tire load, most of the ST tire mfg specify they should be run at the max sidewall pressure regardless of load. It has to do with tire construction and the very high side loads ST tires take during a turn or backing.

I've done that for years, and even though max pressure is significantly higher than the tire pressure base on load, my ST tires have worn evenly and gone a long time, typically 25K miles or so per set and still had tread left, but were getting near the age related replacement time. Neighbor does the same thing, tows close to 20K miles/year and tire wear evenly and he gets 30K+/tire set.

My latest tire set are LRE inflated to 80psi even though by the pressure vs. load it would only be about 50psi. Even with that again, the tires are wearing evenly and the stiffer sidewall does seem to make the trailer more stable.


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