Tire pressure on HF trailer

[GeorgeT]

My Hf trailer manual says "60 psi required" for tire pressure. Was wondering if the 60 psi requirement is needed to handle the weight rating of 1450 lbs or do the tires have to be inflated that much to make them safe no matter what weight you are hauling. What tire pressures lower than the 60 psi requirement have you run your HF trailer with no problems and no excessive treadwear and such. I'd like to be able to run with a bit lower tire pressure to smooth out the bumps. Thanks for your responses.

[mikeschn]

Frank could better answer that question, but I believe that trailer tires are designed for very heavy loads, hence the high pressure ratings.

With our lightweight teardrops and ttts, we can use automotive tires rather than trailer tires, and we can reduce the pressure to keep it from bouncing around like a jack rabbit.

Eariler today there was a thread on reducing tire pressure... I'm in agreement with that!

Mike...

[angib]

This Goodyear Load/Inflation chart pdf doesn't go below 175/80R13 but does show the relationship between capacity and minimum pressure. So for example those 175/80R13 STs (proper trailer tires) will carry 670 lb each at 15 psi!

I read this chart to show that 60 psi max tires can probably carry around 2/3rds of their capacity (on the sidewall) at 30 psi and around half the capacity at 20 psi.

It is interesting to see from these charts that the capacity of tires with different load ratings (eg, 'B', 'C', etc) is the same at the same pressure - the higher rated tires can just take more pressure and so carry more.

Andrew

[BobR]

When vehicles are operated on normal roads it is always best to follow the inflation pressures in the owners manual...anything else and you are setting yourself up for a potential problem.

With that said here is some more info to ponder....

When a vehicle manufacturer selects a tire size for a vehicle, they evaluate the vehicle's gross axle weights, the anticipated use of the tire, and the tire diameter and width. If inflation pressure has varied from that which was recommended by the manufacturer, it's likely that the tire's wear and performance characteristics have also changed.

Under-inflation

If your vehicle's tires are under inflated by only 6 psi it could lead to tire failure. Additionally, the tire's tread life could be reduced by as much as 25%. Lower inflation pressure will allow the tire to deflect (bend) more as it rolls. This will build up internal heat, increase rolling resistance. The smaller the tire, the faster the heat builds up.

Over-inflation

If your tires are over inflated by 6 psi, they could be damaged more easily when running over pot holes or debris in the road.

Effects of Time and Temperature

Tire inflation pressures change due to time and temperature. Tires lose about 1 psi per month due to air escaping through the rubber as it stretches. If you were to check your tires only every six months, it would not be uncommon to find them under inflated by as much as 6 psi. Tire inflation pressures also fluctuate with changes in the outside air temperature. This occurs at a rate of about 1 psi for every 10°F (plus or minus). So the tires you set correctly with an 80°F ambient temperature will be under inflated by 6 psi at 20°F.

If you add the variations of time and temperature together, it is easy to understand why a tire's inflation pressure should be checked frequently. Improper inflation can cause tires to wear irregularly and can void manufacturer's warranty.

For even more info...
https://www.rma.org/getfile.cfm?ID=432&type=publication

[ALAN GEDDES]

I have been told several times that the skinny little 12 inch tires have been known to roll off the rims when underinflated. This from guys with boat trailers. Strictly hearsay, no experience.

[GeorgeT]

My HF is a bit bouncey with 45 psi. With 60 psi I would probably be able to see under it at times through my rear view mirror when pulling over bumps. I could see a 12 inch tire breaking loose from the rim on a boat trailer hauling a heavy boat. I think the little 12 inch tires on these HF trailer based tears should be able to hold up at 30-35 psi with such a light load even going over bumps when the sidewalls are most likely to flex the most. Maybe if you's goin' off road a lot you'd need to keep the pressure up, but then you probably shouldn't be messin' with little skinny tires anyway.