Tire Pressure?

[N80]

Got a new trailer. 8000# 19' flatbed. Tires came from dealer at 80 psi which is the maximum pressure for the tires. I'll be hauling a 3500# car. The little owner's manual for the trailer says keep the pressure at maximum for the tire. Does that sound right? I've never owned my own trailer and do not recall running those sorts of pressures in other trailers. Need quick advice, heading out this afternoon.

Also, truck tires are load range D and have maximum pressure of 50 psi. I normally run about 38 psi when not towing. Any recommendation on truck tire pressures? (2003 F150).

Thanks for the help guys.

 

[RPW]

Yes, when hauling you run your trailer tires at maximum. under inflated tires generate excessive heat leading to blowouts. Same with vehicles.

 

[Diamondpilot]

It's 100% correct. Always run trailer tires at max pressure.

Chris

 

[Diamondpilot]

Vehicle tires should be run at the rate in the door jamb if OEM or somewhere between that value and the max on the sidewall of the tire.

I often run my rear tires 10 psi higher than my front when towing depending on load.

Chris

 

[RedNeckRacin]

Bump up your rear truck tires too. I'm guessing your tongue weight is only going to be a few hundred lbs, but squishy tires are no fun when you are towing. I had E range tires on my 1ton srw diesel that I ran around 50 psi when commuting, but I would bump them to 70 to 80 depending on how heavy the trailer was and if it was a GN or BP. Doesn't have to be to technical.

 

[Egon]

Your truck tire's can be run to maximum shown on the sidewall. Higher pressure will usually keep tire cooler but ride rougher.

On mine load range E are run at 80 psi.

 

[Qapla]

Got a new trailer. 8000# 19' flatbed. Tires came from dealer at 80 psi which is the maximum pressure for the tires. I'll be hauling a 3500# car. The little owner's manual for the trailer says keep the pressure at maximum for the tire. Does that sound right? I've never owned my own trailer and do not recall running those sorts of pressures in other trailers. Need quick advice, heading out this afternoon.

Also, truck tires are load range D and have maximum pressure of 50 psi. I normally run about 38 psi when not towing. Any recommendation on truck tire pressures? (2003 F150).

Thanks for the help guys.

Do the trailer tires actually say that 80 is the max? You need to make sure they are really trailer tires, not car tires mounted on a trailer (they most likely would have "ST" on the side marking if they are trailer tires). One of the differences is, trailer tires have a much stiffer/stronger sidewall designed to carry the weight - a smooth ride is not as important as the ability to carry the load - after all, no one should be riding on the trailer when hauling.

If they are genuine trailer tires, yes, go with the 80

On the truck tires, since they are load range D, make sure not to exceed the max pressure - the next time you need tires, consider getting load range E (truck tires) if you plan on carrying heavy loads and/or plan on pulling that trailer often.

 

[N80]

Thanks guys. Yes, they are real trailer tires and are marked 80. I'm going to put 50 in the rear truck tires and 45 on the front.

 

[Copperhead]

It is really too bad that tire manufacturers do not provide good load pressure tables for the smaller tires. They are pretty good about doing so with heavy truck tires. I have learned over time to extrapolate a ideal pressure for tires based on loading. If you notice, most smaller tires, like those on trailers, will show a max weight rating also. The max pressure is for than max loading. It is not the best idea always to run the max pressure just because it is what the tire is rated for. For instance, my semi truck, the drive tires are rated for 120 PSI. But the load pressure tables from Michelin show that, based on a typical 34,000 lb set of drive axles, the tire pressure for the 445/50R22.5 tires I am using should be around 95 PSI. Must be right, as I got 447,000 miles out of the last set, they still had 8-9/32 tread left, nice even tire wear, and the dealer gave me $150 each for them. I have taken the same concept and extrapolated pressures for my 3/4 ton pickup tires. OEM says run 60 front, 70 back. I run 55 all the way around when empty and only inflate more if I know I will be loading it down significantly. Tire life is great, ride is much better, and even mpg improved slightly because of less rear wheel "hop" on bumpy roads due to OEM recommend pressure.

Trailer tires, take a look at the total weight rating of the tires, determine what actual weight they will be having to deal with, and adjust accordingly. Tires need to absorb road shock that would be transmitted to the suspension, and a proper footprint needs to be on the ground to ensure best wear, best handling, etc. Too high of pressure for the load and uneven tire and suspension wear can be a problem as well as a reduction in performance on wet roads, braking (if trailer has brakes), etc. It is a balancing act to some degree. One doesn't want too low of pressure as sidewall flex can be extreme, but being rock hard is not good either. One of the best ways I have seen to determine the proper pressure is draw a chalk line across the tread, from side to side, on the tire then drive it a few revolutions. Check the chalk mark. More wear in center, then over inflated. More chalk wear at edges, under inflated. One wants a nice even wear across the entire chalk line, and that is the correct inflation for the load. Do that with a max rated load on the trailer and determine a good pressure for that application.

 

[N80]

Follow-up: Pulling this trailer empty is a pain. Very bucky and bumpy. Loaded it pulls great. So, I recently used it to tow some bulky but very light stuff so I dropped the pressure down to 60 psi in the trailer tires. It made a noticeable difference in towing with a light load. Way more comfortable. Probably could run them at 50 psi empty.

So, I agree with Copperhead. Bottom line, I'll run them at 80 when loaded, 50-60 when light.

 

[Egon]

Do you carry one of the small 12 volt compressor's ?

 

[N80]

Do you carry one of the small 12 volt compressor's ?

No, but I should. Usually when I'm towing to the track I have my pancake compressor with me but that requires an outlet.

 

[Diamondpilot]

Have you had them balanced? I don't care what anyone says all tires should be balanced. It will make a huge difference unless you have the hub style wheels. Them things never seem centered right.

 

[SandburRanch]

Mowing side hills I keep my tractor tires inflated to maximum. The X-tra weight on an under inflated down hill tire cannot be good. If on a maximum slope and that tire should roll from the rim, grab that roll of toilet paper. The one thing that may save rolling is fluid still in the up hill tire.

 

[N80]

Have you had them balanced? I don't care what anyone says all tires should be balanced. It will make a huge difference unless you have the hub style wheels. Them things never seem centered right.

No, but I think they have balance weights on them so apparently balanced at factory. The trailer does not buck or bounce on smooth roads even with the tires fully inflated. But any small bump is felt (and heard (ramps)) in the truck. With less air in the tires it just handles road bumps etc a lot better when it is empty or a light load. Will probably tow my tractor soon and will inflate back to 80.

 

[N80]

Mowing side hills I keep my tractor tires inflated to maximum. The X-tra weight on an under inflated down hill tire cannot be good. If on a maximum slope and that tire should roll from the rim, grab that roll of toilet paper. The one thing that may save rolling is fluid still in the up hill tire.

I keep my tractor tires at max inflation. I have rolled the fronts off the rim multiple times while turning downhill on small grades with a load in the bucket and underinflated ag tires. I put tubes in them a while back and it hasn't happened again but I'm pretty diligent about keeping them topped off.

 

[Egon]

Forgot to mention; with the 12 volt compressors plug in wires that are long enough to reach the trailer tire's can be handy when needed.

 

[N80]

Forgot to mention; with the 12 volt compressors plug in wires that are long enough to reach the trailer tire's can be handy when needed.

Good point.

 

[coobie]

Have you had them balanced? I don't care what anyone says all tires should be balanced. It will make a huge difference unless you have the hub style wheels. Them things never seem centered right.

++1 had my 20 ft PJ tandem axle Trailer tires balanced.Empty pulls 100% better.Discount tire manager told me a balanced trailer tire will get 50% more life verses unbalanced tires.Don't know if thats true or not but my trailer pulls a h-ll of a lot better now.

 

[Copperhead]

Probably reasonable, N80, on the pressures you mentioned for you truck when loaded and unloaded. That would be in the ballpark anyway. I still would recommend you contact the tire manufacturer and have them email you a load / pressure chart on your particular tire. I found out though, that if you mention the vehicle, they will punt to the vehicle OEM and not let you have the chart. Just tell them the tire, not the vehicle, and they will most likely send you the chart. BFG emailed me a chart recently on the E rated KO2's I have on my pickup.