Community Forums

retabfc · 08-05-2013, 01:33 PM

Can someone tell me what the proper tire pressure is for a Rockwood TT 21FBRS which is about 4,500 LBS. on the road. all the tires had 25LBS. I keep 50 LBS. in my tires A Rockwood Roo TT about 5,000 LBS.I have over 12,000 miles on these tires with no troubles so far

Thanks For Any Help retabfc

tompen · 08-05-2013, 01:41 PM

Set them at the cold pressure listed on the tires. Pressure will go up when they get hot. This is normal. Invest in a good gauge.

Cliffy · 08-10-2013, 01:30 AM

Set them at the pressure shown on the sidewalls if they are trailer tires.
If they are older than 6 years get rid of them.

Ray,IN · 08-12-2013, 06:55 PM

I agree with the previous 2 replies, with one addition. ST tire manufacturers recommend replacement at 3 years; and give this as the reason they have less tread when new.

Cumminsfan · 08-12-2013, 09:14 PM

I replace my tires every year whether I use them or not. Just too paranoid about blowouts from reading too many RV forums.

Too the OP there's no min/max pressure like car/truck tires. Only PSI you can run in ST tires is the PSI on the sidewall of the tire.

Cliffy · 08-13-2013, 03:17 PM

Michelin and one other tire maker (I can't remember who right now) actually have tire pressure vs load capability tables published on their web sites for ST rated tires. Both are very similar in what they show. As I am way over strong on my TT with load range D tires so I'm using 55 psi instead of 65 just for a little less bounce on the road from harder tires. Using Michelin data I'm still way below tire capacity at 55 psi. Last trip was 5000 miles and the tires still look new.I check pressures every week on the road. It's my feeling that most ST tires are blown up by lack of attention, overloaded with big TTs and old age than any with proper set ups. STs also have a max speed rating of 65 mph. How many times have you been passed by a big 5th doing 70 or more down the road?

FastEagle · 08-15-2013, 04:01 PM

Quote:

Originally Posted by retabfc

Can someone tell me what the proper tire pressure is for a Rockwood TT 21FBRS which is about 4,500 LBS. on the road. all the tires had 25LBS. I keep 50 LBS. in my tires A Rockwood Roo TT about 5,000 LBS.I have over 12,000 miles on these tires with no troubles so far

Thanks For Any Help retabfc

Like your car or truck your trailer also has a tire placard/certification label. That's where you'll find the correct tire pressure (s) for your trailer's tires. They are also displayed in the trailer's owner's manual.

FastEagle

capsfloyd · 08-15-2013, 04:45 PM

If your using higher rated tires , or larger tire that is listed on TT , you will need to go by what's on the side wall of the tires

Campnfools · 08-16-2013, 07:19 PM

We just came home from a trip and ironically I planned on asking a related question. Before I do, I'll insert my answer to the original post. I agree strongly with FastEagle. There should be a placard somewhere on the rig which states tire size and required pressure. This is the pressure you should run and, the only size tire you should use. And, buy a quality tire.

Tire pressures are to be set when the tire is cold. This is my part of the question. We all know that correct tire pressure is critical to safety and tire longevity. I take this very seriously. I carry a compressor with me on every trip. ANY time I move the rig down the road, I check pressures on tow vehicle and trailer. I usually do this either the evening before the run or, early in the morning before the sun has a chance to have a heat effect of the tires. But, what if I had to move unexpectedly and one side of the rig was being hit by the sun and the other wasn't. Any idea how I would adjust for such a scenario?

TeJay · 08-16-2013, 07:57 PM

Well common sense is what I'd use. If one side is hotter then the pressures should be up some. What you are trying to avoid is a situation where you run a tire with low pressure. Variations in tire pressures will occur all day long as you travel and as you hit the sun or moon. Pressure variations from 2-10 lbs will occur. This is observed if you use a TPMS. The manufacturers allow for this change because it will occur.

If you start the morning and your tires on the hot side are up some then you don't have a leak and that's what you are determining by being diligent in regards to your tire pressure.

I'll disagree with some that has been said. The pressure listed on the side of the tire is the maximum pressure for that tire if loaded to its maximum weight. However not every tire out there is carrying its maximum weight. As stated, the sticker on the vehicle usually lists the best tire pressure for that vehicle but it is not always the same as the pressure listed on the sidewall. Since the TT industry usually builds on the CHEAP they will almost always give you a tire that is just barely able to carry the weight of your TT and its cargo.

That said, most TT's are probably loaded to the max weight and therefore should be filled to the pressure listed on the sidewall.

TeJay

Atlee · 08-17-2013, 03:44 AM

I disagree that the size tire on the placard is the neccessarily the size tire you should use.

Sometimes the trailer maker will have a tire on the trailer, that while it meets the letter of the law, does not give any margin of error. In those cases, one should either go to the next size in load range, ie fm C to D, etc. or up a size in tire.

Quote:

Originally Posted by Campnfools

There should be a placard somewhere on the rig which states tire size and required pressure. This is the pressure you should run and, the only size tire you should use. And, buy a quality tire.

TeJay · 08-17-2013, 07:17 AM

I agree with your assessment of the tire size as recommended by the TT manufacturer. If you can go to a larger rated tire for the rim that you have then by all means do so. It is better weight protection for you and your TT. We had three TT with 14" rims. The 14" rim only allowed you to use a tire that was rated one letter higher than what the TT company used. I did change the tire to the next level or load range. At that point you should not use what the sticker rated the first tire because now you have a different tire. You can and probably should use the rating on the sidewall since you will probably load that tire very close to the maximum load.

Here is what I was saying. The pressure rating on the sidewall is only recommended if you are carrying the maximum load. That is the maximum tire pressure for that tire if it is loaded to its maximum weight. Not every tire is loaded to its maximum. In that case, as in many passenger and truck tires use the sticker pressure rating for that tire as recommended by the truck/car manufacturer.

My experience over many many years is often the sidewall pressure rating is the only rating used to inflate the tire. A tire could be used on several vehicles that all weigh different. One should use the sticker rating as recommended by the manufacturer for the best ride for that vehicle.

TeJay

FastEagle · 08-17-2013, 10:35 AM

For the RV trailer tire there is only one correct tire pressure and it’s found on the tire placard and in the owner’s manual. The vehicle manufacturer has told the owner that to protect his investment he needs to keep his tires aired to the recommended pressure (s). The lack of proper tire pressure (s) in RV trailer tires accounts for a very high percentage of the overall failures and is well documented by numerous sources including the NHTSA.

Remember, the ST tire is designed to operate at it’s full potential - all the time.

FastEagle

wingnut60 · 08-17-2013, 11:42 AM

"There should be a placard somewhere on the rig which states tire size and required pressure. This is the pressure you should run and, the only size tire you should use. And, buy a quality tire"

So, you say you should never upsize the tires? And, as to quality tires, take a look at a lot of OEM trailer tires as to origin...do all the mfgs supply 'quality' tires?

Tire discussions seem to be a hotspot like vehicle brands, motor oils and politics...

Joe