Tire Pressure?

[mageorge]

my 2014 Reflection 303 is running with 70-72 pounds of pressure (cold). What are others running? And where do you go to get Nitrogen added? Thank you.

 

[thompsons 369rl]

Our tires are rated to run 80 psi (cold). We try to keep them as close as possible to the rated pressure. The sidewalls of your tires will tell you the rated pressures and loads for that tire. There should also be a sticker on you rig that gives tire size and pressure info. As to running nitrogen, there's a thread that covers that subject, but in most folks opinion, the benefits of running nitrogen vs air are not worth the trouble of finding places that have it.

 

[Mr Lucky]

I run my 303 tires at 80psi {cold}. I check them before I hook up to hit the road. I just add air if needed. I also use the TireTracker TPMS. Works great.

 

[TucsonJim]

When I changed my rubber valve stems for metal stems, I did not refill the tires with nitrogen. If you install a TPMS such as the one in this link, you need to have metal stems. http://tsttruck.com/product/tst-507-flow-thru/ .

It's very difficult to find a source of nitrogen while on the road. You are much better filling a low tire with air instead of waiting to find nitrogen. This link from tirerack.com gives a really good over view of nitrogen vs. air filling of tires. It's not worth the hype in my opinion.
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=191

As for my 337, I always run at 80psi cold. This is measured in the morning before the sun hits the tires.

 

[Retread68]

I am becoming more uneasy about "proper pressure" in tires since my trip last week. I have always aired the tires to 2 lbs under max rating prior to pulling regardless the time of day, ie: at ambient temp prior to pulling. Last week my intent was to start pulling at 0900 hrs and the temp was 54 degrees. When I checked tire pressure on two tires they both were at 70 lbs. Then a camping neighbor came over to chit-chat; and when we concluded it was 1000 hrs. I decided to continue checking the other 2 tires on the 5er and found them to be at 78 lbs. This made me double back and in doing so I found the original 2 tires were now also at 78 lbs.

Thus my daily confusion topic was identified ! When do I really want to put additional air in the tires? The ambient air temp changes quickly where I was and had I added more air based on conditions 1 hr prior to starting my pull there may have been adverse consequences. How much is too much ?!

The older I get, the less I know !

 

[thompsons 369rl]

That's always a tough one. It's one of the reasons I use a TPMS. When traveling, the temps can change drastically. One can only do their best to keep pressures at the rated spec. In extreme conditions, I have had the TPMS tell me there is a over pressure condition. I just pull over and let a few pounds out and continue on my way. Have never had it go the other way unless there was a leak. The TPMS helps take the guesswork out of the equation.

 

[pwrplay]

Just fill to 80 and don't worry about it. You won't hurt the tire if overinflated a little bit. Under inflated is far worse than over inflated.

 

[TucsonJim]

This is a really good article on tire pressure versus temperature and direct sunlight. It explains quite a bit.

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=147

 

[mageorge]

I'm sitting in the Coachlight RV camp ground now where I bought my 303. I'm having some warranty work done, new table top and kitchen island doors. I asked about the tires. The tires say 65# and the sticker on the rig says 80#. The service manager called Grand Design and was told the sticker was not correct.

 

[Canyonlight]

Our VIN # sticker tag does state 65lbs. matching the tires rating. Tucson Jim--great article regarding nitrogen v.s. regular old compressor air......I had forgotten the high % of nitrogen in regular old air.

Dan

 

[thompsons 369rl]

I'm sitting in the Coachlight RV camp ground now where I bought my 303. I'm having some warranty work done, new table top and kitchen island doors. I asked about the tires. The tires say 65# and the sticker on the rig says 80#. The service manager called Grand Design and was told the sticker was not correct.

Wow! That's kind of a big deal IMO. I hope there aren't any more rigs out there with that mistake. Many of us rely on that sticker for proper inflation pressures let alone the fact that, if there were a tire failure due to over inflation, who's responsible for the damage it may cause? Let's hope GD is looking into this and notifies any other owners that may be affected as well as making sure this kind of error doesn't happen again.

BTW
Thanks, Jim for the article. Very informative.

 

[Retread68]

Interesting. My 2015 303 RLS #645 came with E rated tires (80 lbs). That was one of the positive factors in my evaluation of the unit.

Several years ago a tire mfg rep told me the major benefit of using N2 vs regular air was that the N2 would prevent tire rot occurring from the inside out as found with regular air due to moisture in the air. I've run a lot of tires during my years and I don't recall ever having one rot from the inside out; thus I just keep using that old fashioned air and hope it doesn't leak out !

 

[Mr Lucky]

That's always a tough one. It's one of the reasons I use a TPMS. When traveling, the temps can change drastically. One can only do their best to keep pressures at the rated spec. In extreme conditions, I have had the TPMS tell me there is a over pressure condition. I just pull over and let a few pounds out and continue on my way. Have never had it go the other way unless there was a leak. The TPMS helps take the guesswork out of the equation.

Today getting ready to leave for camping trip so first thing I checked was air pressure in cold tires and adjusted to 80lbs . It was very cool in the morning. I was on the highway doing 55-60 miles per hour and my buzzer was going off on my TPMS and my tire pressure was getting over 90 lbs in 2 of the tires. The other 2 tires were around 89 lbs. So I just pulled over and took out 5 lbs in all 4 tires. Also noticed the 2 tires in direct sunlight going down the highway had higher temperature in the tires. Once I was at my campground and my tires had cooled down I filled them back to 80 lbs. I like having a TPMS system. Just got it this year!

 

[Dave and Monica]

The tire pressures increase 10 to 12 psi from my observations when towing. If you check the TPMS manual, they should suggest settings for low and high pressure alarms. I think that you've got the high alarm set too low. I've set ours at 95 psi and have only had it alarm once when we had a 60[SUP]o[/SUP]F swing in ambient temperature the same day.

Dave

 

[Navigator-MGRV]

Our TPMS manual recommends a setting of 20% above the cold tire pressure for the high parameter setting and 10% below the cold tire pressure for the low parameter setting. They also recommend leaving the temperature at the factory default of 158 degrees F. Our cold tire pressure is 80 psi so our high setting is 96 psi and low is 72 psi.

The following is from the TPMS manual...
Every brand of tire operates differently, when some brands reach operating temperature the psi will increase 5 psi, other brands may increase 20 - 22 psi.

We noticed that difference in psi when we had to replace an original tire with another brand. The pressure in the new tire was considerably higher that the other three original tires. Hope that helps!

Kathy

 

[TucsonJim]

Today getting ready to leave for camping trip so first thing I checked was air pressure in cold tires and adjusted to 80lbs . It was very cool in the morning. I was on the highway doing 55-60 miles per hour and my buzzer was going off on my TPMS and my tire pressure was getting over 90 lbs in 2 of the tires. The other 2 tires were around 89 lbs. So I just pulled over and took out 5 lbs in all 4 tires. Also noticed the 2 tires in direct sunlight going down the highway had higher temperature in the tires. Once I was at my campground and my tires had cooled down I filled them back to 80 lbs. I like having a TPMS system. Just got it this year!

Mr Lucky - I'd really recommend against bleeding off the pressure when the tires heat up. They are designed to be filled to 80psi cold, and the engineers who built them understand that the pressure increases with temperature. It will not hurt the tires when the pressure increases. Bleeding off air when they are hot effecively reduces the load carrying capacity of the tires. BTW, on my rig, the tires that are in direct sunlight always have higher pressure and temperature when going down the road.

 

[mtpocket]

I have to agree with TucsonJim. I set mine to 80 before I leave for the day. Sometimes I have to add and some days I may have to let some out. After that, as long as it doesn't go down while traveling I leave it alone. I don't pay attention to how high the pressure goes up on the road. I believe that is taken care of in the tire design. As long as both tires on the same side are within a few pounds and degrees I am not concerned.

 

[Mr Lucky]

Great info guys ,Thanks!

 

[RGMutchler]

The air or nitrogen we put in our tires is a gas and it increases or decreases with temperature in a predictable way. I don't run nitrogen so I have never looked it up but the atmospheric air we put in our tires increases or decreases in pressure about 2% for every 10 degrees. When you run down the highway the temperature in the tire increases or decreases based on ambient air temp and due to the friction created by the tire on the road. For a load range E tire rated at 80 PSI cold that would mean 1.6 pound increase or decrease in pressure for every 10 degrees of temp. Consequently, when the temperature is 60 degrees one morning and you set your pressure at 80 psi but 40 degrees the next morning you will need to readjust the pressure because it will be a little more than 3 degrees lower than it was the morning before at 60 degrees. As to the max pressure I have yet to get any of the tire manufacturers to publish or state a max pressure or a max temperature for their tires. When I have talked to the Tire pressure sensor folks and asked how they arrived at 20% or what ever the different ones recommend they are unable to tell me where the 20% number comes from.
I hope this is useful.

 

[ruskin219]

Check out what is said on the internet about nitrogen filled tires. They do run cooler and supposedly stay inflated longer but basically if you're not a race car driver, nitrogen filled tires are an income generator for tire stores and not needed for consumer application. The good news is that when your nitrogen filled tires need to be brought up to pressure, you can simply add air.