Tire pressure

[Mac58]

Good morning everyone, I’m new to grand design and New to 5th Wheel’s. I’ve had a class A diesel pusher & My question is on my coach. I had it weighed in went to the tire guide to determine tire pressure. How do you do it on these fifth wheels?

[Jlawles2]

Best is to use the recommended tire pressure until you get several trips under you and determine what you will have in the unit. After that find a Cat scale and pay to have it weighed. Start with the empty TV and then reweigh with the trailer. This is so you can determine pin weight along with getting the axle weights for the unit.

Err on the side of caution with tire loads as with the suspension setup in a trailer, it may not be equal between the 2 axles.

[Cate&Rob]

Trailer weight side-to-side will not be equal on many towable RVs. You cannot take the Cat scale weight and divide equally by 4 to determine weight carried by each tire.

Rob

[Yoda]

Good morning everyone, I’m new to grand design and New to 5th Wheel’s. I’ve had a class A diesel pusher & My question is on my coach. I had it weighed in went to the tire guide to determine tire pressure. How do you do it on these fifth wheels?

Just run the max tire pressure on the tire sidewall and go. I have never aired down my tires using weight charts - can cause too many issues such as excessive sidewall flex. and heat build up if not correct. So simply air up and go.

[familytruckster4]

I always use the recommended tire pressure on the placard located on the left front of the trailer. In the tow vehicle its in the door jamb on the drivers door.

[d2reid]

While adjusting the tire pressure according to the weight chart provides a more comfortable ride I use max cold tire pressure on my 5th wheel. There is no one in their to complain about the ride.

The tire pressure charts and max cold PSI are set when the ambient temperature is 70f. If it's warmer out the tire pressure will be more and if it's cold out the tire pressure will be less. I use 1 psi per 5 degrees difference.

In all the things I have read about tire failure under inflation is the leading cause. As a result I use max cold psi (adjusted for temperature) all the time.

I am also a huge fan of Tire Pressure Monitor Systems on 5th wheels. You often don't feel or hear a 5th wheel tire go. The longer you run with a flat the more damage occurs.

[COReflection]

While adjusting the tire pressure according to the weight chart provides a more comfortable ride I use max cold tire pressure on my 5th wheel. There is no one in their to complain about the ride.

The tire pressure charts and max cold PSI are set when the ambient temperature is 70f. If it's warmer out the tire pressure will be more and if it's cold out the tire pressure will be less. I use 1 psi per 5 degrees difference.

In all the things I have read about tire failure under inflation is the leading cause. As a result I use max cold psi (adjusted for temperature) all the time.

I am also a huge fan of Tire Pressure Monitor Systems on 5th wheels. You often don't feel or hear a 5th wheel tire go. The longer you run with a flat the more damage occurs.

Great strategy and one I follow myself. I just recently added the TPMS sensors into my Reflection tires and let the truck monitor the temps and pressures. As far as the cold pressures---I was taught to always reference what's stamped on the tires for cars, trucks, trailers, campers, and etc. I run the cold max all the time and have never had an issue. Many times people change out the tires for something other than what the manufacture quoted so the tags stamped on the vehicles are inaccurate. If you follow what's stamped on the tire---you can't go wrong.....IMHO.

[familytruckster4]

I have the wheels off my Reflection and sitting in the back of my truck right now. I am going to drop them off in the AM to have the GM TPMS sensors installed.

[Cate&Rob]

familytruckster4

Get a TPMS relearn tool. Works on trailer sensors as well as truck sensors. A lot easier than letting pressure out and then refilling. The $10 tool works just as well as the $150 tool. (In my experience on my Ford).

Rob

[Jkwilson]

While adjusting the tire pressure according to the weight chart provides a more comfortable ride I use max cold tire pressure on my 5th wheel. There is no one in their to complain about the ride.

The tire pressure charts and max cold PSI are set when the ambient temperature is 70f. If it's warmer out the tire pressure will be more and if it's cold out the tire pressure will be less. I use 1 psi per 5 degrees difference.

In all the things I have read about tire failure under inflation is the leading cause. As a result I use max cold psi (adjusted for temperature) all the time.

I am also a huge fan of Tire Pressure Monitor Systems on 5th wheels. You often don't feel or hear a 5th wheel tire go. The longer you run with a flat the more damage occurs.

X2!

I own 5 trailers, and all of have run at max cold pressure for almost every mile, and they’ve been towed a lot of miles. Only time I drop the pressure is hauling empty if the trailer wants to bounce.

[Scott'n'Wendy]

While adjusting the tire pressure according to the weight chart provides a more comfortable ride I use max cold tire pressure on my 5th wheel. There is no one in their to complain about the ride.

I have seen numerous posts about higher pressures making for a poor ride. Always wondered who they put back there in the trailer......to get the feedback.......

[familytruckster4]

familytruckster4

Get a TPMS relearn tool. Works on trailer sensors as well as truck sensors. A lot easier than letting pressure out and then refilling. The $10 tool works just as well as the $150 tool. (In my experience on my Ford).

Rob

I have had one for a few years.

[Cate&Rob]

I have a cargo trailer that will bounce off the road if towed empty with full pressure in the tires. I assume a similar affect of tire pressure on an RV. Part of the question is when owners choose to upgrade trailer tires, say from 65 psi D to 80 psi E, and the trailer label says 65 psi. . . should they stay with 65 psi in the E spec tires that say 80 psi on the sidewall? I would say stay at 65 psi since this pressure will carry the GVWR of the trailer (according to the RV manufacturer).

Rob

[howson]

I have a cargo trailer that will bounce off the road if towed empty with full pressure in the tires. I assume a similar affect of tire pressure on an RV. Part of the question is when owners choose to upgrade trailer tires, say from 65 psi D to 80 psi E, and the trailer label says 65 psi. . . should they stay with 65 psi in the E spec tires that say 80 psi on the sidewall? I would say stay at 65 psi since this pressure will carry the GVWR of the trailer (according to the RV manufacturer).

Rob

That's exactly my situation, Rob. I've tracked wear on my 315RLTS' tires closely, so based on difference in the tread depth I know if the tire is under or over inflated. My rig has a sticker that says 80 psi, but run a Sailun tire with a sidewall maximum of 110 psi. Currently (due to known wear patterns) the tires are set to 90 psi.

For those with OEM-spec'd tires I agree with the sentiment to "set it and forget it" (air up to label pressure). For the minority that are not running OEM-spec'd tires, a bit more time and investigation is required (IMO).

For more on the tracking I've done, see https://gdrvowners.com/forum/operati...nd-conclusions

Howard

[Yoda]

The other major factor in ride quality is balancing the tires. Years ago I bought a PJ 30' deck over goose neck and drove it back to Durango from ABQ (3 hours at 65+) I made it about 50 miles before I had to find a tire dealer and get the tires balanced as the trailer was bouncing all over the place. One was so far out they had to dismount and spin the tire. It was still bad so they swapped it out for the spare. Once balanced everything smoothed out. I think we have probably all seen a trailer with at least 1 tire bounding.

As for interior ride - with no one in the 5th wheel. I have a rear kitchen and I can sure tell when things bounce around.

Now Rob Cate&Rob makes a good point if upgrading from say E at 80 psi to G at 110 psi or more (for those with 16" wheels), that staying at 80 is probably correct. Consultation with the tire pressure/load charts is probably in order too as I don't think the capacity is linear with tire pressure.

Keith