Towing an empty toy hauler

[AMink]

As I've mentioned in some other posts, we're looking at getting a 5th wheel TH to replace our '05 Wildcat 29BHS (which is now for sale). As I ponder the gagillion options, models, floorplans, etc. I got to wondering about towing while the TH is empty or lightly loaded. Most of the haulers we're looking at have a capacity far greater than I anticipate needing. I really don't see running with 160 gallons of water, a full fuel station, and a load of toys. Maybe half the water and a quad.

So, the question is, do I lower the tire pressure like I do when running the truck empty or just leave it at max and call it good? It seems like E rated tires (all the ones we're looking at have 16" rims and dual axles) would be pretty tough on all the insides if fully inflated.

 

[Wertles]

I always kept mine at 80psi loaded or not. I never had an issue. I had 16 inch tires with three axles. No science behind what I did but I can't see 20psi lower tires being that significant in terms of a softer ride inside the fifth wheel.

 

[RustyJC]

The tires on our 5th wheel (Goodyear G114 215/75R-17.5) are rated 4,805 lbs @ 120 PSIG. I always run them between 115 and 120 PSIG cold. Manufacturers size the tires on many RVs so that they are running 90% or more of their rated load (I had one that was 97%!). To DRV's credit, our current 5th wheel has a total GAWR of 16,000 lbs, so the factory tires have 3,220 lbs (805 lbs x 4 tires) of margin even at full rated load. Even with that said, I'm not really that worried about ride in the 5th wheel - I'm more concerned with load carrying capacity. I would run them at whatever your loaded inflation pressure is even when you're unloaded.

Rusty

 

[BILLUA]

I put a set of Dexter Easy Ride equalizers on my Fifth Wheel toy hauler and it rides much smoother. Those combined with my Demco Glide Ride makes this thing a dream to tow...
Lowering the tire pressure will not appreciably change the ride of the trailer.

 

[AH64ID]

I have always ran my tires at the proper inflation for the load, and maybe 5psi high when traveling at high speeds for a long distance. I have never had a pressure/load/speed related failure.

Too much air pressure is not better than proper air pressure. Too much air leads to irregular wear, decreased traction, and increased susceptibility to tire failure from punctures and impact (potholes).

You generally will want to run with the water either full or empty as most tanks are not baffled.

 

[RustyJC]

Conversely, in 20 years of towing 5th wheels, I've never had a failure due to puncture or impact, nor have I had traction or wear problems (RV tires will typically age out before they wear out.) All of my problems have been tread separation failures due to manufacturing deficiencies as the tire manufacturer (Goodyear) has covered all of them. I've never had a problem of any kind with Michelin XPS Ribs or Michelin XTAs. With widely varying weights such as you can experience with a toyhauler, you'll be making lots of trips to the scales if you want to use a load versus inflation chart. Your money - your choice.

Rusty

 

[AH64ID]

Doing things the correct way does often take more time, which is why many inflate and forget.

Tire manufactures recommend proper air for the load.

I have fairly easy access to a scale and even then once you weigh certain configurations a few times, and take notes, it's pretty routine to put the proper air in.

 

[Mingoglia]

I always run trailers with max air in the tires, but then again most trailer tires are carrying loads close to their capacity. I like to error on the side of too much air on a trailer, since trailer tires live a miserable life. Too much air only means you'll wear them funny, but most trailer tires fail before you wear out the tread anyway. On the other hand, if you run them too low this leads to increased heat and increased likelihood of failure.

 

[Hoefler]

The tires I have on our fifth wheel are rated for 6,005 pounds at 125 psi each. When inflated for the intended load, 80 psi for 4,000 pounds, I have 7,000 pound axles, the tires ran 20* hotter than the tires on the truck and I lost almost 2 mpg. I inflated them to the 125 psi that is stated on the side wall, I gained back the 2 mpg and now the tires run cooler than the truck. No real difference in ride quality and like others have said, they will age out way before any adverse tire wear, if any, will take hold.

 

[Jim W]

So, the question is, do I lower the tire pressure like I do when running the truck empty or just leave it at max and call it good? It seems like E rated tires (all the ones we're looking at have 16" rims and dual axles) would be pretty tough on all the insides if fully inflated.

Not all of the 16" tires are "E" rated. I found this out on my Cedar Creek trailer by Forest River. This was equipped with 2- 7.000 LBS axle and ST235/85R16 G rated tires at 110PSI. The speed rating on the tires is L; 75MPH max.

I run these at the 110 PSI and check the air pressure every day when towing along with the lug nut torque for each wheel. Nothing moves around in the trailer when towing. We did close to 8,000 miles last year with no breakage of any items on the inside do to tire pressure and the ruff roads.

 

[AH64ID]

Jim, which ST tires are those with a speed rating? Generally, and by defenition, ST tires are 65 mph rated and don't carry standard load indexes or speed ratings. Not all trailer tires are ST, but all ST's are trailer tires.

Just curious if some companies are using the ST designation but building them to non-ST specs.

The tires I have on our fifth wheel are rated for 6,005 pounds at 125 psi each. When inflated for the intended load, 80 psi for 4,000 pounds, I have 7,000 pound axles, the tires ran 20* hotter than the tires on the truck and I lost almost 2 mpg. I inflated them to the 125 psi that is stated on the side wall, I gained back the 2 mpg and now the tires run cooler than the truck. No real difference in ride quality and like others have said, they will age out way before any adverse tire wear, if any, will take hold.

Something in your math or post is off, or appears off.

Two identical tires, or 4 for that matter, can't have a combined load of 6,005 lbs. If you are talking each that's a serious trailer tire but you are over the axle rating at 4K/tire. Or is 80 psi the min you can run for that tire? I have to run 70 psi on my 19.5's even if it's too much air for the weight. It has to do with the sidewall construction and bead seating on xx.5" wheels/tires. I can tell they are overinflated (traction, jarring, etc) but not much I can do. Toyo told me I could drop to 70 vs the published 80.

Which tires are you running?

The OEM wheels on your camper are 17.5's, correct? So probably running something in the LRJ range if the rating is 6K/tire? Tires like that tend to run hotter than radial pickup tires under normal loading. It has to do with the strong but thin sidewall that they use in their construction. My 19.5's are good for 7K/axle at their min inflation pressure and I am only at ± 5,200 lbs and they run hotter than my 17" tires at the pressure for their air... just the nature of the beast with xx.5" tires.

Overinflating does increase fuel mileage and why many people were extremely over inflating their tires, especially back in the 2008 time frame when fuel was thru the roof.

Everyone seems to focus on wear from being overinflated and just ignores the decreases traction. Traction is still important on a trailer if you ever use the brakes. It is much easier to lock up a overinflated tire than a properly inflated one. Personally when my GCW is over 19K lbs I want all the good braking I can get.

They will also puncture and have chord failures much easier when overinflated, thou in your case a LRJ has a pretty serious chord

 

[RustyJC]

Something in your math or post is off.

Two identical tires, or 4 for that matter, can't have a combined load of 6,005 lbs. If you are talking each that's a serious trailer tire but you are over the axle rating at 4K/tire.

Which tires are you running?


Everyone seems to focus on wear from being overinflated and just ignores the decreases traction. Traction is still important on a trailer if you ever use the brakes. It is much easier to lock up a overinflated tire than a properly inflated one. Personally when my GCW is over 19K lbs I want all the good braking I can get.

I really haven't run into tire lockup problems on the trailer, even with the Kodiak disc brake system. Stopping is solid and sure running trailer tire pressures of 115 to 120 PSIG.

Rusty

 

[AH64ID]

I really haven't run into tire lockup problems on the trailer, even with the Kodiak disc brake system. Stopping is solid and sure running trailer tire pressures of 115 to 120 PSIG.

Rusty

I tow a lot on dirt roads and there his a huge difference in braking with over-inflated tires, as there is with wet roads. I ran them at sidewall pressures for a while after everyone's recommendation. The braking is the single biggest reason I went back to proper air, not lazy air, and now my braking is better and I noticed zero change in fuel economy or tire temp on my setup (but the trailer tires aren't a xx.5").

 

[RustyJC]

...I went back to proper air, not lazy air.....

Laziness has nothing to do with it. It's a matter of priorities. My prime priority is to have as much operating load margin as possible - that's achieved by operating the tires at pressures that provide their maximum load rating.

Rusty

 

[AH64ID]

Call it what you want but it's the lazy way to adjust air pressure. It's not the reccommended practice by the engineers that design tires and the only true benefit is it saves time and hassle.

In the end it's less safe than the proper air, but how much is dependant on a host of variables. It is better than under inflated but still not the best.

Do you run your truck tires at sidewall pressure too?

 

[RustyJC]

You seem to be in the minority on this thread. You're welcome to your opinion, but those of us who have towed heavy 5th wheels and other trailers for years are also entitled to operate then in a manner that works for us in our applications and under the conditions we experience. I don't see where that entitles you to call anyone "lazy" or otherwise cast aspersions on our choices. Everything in life is not "my way or the highway".

Rusty

 

[AH64ID]

Take it how you want, but your post #6 tells me it's the lazy way. It is a lot more work, so let's just ignore logic and mfgr recommendations and run sidewall pressure.

Maybe the proper way is the minority but that doesn't make it any less proper, just less popular.

Everyone is entitled to their opinion but that shouldn't overrule the facts. I brought the facts/experiences and you brought the opinions/experiances. In the end everyone can do it how they feel they should but don't discount facts based on opinion. Experiance does go a long way too, but still shouldn't overrule fact.

Never having an issue by doing differently than intended doesn't make it better than the intended way, just means it works but maybe not at safely.

Last summer a buddy towed his 30' 3/4 full TH from MD to ID at 65-80 mph on 5 year old ST's without checking the tire pressure in 2 years. Just because he didn't have a single issue doesn't mean it was the correct way to do it.

You didn't answer my question about your truck tires.

 

[RustyJC]

You didn't answer my question about your truck tires.

No, I don't, but my priorities are different for the truck than for the trailer.

Since you think yours is the only correct opinion and is one shared by anyone who knows anything about trailers, you might check out the recommendations of Discount Tire and etrailer.com as far as trailer tire operating pressure. Both recommend running at maximum rated cold inflation pressure. Wonder why that is? Now it becomes a battle of "experts".

Rusty

 

[AH64ID]

No, I don't, but my priorities are different for the truck than for the trailer.

Why?

Since you think yours is the only correct opinion and is one shared by anyone who knows anything about trailers, you might check out the recommendations of Discount Tire and etrailer.com as far as trailer tire operating pressure. Both recommend running at maximum rated cold inflation pressure. Wonder why that is? Now it becomes a battle of "experts".

Rusty

I guess I missed where e-trailer or discount tire are manufactures of tires.

Most of the information I have been given here is directly from tire manufactures. I agree with their information and use it with my truck/trailer and have based my opinion off of it; however, it's a fact that tire manufacturers recommend proper air and not sidewall air.

 

[Hoefler]

Jim, which ST tires are those with a speed rating? Generally, and by defenition, ST tires are 65 mph rated and don't carry standard load indexes or speed ratings. Not all trailer tires are ST, but all ST's are trailer tires.

Just curious if some companies are using the ST designation but building them to non-ST specs.




Something in your math or post is off, or appears off.

Two identical tires, or 4 for that matter, can't have a combined load of 6,005 lbs. If you are talking each that's a serious trailer tire but you are over the axle rating at 4K/tire. Or is 80 psi the min you can run for that tire? I have to run 70 psi on my 19.5's even if it's too much air for the weight. It has to do with the sidewall construction and bead seating on xx.5" wheels/tires. I can tell they are overinflated (traction, jarring, etc) but not much I can do. Toyo told me I could drop to 70 vs the published 80.

Which tires are you running?

The OEM wheels on your camper are 17.5's, correct? So probably running something in the LRJ range if the rating is 6K/tire? Tires like that tend to run hotter than radial pickup tires under normal loading. It has to do with the strong but thin sidewall that they use in their construction. My 19.5's are good for 7K/axle at their min inflation pressure and I am only at ± 5,200 lbs and they run hotter than my 17" tires at the pressure for their air... just the nature of the beast with xx.5" tires.

Overinflating does increase fuel mileage and why many people were extremely over inflating their tires, especially back in the 2008 time frame when fuel was thru the roof.

Everyone seems to focus on wear from being overinflated and just ignores the decreases traction. Traction is still important on a trailer if you ever use the brakes. It is much easier to lock up a overinflated tire than a properly inflated one. Personally when my GCW is over 19K lbs I want all the good braking I can get.

They will also puncture and have chord failures much easier when overinflated, thou in your case a LRJ has a pretty serious chord

Road Master RM 170 235/75R17.5 with appropriate wheel.

http://roadmastertires.com/by-application/pickup-and-delivery.aspx