heavier trailer tires and fuel economy

fj12ryder wrote:

eHoefler wrote:
I run 17.5 MT tires rated for 6005 pounds per tire and wheel combination on my fifth wheel, wheels weigh 60 pounds each, with tires weighing 65+ pounds. I run them at max psi of 125. Actually get better mileage than the 16" tires they replaced.

I guess what I'm wondering is why. Surely you don't have 20,000+ on those axles? I guess it would make sense if you were running 10,000 lb. axles. Gotta be a darned rough ride for the trailer.

he said why, running at a higher inflation gives him better milage. as long as it doesnt cause a wear issue why not. worried about how rough the rv is put a set of shocks on it. it always gets me that we accept that the tires are part of the suspension of our rv's ST trailers are ment to be run at max psi so 80 so it rough already.

also for thoes saying it is going yo be to rough of a ride do you have your trailer tires ballanced? if not, do you realy cre about how the ride is for the trailer?

eHoefler wrote:
I run 17.5 MT tires rated for 6005 pounds per tire and wheel combination on my fifth wheel, wheels weigh 60 pounds each, with tires weighing 65+ pounds. I run them at max psi of 125. Actually get better mileage than the 16" tires they replaced.

I guess what I'm wondering is why. Surely you don't have 20,000+ on those axles? I guess it would make sense if you were running 10,000 lb. axles. Gotta be a darned rough ride for the trailer.

eHoefler wrote:
I run 17.5 MT tires rated for 6005 pounds per tire and wheel combination on my fifth wheel, wheels weigh 60 pounds each, with tires weighing 65+ pounds. I run them at max psi of 125. Actually get better mileage than the 16" tires they replaced.

You are WAYYYYYYY overinflated. You have less stoping ability and a **** rough ride.

60# ? what wheel are you using? I run the 17.5" Alcoa aluminum wheels and they only weigh 30# each along with the Continental "J" HTL2 Eco Plus 235/75 17.5 @ 65# each. My two axles have 18k on them and 105psi gives me lots of extra capacity.

EDIT: I see it's a gooseneck we are talking about. Still stand by you are wayyyy overinflated.

All I can say is: I towed a 24' TT. a 30' TT and a 35' Fifthwheel with the same truck, 2005 3500 Duramax Dually and couldn't see enough difference in mileage to really tell if there was any.

Not sure why a stiff construction would hurt economy. The steel wheel on a train seems to be very efficient. Soft construction and under inflated would seem more likely to hurt fuel economy.

Besides I assume the OP went with same tire construction ST-ST or LT-LT with only an increase in the load range (ply rating).

Interesting. Thanks. These are on my gooseneck trailer. GVWR =16k but it came with 12 ply tires. Not sure what psi the rims are rated for but I ran 80psi in the old tires.

One of my non rv trailers is a 38' triaxle stock trailer with 7k axles. I had the trailer mfg derate its gvwr from 21k to 16K for tax and registration purposes. It came with ST235/85 16 G @4400 lb capacity cheap brand ST tires ( Hi Run brand ??)
I was aware they had a bad rep doing that type work so I had 6 Sailun S637 ST235/80-16 load G at 4080 lbs capacity ready when my trailer dealer called and said your trailers in. He did the change out for free.
Sold the maypops on CL for more than the trailer mfg sold them for which helped pay most of the cost of those commercial grade all steel carcass 16" Sailun S637.
I keep tires on all my commercial trailers and rv trailers tires at max sidewall 24/7.
Heavy tires rob horse power as any racer/commercial hauler knows. However in my hauling business those heavy tires at max sidewall pressures are worth the extra weight in long term service and higher miles of service. A RV trailer are no different.

Sturdy tires are far more important than slightly less fuel economy IMO.

JIMNLIN wrote:
It matters with tires on a trailer also and can be even more so depending on how much pressure is used in the heavier duty tire.
Some rv folks tend to over tire their trailer like this rv trailer owner found out.

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When it came time for me to replace our tires, I researched many different ways to go. I wound up purchasing 17.5" J rated medium duty truck tires and wheels. When all done and said, it was $5.00 per wheel and tire combo more than just replaceing the 16" tires. This tire and wheel combo is good for 6005 pounds each. Using the inflation chart to get the pressure for the load, I inflated to 80 psi which was good for 4500 pounds per tire. With the first tow with these tires to Kansas City, I have made this trip to the speedway several times before, I was down almost 2 mpg both ways. The tires were 20*-25* hotter than the truck, which I have never experienced before. I inflated them to the side wall pressure, 125 psi for max load, before our trip to Florida. Now the tires run 5*-10* cooler than the truck and my fuel mileage is back where it used to be. I have always run max pressure up until I installed these tires, with what I have experienced, I will continue to run what the side wall indicates.***

One poster mentioned LT tires for a 10000 lb trailer. Its been my experience best idea for trailers with 5.2k and 6k axles/16" wheels and 16" LT tires recommended by the tire mfg for trailer use.

Interesting. Thanks. These are on my gooseneck trailer. GVWR =16k but it came with 12 ply tires. Not sure what psi the rims are rated for but I ran 80psi in the old tires..

The physical weight of the tires will have no effect on MPG
The stiffer construction will have more rolling resistance so it will ding your milage.
If you put too much pressure in them for the load carried only the center of the tire will touch the pavement so your milage will go up.

Think of pedaling a bike with correct air pressure then over filling them how it gets easier.

It matters with tires on a trailer also and can be even more so depending on how much pressure is used in the heavier duty tire.
Some rv folks tend to over tire their trailer like this rv trailer owner found out.

***Senior Member
Joined: 10/22/2011

View Profile

When it came time for me to replace our tires, I researched many different ways to go. I wound up purchasing 17.5" J rated medium duty truck tires and wheels. When all done and said, it was $5.00 per wheel and tire combo more than just replaceing the 16" tires. This tire and wheel combo is good for 6005 pounds each. Using the inflation chart to get the pressure for the load, I inflated to 80 psi which was good for 4500 pounds per tire. With the first tow with these tires to Kansas City, I have made this trip to the speedway several times before, I was down almost 2 mpg both ways. The tires were 20*-25* hotter than the truck, which I have never experienced before. I inflated them to the side wall pressure, 125 psi for max load, before our trip to Florida. Now the tires run 5*-10* cooler than the truck and my fuel mileage is back where it used to be. I have always run max pressure up until I installed these tires, with what I have experienced, I will continue to run what the side wall indicates.***

One poster mentioned LT tires for a 10000 lb trailer. Its been my experience best idea for trailers with 5.2k and 6k axles/16" wheels and 16" LT tires recommended by the tire mfg for trailer use.