heavier trailer tires and fuel economy

[johndeerefarmer]

I know heavier tires on your truck decrease fuel economy but what about on a trailer? Looks like once you get it up to highway speed it wouldn't matter?

why I asked was I got tired of the blowouts on the 12 ply junk and put some heavy 14 ply on my trailer. Wondering if and how much mpg will be affected

Thanks

[time2roll]

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).

[JIMNLIN]

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.

[Lwiddis]

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

[johndeerefarmer]

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.

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

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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..

[Mike134]

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.

[JIMNLIN]

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.

[CapriRacer]

Fuel economy? Complex subject!

Long Version: Barry's Tire Tech: Rolling Resistance and Fuel Economy

Short Version: Rolling resistance in tires can vary widely - up to 60% within the same size.

More pressure = less rolling resistance - all other things being equal, but we are talking about a few percentage points, where differences between tires can be double digit percent.

LT tires get worse fuel economy than equivalent P type tires because LT tires are made of a less compliant rubber (more internal friction = hysteresis)

[eHoefler]

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.

[rhagfo]

johndeerefarmer wrote:
I know heavier tires on your truck decrease fuel economy but what about on a trailer? Looks like once you get it up to highway speed it wouldn't matter?

why I asked was I got tired of the blowouts on the 12 ply junk and put some heavy 14 ply on my trailer. Wondering if and how much mpg will be affected

Thanks
______________________________________________

2020 Ford 350 6.7 PSD & 2017 F150 3.5 EB max tow
GD Reflection 29rs

If you are referring to the 5th wheel in your signature, get a good set of LT tires, and skip crappy ST tires. I run Yokohama LT 235/85-16E tire on our 12,360# GVWR 5th wheel. Your 5th wheel has a GVWR of 10,000#, the LT are more than enough tire for it.

[HTElectrical]

joshuajim wrote:
It’s pretty well known fact that trucks that switch from lighter P tires to heavier LT tires always lose on mileage. Is it the heavier tire,the stiffness of the tire or tread pattern. Who knows.

Rotating mass robbs horsepower.

[joshuajim]

It’s pretty well known fact that trucks that switch from lighter P tires to heavier LT tires always lose on mileage. Is it the heavier tire,the stiffness of the tire or tread pattern. Who knows.

[time2roll]

johndeerefarmer wrote:
I know heavier tires on your truck decrease fuel economy but what about on a trailer? Looks like once you get it up to highway speed it wouldn't matter?

why I asked was I got tired of the blowouts on the 12 ply junk and put some heavy 14 ply on my trailer. Wondering if and how much mpg will be affected

Thanks

Assuming the new tires run at higher pressure... I believe the fuel economy is more likely to increase.

Best if the tire load rating covers the entire trailer GVWR.

[stickdog]

You paid for more tires it shouldn't bother you to pay a little more for the safety they provide.

[StirCrazy]

it will effect it a tiny bit, the physical size has more effect than a small shift in weight. you could also see if there is one that is "energy conserving" or have a lower rooling resistance. this and how tight you pack wheel berrings and set your brakes have a larger effect than just a little bit more weight.

[spoon059]

Yes, there will be some effect. Like Typer0215 stated, it is likely small enough not to worry about. Perhaps the heavier weight and stiffer sidewall will provide less flex in the tire, making it have less rolling resistance anyways. The comfort of knowing you have plenty of available weight carrying capacity makes me happy, even at the potential cost of slightly less fuel economy.