Towing MPGs-gctid396975

[captharv]

Over the weeked we took a cruise to our favorite boat camping island. The ramp is about 80 miles from my home, where we keep the boat. About 30 miles of it are suburban roads, and although the traffic was lite, there were a lot of stoplights. So it was 45 MPH to 0 to 45, you get the idea. The rest of the trip was mostly divided highway, and I tow at 55. Previous trips averaged 8 MPG.

This round trip of 167 miles used 19.2 gal for 8.7 MPG (rounded).

I needed tires on both the SUV and the trailer, so I got Michelin Lattitude Tour radials for the SUV and "E" range (2850# capacity) radial trailer tires, which are inflated to 75#. They are Carlysles, however, they are made sateside. Does not say Made in China on them) The old tires were rated at 60 which is what I ran them at.

The SUV is an Expedition 4X4, 5.4 H/D tow package, and both air conditioners were running, as it was 93* on the way back. The trailer is a magic tilt with radials, and tortion suspension (yes, its set up to be level). The Expy has 94000 miles on it.

Granted, Florida is not hill country, but I think 8.7 MPG for 14,000# gross weight in hot weather with a gas engine is very good. That weigh is from a certified public scale. The boat/trailer is ~7800#, the SUV is ~6300#. These are real world weights, with 1/2 tankage, etc, the way we usually tow.

Previous tow vehicles:

1980 Ford 5.9L 6 cyl, 2.73 axle towing 6K #= 9 MPG

1984 Ramcharger 4X4, 318 2 BBL carb, 3.23 axles same as above but 8 MPG

1991 Ramcharger, 5.9L 4X4, factory H/D tow package throttle body injection 9 MPG on that boat,

7 MPG on the 2452 I am towing now.

The post is to advise that better tires and proper inflation make a differemce, and its not a "My XXXX is better than yours" post.

[Guest]

My 2003 Chev with the 6 liter motor only gets 10, so you're doing well. The boat I tow is a bit heavier. I'm mostly glad for the 4 wheel disk brakes. Going is never the problem. Stopping is.

[Patrevan]

Captharv - I would agree this mileage is nothing to complain about. I have a 1999 Dodge 1500 w/5.9 gas, 4X4, auto. We bought our 265 about 2 yrs ago out of Seattle and towed it back to Calgary. I measured the mileage, closely in both directions. I got 20 mpg doing the drive out from Calgary and 9.5 on the way back with the boat. That boat/trailer was about 7500 lbs. It would have been nearly dry of fluids/gear. A couple of months ago, the admiral and I moved to Vancouver Island and again towed the boat through the mountains, this time more heavily loaded. These trips are significant mountain roads. I didn't measure the mileage this time, but I believe it was similar. (Bear in mind, these figures are based on an Imperial gallon vs. the US gallon, about 20% more). I know these weights are pushing the limits of my rig, and for those who might want to jump in with a comment, the rig is now only about a mile from my launch.

[Jeffw]

You might be over-inflating your new trailer tires at 75 psi. I would get the manufacturers recommendation for the towed weight of 7800 lbs. The reason I say this, is because on my motorhome I had to go up one load range in tires, as they no longer made the load range I needed. The max air pressure for the new tires is 110 psi, where the old ones were 80 or 85, which the RV weight required the max inflation. With the new tires, the dealer and manufacturer recommended 80-85 psi, based on the RV weight as a percentage of the tire's weight capacity. I get an excellent ride vs. 110 psi, and the tires are wearing evenly. Just food for thought...

[captharv]

Jeffw: point well taken.

The maximum on the side of the tires is 85PSI. I used 70-75 as a SWAG.

They ride nice. You can almost forget the trailer is behind you at hiway speeds

[Jeffw]

My bad, I re-read your first post. You said "inflated to 75", I misinterpreted that to mean 75 was the max. No matter though, we're on the same page. I had to buy six tires for the trailer I sold with the 305. Carlyles from Discount Tire. I was told they were made to Discount's specs, in America. Maybe same ones...

[Guest]

Jeez, and to think I was complaining about 12.5 mpg on my recent trip. Of course, my boat weighs half what yours does... 1952, ~4500+ lbs with trailer, Jeep Grand Cherokee w/ 4.7L V8.

I think I need better tires, regardless of MPG. Even at max inflation, there's a lot of flex and bow in them where they hit the road. They look underinflated, even though they are at 50 PSI, (max on the sidewall). I think they are only rated 1870 lbs each...so not enough, (went with the same ones the PO had on the trailer).

[captharv]

Jeff: I did buy them at Discount tire.

Shorty:

Always specify a ST (Special trailer) tire in load range "D".

When I had my 21' welcraft Nova offshore, I put on 7.50 X 14 bias ply in load range D. The ration was somewhere around 1900#/tire @ 60 PSI. They lasted 7 years