Fuel Milage Poll

Tag vs lift axle.

My thoughts and questions on this: a tag axle is basically nothing but a trailer axle right? Ha no driveline going to it and free spinning all the time.

Lift axle is a free spinning axle(basically that lifts off the ground when load weight allows.

If there is no benefit to a lift axle then why do we put them on trailers and get an immediate gain. Some guys report as much as a half a mile to the gallon difference when picking that axle up.

 

Year 2005
Make Pete
Model 379
Engine MXS C15 cat
Trans 18sp
Gear Ratio 3:90
Tire Size 11r 24.5
Type of loads water and pulling equipment (about 100,000lbs loaded)
Normal Cruising Speed 65mph
MPG (or GPM, LOL) Don't know, don't care. I do quite a bit of idling and the cost of fuel does not take a significant chunk out of my bottom line.
Only mods, PDI stage 1 by Haney and Donaldson free flow mufflers.

 

On a trailer you are taking weight from a low rr trailer tire and placing it on another low rr trailer tire. So unlike the drive, there is no change in rolling resistance. But you are still getting the benefit of less rotational inertia so it does takes less energy to accelerate.

But 0.5mpg? Get real. These must be the same guys getting 0.1mpg from the turbo3000D.

See: http://www.sciencedaily.com/articles/c/confirmation_bias.htm

 

1990 Western Star
4964F
3406B factory 425hp
14615 trans(15 over)
3.70 eatons
11r24.5 Kelly KDA drives( going with all-position in the next few weeks)
mostly empty 1 way, 86,000#-95,000# gross the other way
less than 4mpg when I started. Was 5.6mpg until winter blended fuel and idling dropped to 4.7mpg. Added Taylor wing back @ 5.2 or better now.
Speed limit plus 10%. Anything less and I get sleepy.

 

Kw T-800
cat c-15
RTLO18918B
3.73 rears
11R24.5 rubber
107k every load...... Mt on return.

speed limit and or flow of traffic

best days in the summer 5.8 mpg ..... Worst in the winter 4.5 mpg

 

So how much would you say it gains?

 

what's your top 2 ratios?

 

Loss of traction under light loads and/or slow road speeds can be remedied with an air spring spacer or a proportioning valve. Fully loaded and hung up in a driveway or parking lot will require the use of a dump valve to get going again.

 

According to hendrickson, increased tire life and lower maintenance costs is the benefit of installing a trailer axle lift kit. I suppose the fuel savings is to small for them to even mention.