Fuel Milage Poll

Conway truckload's shop sells them to their IC's for <$500/pop. Shop around for a good michelin discount plan and you can probably get pretty close. LOL at $1,000/piece -- that's like what you pay in the middle of nowhere with a blown tire...

The formula for rolling resistance is exceedingly simple. It has been used for 300 years. There is nothing magical about a truck wheel & axle -- it is as simple as it gets.

The formula for calculating the acceleration of a flywheel is more complicated and involves some calculus I don't care to do on a phone. This IS NOT rolling resistance. And it is only applicable under acceleration. KR is probably muddling the two.

Read post 19. Its worked out there...

I heard your call with KR. You asked him some unrelated question, then right before he hung up & as the break music is playing you asked him this. He first said I was flat wrong, then hemmed & hawwed, then said I was missing something and went to break without explaining a thing.

And he has no experience here, he has said many times he's never actually tested it, but that he's heard from people who have done it. People who went from 6x4...


As for Michelin LMAO at the thought of you getting ahold of anyone who knew their head from their ### on a Sunday afternoon/evening. If anything you talked to an art history major CSR who just wanted to placate you so she could get back to Candy Crush.


I'd like to see Fontaine's data, but remember they're dealing with a trailer where the tire RR are equal. We are talking about a tractor where you take weight from a trailer tire and transfer it to a drive tire (and some to a steer). And remember that they're in the business of selling you a product. I suspect their data is emphasizing the inertial gains.



But this is really really really easy to test. Find a rutherford lemming with a 6x2 lift axle, and have them coast to a stop from 5mph 10 times with the axle up, & 10 times with the axle down. Boom, instant, irrefutable proof.

Or attach a spring scale to a towstrap and measure the force it takes to pull the tractor at a constant ~1mph.



Or just buy your lift axle, microblue bearings, fleet air filter, pitsburg power muffler, OPS, FASS, turbo3000D, Polaris oil sample kits -- don't think twice about any of it, and enjoy the real gains alongside the placebos.

 

More truck specs?

 

Year 2010
Make Freightliner
Model Columbia CL-120
Engine DD15 14.8L
Trans Eaton FRO-16210C 10-Speed OD
Gear Ratio 3:42
Tire Size steer 11R 22.5 drive 11R 22.5 LP Michelin Lowest R/R Duals & Drives
Type of loads Flatbed little of this little of that between 50-80k some OD
Type of Trailer Great Dane Steel/Aluminum Combo Freedom LT i think 10,800 Empty

Normal Cruising Speed 55 mph
MPG 7.02 last 30 6.80 last 90

Only Add on's are ScanGauge KR, which has really helped me improve my MPG i hardly ever use the Cruse Control, and Crossfire's on the Drives, wont make any Real Mods till i get the title, then Purchasing a Fontaine Revolution 52 with Super Singles and a Lift Axle,

Future Truck Improvements OPS-1, FASS, Super Singles, APU, and when the time comes for a rebuild its going to Pittsburgh power and Everything is getting MicroBlue and im changing the transmission and Rear end

I dont understand why Companies like CRST Malone lease trucks with all Steel Rims Truck and Trailer, my Freightliner empty weight full of fuel with Tire Chains is 32,500, minus the 500 in the summer no tire chains

 

If you think is full of ####, why do you listen to his show? Your rr formula could becorrect for calculating tire rr, but this is about alot more then just tire rr.

 

My problem with him is he's only 15% full of ####. People learn to trust what he says and then wind up buying the occassional snake oil like turbo3000 & unproven products like microblue or tractor lift axles.


Here is a research report you might find interesting: http://www.rms.nsw.gov.au/heavyvehicles/downloads/greentruck/case-study-lift-axles.pdf

Local hauler with tri-axle trailer measured with lift axle down on empty return for 3 weeks and Lift axle up for 4 weeks. Keep in mind this is on the trailer so, unlike a tractor, there is NO change in rolling resistance with axle up or down. They noted a 1.5% improvement in fuel economy on the return trip (not to overall fuel economy -- on the empty return, where your fuel costs are already much lower).

Page 3 plots % of time spent at various load. This is the most telling because you'll see that virtually all of the difference occured at 80-100% load. When are you at 80-100% load with an empty trailer? When you're hot-rodding on the accelerator... Aside from those high load periods, the load profiles are virtually identical.

The paper refers to the improvement as rolling resistance. They are incorrect, it is the extra rotational inertia where they are seeing the difference. Rolling resistance is always the same at a given speed/weight/equipment/terrain. These inertial losses depend on acceleration.

 

This is a very interesting thread.

 

I don't care if it's rolling resistance or inertia or a freaking parachute. Anything that creates drag is bad. Being able to get those sticky rubber tires off that sticky asphalt has got to raise efficiency. Roi will vary depending on application. 90 percent of my miles are at under 60k pounds, obviously a guy pulling at 80k most of the time with low deadhead will get much less savings than I would.

 

Year: 1998
Make: KW
Model: T800
Engine: M11
Trans: 13OD
Gear Ratio: 4.33
Tire Size: 295/75R22.5
Type of loads: hay, heavy equipment
Normal Cruising Speed: 62
MPG: 6.5-7.0

 

2000
Sterling
AT9522 (condo style 232" wheel base)
Cummins N14
Eaton 13 SPD
3.73
LP 22.5 Super Singles XDA Energy
LTL (avg 40 stops 3 days a week) / Line Haul (1250 miles each way 2 days a week) (NOTE: we own our trailers with LP wide singles)
60MPH
Q1 (2014) avg: 7.886 / 2013 AVG: 8.941

Pittsburgh Power Box set on level 4, Dual 6" straights, Pittsburgh Power Exhaust manifold, Fleet Air felt, Micro blue wheel bearings on truck and trailer, Full synthetic rotella T, low pro fender mirrors, FASS, Michelin SS tires, lots of LED peterbilt style chicken lights, pull our own trailers.

(I also wax it daily and polish all the aluminum for a mirror shine. That helps w/ aerodynamics which increases MPG right?! Lol)

 

99 W900 4 axle 1mm 600 cat 2050 18spd trans 411 rears 46000lbs 11r24.5 rubber grossing average 140000lbs last 1/4 4.2 mpg loaded 5.7 empty. only run 60mph average.