Rolling Resistance

Have you tried the Michelin fuel mileage calculator ?

http://www.michelintruck.com/michelintruck/toolbox/FuelSavcalculator.jsp

That's likely the closest you'll get to " guestimating " before hand.

 

This is very interesting...

http://www.bridgestonetrucktires.com/us_eng/real/magazines/99V4Issue1/ra8.htm

This is very dated however , they are running there cpm calculations at 95 cents a gallon.

 

I have a spread axle trailer and since almost half of my miles are empty, would making the front axle liftable reduce my rolling resistance & help save fuel????

 

granhawler, yes being able to lift an axle will improve fuel milage as well as extend the life of your tires.

 

Yes it will help. I lift mine every chance I get, even when I.m loaded lite I'll keep it up. I'll gain .5 mpg with it up. Only bad thing is you'll have a 48 foot trailer with the axle all the way to the rear and it wont turn as sharp.

 

Absolutely! If it's a normal non drive lift axle you will also save on mechanical frictional losses, recently I did a trip to holland for a friend, there were 2 trucks, one 6*4 and one 6*2 rear lift axle, both scania r620's , both auto gearboxes with the same diffs and both had the same load, the 6*2 was 1mpg better on fuel and I'm told by a person better experienced than me in this field( I'm used to general haulage tractors, 6*2 & 4*2) it can be as much as 2 mpg , Alot of lift axles here would have just single wheels on them to reduce drag even more and Alot of lift axles would steer also , this saves tyres and greatly reduces understeer in wet conditions compared to 6*4 or 6*2 non steer.

Center lift is nicer to drive but rear lift has much better traction even better than tandem drive once you don't go off road, the reason for this is the fifth wheel is mounted behind the drive axle and transfer some weight onto the drive axle it will press the wheels on the drive into the road giving fantastic grip

A lift axle here is far cheaper on a new truck than a double drive, also there is less maintenance , less tyre wear and at our fuel prices 1 mpg would mean about $11,000 to $14,000 per year to me, if 2 mpg is achievable then it's double that, I hope this is of some help to you.

 

Makes a huge difference Granhawler....The less wheels you have on the ground...the less energy you need to move them/drive them

 

Out of curiosity, whats the maximum weight one can haul when a axle is lifted up??

KH