Studying for CDL Permit: Have a question!

10 wheels versus 18 wheels maybe ???

 

Trucks are designed to have a trailer and some weight on them. Without that the rear wheels can tend to skid while braking.

The tractor in my signature pic is no fun to bobtail if the roads are wet or slippery.

 

because the brakes are setup for pulling 80k lbs. easier to loose control/traction bobtail

 

look at the tires of a fully loaded truck and an empty one. the tires on a loaded truck are "flatter". ie: more surface area. also the front brakes are set up with a proportioning valve, meaning when you apply 20#'s of pressure, the front breaks only get 10#'s. this prevents the front tires front skidding .

 

Yeah, once you bobtail, you'll see why.

 

I scaled my bobtail with about 11,500 lbs on the steer axles (5,750 lbs per tire) and 8,500 lbs for the drives (1062.5 lbs per tire). Same surface area per tire but only 18% the weight. When you brake weight is thrown forward onto the steers and the drives don't have much weight to grab the road.

The only time I've ever smoked the tires braking was bobtail when a traffic light changed to red and I had a cloud of smoke waft through the intersection as I barely stopped by the middle of the cross walk. That was on dry pavement.

Other than the limitations of braking you have to pay attention to the fact that rolling a bobtail is almost easier than when you have a trailer. You can't corner. It may feel like a sportscar when you accelerate, but cornering and stopping are an entirely different matter.

 

Reason why most companies forbid bob tail. Only with their permission.