Engine Brake Question

because they cut that ice road into the ice..this causes grooves etc..

Ice is slickest right around 32 F..up there..they well below that temperature...the reason its the slickest at that temp is its not all the way froze...there's a film of water..

Iver taken an ice cube out the freezer to have it stick to your hand?..then get it wet..lot harder to hang on ito huh?

Add to that they are runnin studded tires and chains on the active drive axle and steers..chains on the other drive axle with the power divider off too..

Ice at those temps has nearly as much traction as hot asphalt in az in the middle of summer..when those guys are doing that its cold enough they could spit and it would freeze before it hit the ground..any moisture in the air becomes the traction surface on the ice road...thats a whole different type of driving doing that and whole different set of rules apply...Those trucks are specially equipped for that duty..

petey

 

They drove the truck the best they could WITH WHAT THEY HAD AVAILABLE to them.

Selecting a lower gear on a decent will do NOTHING but over rev the engine unless the service brakes are applied. I'm not sure what the definition of "alot of trucks" is, I've seen (and driven) 1 truck with no engine brake and it sucked. At the end of the day, people are welcome to use the service brakes all the time if they like, I really don't care unless they are driving one of MY trucks. The concept of using an engine brake rather than service brakes to slow a truck down EVEN ON THE FLATS is so mind numbingly OBVIOUS that the whole thought of arguing over it seems ridiculous. The only reason that I even respond to such ludicrous "advice" as only using the jake on hills is that there are new drivers on here that are looking for guidance from drivers in the know and don't want them to be steered wrong. BTW, the invention of the engine brake may have been PROMPTED by the need to slow a truck on a decline without heating up the service brakes but that does not mean that that is the only practical use for it.

 

Exactly..Even in class when I went through 12 years ago the instructor said Don't use the engine brake except on hills..and right ever while acting like she was clearing her throat said "use it all the time if you can"..we got the point

LOL

Petey

 

And here you claim to "know" how to drive? That's a friggin joke in and of itself. Selecting a lower gear absolutely has an effect on the engine's ability to hold the truck at a safe speed as you descend a hill. While a diesel engine does not have much braking power on it's own due to the design, whatever braking force it DOES have is increased as you get to the lower gears. You may need to drop a couple extra gears to get to one that will hold you back without a compression brake as opposed to going down the same hill with a compression brake, but eventually you'll get to one that will hold you.

Yes, a compression brake can and will slow you down on flat ground, but the service brakes will slow you down quicker. I've driven several trucks that didn't have a compression brake, and managed to get on down the road without any incidents just fine. I've also driven several trucks that had compression brakes and drove them just as safely.

Think about this for a minute: The engine brake's rated power is usually less than that of the engine. It might be close, but it will generally be less.

From the CDL manual:

Can you accelerate from 0 to 55 mph in 216 feet? I doubt it...but that illustrates the engine's ability to alter the truck's speed vs. the service brake's ability to slow the truck down. Your compression brakes won't bring you to a stop from 55 mph in anything even remotely CLOSE to the 216 foot standard. Your service brakes will, however, even without the assistance of a compression brake.

 

No, the jake won't..on its own..

Here's a challenge for you mr super trucker..

tractor and empty trailer..

meashure stopping distance from 55 with just svc brakes..then measure it with svc and jakes on level road..I guarantee that with svc and jakes working together it stops shorter

Petey

 

If the service brakes are strong enough to exceed the available traction at the drives, adding additional braking force won't do a #### thing to shorten the stopping distance as once a tire breaks traction, stopping distance increases.

 

Thats just it..with the jakes you don't lock up the tires with the svc brakes..if you are braking that hard either way you risk inducing a skid and loss of vehicle control resulting in a a jackknife to say the least..

You been driving for how long?

Petey

 

I find it funny there is all this debate and yet if you read the owners manual on a brand new truck it says specifically to use them whenever you can to save wear and tear on your service brakes. But maybe thats just what KW says and not anyone else. lol

 

Now we know why more and more signs forbidding the use of exhaust brakes are being put up in towns.Being used when there is really no need. There is no reason to use a Jake with an MT trailer on flat ground in an urban setting.
I use mine IF needed, but try to keep it as quiet as possible, trying to keep stricter noise laws from being enacted.

 

Receipt for my KW I owned until march 2005 for a brake job was 8 grand..replaced all drums, pads, seals and bearings in all hubs..so yeah..its a good reason...

Petey