Why do American trucks still use drum brakes?

ok whatever disc brakes dont fade like drum brakes do. hows that. im done.

 

I have to apologize. I misread your first post that I quoted. I thought you said disks don't fade at all when you said they don't fade like drums which is a big difference.

 

About disk brakes. They are more precigion, that's why EBS and ESP work better with disk brakes.

http://www.youtube.com/watch?v=AHvoPJrXIMU&feature=related

Yeah, mercedes build truck with EBS and drum brakes (trucks for construction works), and as I feel no advantage of EBS with drum brakes. They are too slow

 

There's two main reasons they use drums on trucks
**Cost effectiveness
**You have 10 parking brakes to hold the truck securely. Remember without air, drums are normally closed while discs are normally open.
Also most of your weight shifts to the front when you brake. That's why you see alot of cars with disc on the front and cheaper drums on the rear. When they put discs on the rear, there is a little drum built inside the rotor for the emergency brake. They work better but also costs more.

There's a complete difference on the fade. Drums will expand and since your shoes are pushed by a S-cam they can only go so far. Disc brakes can continue pushing regardless. The pads will get so hot they will glaze though, losing their gripping power.

 

First of all, park brakes may be installed on any caliper, and later EU trucks are with park brakes on all calipers. No air, wheels are locked.

On trailers more then half of axes must be with spring park brakes. If it is two axe trailer - both the axes will be locked w/ air, if three axe semitrailer - two axes minimum.

About gripping power.... disk brakes are well cooled with air, much better then drum brakes. The only bad thing when you put them glow red in deep puddle disks may crack.

There are many owners here, who operate European EBS trailers with disk brakes with US trucktor, and belive me, less accidents, less roll over crashes, less jack knifing.

 

Disk brakes on a tractor trailer are controlled by a brake chamber so why wouldn't they be able to lock the brakes in the same manner as drums?

That's kinda the whole point I was intending to make.

They may be less prone to fade, but they still have their limit. Id like to see how discs hold up to "more than usual" brake use on long 7% grades with gravity having its way with 40 tons.

 

Gonna open a can of worms here...
I understand this brake fade arguement but...
Drum brakes have always served me well in my tender, trivial trucking experience. Isnt taking care of the brakes part of driving a truck? This BS of having brake parts red hot... The only place i want to see brakes glowing red is on race cars...

 

Guys, as I can see you've never had truck with disk brakes. You can't imagine difference in driving. And you see mythic problems, you look for problem where there is no problem and you do not see the real problems.

One thing I agree with you. Disk brakes maintanace is not so exoencive, but repare and additional cost of parts is the real issue, but disk brakes with EBS and ESP and if trailer is with disk brakes, EBS and RSS it really avoids risk if accidents and save trucks and lifes.

 

PaBLO wHY THERE iS STILL NO ESP FOR DRAWBAR COMBINATION IF i AM rIGHT OLY VOLVO HAVE IT

 

Actually the reason that trucks dont have disc brakes yet is more basic than realised.

The trucking industry is as old as the hills. So are the older generation still driving these said trucks. The realization is that truckers are holding back most of the industry.

If all the drivers out there insisted that their new tractors came with disc brakes, then industry would start making drum brakes an option as to the norm. It is only by prefferrence by what you get.

There are kits out there to retrofit trucks with disc if you so prefferred. They (like most truck retrofits) are not cheap, yet your break distance will be considerably less. The other part is, with better stopping power on the truck, it will make the trailer with drum brakes want to pass you more easily now.