Why no four-wheel disk breaks?

Thanks.. picked up a set of Powerstop rotors and pads from AutoParts Warehouse. Not sure if they have the deal still but they offered a package deal of both in one for like $200.00. So far I like them a lot and did notice a bit more stopping power. Definitely no fade with the trailer attached but then again I didn't get any fade with the origionals either. Definitely reduced the amount of brake dust on my front wheels. We'll see how good they wear and if they can come even close to the almost 100k miles I put on the origionals.

 

Time for another let's defend the cheap, outdated, less effective technology?
Alright then, Yeehaw.
1. Drums are cheap
2. If you can't spell brakes, ahh never mind....

If it was intended to be a real truck, and haul heavy loads, and tow, umm 6500#, it should have disc brakes like it's competitor.

 

How many 'real trucks' (ie. semi tractor-trailors) have disc brakes in back? Drums have more braking surface area, and the back brakes do such a small amount of the work, they often last well over 150,000 miles without wearing out.

 

My guess would be 'real trucks' (I assume you mean OTR, aka semi's??) use drums because their braking effort is much less (due to self-servoing) and so the pneumatic system that actuates/de-actuates them can be a lot smaller in capacity and operate at lower, safer, pressures.

That said, I also recall reading somewhere that newer 'real trucks' increasingly use disks in back. Would be interesting to understand how many and which kinds/classes of trucks.

No matter how you spin it, I don't think you can escape the fact Toyota puts drums in back on Tacoma 'cause it's an el cheapo truck. Which sucks cause they charge so much for it. But they work just fine so I'll live with it.

 

actually some of the newer semi's equipped with certain european axles have disc brakes as an option. the new Novabus busses that just came down here are equipped with disc brakes on all axles as well. they create significantly less noise and have far greater stopping power than a conventional all drum setup.

 

Semi trucks run air brakes. 120 psi to the air chamber is plenty to actuate disc or drum brakes. Size of the actuator is not an issue as all the air goes through the treadle/foot valve. The air goes through various control valves, abs for one, then on to the brake chambers. The size of the brake chamber and legnth of the torque arm determine the brake force applied and are varied by the type of brakes used.

Semi truck brake force distribution is much differant than pickups. The rear tractor brakes do the most work while towig a trailer. The trailer pushes down on the fifth wheel.