I’m looking at buying a new small truck and I noticed that Toyota, Chevy and Ford trucks have disc brakes on the front and drum brakes on the back, whlie Nissan has disc brakes all around… at least according to one website I found.
So what is the advantage of drum brakes in this day and age? I would have thought disc brakes would be cheaper and easier to manufacture, or do I have that backwards?. Anyone know the real reason?
Mods: This may belong in the IMHO category…
I don’t have a handy cite, but a friend and ex-co-worker who works at Chrysler (as an actual Engineer designing diesel engines) insists that drum brakes are significantly cheaper than disc brakes, especially on larger vehicles, and that that is the sole reason they’ve lasted as long as they have on some lines. Personally, I don’t see how that can be the case, given the large number of parts that make them up, but I’m not informed enough to argue with him.
If you’ve ever actually taken apart a brake caliper, that kind of gives a hint as to why discs are still more expensive. The manufacturing process for a brake rotor is also a lot more intensive than making a drum because the disc gets put under a lot more stress. Also, in the rear, if you use discs you have to make a separate parking brake whereas a rear drum brake can do double duty.
Plus it really is an area where they can cheap out, because drum brakes are only marginally less effective than disc brakes (especially with ABS) and the fronts do most of work anyways. Realistically, only a few high-performance applications benefit from rear discs and I suspect that most cars that do have rear discs do mostly because of how they look with fancy rims.
Any idea why the Nissan Frontier would have disc brakes all around? I certainly wouldn’t consider it a high performance vehicle…
I can see how drum brakes would cost less to manufacture. It’s not just the number of parts, it’s the cost of the parts. Drum brakes have lots of pieces, sure, but most of them are little cheap things (e.g.springs, simple metal bars or levers). Calipers are significantly more expensive than wheel cylinders. Parking brake mechanisms are simple to incorporate with drum brakes, but with disc brakes require either a complicated caliper that’s yet more expensive or - ready? - little drum brakes inside the rotors. I’m not at all surprised that rear disc systems cost more.
Can’t say I know why, but I’ve observed from way back (1970’s) that Nissan has a penchant for some fancy engineering even when it’s not really needed.
Drum brakes are superior in one area. As a parking brake. Disk brakes make for really shitty parking brakes.
For looks. People think that drum brakes look silly with the fancy newer rims that have a lot of see-though space.
Rear discs are a lot nicer when offroad or towing, two things the Frontier may be used for.
I have a Nissan Pathfinder which uses the Frontier truck frame as it’s base. I also have rear discs. Maybe for want to be able to share a lot of parts they went ahead and put discs on both. Assuming they wanted discs on the Pathfinder.
Knee bone connects to the ankle bone…
The Chevy Tahoe (or is it the Suburban) uses the C-10 frame I think. But does it have rear discs?
About 50 or 60 times.
Most cars I’ve owned have 4-wheel discs, and they use a cable to actuate the rear calipers. As does my current Mustang GT.
Most cars I have owned have had 4 wheel discs, too, and it’s about 50/50. Chrysler seems to like the “drum brake inside the rear disc” idea.
Yes, all but a handful of designs use a cable to operate the parking brake, but I think GreasyJack’s point has to do with the actual mechanism said cable operates. With drum brakes, it’s typically a simple lever and crossbar, which is fairly cheap and easy to add to a basic drum design. With disc brakes, it’s either a mechanism inside the caliper, which adds significant complexity (and expense) to the caliper, or the addition of brake shoes and attendant hardware, which also adds complexity and expense. Disc brake parking brakes are just a lot more involved than drum brake parking brakes.
I assume that by this you mean a car with front discs and ABS on those discs, not a car with ABS on drums, because my understanding was that all ABS systems operate with discs, not drums - or am I wrong?
Is this purely because of the cost/complexity issues already mentioned, or is there a physical reason that makes discs unsuited to acting as a parking brake? Is it because more energy is needed to apply a disc brake with sufficient strength for application as a parking brake, than is needed for a drum? I only ask because disc brakes are generally more efficient than drums, and I can’t quite see why this would be different for parking.
With the smelliest part of it being the automatic adjustment system that is so effective on drum brakes. How many of you want to crawl under the car for a routine brake adjustment? Or pay for another service.
There are instances, like me for example, where the brakes are not applied on a regular basis when backing up. I need to do a few cycles of reverse stop starts just to adjust my brakes:smack:
All of the above. Drums brakes are self-energizing to where once a certain amount of braking force is achieved they apply harder with rotation, or attempted rotation. It costs more to make the parking brake with discs, and it either uses the caliper, which tends to require more applied force to get the same braking effect, or drum parking shoes which are much smaller than drum service brake shoes.
Some of the big differences are that discs can get much more airflow for cooling and the pads tend to wipe water off of the rotors, which only apply when the vehicle is moving.
Thanks, Gary T - as helpful and knowledgable as always.
Damn straight. Even to the point that Landrover were covering all Parking mechanism adjustment warranty claims on the Discovery 3, not only multiple times during the three year warranty, but even up to six months after warranty expired. I have never seen any other manufacturer treat park-brake adjustment as anything other than a serviceable item (At least after 2-3000mls anyway), which might indicate what they thought about the disc braking system.
(I believe they got the problems sorted though and the braking system is much more reliable. I no longer work for a Landrover dealer so not sure on that point)
Most modern European cars have the mechanism in the caliper, not an extra set of small drum brakes.
My Citroen C4 is like this but I haven’t noticed anything weird with the handbrake. It can lock the rear wheels fine while the car is moving.
I would have thought that an employee would be able to type Land Rover correctly. 