Re: Disc Brakes - Are they very expensive Quote:
Originally Posted by greatmana2000 Cost of adding discs over drums is just a marginal increase for the manufacturers .
Braking force is directly proportional to the surface area of the braking material and the force applied for braking . A drum brake has more braking surface area than a disc brake . A disc brake has much better clamping power and that is the reason for using it in the front wheels .
The reason why ABS is better on a 4 disc setup is because discs tend to lock up with excessive force and ABS is good and works well ,but drums seldom lock up ( if designed properly) so without ABS I would prefer a disc and drum setup only .
A good set of brakes should be able to effectively retard the vehicle and not lock up the wheels . Drum brakes are much better in this application as they use lesser pressure but more surface area which results in a better braking compared to a disc brake .
On alot of forums I have come across posts which say that discs cool faster , but discs also heat up much more due to smaller surface area and higher clamping force . Drums dont heat up that much compared to discs , and since drums dont cool off faster , the braking is more better .
The above observations are by me and not technical . |
In Europe ABS on trucks was legally enforced a long time ago. This was quite a few years before disc brakes found their way into anything above 7.5 tons. ABS control can be done on either very effectively.
Either brakes have their advantages and disadvantages. Disc brakes are easier to cool down and clean themselves easier than drum brakes.
When drum brakes are too small, surface material tends to glaze faster and makes them inefficient. Measures for de-glazing are much more expensive on drum brakes.
Many manufacturers still use drums at the rear as they are cheaper to produce and the brake force is so little (only about 15-20% of the total break force) that heat is no problem.
On small cars drum brakes are the better solution at the rear as they are usually lighter than equivalent disc brakes, reducing unsprung wieght unless carbon brakes are applied. |