Why drum brakes? 3

[floattuber]

Why do manufacturers use drum brakes on passenger cars/trucks rather than disk brakes? Because of their simplicity, it seems like disks would be cheaper to build plus they stop better. What advantage do they have over disks?

 

[NormPeterson]

Pat, at least some of the mechanisms that apply rear pads have proven to be somewhat less than good. In severe cases the pad(s) will over-adjust and then not retract leaving you with a very warm wheel or one that stops rolling. Cost me a caliper on my '95 Mazda a couple of years ago, remanufactured because it is no longer available new.

I'm not sure I follow the complaint regarding reducing the rear brake bias by 40%. The harder you stop the less you want the rear brakes to be contributing. But if brake bias is always biased to the front to suit the most severe braking the rears will be under-utilized in easier events (which is arguably the majority of the time for production vehicles).


Norm

 

[patprimmer]

Norm

I did specify if designed correctly. I know some are no correctly designed.

I would thin it is more important for the brakes to be balanced on the rare occasion that they ar used hard than on the many occasions they are used lightly. I base this on the potential for the cost of the consequences vs the likelihood of the results.

Regards
Pat
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[NormPeterson]

Precisely why there are proportioning valves, since bilinear biasing is better than no variability at all. I don't think this is confined to rear disc brake systems, as I replaced a prop valve in a disc/drum braked car about four years ago.


Norm

 

[evelrod]

If your interested in brake bias....Watch till the very end.
Just one of the reasons I have an adjustable prop valve on the rear drum brakes...

http://www.youtube.com/watch?v=ES8zCpdCSU0&NR=1

Rod

 

[patprimmer]

Do you think they needed a bit more anti dive.

Regards
Pat
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[NormPeterson]

<picks jaw up off floor>