do Drum brakes have any advantages?

do Drum brakes have any advantages?

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Discussion

vlc

Original Poster:

1,014 posts

215 months

Monday 6th June 2005
quotequote all
i ask as morgan still uses them, an beyond their 'traditionlists value' - are they in any way better than disc brakes?

i also wonder if they'd useful enough in a hatchback/citycar...?

agent006

11,774 posts

234 months

Monday 6th June 2005
quotequote all
They're available as an option on a few trucks with a view to offroad use. I assume that disks are susceptable to getting mud and crap caught in them.

Other than the elimination of the colling handbrake problem, i can't think of any advantages.

zaktoo

1,401 posts

210 months

Monday 6th June 2005
quotequote all
For non-track use, in a small car, on the rear wheels, I think they're fine. I can't think of any advantages that they have per se, although I suspect they need less workarounds to get a handbrake installed & working - many cars with discs all round have odd setups for the handbrake, con't think of which cars have these kinds of things off-hand, but I have read about them.

Hope this vagueness is of at least some use :P

Ciao

Zak

joospeed

4,473 posts

248 months

Monday 6th June 2005
quotequote all
the advantage of drums is that they're more effective than discs!

qualifying statement :

more effective until they build up heat. Drum brakes don't get rid of heat very effectively because of the trapped air inside them, hence water cooling of racing truck brakes, but until then the larget mean effective radius means greater stoppng power for any given frtiction material and application force.

wizzpig

2,039 posts

198 months

Monday 6th June 2005
quotequote all
And you don't get so much brake dust over your alloys

victormeldrew

8,293 posts

247 months

Monday 6th June 2005
quotequote all
wizzpig said:
And you don't get so much brake dust over your alloys

But of course you'd have steel wheels anyway with your retro drums!

There are other technical advantages, like possible self servo effect (though views are mixed on this, and the servo effect can be seen as a disadvantage of drums just as easily!). Cooling is the main drawback however - but again, heat dissipation from disc brakes is seen as an issue in many applications, where water cooled drums might be preferred.

I can't help thinking carbon fibre drum brakes would be a good idea though.

>> Edited by victormeldrew on Monday 6th June 11:02

egomeister

5,890 posts

233 months

Thursday 16th June 2005
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Drum brakes are the spawn of the devil! When you realise how much easier it is to replace a set of pad than to change brake shoes you'll know what I mean!

victormeldrew

8,293 posts

247 months

Thursday 16th June 2005
quotequote all
Ah, but imagine the fun of trying to prise off a drum thats caked with dust with shoes seized to the drum and the slave cyliders weaping fluid everywhere. Discs are for wimps!

Mutant Rat

9,939 posts

215 months

Thursday 16th June 2005
quotequote all
Drums have better initial bite, but as has already been said, they are unable to dissipate heat as effectively, so braking performance tails off rapidly as they heat up.

They tend to work much better as parking brakes; disc brake handbrake calipers need a lot more leverage to work effectively.

They can also have lower unsprung weight in certain applications, though: the weight of a steel disc and caliper can easily add up to more than a steel lined aluminium drum and the relatively light shoes and slave cylinder.

Jedis (the bike engined Hillclimb single seaters, not the men in cloaks who wave fluorescent tubes around), for example, used to use Mini based drum braking systems for this reason...and, of course, the average UK Hillclimb venue is too short for brake fade to become a problem.

avance70

45 posts

196 months

Thursday 16th June 2005
quotequote all
advantages:

1) the drum brakes are very very well protected compared to the discs, which are the complete opposite.

2) because of the small size & weight of the lower class hatchbacks, drums don't heat up too much, so they're better choice over discs, which are more expensive to install

3) as i said, drums are cheaper in the start, but also they are cheaper to maintain... so cheaper overall

edc

8,415 posts

221 months

Friday 17th June 2005
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avance70 said:
advantages:

1) the drum brakes are very very well protected compared to the discs, which are the complete opposite.

2) because of the small size & weight of the lower class hatchbacks, drums don't heat up too much, so they're better choice over discs, which are more expensive to install

3) as i said, drums are cheaper in the start, but also they are cheaper to maintain... so cheaper overall


1) I cannot recall ever needing 'drum' protection for rear disc brakes.

2) Not sure whether the argument is price or heat. Either way rear disc brakes on hatchbacks don't really get hot and replacement discs and pads are not expensive compared to drums. Of course the compariosn is a bit spurious ecause you are oftencomparing bigger rear discs from a bigger engine car to the drums of a base model.

3) Not sure about the maintenace. There isn't much to do on rear discs. Disc looks scored - change it. Check pad through caliper nd worn - change it. You don't have to take anythign apart for these maintenace checks.