Most agree that disks are best.
Why then do some cars, Focus, Mondeo and even the rally inspired Subaru Impreza have rear drums?
My Volvo 940 has disks all round {plus ABS} and stops even beer than it goes.
Disks are simpler in design, easier and cheaper to service - so why drums at all?
|
cheaper to make drums that keep the water out if driving in heavy rain etc, most disks are open to the elements (which is good for cooling if thats the type of use they are going to give), although you are right
typically vectra has rear disks where equivalent ford has drums, buy hey in a glossy mag ad nobody much notices...
im more concerned by pretty good cars which are spoiled by putting wheels/tyres on them that are just too thin, often the handling/at the limit braking would be so very much better with tyres just an inch wider - there are many examples of this...
|
doesnt anyone else find it annoying that the only way to get slightly wider tyres is to spec the alloys when buying new ? the default steel wheels are often just a little thin tyre wise...
arnt there more people like me who want the wider tyre but are happy to have steel wheels to avoid the toe rags who nick alloys?
|
But steel wheels went out with the dinosaurs!
With all the nice looking alloys about today, you're spoilt for choice!
I certainally for one wouldn't buy a car without alloy wheels today.
Rgds
David
|
Even if you could have a nice flat disc wheel trim with no brake dust in sight?
David
|
|
|
Alloys may look nice, but don't take to clumsy parking. Try walking down the average high street, and looking at the alloy wheels. A very small proportion will be without some damage, and it is either expensive or impossible to repair. Me - I'm paranoid about parking anywhere with a kerb in case I scuff the alloys.
Always amazes me that the small 'city runabouts' sport alloys, as they are usually ruined in a short while. For most people a good looking wheeltrim which can be replaced if necessary at small cost wuld be preferable.
It's my first check on a second hand car - I reckon a set of unmarked alloys is the sign of a careful owner. What on earth do the trade think about them. Must be a nightmare looking at repairing/replacing alloys on a trade-in; or maybe the buyers don't care/notice?
Regards
John
|
|
|
|
|
ABS technology has progressed so far nowadays it can now accurately modulate the braking pressure to drum type brakes whereas before, disc type brakes were the only ones catered for in an ABS system.
Rgds
David
PS. Drum brakes are cheaper to maintain
|
|
|
Rear pads also seem to wear out fairly quickly, whilst rear brake shoes seem to last the lifetime of the car.
We sell/fit about 10 sets of rear pads a month in our workshops, whereas we have fitted TWO sets of rear shoes due to wear this year.
Rgds
David
|
|
I am suprised, front pads for my previous cars were always cheaper than rear shoes and far far easier to fit.
|
|
|
|
|
Am I being stupid or is Paul referring to the small drum type handbrake mechanism on these models as opposed to the actual brakes?
|
Guy,
I think Paul was referring to the type of rear brake and not the handbrake mechanism as found on many Vauxhall models.
David
|
Rear discs are a right pain on lightly laden cars with drivers that never use the brakes.
Seized pads, rusty discs, uneven wear and so on.
Rear shoes in drums do often last 75,000 but an often overlooked point is that the rear wheel cylinders can leak well before this time.
Most of the P.306s I look after with rear drums have needed wheel cylinders well before 50,000 miles.
David
|
Knackered after 50K,
Thats not good!!!!!!!
|
|
|
|
We seem to encounter a lot of rear disc brake squeal with our beloved Xantias.
Usually, a new set of rear pads, suitably lubricated, cures the problem
David
|
|
thought sanding the sheen off the pad was normally all thats needed ?
|
|
|
|
David
Good point about the brake dust.
Changing a wheel on a car with disc brakes is a filthy job, especially at the side of the road in decent clothes, and wheel trims seem to be specially designed to trap it.
To say nothing of having to lay down in the road to get the spare wheel out of the carrier under the boot because it catches on the towbar mounting!
|
|
fraid as much as i could easily afford alloys i tend to go for steel wheels, simply cos they are less of an attraction to your local scum, especially if you have to park in some of our nations dodgier areas, not many police resources go into wheel thefts methinks
|
|
You must also remember that steel wheels are actually lighter and much stronger,but I suppose its people choice.I have to clean my alloys on my beemer every week and never on the steel rims of my xm
|
|
Someone must have sold you a duff set of alloys then - our Xantia's alloys are virtually solid, no thin little spokes to show off the brake discs, yet they are a lot lighter than my BX's steel wheels even with more rubber on!!
|
|
|
|
|
I reckon you get a handbrake with more bite from drum rears...
|
|
|
|
No. my vovlo has seperate drums for the hand brake, but the rear brakes {foot opeartaed} are disks
|
|
|
|
Your most astute David - well done !!!!!!!!!
|
|
|
what has this to do with the disk / drum debate?
Paul?
|
|
|
Hand brakes less effective with disks?
Most of the braking done at the front, that why loats of cars are fitted with drums at the rear.
I think ???????????
|
yea and simplicity of handbrake mechanism with a drum is another reason...
rear brakes do not need to be able to take anywhere near the load of the front ones
there are pros and cons either way
|
I seem to remember that Rolls-Royce retained drums all round long after everyone else had gone over to discs, because they claimed that their drums were the best and they saw no need for an untried innovation.
I think any brake system can be made powerful - there was a car in the thirties(can't recall name) that had enormous drums and a stopping power so great that it was famous for tearing tyres to pieces and breaking springs.
Isn't it the anti-fade properties of disks that makes them better?
Cliff Pope
|
|
|
|
With most bread-and butter family cars drums are a better proposition on the rear because:
1. Most cars are front wheel drive and have their weight biased to the front. Rear brakes do relatively little work and drums are adequate and don't fade with these sorts of loads.
2. Drums give a better handbrake solution.
3. Rear disks suffer excessive corrosion due to their not getting sufficient hard use (sam reason that many camper vans have their disks replaced after only a few thousand miles).
4. Drums are a "fit and forget" item as far as mass fleet sales and servcing goes.
|
|
|
i suggest that if ford fit drums to the rear of some models it is to do with the cost, to them as a manufacturer, not performance. As a mass producer, they will fit the brakes that do the job at the lowest cost. Drums do have some advantages as mentioned above, but do not match the performance of discs. Hence ford fit discs to their higher performance models. Handbrake mechanisms can and have caused a few problems with discs but a well designed unit works fine.
On the subject of tyre width, that Fred tried in vain to raise, it should be remembered that wide tyres do not necesarily equal more grip. A wider tyre has less weight per sq/inch pressing down on it (because the car weight is spread over a wider area) and can grip less if the optimum is exceeded, particularly in wet weather.
|
|
|
