Drums vs. discs

[PerfAdv]

Dunlop developed the Disc brake in 1952. They made it into some british production models in the early to mid-50s.

[Matra et Alpine]

Drum brakes can put more friction material into contact with metal for braking effort than similarly sized discs can. So you still see Drums on large commercial trucks where LOTS of material is needed for the HUGE braking effort to bring a few tens of tons to a stop !! Trucks get around the limitations with HEAVY thick drums and air-assisted braking. Neither of these are practical in a sports car or small family saloon

Discs give a much better 'feel' to braking and don't need as complex adjustment.

Disc brakes are more costly to desisgn and manufacture BUT are MUCH, MUCH cheaper to service. Nothing needs dismantled and adjusted to replace friction material ( well unless it was a Citroen and there you had to remove the manifold to get to the rear pad of the inboard discs )

[PerfAdv]

Disc brakes are more costly to desisgn and manufacture BUT are MUCH, MUCH cheaper to service. Nothing needs dismantled and adjusted to replace friction material ( well unless it was a Citroen and there you had to remove the manifold to get to the rear pad of the inboard discs )

Speaking from personal experience with Mazda sedan I used to have. Whenever, I had the brakes serviced, it had front discs and rear drums, the discs would cost more. The brake pads were more expensive than the shoes required for the rear drums. Also, the drums didn't need resurfacing where as the discs did, adding to the overall cost as well.

The rotors in a disc brake setup are also more likely to need maintenance than a drum. As I have had rotors warp, which then required resurfacing. This then made the rotors thinner and even more susceptable to warping. The need for resurfacing, has atleast for me, cost extra on replacement rotors. In my experience discs cost more than drums to maintain.

A possible explanation: disc brakes on front wheels take most of the abuse, especially in a FWD car.

[Matra et Alpine]

Speaking from personal experience with Mazda sedan I used to have. ....
A possible explanation: disc brakes on front wheels take most of the abuse, especially in a FWD car.

Wow, another example that convinces me that you guys get sold a piece-of-shit at every turn. Your price for a new car may be cheaper than over here, but you clearly are "getting what you paid for"

Only ever had one car where the front rotors needed replacement and that was a FORD and the service manager said that it was cheaper for Ford to replace the rotors for those who complained about the warp than to spend the extra pound getting them made from better material. I've not owned another Ford since

With decent pads and standard rotors I've done 80-100,000 miles.
I've done upwards of 10,000 miles of competitive driving and not had the problem.
On the drums v discs wearing debate, most folks don't bother to check drum wear untill it is VERY bad. Discs are easier to check and hence are changed at the right time rather than later.

Left-foot braking puts HUGE loads on discs much more that 'normal' driving and I've not had rotors warp or wear enough to need resurfaced. Course I change the pads as soon as they wear to THEIR limit - if you don't the risk is higher to damage the rotors.

ah, well it'll be interesting when Chrysler start importing POS to see how many rotor replacements we get before they realise we won't buy POS more than once !!!

[PerfAdv]

It's funny you mentioned a Ford having rotor problems. As Ford owns part of Mazda....cheapest parts is not a good way for quality: job #1 or whatever. I didn't have any brake problems with an Integra I had, which was also driving with more verve than the Mazda.

Something else I've noticed is that European cars tend to get a lot more brake dust buildup. Showing they use softer pads designed to wear away while not harming the rotor. Whereas a harder pad material would cause more rotor wear.

We definitely get suckered with inferior products in the US. Especially those that feel they have to buy American are doomed to defending their actions/problems. Even the gasoline is bad, it caused compression loss in the first BMW V8s of the mid-90s. The block composition couldn't handle the high-sulfur content, it was corroding the cylinder wall. Since then BMW changed to a high nickle and silicone alloy(Nikasil) for the engines.

Give the consumer the cheapest product regardless of possible drawbacks. Its not just automotive, witness the hormone and antibiotic fed poultry and livestock, genetically moded(GMO) grains and veggies, the list goes on... If a politician points to any of these things he's a socialist, marxist, pinko... Don't mess with the CORPs...

[Blue Supra]

Iv got discs on the front of my car and drums on the back, as hard as i stand on the brakes ive never been able to lock up the rears but have the fronts. Can someones explain this?

Also when i brake hard i a shudder through my steering wheel. What does this mean?

[henk4]

Also when i brake hard i a shudder through my steering wheel. What does this mean?

That may mean that your discs are slightly warped.

I changed my front discs after 160.000 km's.

[Blue Supra]

Well this cars got 280000ks on it and i dont think the rotors have EVER been replaced.

[KnifeEdge_2K1]

Iv got discs on the front of my car and drums on the back, as hard as i stand on the brakes ive never been able to lock up the rears but have the fronts. Can someones explain this?

Also when i brake hard i a shudder through my steering wheel. What does this mean?

well since weight transfers to the front during braking usually it would be the back that locks (assuming 50/50 brake bias which is very unusual), newayz drums dont have as much "bite" as disks and since they arnt the best at getting rid of heat they will wear much faster then your disks, this coupled with a front brake bias is probably why you locked your front wheels more often

and also manufacturers dont really want you to lock ur rear wheels as opposed to ur front because that would be the equivalent of pulling the handbrake ... which means losta oversteer

[Blue Supra]

Im thinkn im going to replce the drums with discs anyway out of a TRX bluebird for the hillclimbs and downhills i do, the brakes feel yeh bad when it shudders like that. Nothing wrong with a bit og oversteer as long as u can control it

[Matra et Alpine]

Im thinkn im going to replce the drums with discs anyway out of a TRX bluebird for the hillclimbs and downhills i do, the brakes feel yeh bad when it shudders like that. Nothing wrong with a bit og oversteer as long as u can control it

Knifeedge is spot on, good post

You dont' want rear brake induced oversteer on roads.
It's helpful and necessary on loose surface rallies and in autotests.
BUT on the open road it is bad
WHY ? Because you don't have the engine on-throttle at the time it breaks loose. So it's more likely that as you try to feather power to keep it in the drift or to bring it back in line that it will either not pick up and you go off backwards as the rears are getting engine breaking OR that it snatches and you go into a tank slapper !!
Either way is NOT clever on public roads and just plain embarrasing on track - I know

If you're going to put discs on the rear, go for a smaller rotor, piston and pad AND fit a variable brake bias to allow you to set it up for the best handlng.

Good luck.

[Blue Supra]

good thing i read that Matra, i was just about to open a new thread asking what needs to be done with it...

I user understeer a lot on the track though, get it through the tight corners.. i js oversteer it so the back slips out and i kinda half drift half flick the car through, you know what i mean? it took me a while and a few embarressing moments to get it right but it works well for me now... is that something i shouldnt be doing?

[Matra et Alpine]

good thing i read that Matra, i was just about to open a new thread asking what needs to be done with it...

I user understeer a lot on the track though, get it through the tight corners.. i js oversteer it so the back slips out and i kinda half drift half flick the car through, you know what i mean? it took me a while and a few embarressing moments to get it right but it works well for me now... is that something i shouldnt be doing?

Well that's EXACTLY how I drove when I came back to track nearly 9 years ago. I was lucky and got some great tuition from some seriously good drivers. One of them after 3 laps asked me if I'd driven competitively before and when I said yes he asked if I'd rallied. 'owned' He said I drove like I was rallying and that track needed me to learn different lines, techniques and to THINK more about the 'weight' of the car. He got 3-4 seconds OFF my lap time by the end of the first 20 minutes !!

Scandinavian flicks are spectacular and necessary on twisties and rough surfaces. On most corners though they are the SLOWEST way round
( They're also SOOOOOOO much fun - until you lose it )

Anyway, on track it is smoothness that matters if you want to reduce lap times. Getting the weight transfer of the car to move smoothly and to transition at the right points to maximise turn-in and traction is key to moving quickly.

One of the GREAT movies of the 70s had Jackie Stewart driving a Ford Capri round a track and he was showing different techniques. The classic "club racer" he called it with fast in, hard braking, chucking it round the corner and scrabbling on exit and then the "smooth" one - his No guesses what was faster.

It's also less stressful and effort to drive it smoothly. I used to be knackered after a 20 miunte session on trackdays. Arms throbbing, wrists hurting and sweating like a pig. With a better race technique it's a helluva lot easier as well as faster :0 ( I still come in throbbing, hurting and sweating - but now I've gone faster )

I still keep both styles when I'm out having fun. So I'll do the 'controlled' drive and then do a couple of sessions of getting it sieways, flicking it and coming out on FULL power smoking tyres. Guess which one my kids used to love when they came to watch

[fpv_gtho]

My dad had this 1971 F250 that had god knows what done to it, but by the end of a mega customisation, the original F100 body had an F250 chassis with the original 300 Canadian and 4spd..with i think the drum brakes off an F350. the thing literally locked all the wheels from a slight tap on the brakes, and could crack your neck

[Blue Supra]

Well that's EXACTLY how I drove when I came back to track nearly 9 years ago. I was lucky and got some great tuition from some seriously good drivers. One of them after 3 laps asked me if I'd driven competitively before and when I said yes he asked if I'd rallied. 'owned' He said I drove like I was rallying and that track needed me to learn different lines, techniques and to THINK more about the 'weight' of the car. He got 3-4 seconds OFF my lap time by the end of the first 20 minutes !!

Scandinavian flicks are spectacular and necessary on twisties and rough surfaces. On most corners though they are the SLOWEST way round
( They're also SOOOOOOO much fun - until you lose it )

Anyway, on track it is smoothness that matters if you want to reduce lap times. Getting the weight transfer of the car to move smoothly and to transition at the right points to maximise turn-in and traction is key to moving quickly.

One of the GREAT movies of the 70s had Jackie Stewart driving a Ford Capri round a track and he was showing different techniques. The classic "club racer" he called it with fast in, hard braking, chucking it round the corner and scrabbling on exit and then the "smooth" one - his No guesses what was faster.

It's also less stressful and effort to drive it smoothly. I used to be knackered after a 20 miunte session on trackdays. Arms throbbing, wrists hurting and sweating like a pig. With a better race technique it's a helluva lot easier as well as faster :0 ( I still come in throbbing, hurting and sweating - but now I've gone faster )

I still keep both styles when I'm out having fun. So I'll do the 'controlled' drive and then do a couple of sessions of getting it sieways, flicking it and coming out on FULL power smoking tyres. Guess which one my kids used to love when they came to watch

Youd probably have to show me, im a visual learner...
but put simply (i know im going off topic...)
ie. in a paragraph
whats the fastest way through a corner?