Advantages of drilled/grooved discs
Discussion
I'm generally really impressed with the standard brakes on my E46 330ci. Except that they're awful in the wet, unless dried regularly.
I know that's normal, but I've never had a car so bad - applied brakes in the wet = nothing for 100 meters!
I wondered if grooved or drilled (or both) would help clear the water faster when very wet?
Has anyone had any experience of using these discs? Last time I had grooved discs on my mk1 MR2 and my nova, years ago, and they were rubbish: warped very easily
I know that's normal, but I've never had a car so bad - applied brakes in the wet = nothing for 100 meters!
I wondered if grooved or drilled (or both) would help clear the water faster when very wet?
Has anyone had any experience of using these discs? Last time I had grooved discs on my mk1 MR2 and my nova, years ago, and they were rubbish: warped very easily
Properly made discs, bedded in correctly (as you should bed pads in) should not warp. Warping is usually a sign that the discs have got too hot, too quickly, usually as a result of abuse. Grooved discs work by cleaning up the surface of the pad and allowing the gasses to escape from the face of the pad more effectively. Grooved discs are typically a little noisier than plain ones. Drilling does a better job of ventilating the gasses, but is much noisier. Also you have to realise that all discs crack over time, an undrilled disc is safe until the cracks propagate about 2/3 ov the radial depth, whereas with a drilled disc as soon as the crack spreads between two holes the discs are scrap.
In short, try a better pad first (Ferodo DS2000 is a good place to start). If this doesn't work for you try a grooved disc. IMO drilled and grooved together is only for the track.
In short, try a better pad first (Ferodo DS2000 is a good place to start). If this doesn't work for you try a grooved disc. IMO drilled and grooved together is only for the track.
Patrick1964 said:
Warping is usually a sign that the discs have got too hot, too quickly, usually as a result of abuse.
Patrick1964 said:
In short, try a better pad first (Ferodo DS2000 is a good place to start). If this doesn't work for you try a grooved disc. IMO drilled and grooved together is only for the track.
Would a different pad compound really help the wet brakes problem though? I thought the compounds just differed for friction vs temp. If I replaced the discs after bedding in new pads, would that require another set pads? (my discs have approx 1mm lip)
EFS
Edited by tom g on Tuesday 17th February 10:36
tom g said:
Patrick1964 said:
Warping is usually a sign that the discs have got too hot, too quickly, usually as a result of abuse.
Yes, sorry if that sounded a bit harsh, wasn't meant that way !
Patrick1964 said:
In short, try a better pad first (Ferodo DS2000 is a good place to start). If this doesn't work for you try a grooved disc. IMO drilled and grooved together is only for the track.
Would a different pad compound really help the wet brakes problem though? I thought the compounds just differed for friction vs temp. If I replaced the discs after bedding in new pads, would that require another set pads? (my discs have approx 1mm lip)
I suspect that your current pads are not getting up to a temperature that generates a high coefficient of friction quickly enough, hence my suggestion of better pads first ( I don't know what pads you are using at the moment of course, nor what condition they are in). If your discs are in good condition I really would just try a better pad first, I've had plenty of cars with solid discs that stopped perfectly well on the road with decent pads (3.2 & 964 911's for instance). In my experience (latterly three years as Showroom Manager @ Demon Tweeks, but not there any more) properly bedded in pads will do the job almost every time, a little advanced driver training always pays dividends too - any pad can be overwhelmed if abused (not saying you're doing this by the way). Hope I've helped.
EFS
Edited by tom g on Tuesday 17th February 10:36[/footnote]
[footnote]Edited by Patrick1964 on Tuesday 17th February 11:20Cheers Patrick. The problem is definitely not caused by temperature; the pads work fine when stone cold. I have no problem with fade either. The problem only occurs in heavy rain (the manual recommends periodically applying the brakes to dry them out).
After doing a google, it seems the discs are due a renewal, as a max lip of 0.8mm is allowed (total 1.6mm reduction in thickness). It's normal for discs to last one set of pads.
So I have to change the discs anyway. The question is to stick with OEM, or give some groovy discs a try!
After doing a google, it seems the discs are due a renewal, as a max lip of 0.8mm is allowed (total 1.6mm reduction in thickness). It's normal for discs to last one set of pads.
So I have to change the discs anyway. The question is to stick with OEM, or give some groovy discs a try!
Patrick1964 said:
Properly made discs, bedded in correctly (as you should bed pads in) should not warp. Warping is usually a sign that the discs have got too hot, too quickly, usually as a result of abuse. Grooved discs work by cleaning up the surface of the pad and allowing the gasses to escape from the face of the pad more effectively. Grooved discs are typically a little noisier than plain ones. Drilling does a better job of ventilating the gasses, but is much noisier. Also you have to realise that all discs crack over time, an undrilled disc is safe until the cracks propagate about 2/3 ov the radial depth, whereas with a drilled disc as soon as the crack spreads between two holes the discs are scrap.
In short, try a better pad first (Ferodo DS2000 is a good place to start). If this doesn't work for you try a grooved disc. IMO drilled and grooved together is only for the track.
C**P!! From 1981 ALL Ford "RS" Disks warped. My 1981 2.8 Capri, My 1986 Escort XR3I, My 1988 Escort RS Turbo, My 1987 Capri Special, and virtually every other car I've owned since 1987 has had brake disk problems resulting in "wobbly wheels"!! All the cars listed were bought Brand New by me. Then I bought a 1986 Porsche 944 Turbo in 1991. That had brake disk problems - cured by a local re-skim.In short, try a better pad first (Ferodo DS2000 is a good place to start). If this doesn't work for you try a grooved disc. IMO drilled and grooved together is only for the track.
Modern brake disks still have problems with virtually any manufacturer. It's called "Economies of Scale". The car manufacturers have to produce a product at a competitive price - equal, if not below their competitors (makes sense, doesn't it?). So every component is subject to a price scrutiny - including, sadly, safety items like brake disks/pads. So even the likes of Ferrari, Aston Martin & the sad company Lotus have to compromise. Why do you think that Ferrari & Porsche offer Ceramic brake discs for another ridiculous £6000 as an option? Because they know that drlled cast iron disks are not exactly safe on a circa 190mph car....
If was in the position to supply a car capable of nearly 200mph I would consider it a God Given duty to supply ceramic discs as STANDARD. The CEO's of these companies are mere "bean counters". They know nothing about the lethal missiles that they sell. I rest ny case - & prepare to be sued - if the CEO's quoted dare to.
Edited by mikez328 on Tuesday 17th February 12:36
mikez328 said:
My 1981 2.8 Capri, My 1986 Escort XR3I, My 1988 Escort RS Turbo, My 1987 Capri Special, and virtually every other car I've owned since 1987 has had brake disk problems resulting in "wobbly wheels"!! All the cars listed were bought Brand New by me. Then I bought a 1986 Porsche 944 Turbo in 1991. That had brake disk problems
I suspect that says more about the owner than the manufacturer.I came across this article when googling.
http://www.stoptech.com/tech_info/wp_warped_braked...
warped brake discs are very uncommon; the typical cause of brake judder is unevenly deposited pad compound
http://www.stoptech.com/tech_info/wp_warped_braked...
warped brake discs are very uncommon; the typical cause of brake judder is unevenly deposited pad compound
tom g said:
I'm generally really impressed with the standard brakes on my E46 330ci. Except that they're awful in the wet, unless dried regularly.
I know that's normal, but I've never had a car so bad - applied brakes in the wet = nothing for 100 meters!
I wondered if grooved or drilled (or both) would help clear the water faster when very wet?
Just out of interest, you do know that BMW do a drilled type disc for the front of the 330 as a factory part? I'm not sure if it's a proper type cast with holes ( like Porsche ) or just cross-drilled.I know that's normal, but I've never had a car so bad - applied brakes in the wet = nothing for 100 meters!
I wondered if grooved or drilled (or both) would help clear the water faster when very wet?
Had them on our 330 but I can't say they seemed any better than the standard ones on my cousin's car.
Didn't have the problems in the wet of "nothing for 100 metres" though!
Shropshiremike said:
tom g said:
I'm generally really impressed with the standard brakes on my E46 330ci. Except that they're awful in the wet, unless dried regularly.
I know that's normal, but I've never had a car so bad - applied brakes in the wet = nothing for 100 meters!
I wondered if grooved or drilled (or both) would help clear the water faster when very wet?
Just out of interest, you do know that BMW do a drilled type disc for the front of the 330 as a factory part? I'm not sure if it's a proper type cast with holes ( like Porsche ) or just cross-drilled.I know that's normal, but I've never had a car so bad - applied brakes in the wet = nothing for 100 meters!
I wondered if grooved or drilled (or both) would help clear the water faster when very wet?
Had them on our 330 but I can't say they seemed any better than the standard ones on my cousin's car.
Didn't have the problems in the wet of "nothing for 100 metres" though!
I imagine BMW "motorsport" discs would cost a small fortune!
These look good value link
I've expereinced the wet brakes issue in an e46 and it is truly scary.
I don't think it's disks / pads related though. I think the only thing that would work would be to gaffer tape up the cooling ducts when it's very wet.
On newer BMWs the brakes are actually dried by being applied very slightly in wet weather.
I don't think it's disks / pads related though. I think the only thing that would work would be to gaffer tape up the cooling ducts when it's very wet.
On newer BMWs the brakes are actually dried by being applied very slightly in wet weather.
lee182 said:
BMW performance brakes cost around £1000, that's for the 130i. So shouldn't think that they'll be any dearer than that. The kit consists of a new set of disks and calibers, and some pads. And if you really want to spend some money get a bbk, Stoptech are what I have on the M5.
£1000??I just bought a set of 4 grooved discs AND mintex redbox pads for £230 delivered! (per previous link)
after reading reviews, it seems these discs fare better than OEM, so thought I'd give 'em a try.
tom g said:
lee182 said:
BMW performance brakes cost around £1000, that's for the 130i. So shouldn't think that they'll be any dearer than that. The kit consists of a new set of disks and calibers, and some pads. And if you really want to spend some money get a bbk, Stoptech are what I have on the M5.
£1000??I just bought a set of 4 grooved discs AND mintex redbox pads for £230 delivered! (per previous link)
after reading reviews, it seems these discs fare better than OEM, so thought I'd give 'em a try.
Nope the BMW perfomance upgrade on the 1 series is 6 pot brembo monoblock calipers at the front and 2 pot calipers for the rear plus new disks and pads etc. I actually paid just over £900 for mine.
Not sure if they would fit on an E46 though and anyhow I think your issue is related to the amount of water directed onto the brakes by the brake ducts. New disks / pads won't solve the issue.
Not sure if they would fit on an E46 though and anyhow I think your issue is related to the amount of water directed onto the brakes by the brake ducts. New disks / pads won't solve the issue.
Edited by rm163603 on Thursday 19th February 16:42
obviously performance wise we are talking completely different here, but i bought some grooved discs (255mm rotors on mine, as well as green stuff pads) for my little E21. in the wet they seem to be performing a little better than the standard discs and pads. but then the discs were a fair percentage more than standard ones. you will notice that grooved discs are noisier too under heavy braking, but they are not intrusively loud. hope it sorts your braking issue...and i really hope you are exaggerating the 100metres, as that is really bad!!!!
you could always get brembo or AP racing brakes!! i reckon that would help your problem! but at a cost!
you could always get brembo or AP racing brakes!! i reckon that would help your problem! but at a cost!
I've got black diamond grooved brake discs on the 330d. Braking power is wonderful. I have used the brakes in a real genuine proper manner about 4 times where I was skeptical whether I would have been able to avoid the collision or stop in time if I didn't have them.
If you get 1 incident like that , then they have paid for themselves tbh.
What does the 300 - 400 quid matter when you have the ability to be able to stop a few meters than standard discs, at the end of the day those few meters are could be from you crashing and not crashing.
Same principle with tyres imo.
If you get 1 incident like that , then they have paid for themselves tbh.
What does the 300 - 400 quid matter when you have the ability to be able to stop a few meters than standard discs, at the end of the day those few meters are could be from you crashing and not crashing.
Same principle with tyres imo.
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