motoreiter
Registered user
I have spoke wheels on an 07 GSA with 21k miles and have had two sets of front and rear discs.
Discs - Warped? Definitive answer? Any theories?
- Thread starter Deleted account 211025001
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alleycam
Registered user
3 new discs...
Not a new problem, nor a solution... just my experiences and thoughts.
I've just had all three discs replaced on my GSA with only 11k on the clock. The pulsing was so bad I'd have sworn the discs were corrugated. The majority of the last 4k being motorway miles with almost no braking done. I'm really disappointed with the discs and the common problem they seem to have with warping.
I used to ride an R80RT, and then a K100RT and did huge mileages, many with very hard riding involved. They both sufferred from needing a k-zillion discs through warping, only beaten in parts by the number of head gaskets the 80 needed... The Honda I got in replacement never warped anything...mmmm.
Disappointment abounded to find the warped disc problem on this bike, especially as I'm a steady eddy on this machine... At least I got these latest discs replaced under warranty, but what really took me by surprise was that BMW dealers are instructed not to replace the pads, so your old ones go back in! I always thought this was considered bad practice. The back disc was replaced on the second visit when I found this out, had some pads fitted and also that the rear ones alone were £47 - crikey! (ABS ones apparently are much more expensive... er why?). Sceptical me wonders if the pads price was a factor in not replacing pads as a matter of course?
Got her back now and she's a joy to ride again, lovely!
Al
Not a new problem, nor a solution... just my experiences and thoughts.
I've just had all three discs replaced on my GSA with only 11k on the clock. The pulsing was so bad I'd have sworn the discs were corrugated. The majority of the last 4k being motorway miles with almost no braking done. I'm really disappointed with the discs and the common problem they seem to have with warping.
I used to ride an R80RT, and then a K100RT and did huge mileages, many with very hard riding involved. They both sufferred from needing a k-zillion discs through warping, only beaten in parts by the number of head gaskets the 80 needed... The Honda I got in replacement never warped anything...mmmm.
Disappointment abounded to find the warped disc problem on this bike, especially as I'm a steady eddy on this machine... At least I got these latest discs replaced under warranty, but what really took me by surprise was that BMW dealers are instructed not to replace the pads, so your old ones go back in! I always thought this was considered bad practice. The back disc was replaced on the second visit when I found this out, had some pads fitted and also that the rear ones alone were £47 - crikey! (ABS ones apparently are much more expensive... er why?). Sceptical me wonders if the pads price was a factor in not replacing pads as a matter of course?
Got her back now and she's a joy to ride again, lovely!
Al
bsogri
Registered user
warped discs
this might sound stupid but here we go
my brakes started to pulse and i was sure one of them had warped however one of the lads noticed my back light was flickering on and off,
I relaced the bulb and hey presto pulsating brakes fixed, miracle cure
when a filament blows the brake and tail light function is transfered to the remaining filament which in turn can confuse the canbus system .
Bulb blowing can be caused by old age or corrrosion on terminals behind light
try cleaning these up as well you never know.
It also cured my dash lights which would fade and brighten on a wim
so get a bulb for £1 and try it first it is miles cheaper than discs
this might sound stupid but here we go
my brakes started to pulse and i was sure one of them had warped however one of the lads noticed my back light was flickering on and off,
I relaced the bulb and hey presto pulsating brakes fixed, miracle cure
when a filament blows the brake and tail light function is transfered to the remaining filament which in turn can confuse the canbus system .
Bulb blowing can be caused by old age or corrrosion on terminals behind light
try cleaning these up as well you never know.
It also cured my dash lights which would fade and brighten on a wim
so get a bulb for £1 and try it first it is miles cheaper than discs
Deleted account 211025001
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Deleted account 211025001
Registered user
- Joined
- Feb 3, 2005
- Messages
- 8
- Reaction score
- 10
A further update..........
39,000 miles and I've just picked up the GS after having a set of WMB discs fitted as the EBC ones recently fitted were shagged (and some, I've never ridden a bike with such badly warped discs!).
The reasoning behind spending a stoopid amount of money on MBW discs being that NO make of disc has so far worked and at least the BWM parts are guranteed for 24 months meaning I should never have to pay for a pair of discs again as every time they warp they get replaced under gaurantee
However, the new discs are different to any (including MWB) yet fitted in so much as they are now 'proper' floating discs ie the washers/bobbins are now part of the disc assembly, not separate as before. I can now move the discs from side to side, just like on all other bikes with floating discs. Time will tell but, hey, the problem of warped discs could , just, be a thing of the past
Andres
39,000 miles and I've just picked up the GS after having a set of WMB discs fitted as the EBC ones recently fitted were shagged (and some, I've never ridden a bike with such badly warped discs!).
The reasoning behind spending a stoopid amount of money on MBW discs being that NO make of disc has so far worked and at least the BWM parts are guranteed for 24 months meaning I should never have to pay for a pair of discs again as every time they warp they get replaced under gaurantee
However, the new discs are different to any (including MWB) yet fitted in so much as they are now 'proper' floating discs ie the washers/bobbins are now part of the disc assembly, not separate as before. I can now move the discs from side to side, just like on all other bikes with floating discs. Time will tell but, hey, the problem of warped discs could , just, be a thing of the past
Andres
Kremmen
Registered user
MG also suffer a similar issue with "Braking" wavy distorted discs....it was found that as the machine has only a side stand, when parked any water would run down across the left hand disc & clogging the bobbins.
Simple cleaning & sparing lubrication with a dry lubricant cured a lot of the issues.
Further feed back from the disc company stated that testing of returned unit highlighted that numerous discs hadn't been bed in correctly...... just like an engine discs apparently need to be broken in .... and i suppose have the oil changed
Simple cleaning & sparing lubrication with a dry lubricant cured a lot of the issues.
Further feed back from the disc company stated that testing of returned unit highlighted that numerous discs hadn't been bed in correctly...... just like an engine discs apparently need to be broken in .... and i suppose have the oil changed
Do you use the bike where there is any signifcant water ie through a stream, as this could lead to going through some form of hot / cold cycle on the brakes?
Common way for cars brakes to warp, is where people suddenly brake when they see a deep puddle, in doing so, they load in significant heat to the disc then quench / cool it suddenly.
Clutching at straws I know, but offer this theory, as does seem an odd problem you have.
Common way for cars brakes to warp, is where people suddenly brake when they see a deep puddle, in doing so, they load in significant heat to the disc then quench / cool it suddenly.
Clutching at straws I know, but offer this theory, as does seem an odd problem you have.
However, the new discs are different to any (including MWB) yet fitted in so much as they are now 'proper' floating discs ie the washers/bobbins are now part of the disc assembly, not separate as before. I can now move the discs from side to side, just like on all other bikes with floating discs. Time will tell but, hey, the problem of warped discs could , just, be a thing of the past
That does sound better. I've long held that using 4 pot fixed calipers without fully-floating discs is a bad idea. Long held since I had a set of discs and pads replaced under warranty at 3K miles on my first '04 GS. I believe that it's also a common problem on Ducati Multistradas which use essentially the same Brembo discs and calipers.
tonkatoy
Registered user
However, the new discs are different to any (including MWB) yet fitted in so much as they are now 'proper' floating discs ie the washers/bobbins are now part of the disc assembly, not separate as before. I can now move the discs from side to side, just like on all other bikes with floating discs. Time will tell but, hey, the problem of warped discs could , just, be a thing of the past
Andres
Bad news guys, I've got an 08 GSA with the new type of disks (built in bobbins) and I've just had the front pair replaced at around 11k. The other bad news is that I have two sets of wheels and only one set of discs so I swap them between the wire wheels and the ally ones. The pulsing was occurring on both sets of wheels, also running on different tyres (TKC on the wires and Tourance on the allys. I can confirm the brake pad policy as well, they didn't swap my pads when the swapped the discs.
Somewhere (I thought it was on here, but perhaps not) I read something about bedding discs in. This is something I've been aware of for years so whether new bike or new discs or pads I always run them reasonably gently for several heat cycles. From what I understood the problem comes with inflicting dramatic heat changes on the crystalline structure of the metal. If you run several heat cycles through a set of discs starting gently and getting gradually harder the crystalline structure changes in one way. If you go straight for it hard the crystalline structure changes into a different pattern which predisposes it to warping, in some cases the warping happens almost immediately, in other cases it can take some time.
I'm not saying this will always be the answer. In some cases I can believe that wheel runout has an impact (but then shouldn't it be the same from day 1 ?) and in some cases I can well believe that baked on pad material or rust can cause the problem.
Finally, I have a Blackbird with many more miles than my BM and had an FJR with similar miles. Neither of these suffered with warped discs. What's the difference - both have stainless discs. What are BMW and most car discs made from (cast iron AFAIK).
Sorry, that probably didn't help much
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