Wavy brakes.... WTF?

On Thu, 11 Sep 2003 18:35:01 +0000, Simon Brooke did issue forth:

Quoted message said:

Yup. That's right. It's _like_ a disk brake, only the rotor isn't a disk, it's a sort of weird
sculptured shape.

The Hope Mini also uses a wavy rotor. I seem to recall someone mentioning something about it
allowing better braking by allowing the pads to grab the side of the disk a bit, but I could be
imagining things.

Huw

Simon Brooke muttered:

Quoted message said:

Now I could waste time at this point in a rant about deliberately unbookmarkable websites, but I
shan't. However, because of deliberately unbookmarkable websites I can't direct you to a page
describing what I'm talking about, only to a picture of it: <URL:
magura.commartasl 01.jpgOpen ↗ >

magura.commartasl.htmOpen ↗

--
bob [at] bobarnott [dot] com bobarnott.combobarnott.comOpen ↗
----------------------------------------------------------------------------
"Crash programs fail because they are based on theory that, with nine women pregnant, you can get a
baby in a month."
-- Wernher von Braun

Huw Pritchard said:

On Thu, 11 Sep 2003 18:35:01 +0000, Simon Brooke did issue forth:

Quoted message said:

Yup. That's right. It's _like_ a disk brake, only the rotor isn't a disk, it's a sort of weird
sculptured shape.

The Hope Mini also uses a wavy rotor. I seem to recall someone mentioning something about it
allowing better braking by allowing the pads to grab the side of the disk a bit, but I could be
imagining things.

Huw

It may also help with cooling down the rotor.

But more importantly, it looks much better. 🙂 And if you think that's ridiculous, Hope sell
personalised rotors: hopetech.comrotor.htmOpen ↗
--
Craig Wallace craigwallace.clara.co.ukcraigwallace.clara.co.ukOpen ↗ NGPC - ngppower.fsnet.co.ukngppower.fsnet.co.ukOpen ↗

Craig Wallace said:

Huw Pritchard said:

On Thu, 11 Sep 2003 18:35:01 +0000, Simon Brooke did issue forth:

Quoted message said:

Yup. That's right. It's _like_ a disk brake, only the rotor isn't a disk, it's a sort of weird
sculptured shape.

The Hope Mini also uses a wavy rotor. I seem to recall someone mentioning something about it
allowing better braking by allowing the pads to grab the side of the disk a bit, but I could be
imagining things.

Huw

It may also help with cooling down the rotor.

But more importantly, it looks much better. 🙂

Best of all it gives lawyers something to write about, as it is a patented design by Galfer. Magura
has a licence, other exhibitors at the Eurobike got nasty letters
--
Marten

On Thu, 11 Sep 2003 20:13:42 +0100, Craig Wallace did issue forth:

Quoted message said:

But more importantly, it looks much better. 🙂 And if you think that's ridiculous, Hope sell
personalised rotors: hopetech.comrotor.htmOpen ↗

One of the posters on alt.mountain-bike has a personalised rotor. Anyone who has ever dropped in to
AMB for any length of time might understand:

pritch.co.ukpicture 013.jpgOpen ↗

Huw

M-Gineering import & framebouw said:

Craig Wallace said:

Huw Pritchard said:

On Thu, 11 Sep 2003 18:35:01 +0000, Simon Brooke did issue forth:

> Yup. That's right. It's _like_ a disk brake, only the rotor isn't a disk, it's a sort of weird
> sculptured shape.

The Hope Mini also uses a wavy rotor. I seem to recall someone mentioning something about it
allowing better braking by allowing the pads to grab the side of the disk a bit, but I could be
imagining things.

Huw

It may also help with cooling down the rotor.

But more importantly, it looks much better. 🙂

Best of all it gives lawyers something to write about, as it is a patented design by Galfer. Magura
has a licence, other exhibitors at the Eurobike got nasty letters

Isn't marketing so effective.

Garryb

Quoted message said:

Yup. That's right. It's _like_ a disk brake, only the rotor isn't a disk, it's a sort of weird
sculptured shape.

*WTF*?!

What _on_ _earth_ is the point of a scalloped rotor? Can anyone see any technical (as apart from
marketing) benefit of this design?

Given that it's a brake designed for XC racing, less metal = less weight, also the wavey shape of
the rotor makes it far more efficient at shedding mud and water. You don't have to believe it but it
does work.

Phil

Quoted message said:

Yup. That's right. It's _like_ a disk brake, only the rotor isn't a disk, it's a sort of weird
sculptured shape.

*WTF*?!

What _on_ _earth_ is the point of a scalloped rotor? Can anyone see any technical (as apart from
marketing) benefit of this design?

Given that it's a brake designed for XC racing, less metal = less weight, also the wavey shape of
the rotor makes it far more efficient at shedding mud and water. You don't have to believe it but it
does work.

Phil

Bob said:

magura.commartasl.htmOpen ↗

Interesting bit at the bottom:

"Warning!
1. Disc brake calipers can generate a lot of heat during extreme riding conditions. The resulting
heat transfer from the caliper to the fork and/or frame can have a negative influence on the
mechanical characteristics of both the fork and/or frame. 2. Insufficient heat transfer from the
brake caliper to the frame and the fork, caused by fork and/or frame components having low heat
transfer characteristics (e.g. carbon rear triangles) can cause the brake caliper to overheat,
with the possibility of a total failure of the brake system. This can cause serious personal
injury to yourself and/or others. With respect to product liability we remind you that any
manufacturer (also bicycle mechanic or end consumer!) is responsible for the correct function of
the complete bicycle in this context. "

Not seen that before.

Tony

--
"If you tell the truth you don't have to remember anything." Mark Twain

Bob said:

magura.commartasl.htmOpen ↗

Interesting bit at the bottom:

"Warning!
1. Disc brake calipers can generate a lot of heat during extreme riding conditions. The resulting
heat transfer from the caliper to the fork and/or frame can have a negative influence on the
mechanical characteristics of both the fork and/or frame. 2. Insufficient heat transfer from the
brake caliper to the frame and the fork, caused by fork and/or frame components having low heat
transfer characteristics (e.g. carbon rear triangles) can cause the brake caliper to overheat,
with the possibility of a total failure of the brake system. This can cause serious personal
injury to yourself and/or others. With respect to product liability we remind you that any
manufacturer (also bicycle mechanic or end consumer!) is responsible for the correct function of
the complete bicycle in this context. "

Not seen that before.

Tony

--
"If you tell the truth you don't have to remember anything." Mark Twain

is it not also something to do with providing a better mud / water clearance from the rotor when
braking? I know my comparatively boring round discs get easily clogged up in muddy conditions and
start making horrible noises.

Rupert

"Huw Pritchard" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

On Thu, 11 Sep 2003 18:35:01 +0000, Simon Brooke did issue forth:

Quoted message said:

Yup. That's right. It's _like_ a disk brake, only the rotor isn't a disk, it's a sort of weird
sculptured shape.

The Hope Mini also uses a wavy rotor. I seem to recall someone mentioning something about it
allowing better braking by allowing the pads to grab the side of the disk a bit, but I could be
imagining things.

Huw

is it not also something to do with providing a better mud / water clearance from the rotor when
braking? I know my comparatively boring round discs get easily clogged up in muddy conditions and
start making horrible noises.

Rupert

"Huw Pritchard" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

On Thu, 11 Sep 2003 18:35:01 +0000, Simon Brooke did issue forth:

Quoted message said:

Yup. That's right. It's _like_ a disk brake, only the rotor isn't a disk, it's a sort of weird
sculptured shape.

The Hope Mini also uses a wavy rotor. I seem to recall someone mentioning something about it
allowing better braking by allowing the pads to grab the side of the disk a bit, but I could be
imagining things.

Huw

Tony Raven said:

Bob said:

magura.commartasl.htmOpen ↗

Interesting bit at the bottom:

"Warning!
1. Disc brake calipers can generate a lot of heat during extreme riding conditions. The resulting
heat transfer from the caliper to the fork and/or frame can have a negative influence on the
mechanical characteristics of both the fork and/or frame. 2. Insufficient heat transfer from
the brake caliper to the frame and the fork, caused by fork and/or frame components having low
heat transfer characteristics (e.g. carbon rear triangles) can cause the brake caliper to
overheat, with the possibility of a total failure of the brake system. This can cause serious
personal injury to yourself and/or others. With respect to product liability we remind you that
any manufacturer (also bicycle mechanic or end consumer!) is responsible for the correct
function of the complete bicycle in this context. "

Yup, I noticed that.

Presumably they've had a failure. It makes me think about what happens when you transfer that
much heat into an oil-damped front fork leg (and particularly into just one leg of a pair of
forks), as well.

Surely the answer would be to add more finning to the caliper, as on an air-cooled engine or a
computer heatsink, to increase the area over which the heat can transfer to the air... and I would
have thought that was a more important innovation than wavey edges, and could be made to look just
as k00l in marketing terms.

--
[email hidden] (Simon Brooke) jasmine.org.uk~simonOpen ↗

[ This .sig subject to change without notice ]

Tony Raven said:

Bob said:

magura.commartasl.htmOpen ↗

Interesting bit at the bottom:

"Warning!
1. Disc brake calipers can generate a lot of heat during extreme riding conditions. The resulting
heat transfer from the caliper to the fork and/or frame can have a negative influence on the
mechanical characteristics of both the fork and/or frame. 2. Insufficient heat transfer from
the brake caliper to the frame and the fork, caused by fork and/or frame components having low
heat transfer characteristics (e.g. carbon rear triangles) can cause the brake caliper to
overheat, with the possibility of a total failure of the brake system. This can cause serious
personal injury to yourself and/or others. With respect to product liability we remind you that
any manufacturer (also bicycle mechanic or end consumer!) is responsible for the correct
function of the complete bicycle in this context. "

Yup, I noticed that.

Presumably they've had a failure. It makes me think about what happens when you transfer that
much heat into an oil-damped front fork leg (and particularly into just one leg of a pair of
forks), as well.

Surely the answer would be to add more finning to the caliper, as on an air-cooled engine or a
computer heatsink, to increase the area over which the heat can transfer to the air... and I would
have thought that was a more important innovation than wavey edges, and could be made to look just
as k00l in marketing terms.

--
[email hidden] (Simon Brooke) jasmine.org.uk~simonOpen ↗

[ This .sig subject to change without notice ]

"Simon Brooke" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Quoted message said:

"Warning!
1. Disc brake calipers can generate a lot of heat during extreme riding conditions. The
resulting heat transfer from the caliper to the fork

and/or

Quoted message said:

Quoted message said:

frame can have a negative influence on the mechanical characteristics of both the fork and/or
frame. 2. Insufficient heat transfer from the brake caliper to the frame and the fork, caused by
fork and/or frame

components

Quoted message said:

Quoted message said:

having low heat transfer characteristics (e.g. carbon rear triangles)

can

Quoted message said:

Quoted message said:

cause the brake caliper to overheat, with the possibility of a total

failure

Quoted message said:

Quoted message said:

of the brake system. This can cause serious personal injury to yourself and/or others. With
respect to product liability we remind you that any manufacturer (also bicycle mechanic or end
consumer!) is responsible for

the

Quoted message said:

Quoted message said:

correct function of the complete bicycle in this context. "

Yup, I noticed that.

Presumably they've had a failure. It makes me think about what happens when you transfer that
much heat into an oil-damped front fork leg (and particularly into just one leg of a pair of
forks), as well.

Surely the answer would be to add more finning to the caliper, as on an air-cooled engine or a
computer heatsink, to increase the area over which the heat can transfer to the air... and I would
have thought that was a more important innovation than wavey edges, and could be made to look just
as k00l in marketing terms.

Probably has to do more with the legal department than technical. OK discs can generate heat -- but
you would need a fairly extreme set of conditions to really cook everything.

Fining might help a little -- but braking is an intermittent duty so the change in thermal
resistance is likely to have little real effect.

T

"Simon Brooke" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Quoted message said:

"Warning!
1. Disc brake calipers can generate a lot of heat during extreme riding conditions. The
resulting heat transfer from the caliper to the fork

and/or

Quoted message said:

Quoted message said:

frame can have a negative influence on the mechanical characteristics of both the fork and/or
frame. 2. Insufficient heat transfer from the brake caliper to the frame and the fork, caused by
fork and/or frame

components

Quoted message said:

Quoted message said:

having low heat transfer characteristics (e.g. carbon rear triangles)

can

Quoted message said:

Quoted message said:

cause the brake caliper to overheat, with the possibility of a total

failure

Quoted message said:

Quoted message said:

of the brake system. This can cause serious personal injury to yourself and/or others. With
respect to product liability we remind you that any manufacturer (also bicycle mechanic or end
consumer!) is responsible for

the

Quoted message said:

Quoted message said:

correct function of the complete bicycle in this context. "

Yup, I noticed that.

Presumably they've had a failure. It makes me think about what happens when you transfer that
much heat into an oil-damped front fork leg (and particularly into just one leg of a pair of
forks), as well.

Surely the answer would be to add more finning to the caliper, as on an air-cooled engine or a
computer heatsink, to increase the area over which the heat can transfer to the air... and I would
have thought that was a more important innovation than wavey edges, and could be made to look just
as k00l in marketing terms.

Probably has to do more with the legal department than technical. OK discs can generate heat -- but
you would need a fairly extreme set of conditions to really cook everything.

Fining might help a little -- but braking is an intermittent duty so the change in thermal
resistance is likely to have little real effect.

T

"Philthy" <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

Quoted message said:

Yup. That's right. It's _like_ a disk brake, only the rotor isn't a disk, it's a sort of weird
sculptured shape.

*WTF*?!

What _on_ _earth_ is the point of a scalloped rotor? Can anyone see any technical (as apart from
marketing) benefit of this design?

Given that it's a brake designed for XC racing, less metal = less weight, also the wavey shape of
the rotor makes it far more efficient at shedding mud and water. You don't have to believe it but
it does work.

Phil

All the latest MX and enduro m/c's have them now. They are also finding their way onto top spec
road bikes as well. I guess it could just be a fashion thing but KTM, etc claim less likelihood of
deformation, reduced heat build up and better contamination clearance. There's also some nonsense
about reducing risk of pads binding to the disk.

I still haven't seen a comprehensive technical assessment.

It sort of makes sense when you are chucking 100kilos of KTM around at 100mph but on a push bike?

They do look good and if they work better then who are we to argue?

Matt

Craig Wallace said:

And if you think that's ridiculous, Hope sell personalised rotors:
hopetech.comrotor.htmOpen ↗

Word! My Speedmachine's discs have the word "Speedmachine" write large thereupon. In my defence, I
didn't ask for this - it was something Darth Stuart did off his own bat.

Dave Larrington - legslarry.beerdrinkers.co.uklegslarry.beerdrinkers.co.ukOpen ↗
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Editor - British Human Power Club Newsletter
bhpc.org.ukbhpc.org.ukOpen ↗
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