Ongoing saga of the AMP disk brake
Zach Kaplan
describing all the troubles I have had with the AMP Research disk brake.
20 years later and still all the same problems.
The AMP disk brake which has given me much grief over the past 5 months
has finally come to the last straw. I was quite shocked to discover
yesterday when I removed the wheelcover that 3 of the 32 spokes on the
Moulton rim had broken at the head. We thought this would be a bullet
proof wheel. We analyzed the problem and determined that the primary
factor leading to the fatigue of the spokes was a high frequency
oscillation which the AMP disk brake emitted as a result of its sintered
metal pads on stainless steel rotor. Other contributing factors were the
too thin and poorly radiused AMP hub flanges and the extra loading put
on the spokes by the stopping forces of the disk brake. This is it- I am
through with this brake. It suffers from about a dozen serious design
flaws. I tried to get AMP to take it back earlier after the third
warranty replacement and they refused. I guess I will have to write off
the $250 wholesale I have in the brake/hub as a learning experience on
the dangers of under designing and making things overly light weight.
For now I am going back to a caliper brake on the front wheel, an IBC
hydraulic that I happen to have sitting around. Although it heats up the
rim, wears the rim, and has a time delay in the rain, at least its
performance is proven and known. To get around the rim heating safety
problem, I thought of a water cooled rim system. Right next to my
Camelbak tube I will have another tube going down to the fork crown.
Here I will have a Y- fitting with two smaller tubes terminating next to
each brake block. I will fit the ends of these tubes with the nozzles
from the caps of contact lens fluid bottles. When I am going down a hill
and start to smell the pads burning I will simply take a swig from the
Camelbak and then backwash it into the other tube to cool the rim and
brake pads. This system will be light, simple, and easy to operate hands
free. I don't know if anyone has tried this before but it makes sense as
the thing to do for me.
Zach Kaplan
p.s.- Remember, if you want to have the highest tech disk brakes, buy
from AMP Research, the company that does its prototype testing on paying
customers!
Matt O'Toole
>Bill's story about his disk brake experiences did an excellent job of
>describing all the troubles I have had with the AMP Research disk brake.
>20 years later and still all the same problems.
>The AMP disk brake which has given me much grief over the past 5 months
>has finally come to the last straw. I was quite shocked to discover
>yesterday when I removed the wheelcover that 3 of the 32 spokes on the
>Moulton rim had broken at the head. We thought this would be a bullet
>proof wheel. We analyzed the problem and determined that the primary
>factor leading to the fatigue of the spokes was a high frequency
>oscillation which the AMP disk brake emitted as a result of its sintered
>metal pads on stainless steel rotor.
I'd love to know how you arrived at this conclusion. Many of us out
here are capable of understanding the mechanics and materials involved
in such a situation, so don't hold back.
>Other contributing factors were the
>too thin and poorly radiused AMP hub flanges and the extra loading put
>on the spokes by the stopping forces of the disk brake.
Not having looked at one that closely, I'll reserve judgement, but I
think that a plain hole or a chamfered one would be better than a
radiused one for a hard steel spoke in a soft aluminum flange.
>This is it- I am
>through with this brake. It suffers from about a dozen serious design
>flaws.
Lay them out! Armed with some real information, fellow cyclists could
spare thamselves making the same mistakes you did.
>I tried to get AMP to take it back earlier after the third
>warranty replacement and they refused. I guess I will have to write off
>the $250 wholesale I have in the brake/hub as a learning experience on
>the dangers of under designing and making things overly light weight.
First it was some esoteric vibration situation that caused spoke
failure, and now it's "under design" and "light weight". Hmm.
>For now I am going back to a caliper brake on the front wheel, an IBC
>hydraulic that I happen to have sitting around. Although it heats up the
>rim, wears the rim, and has a time delay in the rain, at least its
>performance is proven and known.
Fair enough.
>To get around the rim heating safety
>problem, I thought of a water cooled rim system. Right next to my
>Camelbak tube I will have another tube going down to the fork crown.
>Here I will have a Y- fitting with two smaller tubes terminating next to
>each brake block. I will fit the ends of these tubes with the nozzles
>from the caps of contact lens fluid bottles. When I am going down a hill
>and start to smell the pads burning I will simply take a swig from the
>Camelbak and then backwash it into the other tube to cool the rim and
>brake pads. This system will be light, simple, and easy to operate hands
>free. I don't know if anyone has tried this before but it makes sense as
>the thing to do for me.
Maybe you could sell the system to the pro road racers that descend
the mountain passes of the Tour de France, at over 60mph for extended
periods, with wimpy caliper brakes. ;-)
>p.s.- Remember, if you want to have the highest tech disk brakes, buy
>from AMP Research, the company that does its prototype testing on paying
>customers!
Hey, it's a lot cheaper than paying a real salary to a degreed and
licensed professional engineer. It's even cheaper than paying a
consulting fee to a starving engineer.
What's the best way to remove a fishhook?
Matt O.
UCDCLRS
>
> Zach Kaplan <zaka...@sirius.com> wrote:
>
> >Bill's story about his disk brake experiences did an excellent job of
> >describing all the troubles I have had with the AMP Research disk brake.
> >20 years later and still all the same problems.
>
tandem. The stresses on a lightweight brake (any) could often be
too much. Unfortunately, this is where a disc holds the most
potential, and the AMP brake probably isn't beefy enough for a
tandem.
> >The AMP disk brake which has given me much grief over the past 5 months
> >has finally come to the last straw. I was quite shocked to discover
> >yesterday when I removed the wheelcover that 3 of the 32 spokes on the
> >Moulton rim had broken at the head. We thought this would be a bullet
> >proof wheel. We analyzed the problem and determined that the primary
> >factor leading to the fatigue of the spokes was a high frequency
> >oscillation which the AMP disk brake emitted as a result of its sintered
> >metal pads on stainless steel rotor.
>
AMP has recently switched to organic brake pads, instead of the
metal ones that they used last year. While this has slightly
decreased the power from the brake, it should help with the problem
you are describing. As Matt said, please describe the problems in
more detail. I am considering getting this brake, and would like
all the information I can get.
> >Other contributing factors were the
> >too thin and poorly radiused AMP hub flanges and the extra loading put
> >on the spokes by the stopping forces of the disk brake.
>
Without more information, it sounds more like a poorly built wheel,
than a design problem with the hub and brake. Please give us more
detail.
> >This is it- I am
> >through with this brake. It suffers from about a dozen serious design
> >flaws.
>
> Lay them out! Armed with some real information, fellow cyclists could
> spare thamselves making the same mistakes you did.
Yes, please do.
>
> >I tried to get AMP to take it back earlier after the third
> >warranty replacement and they refused. I guess I will have to write off
> >the $250 wholesale I have in the brake/hub as a learning experience on
> >the dangers of under designing and making things overly light weight.
>
It is too bad that they wouldn't take it back, but there are very
few companies that would. What exactly were all the warranty
services for. I would like some more info.
> >To get around the rim heating safety
> >problem, I thought of a water cooled rim system. Right next to my
> >Camelbak tube I will have another tube going down to the fork crown.
> >Here I will have a Y- fitting with two smaller tubes terminating next to
> >each brake block. I will fit the ends of these tubes with the nozzles
> >from the caps of contact lens fluid bottles. When I am going down a hill
> >and start to smell the pads burning I will simply take a swig from the
> >Camelbak and then backwash it into the other tube to cool the rim and
> >brake pads. This system will be light, simple, and easy to operate hands
> >free. I don't know if anyone has tried this before but it makes sense as
> >the thing to do for me.
Are you using the brake on a tandem and/or on the road? I have
never smelled the pads of any brake burning on any bike. I could
see it happening on a tandem, but not a single bike. BTW, a little
bit of backwash isn't going to cool the wheel.
>
> Maybe you could sell the system to the pro road racers that descend
> the mountain passes of the Tour de France, at over 60mph for extended
> periods, with wimpy caliper brakes. ;-)
>
<g>
> >p.s.- Remember, if you want to have the highest tech disk brakes, buy
> >from AMP Research, the company that does its prototype testing on paying
> >customers!
>
Oh, like no one else in the bike biz does this? Rock Shox,
Answer/Manitou, Pro-Flex, Trek, etc. I don't think AMP is any worse
about it. They all try and work the problems out before the product
goes into production, a company would be crazy not to, but there are
problems that don't surface under testing lab or racing team
conditions. Problems tend to show up in production manufacturing,
that weren't there for testing. This does not excuse any company
from their responsibility, but it happens at some time to everyone.
RS didn't adequately test the damping cartridges on the 95 Judy's,
and huge numbers of them went out to the public. Trek didn't test
the first year of OCLV frames enough and many of them came back to
them cracked.
jcb
jim frost
>Are you using the brake on a tandem and/or on the road? I have
>never smelled the pads of any brake burning on any bike. I could
>see it happening on a tandem, but not a single bike.
My Shimano STX cantis with stock pads, on my single-seat GT, burned on
one descent -- then glazed over and braking remained terrible all day.
I don't know what it was about that particular day; I'd been down that
descent many times in the past and it isn't long enough that I would
have expected overheating.
Whatever the cause, I never rode with those pads again. I suppose
that's what I get for going for cheap components. :-)
jim frost
ji...@world.std.com
--
http://world.std.com/~jimf
Ray Ruyack
I've been using their disc for 1.5 years with 0 problems. I ride
aggressively and am not light (165lbs). When I had the wheel built I
followed AMP's guidelines - no stupid spokes, and no alloy nipples. The
wheel is still round with no hops. The thing has lived through 2 sets of
pads - I use the organic pads. I have not felt/seen/heard of the
osciliation you mention. How have you measured this? The wheel itself is
a Mavic 231 - not an overly heavy hoop, or what some even consider
durable.
Just my .02 since I feel their stuff works.
Ray
Ray Ruyack "Work less, ride more."
Winwebb
modulus carbon mononcoque front section and swingarm style aluminum
monocoque chainstays. On the rear of the bike was an AMP disk brake/hub
mounted to a GT cnc'd conventional flanged hub. GT Factory BMX and
Downhill World Champion Mike King took this bird flying for a test/photo
shoot for BMX Plus Magazine. During the test King liked the brake
performance, but blew out the flange adapter screws that attach the
adapter to the hub, but of course this brake wasn't designed with BMX'ers
in mind.
The AMP is a good race specific brake, but word on the downhill circuit
last year was that "formula" disk brakes out of Germany were the hot
setup.
Mike Webb
Zach Kaplan
>Bill's story about his disk brake experiences did an excellent job of
>describing all the troubles I have had with the AMP Research disk brake.
>20 years later and still all the same problems.
>
>has finally come to the last straw. I was quite shocked to discover
>yesterday when I removed the wheelcover that 3 of the 32 spokes on the
>Moulton rim had broken at the head. We thought this would be a bullet
>proof wheel. We analyzed the problem and determined that the primary
>factor leading to the fatigue of the spokes was a high frequency
>oscillation which the AMP disk brake emitted as a result of its sintered
I realized there was some confusion created by my previous post above.
People had wondered how a disk brake could have so many failures on a
mountain bike. I must make it clear that the bike the AMP disk brake
was installed on the front of is not a mountain bike but rather a fully
faired recumbent HPV. I cruise at speeds of around 50 km/h and on minor
downhills it easily coasts to speeds of around 100 km/h.The heat loading
and general wear rate on bicycle brakes is higher with this sort of
aerodynamic bike. How much higher I didn't realize until I experienced
the various failures.I should have asked when I first ordered the brake
if it was tandem rated which it turns out it is not. I had assumed that
since one of the major selling features was its massive stopping power
and long life pads that it would be up to the task of controlling
the speed of something which actually out coasts any tandem I have
encountered.
I recently contacted AMP Research about the problem and they are going
to take the brake back to look at it. They let me know that the
recommended spoking is to use 2.0mm spokes in a 3 cross pattern. Because
of the 17" front wheel I use, I chose 1.8mm spokes in a 2 cross pattern.
For a wheel this small this configuration would normally be considered
overbuilt but this doesn't appear so when a disk brake is involved.I
wish it came with more detailed instructions initially.It turns out that
the AMP disk brakes are normally only sold with AMP mountain bikes. They
were doing me a special favour by selling it for an HPV application and
as such the normal warranty doesn't apply. They did tell me some of
their brakes have been tried out on tandems with good results but that
they wouldn't warranty them for that application either.
I may also switch back to the newer organic pads to cut down on the
high frequency oscillation and pad rub noise. The first organic pads
wore out in three weeks but that was in very rainy weather using
primarily the front brake. Now that I have a better rear brake, I am
able to distribute the braking load between the wheels more equally so
the organic pads may stand up better in future use.
Last week I was about ready to sell or the brake or put it in my broken
parts collection, but I will give it one more chance with 2.0mm spokes,
a rebuilt caliper, and organic pads. I figure I still have the special
mount on my fork so it is worth trying to get it to work again. For the
past several days I have been using an IBC hydraulic caliper brake
instead of the disk and the stopping power of it is much less in
comparison. When it was working the AMP disk could lift the rear wheel
slightly on the long, low recumbent (51% of weight on front wheel).The
IBC caliper brake can't even come close to that.
Today I ordered a Hope full hydraulic brake which I am realistically
not expecting for 6 months since the new version is just going into
limited production. I will keep the list updated about my continuing
disk brake experiences.
Zach Kaplan zaka...@sirius.com
Zach Kaplan
Ray Ruyack
exceeds what AMP designed the brake for.
Ray Ruyack
asked me to kindly post this response that they e-mail to me:
Date: 96-01-30 19:41:58 EST
From: fb...@mail.deltanet.com (Chad Battistone)
To: Ray Ruyack
What Mr. Kaplan fails to state is that he is using the AMP D1 Disc brake
in
an application in which the brake was never designed to handle. He has the
brake mounted on what he calls a H.P.V. (Human Powered Vehicle) not a
mountain bike, he also fails to state that he regularly travels down long
descents at speeds in excess of 55mph while dragging the brake to scrub
off
speed instead of using a pumping action to slow the vehicle and allow the
brakes to remain cool. After explaining to Mr. Kaplan that he was indeed
abusing the brakes he remarked that all disc brake guys use this same
excuse, but anyone who has ever followed someone down a mountain pass who
is riding the brakes in their car can attest to the strong smell
associated
with a ruined set of (you guessed it) Disc Brake Pads. Mr. Kaplan also
fails
to state that he got nothing but fast and courteous service from AMP even
going as far as having Horst Leitner himself talk with Mr. Kaplan about
his
problems. Horst was under the impression that we had helped him understand
the proper use of his brakes and solved his problem. Then we find this
selective account of his "Saga". We at AMP RESEARCH feel the rider is #1
and if one individual and his "Prototype Application" can’t be made happy
despite
repeated attempts by our service staff then please do not let that
discourage you from trying our high quality Mountain bike products. We
are
speaking with Mr. Kaplan and will make every attempt to satisfy his unique
needs.
AMP RESEARCH
LAGUNA BEACH
Zach Kaplan
>Zach Kaplan <zaka...@sirius.com> wrote:
>
>>Bill's story about his disk brake experiences did an excellent job of
>>describing all the troubles I have had with the AMP Research disk brake.
>>20 years later and still all the same problems.
>
>>The AMP disk brake which has given me much grief over the past 5 months
>>has finally come to the last straw. I was quite shocked to discover
>>yesterday when I removed the wheelcover that 3 of the 32 spokes on the
>>Moulton rim had broken at the head. We thought this would be a bullet
>>proof wheel. We analyzed the problem and determined that the primary
>>factor leading to the fatigue of the spokes was a high frequency
>>oscillation which the AMP disk brake emitted as a result of its sintered
>>metal pads on stainless steel rotor.
>
>here are capable of understanding the mechanics and materials involved
>in such a situation, so don't hold back.
The high frequency vibration from the sintered metal brake pads was not
insignificant. Although the wheel was built with uniformly tight spokes,
under braking loads this vibration caused them, the fork, and handlebar
to oscillate. This oscillation greatly increased the number of fatigue
cycles the spokes received. In 5 months of operation they received the
fatigue cycles of perhaps ten years of normal riding. All 3 spokes which
failed broke at the elbows and all three were pulling spokes on the
inside of the hub flange.If they were better supported such as with
washers under them they may not have broken so quickly. AMP did not
provide any special wheel building instructions so I used 32 1.8 mm
spokes in a 2 cross pattern as that looked like it would have the best
weight-strength ratio for a 17" front wheel. Normally this size wheel
would be built with far less spokes but the AMP hub was only available
in 32 holes. Just recently I found out from AMP that the only spoking
they recommend is 2.0mm spokes in a 3 cross pattern. I wish I had know
that at the time and plan to rebuild the wheel this way after I get
the brake back from them.This might be a word of warning to others
building wheels for disk brake use.
>>This is it- I am
>>through with this brake. It suffers from about a dozen serious design
>>flaws.
>
>Lay them out! Armed with some real information, fellow cyclists could
>spare thamselves making the same mistakes you did.
The primary flaws are being built too light without enough margin of
error for heavy braking or long term durability. Building ultra light
parts is fine so long as they are not represented as being reliable or
durable. One problem with disk brakes in general is they are being made
to compete in weight with cantilever brakes which use the entire rim to
dissipate heat and thus the parts don't reach as high a peak
temperature. I happened to be using the AMP brake on a bike which gives
the brakes higher heat loading than a conventional mountain bike but
still the problems I experienced could also come up on mountain bikes on
long downhills. Here are some failures for you:
1. One week after getting the brake the thin, intricately shaped
H-spring which keeps the pads away from the rotor broke in two pieces.
Replacement was difficult since I was in Europe at the time. A new one
was air mailed from AMP USA at my cost.
2.The original floating rotor design with sintered metal pads made lots
of noise when coasting and the rotor would make rattling noises going
over bumps. Overall it worked fine for two months.
3.I noticed the CrMo rotor was hammering the slots on the aluminium
spider that it floats on. This increased the play when holding the bike
with just the front brake and was also creating stress risers in the
aluminium spider.
4. While coasting down a hill at 90 km/h on a cold brake (hadn't braked
for about half an hour) I went to apply the front brake for a corner.
The lever went all the way down to the bars. Luckily it wasn't that
essential to slow down for that corner and I was able to stay on the
road.
5. I noticed that when the brake was hot it would operate fine but the
lever would bottom out when cold. I did a quick pad adjustment and
continued on the ride. Throughout the day the situation got worse. It
got to the point where I would have to bottom the lever out coasting
for about 2 minutes before the brake would begin supplying adequate
braking force to stop the bike.
6. When I finished the ride I looked at the caliper and noted some
evidence of hydraulic fluid leakage.I telephoned AMP and they agreed to
take the brake back (this was now my second one) to look at it. I told
them about the rotor problem as well and it was agreed to upgrade this
and the pads to the 1996 specification with non floating, ventilated
stainless steel rotor and organic pads.
7. I received and installed the new (3rd) unit. My initial impressions
were that it worked great.No more rattling of the rotor or metalic
rubbing noises of the pads.The braking felt smoother with better
modulation though absolute stopping power was somewhat less. Still much
more better than cantilevers.
8. I noticed lever travel was significantly less when the brake was
hot than when cold, though not anything like failure #4.
9. After about one week I pressed the pad adjustment button as the
lever travel when cold was increasing. I noticed the pad adjustment
button stayed down rather than popping back up as they normally do.
10. Three weeks after putting unit #3 into operation there was a period
of heavy rain for several days. I did a great deal of riding in this
rain and noted the pads needed to be brought closer to the rotor several
times in one day as the brake lever was bottoming out.Towards the end
of that day the brake began squeeling. At the end of the day I looked
at the pads. It appeared most of the organic friction layer had worn
off.
11. While waiting for an e-mail reply back from AMP the next day I had
to go out on a 10 km errand. I tried using mostly the rear brake but
for some quick stops I had to use the front one fairly hard and it was
a much louder squeeling than before. It was about as loud and the same
tone as a bus with poorly maintained brakes coming to a stop.
12. The reply from AMP indicated that the bike I was using the brake
on put much more loading on the brake than a mountain bike. They said
unit #2 which I sent back to them had more wear on the sintered metal
pads than they had ever seen before. Apparently no one else had fully
worn a set of the sintered metal pads out before. They admitted that the
newer organic pads won't last as long. I bought some sintered metal
replacement pads from them with the understanding the pads would last
longer but also wear the rotor out faster. Rotor wear didn't seem
excessive with the original sintered metal pads so this seemed like a
reasonable compromise.
13. At one point in the e-mail I asked for the refund to save us the
hassle of having to keep dealing with this brake. I was told to talk to
Horst Leitner, the designer of the brake which I did. He told me
basically that I was using the brake for the wrong application and that
a motorcycle brake would suit me better (how much do those weigh and how
much drag do they have? I'd sure hate to have to lug one up a hill). I
wish AMP had made it clear their brake wasn't tandem or HPV rated in the
beginning. One thing which drew me to the AMP disk brake in the
beginning were there claims of tremendous stopping power, long pad life,
and self-adjusting pads with no need for regular maintenance. Getting
braking heat away from the small wheel rim was another top priority
which lead me to a disk brake.
14. The replacement sintered metal pads have noticeably higher stopping
power but do emit a squeeling noise when braking and vibration which
can be felt through the handlebar. The squeeling noise is greater when
the brake is cold.
15. A continuous metalic rubbing noise is noted as the stainless steel
disk is non floating.
16. There is still a significant difference in lever travel when the
brake is cold vs. hot. When cold the lever goes almost all the way to
the bar and when hot the brake starts to self apply. I work around this
by loosening the brake lever barrel adjuster on long downhills when the
brake starts to drag.
17. Hub bearings are found to be rough so I open the cartridges up to
clean and relube them and noted there was very little grease in them. I
also notice the 12mm aluminium axle steps down to 11mm between the
bearings.
18. Approximately ten days ago I discover the three broken spokes as
mentioned in the original posting.
19. I continued to ride the bike for several days with the broken
spokes as the wheel was still fairly true being a 17" wheel which is
often only set up with 14, 16, or 20 spokes. I still had 29 working
spokes on this wheel.I noticed the lever began to bottom out no matter
how much I pressed down on the pad adjustment button and tightened
the brake lever adjusting barrel. Interestingly the pads still rubbed
the rotor. At this point I examined the caliper and found hydraulic
fluid leaking out of the pad adjustment button area.
I have taken the AMP disk brake off and am running an IBC hydraulic
caliper brake for the time being. I am sending the AMP unit back to
them so they can look at it.
When I get it back I will either sell it or give it one more try.
Their design does have potential. Perhaps they could use a higher
temperature, longer wearing composite material for the pads and
possibly the rotor. Also I would like to see full hydraulic operation
from the brake lever for better modulation, more consistent lever to
braking ratios, and to elliminate high temperature self application.
Presently the amount of fluid contained in the caliper is quite small
and the caliper does get very hot causing the fluid to expand, pressing
on the pistons and applying the brake pads.
>Maybe you could sell the system to the pro road racers that descend
>the mountain passes of the Tour de France, at over 60mph for extended
>periods, with wimpy caliper brakes. ;-)
At least they've got relatively large diameter rims to dissipate all
that heat. Or maybe they are such good riders and the roads are closed
so they don't have to use their brakes much.
>>p.s.- Remember, if you want to have the highest tech disk brakes, buy
>>from AMP Research, the company that does its prototype testing on paying
>>customers!
>Hey, it's a lot cheaper than paying a real salary to a degreed and
>licensed professional engineer. It's even cheaper than paying a
>consulting fee to a starving engineer.
Very true. I don't mind helping to support small companies bring
innovative products to the market. However when it comes to something
safety related like brakes I'd hope they would be thoroughly tested
before I buy them.
>What's the best way to remove a fishhook?
Well, I've never tried but my guess would be to cut the barbed tip of
the hook off and then pull the rest of the hook back through the skin
the way it came in. This is assuming you are trying to remove the
hook from your own skin, not a fish.
Zach Kaplan
Alain Yong
>This year at Anaheim, GT displayed a working concept bike with a high
>modulus carbon mononcoque front section and swingarm style aluminum
>monocoque chainstays. On the rear of the bike was an AMP disk brake/hub
>mounted to a GT cnc'd conventional flanged hub. GT Factory BMX and
>Downhill World Champion Mike King took this bird flying for a test/photo
>shoot for BMX Plus Magazine. During the test King liked the brake
>performance, but blew out the flange adapter screws that attach the
>adapter to the hub, but of course this brake wasn't designed with BMX'ers
>in mind.
Mike King is a BMX/MOuntain biker all at the same time. What do you mean
that this brake isn't designed for BMX'ers. I mean, it's not the frame or anything.
IN terms of the comparison between bmx and mountain bike frames, there's off
course different stresses. The brakes of a mountain bike and a bmx shouldnt be
any different. If anyting, the mtb brake would get more stressed due to it's higher
speeds and more braking application due to downhills. IN a bmx race, you race
in a circuit where the brakes are hardly used.... so...yeah..
Alain Yong
>I realized there was some confusion created by my previous post above.
>People had wondered how a disk brake could have so many failures on a
>mountain bike. I must make it clear that the bike the AMP disk brake
>was installed on the front of is not a mountain bike but rather a fully
>faired recumbent HPV. I cruise at speeds of around 50 km/h and on minor
>downhills it easily coasts to speeds of around 100 km/h.The heat loading
>and general wear rate on bicycle brakes is higher with this sort of
>aerodynamic bike. How much higher I didn't realize until I experienced
>the various failures.I should have asked when I first ordered the brake
>if it was tandem rated which it turns out it is not. I had assumed that
>since one of the major selling features was its massive stopping power
>and long life pads that it would be up to the task of controlling
>the speed of something which actually out coasts any tandem I have
>encountered.
wow.. can you really ride yer tandem at 100 km/h?? Are you sure it's not
a computer malfunction?? Where is this done.. on a downhill race??? Wow.....
>
>I recently contacted AMP Research about the problem and they are going
>to take the brake back to look at it. They let me know that the
>recommended spoking is to use 2.0mm spokes in a 3 cross pattern. Because
>of the 17" front wheel I use, I chose 1.8mm spokes in a 2 cross pattern.
>For a wheel this small this configuration would normally be considered
>overbuilt but this doesn't appear so when a disk brake is involved.I
>wish it came with more detailed instructions initially.It turns out that
>the AMP disk brakes are normally only sold with AMP mountain bikes. They
>were doing me a special favour by selling it for an HPV application and
>as such the normal warranty doesn't apply. They did tell me some of
>their brakes have been tried out on tandems with good results but that
>they wouldn't warranty them for that application either.>
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
don't you hate that. I mean, they sell the brakes stating good braking
power for use in applications where stoping power is very important such
as a tandem. What really bugs me is that.. let's look at bike frames for example.
Specialized sells the S-works bikes saying it's for like hardcore riders. But then
the warranty says that warranty is void if the bike is used for like competition etc..
I mean.. isn't this just ironic.. and tons of companies are doing this. I realize they're
just trying to cover their butts but can't they have a realistic warranty.
Brian Edmonds
Well, someone from AMP actually...
Ray> Mr. Kaplan also fails to state that he got nothing but fast and
Ray> courteous service from AMP even going as far as having Horst
Ray> Leitner himself talk with Mr. Kaplan about his problems.
Funny, I got the exact opposite impression from his posts, in that he
found dealing with AMP an agreeable experience, but that he wished they
had given him more information about the brake up front, especially the
conditions it was designed to operate under.
Ray> We are speaking with Mr. Kaplan and will make every attempt to
Ray> satisfy his unique needs.
Not unique thank you, but certainly unusual. I have every expectation
that I also will be investigating disk brakes for similar application
within a few years time.
--
o Brian Edmonds <edm...@cs.ubc.ca> (occasional MSc student)
\\_/\_, Applications Analyst, University of British Columbia, Canada
(*) (*) See http://www.cs.ubc.ca/spider/edmonds for me and my hobbies
Ray Ruyack
Actually, I'm not from AMP. I own their products but have no relationship
whatsoever to the company either as an employee or sponsored rider. I
have, over the course of 3 years, gotten to know the people there and have
assisted them in securing a dial-up internet provider and provided
assistance and direction in creating their web page. My remuneration for
my assistance was 2 AMP water bottles and a Milhouse linkage cover for my
fork when they were packing to go back to CA. after the Philly Interbike
show. I've bought all of my AMP product at regular dealer prices through
the shop that I am affiliated with.
Ray