Summary
of test report from MountainBike
(Germany) Jan. 2001:
New disk brake test
The
German bike-mag "MountainBike"
published another test report of current disk brakes in their current issue
(Jan 2001). They tested 16 disks in the lab and on the trail. They only
tested XC disks, no DH or "tandem" versions, but since many tandemists
have recently expressed interest in the newer cable-operated disks, I'll
sum up the results here. I'll concentrate on the part testing performance
on an extended downhill, as this is what interests tandemists most. The
only disk brakes capable of slowing down a tandem safely on long descents
are still the Magura Gustav M and the Hope
DH-4 (neither of them included in this test).
Cable operated:
Avid ball-bearing disk, 165mm diam:
well-modulated for a mechanical brake. Downhill performance: heavy fading
very early, brake stops functioning at 900W as plastic parts melt.
Hayes
HMX-1, 160mm: modulation quite good. Downhill performance: heavy fading
early during 900W stage, very rapid pad wear, brake stops functioning at
900W as plastic parts melt.
Shimano
Deore mechanical, 160mm: very poor modulation, lots of hand strength needed.
DH test: very rapid pad wear (needs to be readjusted several times during
test), heavy fading during 1100W stage and pad worn out.
Hydraulic disks (I concentrate
on the products with relevance to the tandem market and the best-value
leader):
Formula
Evoluzione 9.5, 160mm (THIS IS THE BRAKE USED BY SANTANA
WITH A LARGER 203MM ROTOR): powerful, poor wet weather performance, good
modulation, extremely soft feel at the lever. DH test: tube melts off at
1100W, until then no problem.
Hayes
FH, 160mm (HAYES WARNS AGAINST THE USE OF THEIR DISKS ON TANDEMS but used
by some teams): very good performance wet and dry, feel at the lever a
bit too hard, very noisy. DH test: heavy fading early on (700W), loss of
brake power at 900W, can be regained by pumping the lever.
Hope
Pro, 185mm (Hope does not market specifically to the tandem crowd, but
does approve of the use of their brakes on tandems in private communication):
perfect lever design, excellent modulation and stopping power, little pad
wear, almost impossible to improve. DH test: lever moves out a bit due
to (semi-)closed design, disk warped temporarily after 1100W stage, but
goes back to round after cooling off.
Hope
XC-4, 150mm (same caliper as DH-4, same "semi-open" lever as Pro): less
power than Pro, but otherwise excellent. DH test: No fading even at 1100W,
but needed to be adjusted at the lever as it would have locked locked up
otherwise. THIS LETS ME ASSUME THAT THE DH-4 WITH ITS LARGER DISK AND EXPANSION
CHAMBER ("open design") MIGHT INDEED BE THE PERFECT TANDEM DISK BRAKE!
Magura
Julie, 180mm (rear 160mm) (NOT TANDEM RATED, BUT AT WAY UNDER $100 A STEAL
FOR ANY SINGLE - I've got one on my foul-weather MTB):
good modulation and power, not for small hands (lever too far away from
bar). DH test: slight fading, no other problems even at 1100W!!
Shimano
Deore XT, 160mm (NOT TANDEM RATED; INCLUDED BECAUSE IT'S PROBABLY THE MOST
POPULAR DISK): gooid power and excellent modulation, very noisy. DH test:
heavy fading at 700 W, loss of brake power, lever needs to be pumped to
keep it working.
Other brakes tested: Bassano Grimeca
System 8, Formula B-4, Magura Clara, Magura Louise, Shimano Deore hydraulic,
SR Suntour 700 HD, Tektro Gemini.
Hans Christoph Timm
<hans.christoph.timm@politik.uni-freiburg.de>