AMP RESEARCH, ROCKSHOX DISK BRAKE INFO(memo)

(VIA: MountainBikeReview.com's Forum Archives - RockShox Disc Brakes(4 posts) )
http://archive.mtbr.com/09/0EF9CAE3.php

I use/own a lot of them (tons of info inside)... DeeEight
Mar 16, 2003 7:21 PM
the Rockshox calipers differed from the Amp ones first in size (larger, more oil
volume, cooling fins milled in caliper body, gold annodized instead of plain silver)
but were virtually identical weight.

The Amp/RS rear rotor bolt circle diameters are identical to each other AND to
6-bolt international standard. So they'll fit IS pattern rear hubs also. The
front hub rotor patterns are different between Amp (smaller circle) and RS and
not the same as IS at all.

Also the actual disc rotor sizes are different for all the brakes, RS rotors
are larger diameter because they have IS caliper mounts that put the
caliper further from the axle than Amp's 2-bolt caliper mount. The calipers are
interchangeable between the two styles of floating mount, and there was a special
mount made for GT Lobo rear suspension bikes by Rockshox also. Furthermore the
front rotors are always larger than the rear rotors, and Rockshox had two sizes
of front rotors, a 163mm XC rotor and a 184mm DH rotor for Boxxer forks. Amp
made its own front hubs and the rear hubs used an adapter flange that bolted onto
the left flange of any shimano parallax rear hub (except XTR), and you laced the
wheel using this adapter's flange and the normal drive side flange.

A critical point for the brakes is since they're identical in master/slave piston
ratios inside the caliper bodies, they both work best with a short cable pull/high
leverage ratio brake lever. Old canti-brake levers in other words. Avid levers are
probably the best most can find since you can adjust the leverage but others work well.
I used some nice feeling Tektro CNC machined billet levers myself on mine. If you use
V-brake levers the power won't feel that good compared to many other disc brands but with
the right levers they make great XC discs. As for freeride/DH use, well, most prefer full
hydraulic for that these days but they'll do a decent job of it, especially if your fork will
allow the larger diameter rotor they made for the Boxxer forks.

Another thing to consider about RS/Amp discs is the weights, as they're cable actuated
hydraulic calipers, they're pretty damn light compared to full hydraulic systems. Weights are
as follows (includes oil in calipers)...

- Amp D-1 caliper with Amp mount 145g
- Rockshox caliper with IS mount 175g
- Rockshox caliper without mount 145g
- hardware for either caliper/mount 15g
- GT Lobo caliper mount and hardware 90g
- Amp front rotor (152mm) 100g
- Amp rear rotor (133mm) 90g
- Rockshox Boxxer rotor (184mm) 170g
- Rockshox front rotor (163mm) 110g
- Rockshox rear rotor (144mm) 100g
- Rockshox/WhiteIndustries front hub 220g
- Amp front hub 145g

I don't have weights for the Amp Flange adapter but its approx 20grams,
and nothing for a rear hub for the rockshox but King offered hubs for
both RS and Amp rotors, and White Industries made rear hubs for RS.
The boxxer rotor weighs so much more because it isn't crossdrilled like
the other rotors are and they'll all made from stainless steel. But still,
for the diameters involved the rotor weights are pretty good. The caliper
weights are identical to XTR V-brakes. I have a RS caliper and rotor
and hub on the front end of my Amp B3 (Mozo XMO fork) and a Amp rear caliper,
rotor and Amp/Shimano hub adapter (on a Deore LX hub) in back. My Warp project
bike (All Mountain / Light-freeride) will be getting a complete RS caliper/rotor
setup but not sure if i'll try and adapter the front rotor to work with one of the
184mm Boxxer rotors I have or not.