16 February 2010

bikefix Exclusive: Rotor Roundup

In my review of the Hope Mono Mini Pro disc brakes a while ago, I mentioned reducing rotor weight as an easy way to shave some rolling weight from one’s bike (wheels and tires are still the best). At great expense to myself, I ordered a bunch of hot new lightweight rotors, which I then I weighed. I also had some other rotors floating around which I included. I've compiled the small list below for your benefit. I am usually not such a weight weenie, but this is a case (as with wheels and tires) where it pays off- and it’s been a cold wet winter which gives me more time to obsess over stuff. All rotor weights below are from 160mm rotors. All the rotors listed use a tried-and-true stainless steel braking surface. I intentionally left out some of the crazy high-end rotors made out of aluminum, titanium, or unobtainium.

Rotor weights:
Hope Pro78g
Ashima Air85g (claimed)
Formula R188g
Formula R1 2-piece88g
Hope 2 Piece89g
Avid XX97g
Magura Marta SL105g
Formula Oro108g
Avid G2 Cleansweep116g
Shimano XTR (Centerlock)127g
Shimano XT (Centerlock)130g

Other useful weights:
6 titanium rotor bolts7g
6 steel rotor bolts13g
Shimano Centerlock lockring9g
DT Swiss Centerlock-to-6 bolt converter30g

One interesting point that is often discussed around here: DT’s Centerlock hubs are lighter than their 6-bolt hubs of the same spec. DT is one of the few manufacturers who make both a 6-bolt and a Centerlock hub that otherwise have the same specifications. This is important to understand because some other manufacturers make 6-bolt hubs that are lighter than, or almost as light, as DT’s Centerlocks- so the total weight of the entire system (hub, rotor, and bolts or lockring) is what you need to consider.



uki said...

Interesting comparison, Charlie. Do you know if the Hope Pro rotors are available for aftermarket purchase? How to distinguish them from the regular Hope 2 piece rotors? I suspect that most "Hope Floating Lightweight Rotors" available in online stores are not the 78g Pro version.

Charles said...

According to Hope USA, You can buy the "pro" rotors separately, but only directly from them. That would make sense because the demand for this type of thing is so small that most shops and distributors probably never thought to order the rotors separately for the aftermarket. One interesting thing I've since found out is that Hopes' 2-piece rotors don't always fit perfectly with other calipers (depth issues)which leads to a little "finagling" for a descent fit.