I recently picked a pair of refurbed Gravitas SL for $400 from Ciamillo. I put off posting my first impressions until I tried the brakes with comparable pads to what I was running before. With that being said, the Gravitas with Zipp Tangente cork pads on Reynolds DV46 can be summed up as a crap in the pants experience. With Swiss Stop Black Prince pads, braking performance is quite good.
Most recent setup: Planet X Brakes, Swiss Stop Yellow and Reynolds DV46 tubular
Other experiences: Campag Athena with Campy Aluminum WheelsPerformance
Overall, with the Black Prince pads, I'd be hard pressed to tell the difference in performance between the Planet X setup and this. Modulation is good and power has never left me feeling concerned about being able to stop. In other words, they are powerful enough for emergency stops during Cat 4 and 5 crits and tightly formed packs in road races.Setup
The brakes came with zero instructions and completely disassembled with several shims. It took me awhile to figure out that they were shims and their purpose (the pad holders are very low profile so additional shims are necessary).
The rear brake backing was larger than my brake bridge, so I had to recycle a washer from the planet x brakes.
Last complaint is that I had to really crank down on the tensioner to prevent the cable from slipping. I feel that I exceeded whatever recommended torque specs that would have been stated had instructions been available. This could be the Alligator cables. They do seem to not want to stay put.
On the plus side, centering these with the Alligator cables is very easy. Not sure how they would fare with super stiff housing like my old Yokozunas.Other Thoughts
The brakes look gorgeous, much better than the pictures. Weight with minimal amount of shims and pad holders was 139 grams. Complete set with 18g of Zipp cork pads was 159g. Weight with Swiss Stop Black Prince Pads (highly recommended) is 174g.