I first became aware of Zero Gravity brakes in 2004 when Iban Mayo used them at the Tour de France on the way to finishing in third place. In 2005, Francis Cebedo, the founder off Mtbr.com & RoadBikeReview.com, got his hands on a set of the original OG-05 Ti calipers and wrote this review. After reading his insights and seeing the brakes on Francis' bike, I decided to order a pair for myself. It was a good move. They were incredibly light and offered excellent braking. In fact I liked them so much that a few years later I purchased the slightly heavier but stiffer Zero Gravity GSL's (230 grams) for another bike.

When the Gravitas came out in 2009, I was intrigued by the all-carbon construction, light weight, and $875 price. I toyed with the idea of buying a pair, but in the end the price was just too steep. Luckily I held out, as Zero Gravity has just recently started offering refurbished Gravitas brakes for $399. At that price I couldn't resist.

Zero Gravity Gravitas SL Brakeset Highlights
  • Cost: $399 refurbished (without brake pads), new originally $875.
  • Claimed weight: 138 grams without pads. Actual, 142 grams. 166 grams with pads
  • Heritage of innovation: founder Ted Ciamillo is a leader in aftermarket bike brakes
  • Function: While one of the lightest brakes available, provides excellent stopping power
  • Functionality: Spacers accommodate a wide range of rims, from 19mm old school to 27mm Zipp Firecrest
Installation

Ted Ciamillo gets some flak from the cycling community because his brakes can be tricky to set up. And they are. However, I personally think cyclists need to understand and appreciate that Ciamillo runs a boutique business. It's a small shop and I'd venture to guess that Shimano probably produces more brakes in a week than Ciamillo cranks out in a year. His brakes are like Ferraris: They require close tolerances and a mechanic who knows what they're doing. Unlike a Ferrari, however, once you get Zero Gravity brakes dialed in, they don't require constant tuning.

It's also worth noting that at one point I emailed Ciamillo because I was having problems installing my rear brake, and he responded very quickly, asking that I call him. He diagnosed the problem and I was able to get my brakes functioning correctly.



You need seven tools to install these brakes (in addition to Campagnolo 2000+ brake pads, which are sold separately):
  • 5mm and 3mm Allen wrench. The 5mm is for the brake bolt, the 3mm is for the bolt that clamps the cable.
  • 13mm or 1/2 inch cone wrench to hold the nut behind the brake. You also use this wrench to center the calipers.
  • T-20 and T-30 Torx bits. The T-20 is for the brake pads. The T-30 is to adjust the tension of the brake calipers. If the brake is "sticky" and doesn't return fully, loosen the brake bolt then hold the nut with the cone wrench and rotate the front-facing Torx bolt counter-clockwise with the T-30 bit.
  • Electrician's tape. Place the tape around the nut to prevent scratches.
  • Cable cutters for housing and cable.
There are a few tricks to the install. First, do not compress the brake by pushing in the brake by the brake pads with your fingers. This can weaken the return spring. Second, make sure to trim the brake cable so when inserted into the brake arm it doesn't push the brake to one side. Additionally, make sure it isn't too short which will make the brake pivot to the other side.



The brakes also come with three sets of washers for the brake pads. There is a washer with a flat side and concave one on the other side. The washer with the flat side needs to have the flat side flush with the brake. The concave side mates to the brake pad holder. There are two additional spacers that are bent on both sides, one thick and one thin. Use all three if your rim is a narrow 19mm wide. Remove the two bent spacers if you are running super wide Zipp or Hed wheels.

For rims widths that are in between, experiment to see what fits best. I tried using the rear brakes with just the flat/concave washer on my Easton EA90 SLX rims and braking performance wasn't great. Adding the thick spacer improved braking dramatically.

Another feature is the routing of the cable through the cinching bolt. You thread the cable through the brake arm and then behind the cinch bolt through a pre-drilled hole. This guarantees alignment while also making it easier to secure.

Cable Threading to Cinch Bolt

These brakes are designed to have maximum leverage with very little pull on the levers. Ciamillo advises just 1mm of clearance between the shoes and the rim. So make sure your cable is tight and raise the cam arm while adjusting. You can pinch the brake pads against the rims while doing this without potentially weakening the return spring.



Weight

Zero Gravity first entered the after-market scene nine years ago. Today, it continues to push the envelope of light weight without a sacrifice braking performance. If you review the chart below (courtesy of Fairwheel Bikes), you'll notice how the Gravitas is the second lightest brakeset while also being priced the same as the much heavier Campy Super Record and new Dura Ace.



Performance

Once dialed, the brakes work very well. You can lock up the wheels easily if needed (though that's never a great idea). Even the rear brake will "skid" the tire when applied on its own. You will note that there is less modulation than with Shimano's Dura Ace brakes. That said, this past weekend, I went on a 58-mile ride that included some major descents and had no problems. But I'm more of an abrupt stopper and don't typically feather the brakes. If you are someone who likes to modulate the brakes in fine increments, these may not be the brakes for you.

Design

From the carbon weave to the slick logo, the Zero Gravity Gravitas SL Brakeset is an attention grabber. The braking performance is solid, and the thoughtful brake cable installation and ability to adjust to reduce friction are also nice features.

Summary

While lacking in modulation, these brakes are incredibly light, look great, and provide excellent stopping power. And if you buy a refurbished set, you are getting good deal for the money.

Rating:
4.5/5 stars; These refurbished brakes are a good value for a superlight brake that provides excellent stopping power. You just need to be patient during the install.