Shimano gave us a short ride opportunity to test out their new hydraulic road brakes on the latest 11-speed Ultegra Di2 group. On the ride, we had access to Dave Lawrence, their road product manager, and questions and braking were done hard and fast. Here’s what we learned:
First off, our bikes were using preproduction units, so take all this with that minor caveat. They were quite polished and probably look exactly like what you’ll see at the end of the year when parts start shipping.
The calipers are based on XT mountain bike brakes. As in, they basically are XT mountain bike calipers. This let them get a group on the road without starting from scratch, and it let them take advantage of the finned IceTech pads and trickle down Freeza rotor design to maximize cooling. They’re so confident in the combination’s ability to shed heat that they’re spec’ing 140mm rotors for all. As long as you use both the finned pads and Freeza rotors, there’s no rider weight limit.
They used their older brake hose that has a bit more flex, so it’s intentionally mushier than the current XT-level MTB hoses. So the on/off of the full engagement is less severe. That means you’re less likely to lock up the wheels unintentionally because it’s purposely lacking the bite of their trail brakes.
Because these are just the initial offering, it’s likely higher end units in the future could see a sleeker design with the hose running to the inside of the caliper.
Like their mountain bike brakes, it’s a one-way full bleed. Push fluid in from the caliper and out the top of the shifter. It’s all lined up so gravity and rising air works in your favor. Just below the bleed port is the reach adjust, and below that you can see the silver ServoWave rollers. Unlike on mountain bikes where ServoWave changes the rate of pad movement, it’s used here to simply provide a consistent lever feel throughout the stroke.
All of these adjustments are accessed by removing the silver top cap.
Free stroke adjustment is under the hiod on the inside and controls how much lever pull you have before the pads make contact with the rotor. Back the bolt out and the pads will make contact quicker. This could be the key adjustment to getting the direct braking feel most riders will likely want.
RIDE IMPRESSIONS
First, the good: Hood ergonomics are every bit as comfortable and sleek as the normal mechanical parts. Lever feel is super smooth, and modulation of braking power was pretty good.
I say *pretty* good because there were some potential issues with these preproduction units that resulted in a lack of full, confident braking power.
