Chick, chick - boom, and victory, right? In reality most true sprinters have styles that won't change with Shimano's new SW-7972 'Sprint' satellite shifter for their Dura-Ace Di2 group, but that doesn't mean the new gizmo isn't really, really cool.
The sprint shifter is like a hair trigger - which requires careful placement (both in initial installation and hand placement when riding) as not to produce accidental shifts. Actuation takes little more than a twitch of a riders thumb to change a gear.
Each lever or button, as they're better described, performs a single task: the right drops the chain into a higher gear, while the left bumps it up to a lower gear. The shifters come programmed to only operate the rear derailleur and plug into the Di2 Dual Control levers.
Shimano gave us a day to become familiar with the new shifters out on the open road, and we came away from this first ride trying to answer the question: why wouldn't a Di2 user want this shifter option? We couldn't see why not.
If you're a Di2 user who hangs out in the drops, this accessory is a must have
What they're for
In a flat straight field sprint the sprinters are generally up to launch speed and in the right gear before the sprint even starts. From here the legs take over and it's a true test of leg power, speed and mental wit. So there's not much for Shimano's new satellite shifter to do. Rather - in the grand scheme - the shifter is an extension of what Di2 already does as a whole - make shifting easier.
It's the sprints that have tricky technical final kilometres or grades that are easy to misjudge, where this new option will prove its worth. We also believe the sprint shifter will prove just as useful to the domestiques and Classics riders who spend long days riding in the drops through the wind. Actually this scenario seems like it will become the preferred use, rather than the new shifters being reserved solely for sprinters.
There are countless times in our collective racing past when we've been strung out in a gutter somewhere, willing every bit of energy we have into our legs and truly believing we didn't have the energy to shift, when we'd have considered the slight flick it takes to operate these a godsend.
Finally, if you're a casual cruiser who rarely spends any time in the drops, you might not have a good reason to add them. In fact, if this best describes your style you could likely benefit from the SW-7970 satellite shifter, which mounts on the bar top, while a weight and price was not available for the new sprint shifter at press time, the aforementioned bar-top satellite shifter weighs 71g and costs US$94.99.
The shifter-handlebar tape interface
The only disappointing issue with the shifter is how it interacts with handlebar tape. It protrudes through a hole in the tape that a mechanic must custom cut, which depending on the wrench may or may not look very clean. We expected Shimano to mold a little silicon gasket that could hide these rough edges but they didn't. It seems, however, a small price to pay for this new drop bar convenience.