Compass 11-speed ChainringsJan Heine
Compass Cycles is introducing the first-ever 11-speed-compatible René Herse cranks and chainrings. And the first-ever René Herse chainrings with ramps and pins. These are not just any ramps and pins: They’re carefully engineered to shift as well as the best cranks from the big manufacturers. We are proud to offer this performance with useful chainring sizes – plus the beauty and light weight of the classic René Herse cranks.
The shifting performance of our new cranks is a bigger deal than it may sound at first, because developing chainrings at this level is a major undertaking. Our engineering team has spent almost 18 months on this project. We tested prototypes for thousands of miles (above) before settling on a final design. (Many readers have wondered how the Firefly’s 11-speed drivetrain worked with the René Herse cranks, and why that simple question didn’t get a simple answer…)
There are plenty of ‘ramped-and-pinned’ chainrings out there, because it’s not hard to cut a few ramps into chainrings and rivet in some pins. But, the ramps and pins don’t do much unless they are carefully aligned with the chain path. To work well, the chain has to hit the pin just right, in the middle of an outer link. Then it gets transported seamlessly to the big ring, and the ramp only acts as a cut-out to provide an easier path for the chain.
Another key element is to treat this as a dynamic system, spinning at 50-130 rpm. When we looked at other chainrings, we quickly discovered that this was the biggest difference between the best-shifting chainrings and those that offer only so-so performance. It became clear that the three big makers understand this, but everybody else seems to design their chainrings as a static system. Here is what ‘static’ means: When you put a chain half on the small and half on the big ring (above), it fits beautifully. But when you shift while pedaling, the teeth don’t have time to snug in between the links of the chain (which is running at an angle during the shifts). As a result, the chain rides up on the chainring and the carefully-planned alignment of the chain path is compromised.
By comparison, the chain seems to fit a little less perfectly on the ‘dynamic’ chainrings from the big makers – until you are pedaling. Then you are surprised by the smooth shifts. We benchmarked Shimano’s Ultegra cranks – widely known as the best-shifting in the business – for the performance that our 11-speed René Herse cranks had to match. Now we feel that we have achieved that goal, and so we are introducing the first 11-speed-compatible René Herse chainrings in a 46-30 combination. And of course, the excellent shifting performance of these rings works with 10- and 9-speed derailleurs, too.
While the upshifts get a lot of attention, the downshifts are just as important with 11-speed, because the distance between the rings is so small that the chain no longer can just be ‘thrown’ to the inside and then land on the inner ring, as it was with older systems. The new René Herse 11-speed chainrings feature special tooth profiles to facilitate downshifts. The chainrings also are machined specifically to reduce the gap between the rings, so the ultra-narrow 11-speed chains cannot get caught between the rings.
Instead of requiring you to buy completely new cranks, only the outer chainring is new. What this means is that older Compass-made René Herse cranks can be retrofitted. However, the 46-30 ring should be used with a 30-tooth inner ring, otherwise, the chain path doesn’t work properly. The small chainrings remain unchanged, because they don’t do anything during shifts, except release the chain upward. Because only the outer ring is new, this also means that our 46-30 tandem cranks (below) are 11-speed-compatible, too.
The production chainrings have just arrived, so we don’t have photos yet, but rest assured that they match the beautiful finish of our other chainrings. (The photo of the ramped-and-pinned rings show unpolished prototypes.) In the future, we also plan to offer other popular chainring combinations with 11-speed compatibility.
Click here to order 11-speed cranksets or chainrings.