by Nick Zuzelski
In the craze of clutched rear derailleur technology coming out these days, Shimano's newest offering is targeted to fit the market of gravity riders looking for performance while keeping some hard earned money in their pocket. Enter Zee.
Zee RD-M640 Highlights
- 10-Speed Only
- Short Cage
- Weight: 250 grams
- MSRP: $109.99
The Zee rear derailleur features Shimano's Shadow Plus technology. Translation: The rear derailleur is strategically mounted and tucked in with a low profile design, decreasing the vulnerability of hits or impacts, and thanks to an innovative clutch, you aren't going to hear much chainslap noise while blitzing through rocks and braking bumps. The clutch is fully serviceable and adjustable so you can keep things maintained and running smoothly after some use and abuse throughout the season.
New to the whole clutched derailleur technology? Shimano has integrated a one-way clutch mechanism into the derailleur knuckle. This provides significantly increased resistance when the chain pulls on the cage, preventing excessive chain slack, which was previously the cause of the dreaded chain slap and poor retention.
All of Shimano's clutched derailleurs have an "on" and "off" mode, activated by a small gold switch. The only time we saw a need to put the switch in "off" mode was during wheel removal and chain installation to allow the derailleur to swing forward with less force.
Shimano offers two models of the Zee - A "DH spec" that fits up to a 28 tooth cassette, and a "Freeride spec" that fits up to a 36 tooth cassette. This is accomplished using a different sized b-link that can be purchased independently for converting your rear derailleur between modes.
On The Trail
We have been running both the DH spec on a downhill bike and the Freeride spec on a 1x10 trail bike. Both setups are holding up following some muddy, rocky abuse.
One area we have really enjoyed has been the benefits seen on the trail bike. The option to have both a clutched rear derailleur AND a short cage able to handle a wide range 11-36 cassette? Yes please.
Combined with the Zee shifter, shifting performance is crisp, precise and snappy quick. The derailleur has been a set-and-forget endeavor and has been free of any ghost shifting and skipping after a proper flogging on the trails for a few months.
One of the reasons we are seeing such great long term durability and continued performance in this derailleur can be greatly contributed to the extremely low profile of the Shadow Technology. The main derailleur body is much less exposed and seems to hide from rocks, stumps, and shuttling abuse that destroys more conventional designs.
Zee's clutch has virtually eliminated chain slap. Since installation, our test bikes have been silent slayers. No more ugly excessive tape or old tubes/tires/who knows what needed to keep your frame quiet and unscathed. Win. But wait… this has developed an unforeseen yet small downside - we have routinely scared the $#% out of hikers and slower descenders when running in Zee stealth mode. Sometimes it is nice to have a little noise to let people know that you're coming up behind them. I think we'll survive though.
If you have yet to throw your leg over a bike with a clutched rear derailleur, you better believe the hype - this new breakthrough is making bikes so quiet and dialed that you will never want to be without a clutched setup again. It's that good.
While the clutch is fully serviceable and adjustable, we haven't had the need to adjust any factory settings. They're working great, but it is nice to know that some adjustability is available if needed.
What's The Bottom Line?
Given the impressive features, performance, and durability we've experienced, it's hard to call the Shimano Zee rear derailleur a compromise. Coming in at half the cost of the Saint equivalent, this is a very good choice for budget-minded riders looking for solid shifting performance with Shimano's proven Shadow Plus technology.
Visit www.crusheveryline.com for more details.