Shimano Zee M640 mountain bike transmission review£147.00

Business-like single-ring setup

BikeRadar score4/5

Shimano’s Zee is a cunning crossbreed of SLX and Saint that deserves to be used a lot more widely than it is.

For a start, it’s a dedicated single-ring system so there’s no left-hand/front shifter. While the triggers aren’t longer than normal as they are on Saint, you do get a dimple-gripped thumb lever.

The rear derailleur cage is also kept short enough to keep the chain really tight and secure. There are different versions for close-ratio (28t max) and standard (36t max) cassettes too. That translates into sharper and more precise shifts than with a longer cage derailleur – especially when the bike is being battered all over the place – even though the shifter internals are mechanically identical to SLX.


The rear derailleur cage is short enough to keep the chain really tight and secure

The derailleur cage is alloy, rather than the steel found on SLX, and the on/off switch for the Shadow Plus clutch mechanism is anodised alloy rather than plastic. The thick alloy ‘X’ outer plate, pressed steel inner, direct mount compatibility and tunable-strength clutch are shared with the SLX derailleur.

The cost-effective SLX chain and cassette are the obvious value and durability match to complete the setup.

This article was originally published in Mountain Biking UK magazine, available on Apple Newsstand and Zinio.

Guy Kesteven

Freelance Writer, UK
Guy started filling his brain with cycle stats and steaming up bike shop windows back in 1980. He worked the other side of those windows from '89 while getting a degree in “describing broken things covered in mud" (archaeology). Dug historical holes in the ground through the early '90s, then became a pro bike tester in '97. Guy has ridden thousands of bikes and even more components the world over since then and can remember them all in vivid, haunting detail. Can't remember where the car keys are, though.
  • Age: 45
  • Height: 180cm / 5' 11"
  • Weight: 68kg / 150lb
  • Waist: 76cm / 30in
  • Chest: 91cm / 36in
  • Discipline: Strict sadomasochist
  • Preferred Terrain: Technical off-piste singletrack and twisted back roads. Up, down, along — so long as it's faster than the last time he did it he's happy.
  • Current Bikes: An ever changing herd of test machines from Tri bikes to fat bikes and everything in between.
  • Dream Bike: His Nicolai Helius AM custom tandem
  • Beer of Choice: Theakston's Old Peculier (not Peculiar)
  • Location: Yorkshire, UK

Related Articles

Back to top