The Shimano Zee M640 disc brake comes with a Servo-Wave brake lever, 4-piston ceramic disc brake caliper, high-power hose and short lever for stiffness.

>>> The best mountain bike disc brakes

Reader review by Owen Franssen | Trail/Enduro/Gravity rider
Instagram: @emerald_mtb

What rotor size?

203mmm front, 180mm rear.

How long have you had it?

Two years.

Tell us about the features. Lever reach, bite point adjust, ease of pad replacement etc.

Reach is adjustable with an Allen key, with enough range to make the levers comfortable to use – close enough to the bar to rest my index fingers without strain but without trapping any fingers when pressed. There is no bite point adjustment, but you can overcome this with some clever bleeding. The pads are easy to change. Simply remove the split pin holding the pads in and they drop out. Fitting the new ones is just as easy, just in reverse. Just remember to have a small pair of pointy nosed pliers handy to bend the end of the split pin and secure your new pads.

How easy is it to bleed?

Using the correct kit (which is made up of a small funnel, syringe and hose) bleeding is very easy with access to the reservoir on top of either lever behind a small screw, and at the calipers via a bleed nipple and 8mm nut. Top top up the mineral brake fluid you just pour a small amount into the funnel, insert the stopper, remove the funnel and close the reservoir. For a full bleed, you squeeze new fluid in from the caliper end using the syringe until you start to see clean fluid bubble up into the funnel at the reservoir.

How powerful is the disc brake?

Both ends are more than powerful enough to lock the wheels at speed.

How much feel and modulation does the disc brake offer?

These brakes offer plenty of feel, enough to allow you to drag the brakes without locking the wheels. With some experimenting to arrive at the setup that feels best to me, I have the front caliper engage much slower than the rear, allowing for a very controlled actuation, while the rear wheel is set to go from nothing to lock much quicker.

Ergonomics. How does the brake lever feel and function?

The brake levers are short, ideal for one-finger braking. They have a nice rounded profile that makes it very comfortable to leave your braking finger resting on the lever for long periods. And the hook at the end of each lever helps to prevent your finger slipping off when pulling on the brakes hard.

What sort of riding does this disc brake work best in? XC racing, trail riding, enduro, downhill etc.

While I haven’t ridden any XC with these brakes, I use them regularly on trails, enduro courses and at the bike park. They perform flawlessly at all of these.

Reliability. How well has the disc brake stood up to use? How frequently does it require bleeding? etc.

I’ve found the Zee brakes to be totally reliable. Even on some of the longest descents of up to twenty minutes, I have noticed any fade or loss of performance. I tend to only need to bleed the brakes when I replace the pads, or occasionally if I’m using very work pads. The only issue I have come across is that the pads are very susceptible to contamination from bike cleaners, and I’ve had to replace a couple of sets of only part worn pads because of this.