Decent power with minimal one-finger effort. Friends say they are easy to bleed.

Carbon lever blades snap easily and might not be replaceable for all practical purposes. Poor modulation. Lever "Free Stroke" adjustment is worthless / just for show. Cheap at the small part level.

Overall, these brakes under-deliver as a high-end MTB product -- they are a "commodity" product, not a "boutique" product. I'll be moving these to my old backup bike. I put these on my new custom-built Bronson because I had some decent experiences with XT brakes on some demo bikes, I noticed some respected high-end bikes are coming with XT/XTR, I wanted a bit more power than I had with other brakes, and I took it on faith that Shimano would not "do me wrong" with an XTR level product. Unfortunately, I've experienced problems, including part breakage, in only 8 weeks of use. First, I've already snapped a lever blade. The lever blades are fragile -- they are "Carbon", but not "Carbon Fiber" -- it's the "Fiber" that makes "Carbon Fiber" durable and stiff. The blade snapped on the most benign little failed climb attempt when I laid the bike over to the side. Then I notice that replacement blades are almost impossibly to find (two-month backorder at the only retailer who carries them?) and probably not possible to actually replace without factory specialized tools, i.e., the blade/master cylinder assembly is designed to be replaced as a unit -- it is not designed for easy individual part replacement, even for the lever blade. Other problems: the blade "Free Stroke" adjustment is just a cheap Phillips head screw -- on one side I could not get it to turn -- head probably stripped now; on the other side it barely turned but didn't seem to have any effect on the blade feel. As for braking performance when not broken, it was just OK. Pretty good on basic XC style riding and good when you want to slam on max braking power quickly for a two-wheel skid, but the lack of modulation is a problem as you move into aggressive trail and enduro style riding. For example, almost impossible to feather rear brake for a wheelie or wheelie drop-in / launch over a ledge -- tap the rear brake lever during a wheelie and the bike wants to snap-rotate down/forward; also, on high-speed turns/berms, the back wheel wants to lock up causing an unintentional rear tire skid. Finally, compared to my old Hopes, every little part on the Shimano's just looks cheap -- lots of off-the-shelf pins, rivets and screws. E.g., the Shimano lever reach adjustment is vinyl covered (steel?) with a "heavy" action -- clumsy to use with sweaty full-finger gloves on the trail -- versus the Hope's crisply machined notched aluminum with light accurate action.

Similar Products Used:

Hope M4 circa 2011. Magura Marta SL circa 2006.

great braking while they work

master cylinder dies quickly and not rebuildable

These were a warranty replacement from shimano for a 2015 xtr rear brake that the master cylinder started leaking after about 8 months. This one lasted about the same. It worked great until I had issues with the lever sinking towards the bar under prolonged braking. Took them into the shop and it was doing the same thing as the last set, master cylinder leaking once again. Too bad these aren't reliable, they work great.

1 finger braking, no GD vibration. when are other POS companies going to figure out that vibration = garbage?

YOU CANNOT REBUILD THE MASTER CYLINDER??? I have had some banjo fitting failures in the past, but they were warrantied. I-Spec. I disagree with the other poster. I had the I spec on in 2012 and there wasn't enough adjustment to get the effing shifter out of my thumb knuckle. Maybe its better now. Once I rode one set, I bought 5 other sets. DH, XC, out of town XC, DH (saint), Wife's bike, and my dad put them on his. It's like crack. you need this.

I'm not sure exactly why, but I have had some of these pads foul after extended periods of disuse (out of town bike that I ride every 6 months). I haven't ridden them, but with the cheapest shimano rotors, I have gobs of power. get resin pads for the rear if its dusty, or ear plugs.

Light, very powerful for true one finger operation, incredible modulation, self centering, very easy bleed uses mineral oil. Lot's of adjustments range for the lever, and easy to set free-stroke adjustment.

None to report.

Excellent brakes. They are so flow less that it is hard to comment other than saying that you simply do not notice them. They stop, quick, with very little one finger pressure. The I-spec II clamp is great leaving a VERY clean bar.

Similar Products Used:

Magura SL, XTR M975