I wave these brakes on a trek 3900 I Rebuild from leftover parts from my other bikes+ some new ones, So this is a bike I don’t ride often, But 2 years ago I rode these the bike with these brakes the whole winter, in various temperatures down to -11 Celsius ,And of course I used the brakes very often, but I noticed oil leaking trough the master cylinder on the left/rear brake, So I checked it it was the Torx screws that were the issue, but that was not the case, the threads I in the master cylinder were destroyed, they were polished to powder, so the screws did not hold the seal and the lid in place properly, so I ordered a new complete lever, but after only 2 trips about 10 Km each trip, the part which pushes the got scratched,and this was not caused by a crash, these brakes are just too weak.
The lever body is flexing when you press the lever blade all the way, Which I probably why the part that pushes the piston in gets scratched, and why the threads fail, and why the brake leak.
But there is significantly less flex in the 396 than m615, the m615 flex about halfway,and the m396 flex at near to all the way.
I had not had any issues with the seal in the calliper, or the calliper, But I have not ridden the bike with these brakes as often so it’s most likely why.
This is a way too flexible & weak brake, I strongly advise against buying these.
I have used these brakes on 3 bikes, some more than others, the one That the threads for the Torx screws failed, was the one I used on my main bike.
The brake lever body/Master cylinder flex when braking harder than 50%,which is why the plastic lid & the separator & the Master piston unit to bend or get damaged, and cause leaks, so the lever will be soaked in oil, and oil will spit out through the middle where the plastic lid is.I compared the flexing in the levers on m396&m615 and there is significantly more flex in the m615, if you press the lever blade half way you wont see flex on the m396,but on the m615 you will.
Leaking caused by plastic cover bending upwards, and front and the back is also being pushed upwards but sideways too, causing a leak.
temperature changes, will cause this, a minor hit can cause this. the design is clearly flawed.
I had to replace one master cylinder due to failed threads, and I had the leaking issues with the new one too,but with a set of pliers it was fixed, by pressing the cover into the master cylinder until it was straight/flat against the master cylinder,but this is pointless to do, you are better off buying a mechanical brake or a proper hydraulic brake.
Impossible so far to get placement seals/grommets/diaphragms, or just the master cylinder separately.
I don’t know what caused the threads to fail, it was certainly not over torquing the screws,I don’t know if its caused by fluid pushing the parts and girding the threads apart until they are so polished that they cant hold the cover, maybe I don’t know, I certainly was not a crash that caused it,because I never crashed with this particular brake.
Hinged clamp,no need to remove grips & shifter.
the levers are easy to bend back if you bent them,which I have done on 2 bikes so far.
good braking power,at least if you use Metal pads, ( if its wet or ride a lot)
it’s not too expensive
it’s not too heavy
no need to take off grips to take off the brake, because of the swing arm clamping mechanism.
The Brake Lever will bend if you crash into a tree(before I upgraded the handle bars i was used to ride on the fuel ex 7 with 720 bars),at low-speed,don’t just let the bike fall on the ground,it can bend the brake lever.
You can of course bend it back with proper tools and technique.
M615 Piston seals:
IUY 21.1 25 3.19 78 NOK
The Both brakes are too fragile.
Because the brake lever body/master cylinder is way too flexible and that there is a palstic lid,instead of metal lid,which causes the brake to leak.
I have seen a lot of reviews claiming these brakes are a good value at a low price point.
I agree with the braking power for the money is there, but not the reliability, these brakes are too fragile.
same goes for the other brakes with the similar design, for example, M396, M395,but at least it’s possible to get seals for M396, M395.
I have been riding world cup level XC terrain to trail/enduro/downhill level terrain with this wheel, But have not done any crazy high jumps or crashed badly, abused the wheel.
But I would not big jumps or downhill rampage on this wheel.
the spoke tension has been regularly checked, and the wheel has been trued by the bike mechanic, punctured and lately by me.
I ran 40 psi in the rear tyres.
I punctured few times and hit edges of stair steps, but no harm was done.
I have used this wheel for few years, at least 3 years.
I have done alto of jumps ridden up stairs and puncturing and wheel was fine, and riding down stairs with loss of air, and eventually hitting the rear wheel to stair several stair steps, the wheel has not shown any signs of bends or flat spots.
Stays true for long time
I only broke one spoke, even when some of the spokes were bit too lose and after hard riding the wheel stayed true, it got trued, and of course I need to get the spokes tensioned, but I was just not checking the spoke tension how much I should have, but nowadays I do it regularly.
Shimano hub is easy to service
the spokes are pretty thick.
The hub is FH-M475 viam
which is not a great hub.
I have bent the axle on all of my M475 hubs, which resulted in damaged cones, and sigly worn bearings, I don’t think I have ever ridden hard with too loose cones, but it noticed loose cones few times, but I checked for this often.
The dust seal/caps are horrible, a rubber seal is need, just a metal ring does not protect the bearings from hairs, dirt, water, and other things & the grease comes out which result in short maintenance intervals.
worth riding At least 5-7 days in a week, the free hub for me it got worn out after year season of use, it happen on several free hubs, on other wheels too.
wit this hub design, it’s important to check the bearings and cones,and do regular maintenance, if the bearings or the cones wear out, the wheel will have wobble and the cassette & freehub will wear out faster.
the freehub got pretty low engagement,there is few degrees of pedalling movement until it engages,which is noticeable if you are a experienced rider.
At the time of writing this review I am using Hope Pro 4 hubs, on my fuel ex 7 29er, and I love’em. but there are more good options.
decent wheel for xc & trail riding, but the hubs have it’s flaws.
This wheel is noticeably heavier than the stock/original Bontrager Ranger rear wheel, the performance is definitely worth it.
36 spoke double wall 26er wheel is a very strong wheel.
but the hub
IF you want a wheel that you can swap between old school Vbrake bike and a disk brake bike, this rim is a good choice.
But as the hub is not user-friendly and not goo, I can’t recommend this as a package deal.
If I use the 42T cog on the cassette the chain will fall off when back-pedalling, but when I shift up to 37T cog the chain stays in place no matter how hard I pack pedal.
On Hope Pro 4 freehub:
the Pro 4 free hub, is 11 speed compatible, which means it’s wider, and comes with a spacer,and with 11speed cassette, the cassette is closer to the frame/more outwards to the right, which gives a better chain line, so the backpedalling issues is gone,Unless you backpedal at unrealistic speed,then it will fall off,but I have done 180 U turns in 1stgear(42T) and the chain never fell off.
So if your rear hub is compatible with a wider freehub,you should get one.
Huge noise reduction when riding:
The first thing I noticed after I upgraded to 1×11 is that all the slapping ,banging and scraping noises are gone from my bike.
The narrow wide chain-ring will make more sound than the triple chain-ring, but when ring in rough terrain or jumping, the noise is a lot less than a conventional triple ring set-up would make.
There is big difference in the force needed to press to press the small trigger(up shift),but I got used to it after days ,and it did not feel as hard to press, and I like the shifter feel,I get less accidental shifts this way.
The change in gear is instant like promised.
The possibility to shift by bending you finger and do a finger kick motion,which you can’t do with Sram shifters.
(like this(https://youtu.be/7HvJma35fZA) to push the lever/trigger is gone, as the Shimano Deore 10 Spd had.But for me this is a acceptable compromise.
But there will be no accidental shifts
There is huge difference in the force required to push the triggers between SL-M610 & M8000 , so if you plan to upgrade a kids bike you might want to let the kid try it out first,but for the youngest I recommend getting SL-M610 or something similar.
you can shift down 4 gears
The I-Spec B shifter will have rotational play,because of the pin system, it’s not avoidable.
The screw came with a lot of Blue thread-locker,so needed to try few times until I finally got it tight without loose shifter.
But the adjustment screws did not,so you have to buy thread locker for them, I used Loctite 243.
The rear Derailleur:
A lot stiffer Clutch system, which is good.
Very smooth,fast shifting movement.
Esy to service, as long as you got magnetic bowl, and are careful with the round seal fo the spring assambly.
Race Face Narrow wide:
The chain will not fall off no matter how hard I ride, if it falls off you must be crashing really hard.
There is some drag when pedalling but this is not noticeable when riding, the chain still wants to be on the ring for about a half of a second, but this is impossible to avoid with Narrow Wide.
set up used in test: 2010 trek 6300 1 x10 36-11T cassette Shimano SLX Shadow Plus, with 36T Race Face Narrow Wide chain ring.The chain dropped when it was in 24 Tooth cog, but when I tried in 21 cog it stayed on. Even on stairs that were not that steep probably 40 degrees,the chain fell off.
Pros of 1×11:
You get all the gears you need if you just select the right chairing for you.
a lot quieter drive train
dropping the chain is rare unless you ride in low gears down steep stairs.
No front chain rigns to deal with
easier to clean the drive train,less dirt & mud on the drive train
if you want to sue a chain guide, you can use a single ring chain guide which will be more secure,and look better
if you use a wide range cassette with a 9T cog you can get the a pretty high gear as you could with triple rings,but with 11-42 with 36T cassette I get a pretty good range,but once I get on the 1km flat straights I will run out of gears
Cons of 1×11: There are no real cons riding 1×11 it will havefaster wearing cassette and chain of course,but that’s not a reason to not upgrade. the 37 and 42 cogs are the fastest wearing cogs, because of the bigger chain angle.
the cassette & chainring wore out at the end of the season like it did with 10×3, maybe few weeks sooner wear. I don’t have to shift as often and skip so many gear so often,so I get less side to side wear on the chain,by using 1×11,so the chain growth will be less.
If i changed the chain,a lot earlier, the cassette and ring would have lasted longer,but I had no spare chains,but I have a stock of chains now.
The Rear derailleur cage will have visible wear, with 1x setup,because of the chain line the chain will hit the plates,but its not a big deal.
I absolutely recommend Both the Xt m8000 drivetrain and the Race Face Narrow Wide single chaining.