This rear derailleur has been on some long rides, and got some abuse.
I have ridden this rear derailleur since 2015, some weeks in 2016 & the whole 2016/2017 winter plus one winter, and some weeks and days in the summer of 2017.
I ride a lot, I ride at least 5 days in a week, from 1 hour few hours, depending on how I ride up to 20 plus km, some times less, but my point is I ride a lot
I have mostly used this rear derailleur with 1x setup.
Some times I am unlucky and crash or mess up on a technical climb, and this is why the rear derailleur got some scratches, It had some scratches before the crash, for smaller impacts, but the last crash really shows damage, but it’s only cosmetic damage, so my conclusion is that this is a robust rear derailer able to take a lot of abuse, but the pins and swing arms are not replaceable, So when has play you have to get a new rear derailleur.
I crashed off a 1 m concrete wall, the cage was grinding against the wall, I had shifting issues, First I thought they might be the result of the crash, But later I found it not to be the case.
I Did an inspection on the rear dérailleur, I checked all the adjustment screws I took off the cage and did a service, the cage was bent, So I straightened it, but the shifting issues were still present. So I checked the, but then I checked for play, the rear dérailleur had huge play, so it was definitely the play. causing issues.
but I straightened it, but after few days of riding, I noticed shifting issues, So I checked the all the adjustment screws, but then I checked for play, the rear dérailleur had huge play, so it was definitely the play. causing issues.
after riding few weeks with, there was just too much play to do up-shifts, the play caused the Rd to hesitate on shifts.
SLX M675 comes with bad jockey wheels, but you can upgrade to proper jockey wheels, the problem with the stock jockey wheels is that the that the jockey wheel and the metal ring grind against with other and cause damage to the jockey wheel which causes it to not spin smoothly.
Even upgrading to XT jockey wheels which work better, they are not that great, Hope has better spacers, they are Labyrinth style spacers
I recompared upgrading to Hope jockey wheels or similar, with proper bearings & proper cover.
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.