How To Install A Rear Derailleur | Mountain Bike Maintenance
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How To Install A Rear Derailleur | Mountain Bike Maintenance

November 7, 2019

– In this mechanical video I’m going to show you
how instal a rear mech. Okay so I start off by showing you how to take your rear mech off. Maybe it’s broken or
maybe you’re upgrading it. The very first step to
this is to change gear right down to the bottom of the block into your highest gear. So next thing to do is to turn your clutch off if you’ve got one. Shimano XTR does so we
just push that forward. And now we’re gonna undo the bolt that’s holding the rear
cable into the rear mech. It’s a four mil allen key on Shimano. On SRAM I think it’s a T25. You might want to check that. Next job is just to
chop off that cable end if you’ve got one on there that keeps that cable neat so you can then unthread that gear cable from the rear mech. So I’ll just pull that out. I just freed that up. Next job is to split the chain. So you’ve got a couple of options when it comes
to splitting the chain. If you’ve got a SRAM chain, more than likely you’ll
have a power link in there and you can use one of these tools just to push that power link together and then ‘s gonna pop it apart and you can split the chain. This however is Shimano so I have to use a proper chain tool and actually split the chain. You can see here there’s that one pin that you use to join the chain and I always split it at that point. So I’m using my proper
chain tool just to do that. So now just unthread the
chain form the rear mech so just pulling it over the jockey wheels. And that leaves it free to now remove. On Shimano it’s a five
mil allen key just here. On SRAM again it’s a T25. So I just want to take it
around that way from here. And just spin that bolt out, keep hold of the mech as it comes out. And that’s it. Dead easy. Okay so now to instal a rear mech unsurprisingly it’s actually that same process but in reverse. But the first thing I do before actually doing that, is check that my rear hanger, so where my mech mounts to the bike, is nice and straight. These do stick out off the bike obviously and they can get a little bit of damage so twisted or bent. They need to be absolutely
straight and vertical. So just look down the bike and try to make sure that’s right before you put on a new mech or you might just want to
buy a new one of these. So to instal this Shimano XTR mech, it’s slightly unusual, see how this actually goes around either side of that mech hanger. It’s more normal to have a rear mech that just sits on this side. But it’s pretty easy to be honest, to instal this. Just make sure the
threads are nice and clean inside the hanger and on the mech. Slightly greased. And you just need to make sure that this B-tension screw goes behind this stop on the hanger. So quite easy, but just make sure it sits far enough back where it takes it around so that stop sits on that bolt. And just wind that in. So just be careful when you start this thread off that it’s nice and square so you don’t cross thread it. They are quite fine so it can be done. So you can see how that allen key is spinning nice and freely all the way in and I know that I’ve done it right. Okay so now you can just
thread the chain back through the rear mech. With Shimano make sure that the writing on the chain faces out. And on the other side there’s
no text on there at all. I stick it over the cassette. And it goes around the cassette, up and over the top jockey wheel, down and in to the cage and then round the bottom of the bottom jockey wheel. So just make sure you’re
doing that correctly. There is a guide here
on the rear mech as well and you need to make sure that goes to the right side so that is goes straight
to our next jockey wheel. So on this one it’s to the back of it. Round the bottom there. And I’ll always join my chain down here below the chain stay. So with the chain all
threaded through the mech and around the chain rings correctly, I’m just gonna re-join the chain. And then I might as well turn my clutch back on once I’m done here. And so now it’s time to
thread the cable through. So on this bike I’m just doing the reverse of what I did before. So I thread that cable through. Making sure the outer cable is butted right up to that stop. And then it’s time to get that cable into that pinch bolt. It’s dead easy on this Shimano, it’s just straight there. On SRAM you have a bit of a wheel, so you have to thread it around the wheel and then it bolts down here somewhere but it’s the same theory. So I’m ready to now pinch this cable into the rear mech. But before I do that I’ll
make sure the shifter, the barrel adjustment on that is wound clockwise all the way in so I’ve got some adjustment after at the shifter for some fine tuning. So put a bit of tension on to that cable, don’t go crazy just a bit
between your fingertips. And then just tighten that bolt down. There’s a washer underneath that bolt. It’s got a flat side on it so that when you tighten it in to the mech, it’s not gonna spin and it’s gonna pinch that cable correctly. So just make sure that it’s set in the correct sort of orientation before you start tightening that bolt. If you’ve got a new cable end, it’s a good idea to crimp one on to that cable to keep it nice and tidy. And the final job is to set up that rear mech by
setting the cable tension on your barrel adjuster on the shifter. Setting your B-tension screw and your high and low screw. We’ve done a whole video about that. Click up there that’ll take you through to that one. Click on the GMA logo to subscribe, or click just down there for how to split your chain. Give us a thumbs up if you found this video useful.

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  1. any ideas of how to tighten my rear tire.The tire wobbles from side to side and the hub holding it in place has completely come away….? (I have a carrera hellcat)

  2. @3:12 i got my chain the wrong side of the guide and it carved a huge groove into the guide. Thanks for showing me the right way to do it. 😐

  3. if I remember correctly you shouldn't be splitting and joining chain in the same place twice, since joining pin won't be fitting as securely as it should, and eventually it can lead to chain snapping under high load.

  4. Dangit, i was looking for this video a week ago when i was installing a groupset and i put the derailleur on (i eventually figured it out)

  5. Good video. Also worth mentioning that when you're replacing your derailleur it's a good time to go ahead and replace your derailleur cable.

  6. #askgmbn hey guys are lessons really worth it? I'm considering a lesson on jumping at a certain bike park!! but at £80 do you get your money worth or are you just better off watching videos and keep practicing?
    What does a lesson offer more than tutorial videos and practice?

  7. Can u guys do a series where u build a mountain bike from scratch it would really help to know how to fix and replace every part on a bike and the basics and more complex stuff

  8. Hey gmbn could you please help me I have a shirmano deore derailleur and when I have it in on the first chain ring on the front and when I get passed about 5 gear there is no tension on the chain at all could you please reply to this thanks

  9. Just FYI would have been nice to see you use a derailleur hanger alignment tool (I'm sure you have one there amongst all those pretty gadgets in the background), as a lot of people don't even know this tool exists for ensuring your derailleur hanger is straight.

  10. #askgmbn hey lads, just watched your vid and am slightly concerned now! I recently went 1 x 10 Deore XT and the mechanic whos fitted the chain has put the writing to the inside of the bike? but in this vid you say to make sure the writings on the outside? how will this affect me bikin'?! keep up the solid work fellas!

  11. Technically it's better to adjust at least your high limit screw on the derailleur before you attach the cable. This way there is no possibility of cable tension playing around with the limit. If you've not put in the chain yet, you can really adjust both the high and low limit screws before re-running the chain.

  12. Great video guys, can you do a video on the pros and cons of a single chain ring and the pros and cons of a triple chain ring. And I'm looking forward to receiving my gmbn jersey.

  13. hi, you can also remove the second jockey wheel instead of breaking the chain.even more if it's not have a power link . but maybe that need's more mechanic skills …

  14. I shimano actually tell you to never break the chain at the same place twice as the act of pushing the new pin through removes some of the metal from the plates.

  15. Hey Donny! I see a DAG 2.2 on the stage left pegboard yet you just eyeball your hanger. Show the people the proper tool and they learn more. Sorry for yelling 😀

  16. I can't give you a full thumbs up for this one. Derailer hangers can't just be "eyed up", you need the Park DAG-2 or similar, even for if you're installing a brand new hanger too. Not every hanger or frame is perfect, and a slight irregularity in the hanger will have you moronically adjusting the cable tension back and forth for hours if you haven't realised it.

  17. Hei! just giving two idea s for a new video, what about "when to change cleats" and "how to perfom a bike fit at home". Great videos, keep going!

  18. #askgmbn can I replace my brake levers on my bikes with different levers? (Regular Deore to XTs, XTR, SLX ) Or would there be issues?

  19. #askGMBN how do I set the best tension on a clutched derailleur as to not affect my suspension? Is there a good starting point, or is it found through trial and error?

  20. For those who do not have a chain tool at home, would it not be possible to do this job by removing the jockey wheels?

  21. You are never supposed to press out the shimano connecting pin. break the chain in another place, the new connecting pin is actually stronger than the surrounding pins when installed properly.

  22. You don't actually have to split the chain, removing the jockey wheels and mech cage works as well, but can be a little more fiddly when re-mounting.

  23. i am not trying to advertise myself just saying yaw have inspired me to make my one mountain biking videos thank you so much

  24. Hi guys

    I just changed my rear mech on my 2015 Trek Slash.
    It had a 3×10 drivetrain and a Sram X9 mech.
    I went to a 1×10, upgraded to a 11-42 cassette and found out the Sram mech had trouble shifting.
    So I bought a Shimano Deore M6000 mech.
    Put it on today but no luck installing.

    Ashamed to ask this question but;

    Do I need a Shimano chain and shift lever now to? (still the Sram on there)


  25. I was under the impression that 'installing a rear derailleur' video should include the cables as well. I often find technicians in various industries to be good at what they do, but rubbish when it comes to putting themselves in the place of the learner and communicating effectively.

  26. Good vid, if I'm only swapping the rear shifter should all the adjustments be made with the cable tentioner or will I have to adjust the rear mech too?
    Thanks heaps

  27. You shouldn't gust through the video. Be systematic, and show close-ups, and anticipate questions by the viewer.

  28. My Shimano Zee derailleur doesn't hit the lip bit and it swings up and hits my chainstay , is there something missing ?

  29. Great video but one thing ill add is when loosening the chain pin don't actually pop it all the way out because then it's like almost impossible unless you have super steady hands and no oil on you're chain to put it back in just leave it in the last piece of the link.

  30. I can't understand a word you are saying. Spit the marbles out of your mouth and stop substituting normal English words with some thing generic an unmeaningful. For example it's not a "mech" it's a derailleur. Just about everything in the room could be described as a mech (mechanical device) pr person.

  31. I have the exact same mech! It's such good quality and the clutch is really useful in reducing the slack in your chain. I would recommend it to anyone who is an extreme rider.

  32. I don't mean any offence but why do alot of these videos seem to want to show the guys face more so than nice long detailed closeups.
    Your a bicycle "mechanic" stop flexing.
    Now I've not owned a bike for over 25 yearsand don't get me wrong I understand this sounds rediculous but even stuff like what angle should the derailleur be at the point the bolt bites down,oh no wait we best have a look to see how pretty boy Is looking.
    I don't know the first thing about bikes which is what I'm looking for soooo more closeup with his voice in the background,it's the bike not the hairdo I want to see.

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    I did not show yet my final design/prototype…very confidential.
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