Shimano Nexus 8 Speed Hub Reassembly - Putting It Back Together...

I just discovered during my Shimano Alfine 8 sp. install today, after spending more time than I am willing to admit to get the shift assembly onto the hub, I was trying to put a square peg into a round hole! No matter how many videos I watched today, including this one, turns out I have the needed parts for a Nexus, NOT a Alfine, and the two are similar enough to not be noticeable (until you know what to look for) in watching a video, or many videos! I ordered my Alfine hub off Amazon , and right below they had a "needed small parts kit," but that kit is not for the Alfine. Just a heads up....

Thanks for videos on these hubs I now can take them a part and rebuild them no problem.

Hey RJ, thank you so much for this video. Used this together with other sources in order to repair/rebuild my Inter Nexus 4 - because I hadn't taken any pictures.. Unfortunately the hub is still broken although I can't see how/where, but it didn't shift anyway when I got it. Unfortunately also my rear wheel doesn't rotate with the chain any longer. I gave up after having taken the hub apart for the 12th time ;) (I can dismantle/reassemble it in my sleep).

Thank you for the detailed videos on bike fixing!

Do you think lithium grease ore marine grease would work?

Amazing understanding for machinery,mechanism and gadget!
There’s no mentor about bicycle mechanism like you in Japan , though SHIMANO is made in our nation Japan😭
Thank you so much indeed. May god bless your hand and soul.
Domo Arigatou❗️

You were able to put it back cuz you are the inventor of that.

Perfect video RJ, the other Shimano ones are almost all Russian.
I now have a Nexus 7i with a nice trigger shifter. Perfect gears for medium hills, city and highway. It came with 44/22T, too slow for me. Now going to try 18T. The stupid roller brake makes it way slower than my finicky shift SA XL-RD5w. This 5w IS the fastest hub I've ever had, done 46 mph on a 8% hill.

But I want to tell everyone to not be so afraid of a little play in ANY bearings. The 7i came tight and so did every pedal I ever bought. The 7i coasts way farther now, it was worse than my Rohloff ever was. LOL.

wonderful 👍

Thnx. Used it to fix mine!!

What could be the problem: no tension at all in the cable barrel cj-8s40?

Dude you are awesome! I was having the exact same probleme of standing in front of a complete disassembled hub and now i can piggyback of your video.

Thank you so much for the teaching, but you really should wear gloves when playing around with these kinds of oils and lubricants.

،شكرا

Very useful video! I have a Nexus 8 inter8, model number SG-C6000-8R. What I discovered is that I have a needle bearing type of clutch...so I do not have the pawls like other hubs have. I had removed the roller bearing ring and did not put enough tension on the spring when I reassembled it. The symptom I had was that when I shifted to 5th or higher, I could not pedal any longer...it locked up but the wheel kept spinning. I'd attach a photo of what my clutch looks like but I couldn't figure out how to include a photo....Thanks again!

pls explain shimano nexus sg5r30 reassemly thank you

Hi from Romania.
What grease use you ?
I use Total with calciu and litiu.

thanks so much

This is the best video out there showing one of these gearboxes going together. I have a nexus 7 speed that won't shift to 1st or 2nd gear.

Incredible. You are like a mad scientist! I have no idea how you can understand all the intricacies. Very impressive. I am having problems with my hub and I was hoping there would be a quick fix. Something got caught between the hub and the wheel and now when i pedal, everything slips and i can't propel the bike forward. Any ideas?

تحياتي.براغواليك.بوط.
فيتاس.بيكلة.خطير.
بيسراحة.خاص.فوق
الباك.هد.الحركات.القوية

Great work and info

17.02. i need to replace that ring, found a broken piece of it when i diambled the gear my gear jumps over in 4 and 8 and make a noisy metallic sound

Grad jop thanks ....god luk

I do not try to do teardown my 7 speed hub, it would not ever be whole again after that.

Can you imagine the kind of brain you need to design these mechanisms.. 😵‍💫

Mechanic work is a lot like trail riding. You make it all the way over the mountain and then get thrown by one little bump.

Next stop, brain surgery!🤯 😂
Enjoyed the video thx 👍

@RJTheBikeGuy can you do a nexus 7

Loved this video

Fantastic work RJ! I couldn't stop watching how this transmission (basically what it is) goes back together and how it works. I thought I had the 3 speed Sturmey Archer down then this comes along and .. wow.

Good effort 👌

Hey how did you manage to get the carrier unit back together? Just asking

great respect its really unbelievable to get this thing together

I guess u got have certain kind bike frame
Axle stananary

I really enjoyed watching. Two years ago I fucked up a very dirty shimano 3 speed hub from my sons bike. I thought, well I can do this! I Watched reassembling videos but at the end it diden't work. Finally I bought a 2nd hand inner work for less and finished the job. Could not sleep for 2 nights, felt very disappointed in my skills. Your video reminds me about that my struggeling moments with the shimano hub. BUT, I really got BIG respect for the engineers who invented these hubs with so much parts, all designed with a purpose and all work together. Me myself, I am am audio/video composer but when I got a BMW R60/5 (1971)from my dad 15 years ago, I started to appriciate the wonderfull world of mechanical enginering. Great Video !!!

Great video RJ. I was a bike mechanic when I was younger. When one of these things showed up at the shop it really separated the guys that thought they knew (me) from the very very few that did. Your video was a great aid to me while servicing a nexus 8 with lots of drag. Thank you for putting this together.

lithium grease?

To me it looks like either the tabs on the turning thing that push down the pawls, or the parts of the pawls that get pushed down are worn out, which causes them to stay up too much. I guess the grime and sand that was in there before might've done that damage.
Amazing job on reassembly and explaining all the workings of the hub at the end!

The second that he opened the casing and I saw the brown grease I knew that rust had formed from water ingress. This hub gear is an incredible feat of design and engineering, but it is obviously a nightmare to service. Because of the size restraints the tolerances are small so once it corrodes as indicated by the grease colour there's a very high probability that it's game over. Shimano states that this hub must be serviced every two years, which should mean a full disassembly, comprehensive cleaning with ultrasonic, regreasing and the oil bath and reassembly - quite frankly that is economically unviable. It is manufactured to sell and then fail after 5 or 6 years. Compare that with an old Sturmey Archer 3 speed which will probably last for at least two centuries of use. This is a very poor product for the consumer and a good product for Shimano's profits. It's extraordinarily impressive and sadly embodies what has gone wrong with our society.
I wouldn't touch one of these with a barge pole.
All the best everyone. 👍

Do you think thumb shifter will work as a replacement for the revo shifter?

Any disassembly means laying everything out in line doing / using a diagram, filming or photographing as you go. Back in the day imagine how difficult it was doing it from memory if you hadn't planned it out ?

Amazing 🤩

Very interesting. I hope you do a video on the next step of diagnosing the pall problem.