How to strip and rebuild a Nexus 3 speed hub 

Everywhere, and as much as you can fit! 😁 Just a joke, but you can apply a liberal amount of Shimano white grease all over the guts of the Nexus.

It turns out that the 2 head bearings are opposed by a single tail bearing. It is a bitof a weird set up but you can safely tighten it right up to the shoulder. The brake side bearing takes all the tension adjustment

ha ha, the best this piece of schiser can work is like a swiss garbage truck

High temperature bearing grease

great to hear my work has helped you.....now all you have to do is take it apart another thousand times till you can strip it in 30 seconds flat, then teach someone else!

the 3 gears are 1direct drive, 1ring drive , and 3 planet drive(dont quote me on that) the shifting is accomplished by the shape of the bell housing governing which set of ratchets engage the hub shell hope this helps

ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-mUyv7mLgCFQ.html

im a leftie, in a right handers world

The question for me was what grease to use on the bearing on the brake side. Ended up using regular bearing grease.

what parts are you talking about?

VomDeich , their is another length of the actuator pin of 95mm. Used sometimes in Hollandbikes, essential is the length of 14mm outside the axle!

It should be ok to remove th ebrake shoes, it might pay to remove the 5 hardened rolls that activate the shoes, you need to take that surclip off. the braking action grinds hardened steel past hardened steel behind the same grease seal as the rest of the moving parts. with all this hardened metal muck floating around, wear sets in, as wear sets in, gaps increase, pins move, springs drop out, munched spring wire migrates into the bell housing, and jams it between 2 gears, when this happens the hub locks up but the wheel is still moving foward with a huge mechanical advantage over the NO TURN washer on the axle. the axle spins in the no turn washer, and the hub is cactused... all because some pea-brained dimwit put the brakes behind the same grease seal as the rest of the moving parts

Can you post a vid of exactly what you are talking about? I'd hate to mess it up.

the nexus 4 speed is a good one, i havnt had much to do with it, so cant say for certain, but the one i did take apart looked very well designed. Sturmy Archer 3 speed hubs are known to still work 50 years later, but they arent the most efficient i ride recumbent ICE Trikes these days, so much safer than Mulga Bill's "Two Wheeled Outlaw" im not surprised in the least about your unfortunate incident, we had a few lockups, usually the axle turned in the no turn washer, kind of a fusable link, but total system lockups arent unheard of i suggest youpost a video of pulling apart the offending hub, according to my video, and showing the damage, probably spring fragments or other fractured bits have ended up inside the bell housing and jammed two gears against eachother when you tried to shift gears stay safe, and again i highly recommend you switch to a three wheeled tadpole

@@AdamEdington How does this happen, that you would have spring fragments/ fractured bits, inside a sealed hub? And if springs broke, where do you get replacement parts? Thanks for your input.

@@cchemmes5831 as the brake is used, fine particles of hardened steel start grinding everything, clearances increase, pins migrate, springs drop out, sometimes the drive input sheds some fragments off the thin lip. I never got to order replacement parts, just cannibalise another hub for spare parts

@@AdamEdington Thanks for the input. Mine was new/ used only a few times before crashing, so that seems messed up for a sealed, supposedly high quality hub. My brake is a separate roller brake as well.

@@cchemmes5831 ok, did one of the cam rollers come loose? We did get a fleet of those a little while before I left, never had any problems with them so only poked my nose in once.. so let me postulate from ignorance and partial knowledge.. There should be a circlip to retain the hardened rollers, maybe the anchor bolt came loose, Send me a photo of the damage, edington.machining@gmail.com

+daniel hegner in the gears, and bearings, use slurpy grease, shimano puts out a special formulation, DO NOT use HTB it is too thick and viscous to let the ratchet work, i have seen about 4 hub lockups caused by some idiot using HTB

@Will Swift gotta be careful of mixing lighter hydrocarbons with heavier hydrocarbons, over time they have a tendency to separate and leave behind the heavier more viscous stuff

Does the apply for nexus 5 speed when it comes to the circlip remover? And how do I remember the position of all those parts?

This took a number of takes, so rather than clean it each time, which would have been time consuming, I decided to film it dry

the push rod tends to get bent and is a bit sticky in the hole down the centre of the axle, make sure you have the right length push rod, but there could be one or two springs come adrift jamming the bell housing to the axle, it might be worth taking apart, and giving it a scientific poke! it could be a badly adjusted or seized cable... the marker should be between the lines in second gear let me know what you find,

@@mortenhansen3455 yes it takes a little click to get it out, which is the plastic grease guard on drive side doing it's thing

Yes, it isn't hard, but the difficulty comes when you run a fleet of 500 of these things for general public hire, pretty soon you get 3 hub lockups per week, the axle spins in the no turn washer, and screws the entire hub. In my opinion the designer of these hubs was smoking something weird.

@@freesocialrockclimbing haha yeah it definitely has some flaws :D

Check the springs on the pawls, they may be damaged, and not forcing the proper engagement. Check the length of the push pin, it should have 14mm of stick out Check the alignment of the indicator in the gear shifter clamp on mechanism @ gear 2 The gears should have a bit of white grease in them

I usually found that the quickest way to fix it was to strip it down to the bare mines, and reassemble, The strip down takes less than 30 seconds, the reassembly takes less than a minute, if you have your tools in a row. Look for extraneous broken shards of metal causing a constipated hub

@@AdamEdington Cheers mate! Might give it a go soon, but I am expecting the strip down and reassembly will take longer on my behalf ;) Thank you for your kind advice!

@@hunnicke1986 usually something is not moving as far as it should, or jammed up with some thing where it's not meant to be Push pin should have 14mm stickout

​@@AdamEdingtoncheers! I couldn't find the missing part/link/fault so I stick to 2 out of 3 gears for now 😂 Now I got a new problem. On an advice from a friend, I removed a lot of the thick chain grease I had used before (I am new to this and learning) and then I gave the whole thing Caramba Premium MultiÖil. Now the foot brake screams when used. What would you suggest to fix it? Put the whole thing in transmission oil (as I got recommended from a local bike mechanic)? 🙂

@@hunnicke1986 ok that makes a bit more diagnostic sense. I'm going to need you to run a few more tests for me It's a bit hard for me to do this remotely, but Test number 1 attempt to shove it into 3rd gear and wait. 5 minutes and try , perhaps give the shell a knock or 2 every now and then Test number 2 are you certain that it is actually gears 1 and 2 that activate and not 2 and 3 and 1 is sticky How far did you strip the axle down, did you take the bell housing off the axle ...this is what shifts the engagement If the grease is too thick, the springs don't have enough oomph to drive that the pawls, which still think the bell housing is in position B when the bell housing is in position C creating a double ratio lock where gear 3 is actually engaged, but gear 2 fails to disengage See description for correct lubrication

English Mi no habla Espanol

I do not speak spanish

The brake on mine is all messed up, is there a way to replace it with a different one?

@@simiken1234 sorry for the late reply, I only just found this question. Find another hub and cannibalize parts, but be ware of different axle lengths. Shouldn't affect breaks though

Use shimano white grease for breaks, Strip fully, wipe clean, inspect for foreign matter, broken bits of metal etc, reassemble, as per video. Can't go far wrong.

The matching cutouts in hub shell would need to be reversed as well

Dunno, it's years since I had a good look as I'm no longer volunteering there, cos I got a job

After several takes, and many bloopers, it was decided to strip out all the grease to clarify the shape of the parts

white shimano grease, do not use HTB... it isnt slurpy enough

keep yer eyes peeled for spring fragments jamming up the bell housing

@@AdamEdington Thank you Adam👍 I’ll let you know what I find.

@@AdamEdington If it is spring fragments, then I suppose I’ll be in need of a spring.

@@brythecracker the other source of fragments is the rim of the drive side bearing assembly with those opposing pals.this piece is very prone to shedding hardened(brittle) fragments into the works..

@@AdamEdington Thanks Adam👍

i assume you mean the brake reaction arm.... this goes on the non drive side

Get a off center sprocket At HSBC bicycle.com😁

Hbbc bicycle. Com

the most common fault in my experience running a fleet of 500, is for enough wear to open up some clearances... pin drops out far enough to let a spring drop out of the drive side bearing assembly , spring works its way to gears and gets munched, munched spring bits work their way into the bell housing, and it jams between 2 gears and locks the axle. once this happens, ya kinda know about it! next most common is for the drive side bearing housing to fracture at the thin lip and shed hardened shards into the works... same effect

@@AdamEdington Thanks a lot, Adam, and for the video which is excellent. Quess I´ll go for a total replacement - as usual:)

take it apart as per video, check that nothing untoward is going on, put back together, set bell crank between the lines on gear 2, and check the length of the push pin, 81mm or 86mm then get back to me

Adam Edington Thanks a lot. Will do. Awesome stuff.