Shimano Hollowtech II bottom bracket replacement / repair - part 2
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- Опубліковано 22 сер 2024
- Instructional video showing how to remove the Shimano Hollowtech 2 bottom bracket
Part 2: servicing of bearing.
Tools required: thin screw driver and grease
Top tip: it is not possible to inspect the ball bearing races, so if following greasing, the bearing does not run smooth, replace it. They are not expensive compared to other types of bottom bracket ( ebay suggested )
I agree with some of the comments about cleaning out the old grease/dirt but at the very least he's taught me to pull the thing apart. Good work!
Thank you, helpful video. Appreciated..... and to everyone suggesting get another because they are cheap ---- It's a good idea to clean, replace and reuse anything you can......... Eventually all manufacturing material will be scarce. Two centuries from now we will be remembered in history as the biggest wasters since the dawn of time. I'm going to clean mine up, not because its easier but because this guy just showed me how.
This is what I'm going to do next year when the Summer starts. Give my rig a proper grease on all linkages, bearings and moving parts.
I will never throw away another BB before its fully expired as I too hate wasting materials that have had a lot of resources to produce.
To all asking about "do not disassemble". It's not a good idea to remove the seals and put them back if you don't have the right tool. The manufacturer wants to avoid the responsibility from having their parts damaged due to removing the bearing seals. Once you remove the seals, water will get in much easier through the hold you popped, unless you are very careful and greased it properly with water repellent grease.
Thanks for the video. I will do mine too. I love the idea of taking things apart and clean up rather than buying the parts, especially the bearings are still good.
This is a good video, thanks for posting.
Shimano are very annoying using 24mm spindles because they actually use stock 6805 bearings that are actually 25mm ID, 37mm OD x 7mm wide (I think the OEM is NTN).
A 24mm spindle dia. is purely for patent purposes (Campag. use 25mm).
We have this bizarre situation now where all aftermarket BB (Hope, Wheels, Rotor etc) are using 6805N (i.e. non-standard bearing size because the inner race is 24mm not 25mm). I wonder if this why Shimano specify not to disassemble their bottom brackets so
1. You don't spot what they've done,
2. Realise you can buy an off the shelf 6805 bearing and fit that to the cup.
3. Use another BB cup and instead fit a premium 6805 (SKF, NTN, FAG, NSK with LLU seals, which are a fraction more expensive but last a lot longer) then stick a top hat insert in (e.g. Kinetic bike bearings for £4/pair).
Thus; this removes the need for you to ever buy complete bottom brackets again, you can leave the cups in the frame and press-fit a new set in without ever disturbing the actual threaded cup (or press fit cup-frame interface), plus you can throw your worn bearings in the metal recycling skip when you're done.
This is not quite right. Shimano 6805 rd bearings are 25mm i.d. The top hat seal reduces the diameter to 24mm to fit the spindle. They are 6mm deep, not 7mm which is the non standard aspect to them. You can fit standard 6805 bearings if you shave the small step on the underside of the top hat seal. But this will affect how the pressure on the outer bearing seal from the cranks acts with regard to bearing preload, given that the top hat seal isn't directly preloading the bearing with that step gone, only indirectly by compressing the rubber seal.
Glad for this video in that it showed me how the parts come out, and good tips on not damaging the rubber seal face. But I tried with thin screwdriver and could see how I was going to snap the outer seal.
So for anyone who wants an alternative, I found the best way was to use a small sharp very thin pointy knife (I used a global paring knife but maybe a swiss army knife would work) go in under the seal parallel to the top face, and then with the knife on a tangent to the cup surface, lever up the seal all the way around using the large surface area of the knife blade against the seal to make sure the pressure wasn't concentrated on a single point (which is the issue I found with the thin screwdriver) Seal popped out with no effort.
Then I did use a screwdriver for the inner seal lifting from underneath as the video.
Was amazed to find one set of bearings had totally seized with rust. Not my bike :)
Soak it in solvent (mineral spirits) overnight to get all the old gunk out of the bearings. Then dry and repack with grease. You have it apart, might as well do a proper cleaning.
@DBRising are mineral spirits citric acid based?
WARNING: Shimano changed the material they make the plastic caps out of it is now very brittle and almost impossible to get out in one piece. Best thing is to get a cheap aftermarket BB that uses standard 6805 bearings, once the cheap bearings fail knock them out (easy to do as the inner race is accessible) and replace with, high quality bearings from FAG, NTN, NSK etc. You get a high performance BB that will give a Chris King or Hope a run for its money at a fraction of the cost. Don't forget you will need 2x 1mm spacers for correct chain line on a road bike (Nukeproof sell them or you can use cassette spacers)
“Do not dissasemble” said Shimano 😂
Nice tutorial, thank you
Actually the Hollow tech 2 bearings can be serviced and add in new bearing balls in 5 minutes after removing the bearing from the cup with a hot air station or blow torch slowly going around the cup. To put back the bearing out it in the freezer for 2 hours then take it out and it goes in to the cup easily. These small balls don't last long you need to do a full service which is to replace the balls.
if anybody wants to know, the bearings size for shimano a kind of rare, they are 25X37X6....not the more common 25X37X7....you can find the 6 mm width version on ebay however but just watch out for the size since both of these version are unfortunately numbered 6805
Bearings are 6805N (N for narrow, 6mm)
"do not disassemble" yea right! :) thanks for the vid!
You can actually replace the bearings...
Bearing #6805.
It's cheaper than buying the whole SM-BB52 set. A very good Japanese or USA made bearings about just 20% of the cost. And i have been doing that several times already.
Just make sure you're best or very good or at least good in pulling out and pressing in the bearings so you don't damage the housing.
Good old Filipino ingenuity.
+Joel Cartujano people here are obviously lazy, or not mechanically inclined to do a service, or both. Shame how we just wanna throw everything away, constantly replace what was well and good. i guess that's our society. Though i woulda thoroughly cleaned those bearings 100%, but that's me.
Oo good to know. I bet I could find some ceramic bearings for not too much. Not worth it to spend $100 on a ceramic bottom bracket, but if I could find the bearings themselves I'm sure it wouldn't be too bad.
Mate, am planning to rebuild my bb70, do you know which bearing number i can use?
Take note that this 6805 bearing size is not a standard 6805 bearing size. Shimano one is 6805 RD, which is 1mm thinner than standard 6805.
Also it has a little lip groove on inner race for seal lock retention.
These 2 factors make it not so ideal to interchange from industrial bearings
Don't rule out replacing though, because now it's 2018 and companies like Enduro sell stainless steel angular contact bearings, which are much better than the standard rollers you're re-greasing here. They handle side loads much better when you put the preload on as well as the bearing loads are put on the middle part of the races where it should be instead of the balls being pushed out toward the edge.
U can also use brake cleaner and compressor to clean bearing or just replace old ones.
Let sit in solvent
Blow out with compressed air
Repeat till clean.
Add small anount of grease
Blow out with compressed air
Test bearing integrity
If both are fine
Re pack with grease
Reinstall
Done.
This guys version is ghetto
These are they guys that are dangerus and expensive.
Shop fleecing system hard at work.
yeah, definitely didn't remove the sand, metal and degraded grease that is the problem. He did do a decent job of adding grease though, but it should have been labeled as that since once you have it apart you should get the problem grease out. I've used Simple Green solvent but maybe something more aggressive will work better. would Dawn work out?
its actually a re-lubrication of the bearings, not at replacement ;) i expacted you show how to get the old bearings out a shimano bracket. but its a nice video to maintainance the old bearings. thanks :)
www.ebay.co.uk/itm/Tool-for-Hollowtech-II-bearing-puller-press-BITUL-/282369023573
Something to consider, if someone wants to do it an actual replacement.
Excellent video,worked like a charm.
a hack is recommended to press the seal out and press it back in a reversed manner (front side of the seal is open while the back one has a prptector). thus, the lifetime of the BB will be extended and better sealing effect will be achieved
Will try this on my older bearings, got some new ones arriving soon so no risk if I mess up
You could have clean the bearing using some degreaser to remove dust particle attached into it before just adding grease into it.
Apparently you got to be super careful with degreaser and make sure its ALL removed before applying new grease, which is a nightmare for humble beginner
yes 30$ is not the world but they claim that you should replace them each 5 000miles and if you make 10-15 000 miles a year thats already 90$ a year... it starts stacking up... and some others like truvativ bb comes 50$ around 150$ a year. with re-greasing it doesn't do any harm to any bike part soo why not? and usually it it will last 10 000miles+ before bearings really wear out...
No. the bearing should have 1/3 the internal spacing filled with grease not 'as much as you think is reasonable"
I tried to lever the cap of gently as shown in your video but ended up snapping part of it off, any tips on how to do it properly?
I'm pretty sure I have the same style BB as you, mine is a BB-RS500.
ty i was having problems on how to grease it coz it say do not disassemble it
he-he, on the bearing body itself it is written "do not disassemble"
Siempre se aprenden cosas,muy bien.
So you disassembled the bearing, while the label "do not disassemble" clearly pointed towards the camera. I think the idea is that the bearings are saled, and you should replace them, rather than trying to add grease.
That said, thanks for the helpful videos.
No degreaser ?? If there was any dirt you just pushed that in with the rag.
It's not like you have to clean it in the exact way he showed...
Thanks so much for the video.
That plastic spacer came out too easily. Must have already serviced these bearings a few times.
Specialized rear bearing systems
I Broke the seal lifting the cover, just an fyi
Is it possible to remove the bearings completely from bracket and install new set of bearings?
Artūras Baranovskij its 10euro for a new set search for SM-BB52
+Artūras Baranovskij You can actually replace the bearings...
Bearing #6805.
It's cheaper than buying the whole SM-BB52 set. A very good Japanese or USA made bearings about just 20% of the cost. And i have been doing that several times already.
Just make sure you're best or very good or at least good in pulling out and pressing in the bearings so you don't damage the housing.
Good old Filipino ingenuity.
Original bearings of BB51 have a label 6805-RD, size 25x37x6. There are a
lot of offers in ebay for 6805, but most of them have size 25x37x7. It
means they are 1mm thicker. When you put them back in the bearing's cup
You can't place that plastic top cover back any more. It sticks out a
little bit. This is how I damaged it. So whether you are ultra cautious
whether you buy 25x37x6.
P.S. There is no point to buy BB51 as the metal of bearing balls is unbelievably rust addicted. I guess BB52 is not really different.
Clearly stated on the bearing housing "do not disassemble"
lol
+Dan Henderson well, with experienced mechanics. Industrial component can be disassembled and back without lacking any designed feather.
+Dan Henderson That's because they want you to buy another one from Shimano instead of cleaning and getting new grease. First thing I do with my bike i look if it is possible to repair by myself, if not than buy new one or taking my bike to professional service near my city.
As you can see, it can be easily disassembled, serviced and assembled back without any damage. So Shimano just wants us to buy new bottom brackets)
***** The newer version of the Bottom Bracket simply can't be disassembled at all. However, if we do keep it clean mostly, there is little needs to open it up.
How much newer (2016)? I've just serviced BB from 2015's XT chainset (M785 double), it was exactly the same inside as in this video.
Péssimo serviço, tem que aprender muito. A graça Velha tem que ser retirada.
tried it with a tiagra bb4600 but to no avail. it's stuck so tight, it seems to have been glued of some kind.
No limpió los balines con gasolina , o algo lo que quieras...!
Thanks for the video’s
can you take the whole bearing apart?
Yes you can, I've done it several times where I remove the whole bearing from the housing and then remove the balls from the outer and inner rings, clean them, check for dents and most of the times if you haven't used it for more than a year, the ring grooves are still very smooth. I'll prepare a video to show the process. You don't need special tools to accomplish it.
Me also i have tried removing the bearing from its housing. I specialy use TOP1 water resistant grease to repack my bearing with new grease
Are there only bearings on one side???
no
do you know what is the size for the bearing? i believe the bottom bracket for road bike?
Quality bearings from a bearing shop will cost almost the same as the cost of a new BB, unless you buy some Chinese junk bearings. It's generally not worth replacing just the bearings.
I wonder why your bearing cups say Do Not Disassemble? Could it be that there is a special bond holding the bearing shields in place?
Bottom.brackets are perishable parts aren't they? They're not deigned to be serviced over and over and reused?
+Icecyclist
Do Not Disassemble
So you need to buy the whole set
+Icecyclist
You can actually replace the bearings...
Bearing #6805.
It's cheaper than buying the whole SM-BB52 set. A very good Japanese or USA made bearings about just 20% of the cost. And i have been doing that several times already.
Just make sure you're best or very good or at least good in pulling out and pressing in the bearings so you don't damage the housing.
Good old Filipino ingenuity.
+Icecyclist "Do Not Disassemble" is synonymous with "Buy More Things From Us".
Diesel That's correct, it's just a marketing ploy for people to buy another bb.
Nice work
Those are currently 9e online to buy, im not sure when you made this video,im guessing 15 yrs ago. But is it actually worth doing this now considering the low replacement cost.
+Kiwifix
You can actually replace the bearings...
Bearing #6805.
It's cheaper than buying the whole SM-BB52 set. A very good Japanese or USA made bearings about just 20% of the cost. And i have been doing that several times already.
Just make sure you're best or very good or at least good in pulling out and pressing in the bearings so you don't damage the housing.
Good old Filipino ingenuity.
What type of grease did you use or recommend?Lithium, waterproof, marine, auto wheel bearing grease?
Damn. Whilst prising the outer cover off with a flat bladed screwdriver I cracked it. It's really fragile and I've no idea how it came off so easily in the video. Be careful out there people.
@DBRising Good excuse for an upgrade I suppose 😄
Someone needs to come up with a hack to replace those with sealed bearings.
hmmm. degreaser and some cleaning should of been done.. that or just replace it. they're 30$
My bearing cover was fucking brittle and i sliced my hand open with the screwdriver trying to pry it off
Thank you, very helpful video!
What to do when have a bit slack on it?
Replace the bearing.
would anyone know the size of the bearings for the new version SBB 9000?
Interesting how the bearing housings clearly say, "Do not disassemble."
+Salina Bicyclist
Do Not Disassemble
So you need to buy the whole set
+Salina Bicyclist
You can actually replace the bearings...
Bearing #6805.
It's cheaper than buying the whole SM-BB52 set. A very good Japanese or USA made bearings about just 20% of the cost. And i have been doing that several times already.
Just make sure you're best or very good or at least good in pulling out and pressing in the bearings so you don't damage the housing.
Good old Filipino ingenuity.
He dared work on something I consider trash, and should be thrown away! How dare he. Come on moron, "do not disassemble" and "no user serviceable parts". Is just business speak for 'I'd really like if you just bought another'
OK--Even if you clean the bearing well---you still have a WORN clean bearing.
if the crank isn't sloppy, run it
Seriously? Just adding more grease to your already contaminated grease is a terrible idea. You haven't even replaced the bearings!
Just buy a new bottom bracket. They're $30.
he should at least remove the bearings and completely strip out the old grease.
but yeah, at a tenner (GBP) you may as well replace the whole BB
+David Fischer
You can actually replace the bearings...
Bearing #6805.
It's cheaper than buying the whole SM-BB52 set. A very good Japanese or USA made bearings about just 20% of the cost. And i have been doing that several times already.
Just make sure you're best or very good or at least good in pulling out and pressing in the bearings so you don't damage the housing.
Good old Filipino ingenuity.
+David Fischer Why would you waste $30 on an ENTIRE bottom bracket, when all you have to do is service the old one by re-greasing the bearings? This generation..
The fact that he's not even bothering to remove the contaminated grease and replace the bearings is not addressing his issue.
And I'm older than you think... ;-)
Gracias!
Do not disassemble.
A new bottom bracket cost between S22 for the Ultegra and $32 for the Dora - Ace on ebay so why on earth take a chance on such a critical part instead of replacing which is done so little? Not worth it.
numbers quickly add up when it comes to bikes. I've serviced my UN55 BB several times, they are not even supposed to be disassembled but I do, I;ve had it for 10 years and did 60 or 70000 km with it, not because i couldnt buy a new one but out of curiosity, to see how far i could push it.
+Drew Labat Why would you throw away a $32 part that will end up in landfill, to buy another, when you can service the bearings yourself? What ever happened to self reliance? You do know that this is how bicycles have been for decades, with square taper cups and cones..? Every year or so you clean out the cups, re grease the bearings and you are good to go for another year. Disposable cartridge bearings are a new and totally unnecessary phenomenon, marketed to you just to make the company more money.
Because it is easier to clean old bottom bracket than it is to buy, deinstall and install the new one + you will safe the money.