Shimano Hollowtech II bottom bracket bearing replacement - hack

0:00[Music] thank you to get a French man to jump off a bridge you should tell him that it is for love

0:22to get a German to jump off a bridge you tell him that it's his duty but how do you get a Serbian to jump off a bridge you tell him it is forbidden here I have some Japanese bicycle parts and see what this label

0:43says do not disassemble this is Shimano Hollow Tech 2 bottom bracket and it's toast it's completely toast it turns very roughly and it's like a violin while you're right so it's

1:03way past its prime and Shimano says do not disassemble it however I pay the what shiman asked for this part and I think that it is Fair since they didn't pay me to do what I think that I should and my idea is to try to disassemble this and see if I can replace the

1:25bearing because everything else is okay it's just the bearing that's toast and I'm curious to see what will happen I have not tried this before in practice in practice on any bicycle or or anyway so this is a bit of an experiment to satisfy my own curiosity

1:46I'm not sure if it will be successful but I'll put a fail in the video's title and the thumbnail if it turns out to not be successful so we'll give it a go

1:59the first thing to do is to pry out these plastic covers they are used to they are pushed against the the the cranks when you when you put them on on these bottom brackets and so that's the first thing that we will try to remove and for that I am not sure if the

2:22bearing puller is the right tool but I will since it is plastic but I will first give it a go with the with the screwdriver and try to be as gentle as possible I'm trying to get it in

2:44no it's not working very well so let's let's give it a go with the with a puller and see how we fare if it will be destroyed or not so we need something to cover 24 millimeters diameter let me get a

3:05measurement tool okay so let's see this should be about 25 24 24 millimeters okay so this is the the tool for that and let's see if we can get it I've already made videos about how this bearing puller is used so I will not get

3:27into too much details but if you are interested I if I don't forget when I upload this I'll make a video about that pop-up in your top right hand corner so that you can see so here we have it set up and I'll try to use just my hands no not working okay as

3:48expected so we will need to be creative and to use some kinetic energy I already also have a video about physics kinetic energy and similar okay so it's completely out from the first go and it's not destroyed

4:09so this looks promising let me check is it not destroyed no it is destroyed as you can see it's broken it's broken it was catching on to this bearing and now I've completely ruined it okay so the bearing puller is not the

4:32right tool for the job let's see about using a screwdriver no this is too flimsy and it's getting damaged in a similar matter in a similar way but okay this one looks a bit less

4:54damaged let's let's compare them okay we will see if this will be useful when we put this back together Okay so that that's out of the way let's remove this tool we will not be needing it

5:17or we will we will be needing it for the bearings but first I want to see about this seal on the on the outside I'm curious to see if it is a part of the bearing or no this looks like something that Shimano put on top and here you can see

5:39the part where it sits let's take one of these that I had already disassembled let's check it out no I'm not sure we'll see when we take the bearing out what it's all about so let's put something okay so we have these parts and we have

6:01this and the the metal part sorry try to clean it the metal part goes to the inside towards the bearings and this part that has like a Groove if you can see it it goes on the outside

6:22Okay so that's that's we may be reusing this or maybe not we'll see about that so this is the bearing the outer side is pressed against the the shell and the inside moves though

6:43very roughly and you can now clean and lubricate this use some Degreaser to clean it and then wait uh rinse it and wait for it to dry and put some grease in it and then put this back but these bearings are ridden for too long in a very bad

7:03condition so I'm not optimistic about the the result of such an operation so we will try to remove them and see if we can replace them and what this does when it's in place it just sits there it does

7:25nothing practically as far as I can tell I'm not sure if it has any function to to turn but I think this inner race does all the work with this pressed against it and turning in unison and it has a

7:45bit of an reason Edge towards the inside to catch on the inside of the of the bearing here as you can see there's a bit of room here and that's where this gets caught so that it stays in place okay so that's for the for the bearing

8:07the same is for the other side so the same Principle as far as I can tell and let's try to pull this out

8:17this is also this will be 25 millimeters yes it's 24.99 so it's nominal 25 millimeters on the inside so this one reduces it to 24 millimeters that fit Shimano holotec 2 cranks so that's that's about it

8:40not the most precise measurement the way I did it but that should be it okay so let's try to pull this out so we can use this again

9:05okay it's nicely seated as far as I can tell all right let's give it a whack or two checking if it's moving

9:30okay we will have to use some magic all right I'm trying to align it

9:50so that the Vice keeps the outer edge in place and I can just work this out and so this is far from the the way to do it it's better to do it when it's on the bike this is a very bad hack so don't do as I do do as I say

10:13Okay so we've got some parts out I'm not sure where this came from we'll see okay

10:42let's put this back for now we may need it for the other for the other one and let's see where did this piece of rubber come from okay I know it's from my desk additional parts okay so the bearing is out

11:03and here it is so that was not a good way to take out the bearing I should have used something to keep it perpendicular and to keep it firmly in place and pull it out so uh should have done it on a bicycle

11:24so here is the bearing it's out and this is the the cup that holds it in place and so the

11:34the important things now to do with bearings is to measure the the inner diameter so this is probably 25 millimeters nominal size okay then to measure the outer diameter and that is in this case 37 millimeters so we have 25 by 37 and finally to

11:55measure the thickness this is six millimeters now we are coming we will come to a problem Shimano used six millimeter thick bearings bearing the tar 25 on the inside side 37 on the outside and uh seven millimeter

12:18thick are very easy to find these are those bearings they are very easy and very cheap and simple to come by even in my country but the ones that are six millimeters thick are next to impossible to buy you can probably store some from China and hope for a good quality and you can also

12:42order some custom orders and then they cost more than the the whole set of Shimano bottom bracket with cups and everything so I'm not sure if that was done deliberately to prevent you from making these are simple and not have to pay for more Shimano Parts but that's what it does in

13:03effect you can have problems finding the proper size bearings and so Shimano Road hubs are about one millimeter thicker this is 11.3 millimeters from the part detaches the frame to the outside so

13:25they are about one millimeter thicker compared to their mountain bike let's see where it's written mountain bike MTB or something mountains here this is their mountain bike Hollow Tech 2 Cup this is about one millimeter narrower thinner whatever so I cannot

13:46believe that there was not enough room here to place a bearing that is one millimeter thicker there is some room here as you can see on the inside from the from the this section to the to the to here so there is some material

14:06this is aluminum it's pretty soft but I think it might have been safe to machine it a bit deeper so that you can place a a thicker bearing but I'm not sure a good mechanical engineer would probably be able to calculate this and of course making this

14:27out of steel wood give you about 20 grams more of weight which is unforgivable in the world of cycling so it's better to have stuff that's less durable and and more expensive but let's see what happens if I try to install these seven millimeter bearings I am

14:48curious I've never done this before and I would like to see the results and how it would all align and fit and at this moment I don't have a bicycle frame to try these bearings in practice so after I I do this I will have to make a

15:12follow-up video but first I want to see if it looks as if it might work or if it looks all wrong right away and so I will try to install a bearing here before I installed the bearing this one

15:30has seals which are symmetrical on both sides and some bearings have seals that protect from dirt better on only on one side it's usually red colored and you usually put that to the outside and of course follow the the instructions and double check but

15:52generally not all the bearings have the same quality of seals on both both sides and so here I'm putting some mounting paste on the the cup and I'll also put some mounting say paste on the outside of this bearing and just to be sure and hopefully it

16:14will nicely slide in here it also helps to sometimes to cool the bearing a bit in a freezer but I don't think it will be necessary in this case just trying to to get it aligned as best as I can before trying to

16:34press it in okay this looks acceptable now let's give it a try with some so I need 25 by 37. okay this is the the right tool for the job it should go in and I also expect it to to go in

16:54smoothly it should be just slightly smaller diameter than the the copy as it goes in smoothly that's important but in this case this will probably this bearing will probably be protruding a bit out so that's not critical so we want the proper

17:15bearing press and on the other side let's see about something big this is about this looks to be about right and now let us try to

17:36to get this installed okay so trying to keep it parallel it's not looking bad okay

17:58let's give it a go it's going in very nicely very smoothly and I will feel when it bottoms out okay this is about right all right let's loosen it a bit and see what we did here

18:22Okay so this is how this one sits the seven millimeter bearing and let's compare it to the other one so we have one millimeter less of space here that's evident this is the the one we we are talking about from this house let's put this

18:42away to not confuse me okay so let's take this out and compare it okay so yes I'm not sure if you can see but there is a room about one millimeter and here it's almost flush

19:03we could even try to measure that so let's try to measure that how deep it is what does it say 1.69 okay let's see about this one

19:290.62 okay so about one millimeter less as expected so

19:36the first thing that I'm curious about is whether this will fit if I try to press it in okay it seems to be fitting all right and now let's try to put this on the the bearing that we've installed that is a bit wider let's see

19:57how that looks like first on a bearing that's outside of a hub over of a cup let's try to press one in without breaking it hopefully it's not going very easily okay please cooperate don't make my life

20:20hard okay so we are having a bit of a problem here but okay it went in and you can see the the lower lip is not protruding further out from the the bearing but it is held on firmly Okay so will that be enough for the the

20:42crank to slide inside and it rhymes hopefully the only way to really test it is to give it the to install it on a bicycle and give it a go and unfortunately that will not be so simple to do today let's try to get this

21:03out if I manage pretty stubborn okay

21:28okay so it's out try to clean it

21:50okay there it is and I'll just try to press it in this is plastic and it should slide in relatively easily okay and so now let's see this feels very smooth and it looks

22:12to be okay but again the only way to truly know is to try to install some cranks and see how this fares width with cranks so let's try to do the other one and then I will try to find the bicycle to install this and see see how they how they fare

22:35so that's uh the the first the first part of the procedure is successful but we still don't know if the patient will survive

22:47I'll I'll give this a go on my bicycle on the first chance I get and I will put it in the videos comment if if it is wall if you if it is successful or not after a few rides at least and then follow up after a year or so hopefully so for now as far as I can

23:09tell it looks promising and I'm yet to confirm about the durability uh as far as I'm experienced the Shimano holotech 2 bottom brackets are not nearly as durable as their Square taper brackets are when it comes to the bearing life

23:30and so pretty quickly you get some creaking scratching going the dirt enters and so you can pry off these plastic parts and clean them and lubricate them that helps if you do it right away but even with that they don't last nearly as much they last about one third of the lifetime of those Square tip or

23:52bottom brackets because there the bearings are a bit better hidden inside the frame sorry about that so the the bearing life is not not as good as with those Square taper bottom brackets where the bearings are more out of the way inside the frame and not sitting on the outside as they are with holotech two bearings

24:14and so these are not super expensive but they are not free and it's a lot cheaper to just replace bearings and that's why I was very curious to see if replacing the bearings will work and there was a time in my city where none of these were available to buy it happens quite often

24:35in in Serbia and so that was another reason why I thought it was a good idea to give this experiment a go and again I'm sorry that I cannot say right away all this is going to work I wanted to record the procedure and I will make a follow-up comments and maybe a video after I've done I've put them to the

24:57test to see about durability because that is the only real test even if I were able to use a computer simulated computer simulation to see about the load distribution and how this affects the affects everything which is beyond my levels of skills and expertise by the

25:18way even if I were able to do that the the real final test is when you put it on your bike and put it on some rough trails and give it a go after ideally one year or more so for now I can only say that this looks promising I cannot say that you should do this at

25:39home I cannot say that it's worth your time and effort I can only say that for me it looks promising and I will give it to go on my bicycle and then we will see what happens so that's it for today a bit of an unfinished video sorry to say thank you very much for watching I hope this was at least a

26:00little bit entertaining if nothing else and I will see in some other video thank you again for watching and cheers stay cool

26:11hi this video will in this video I'm not sure if it will be unfinished because I did manage to do what I was planning to do but it takes a few months at least of testing to confirm if it is a good solution the reason why I bothered is because

26:34Shimano holotec 2 bottom brackets are what I would consider to be the the least bad in practice of all the available Alternatives but their biggest downside is their durability compared to Square taper bottom brackets for example where the bearings are bit inside the

26:54frame not on the outside so that is their downside and I was curious to see if there their bearings can be replaced the cartridge bearings so that you don't have to buy the whole set of Cups and bearings and then just go and buy standard relativity bearings and make

27:16this last longer and so for now I still don't have the the right answer but I think that I have the the right procedure on how to do it with the bearings that I could find available so that was the the video and I will make follow-up in the video's comments after a while after having

27:37tested this to see how they perform perform in in real life but apart from their the durability of the bearings which is not very good the the holotech two bottom brackets do let you set the bearing preloads adjust it relatively simply and easily and they also

28:00don't have a if you don't buy some super light super weak cranks with the weak axle they don't have in and of themselves a risk of having some failures that are critical so that your cranks break and you get your foot lost and then lose balance and go in

28:23traffic or something so they are a lot simpler compared to square taper to inspect regularly open clean and check if they're spinning smoothly so those are their advantages and their disadvantage this is the the low bearing durability and when the bearings do get seized then they wear

28:44out the axle very quickly and so you should inspect these on a regular basis I would say once a month is probably if you ride a lot a good idea to be on the safe side and so uh the the manufacturers still have not designed a bottom bracket that

29:06is really really inherently safe and that when you neglect it the only downside is that you have a bearing that turns poorly there are there are all the systems as far as I know existing have some downsides that can cause critical failures only with these ones it's simpler to more regularly inspect and

29:27check for those they are very easily disassembled and reassembled again unlike Square taper for example that requires a bit of force and extra tools and so on so that's uh some explanation of why I or one more reason why I bothered to test

29:47this in the in the first place and I am already skeptical because the one of these two is not spinning very smoothly and so I'm not sure that I should even go with the experiment but I am a curious monkey so I will give it a try I'm not sure what effects how

30:09successful the the whole procedure ends up and how well you can preserve these plastic things and I've got my concerns and I will also I'm also curious to test them without this Plastics to see how that Works in that case I would get the same

30:31chain line exactly because I'm removing one millimeter effectively with this so but but this on the inside needs to be snug to fit the the axle so it will probably not work without at least this part and when I remove this seal it it spins smoothly and this seal is not really

30:54important because I've used the bearing with the seal so I will I will see how it fits on a bicycle when I mount it and and see how it fares in practice so but that is all I have for you today and thank you very much again for watching and I will see you in some other video

31:11cheers and stay cool [Music] thank you