MyRedTrek

I'm going to service the bottom bracket on my Trek Verve2 hybrid. I don't have any reason to think it's trashed and haven't had problems with it but I'm curious if there's such a thing as an upgrade BB or is what's on there likely as good as I'll ever need or want for this particular bike?

J.Higgins 

I'm not saying this to antagonize you, just curious why you want to service it or haven't had any problems with it.

Now that I got that out of the way, swapping into any new sealed BB of the correct size would be a way to upgrade what you have in there. In fact, you probably have a BB that is one of the lesser-known component brands, probably Chinese. I could be wrong of course, but it probably is not a Shimano. If its not a Shimano, then installing a new Shimano would be the way to go, but honestly - let it go for a while. A BB will last quite a while if you aren't putting 100 miles a day on it, and I think its safe to assume that you won't be doing that kind of mileage on a Verve. The next step up from this would be ceramic bearings, but that would be way overkill on a bike like that.

sch

Here is the OEM BB: https://www.trekbikes.com/us/en_US/e...ket/p/1040693/
which at $12 is about half the price of the Shimano 300 series equivalent, which itself is half or a third of the price of "high end" BB. As J Higgins states, there is no
reason at all to change the BB until it gets noisy, which typically is somewhere between 5,000 and 20,000 miles. You will need $20-40 worth of tools to R&R the BB yourself.

Crankycrank

I have to ask what are you wanting to achieve by "upgrading" a working BB. There's really not much to gain by replacing it with anything else. Sure you get get more durable, lighter, maybe nearly imperceptible less drag when riding but but your bike isn't a lightweight speedster as is. Not throwing an insult at your bike by the way, just can't see any gain in shelling out more money for something not needed.

Rolla

The bottom bracket is probably the last part I'd needlessly "service," but there are several square-taper cartridge units that I'd consider an upgrade. The Shimano UN300 is kind of the standard, but if you really want to throw money at this bike, get a Phil Wood .

Iride01 

To answer the thread title... only if you are going to change up the gearing on the crankset or want a change in crank length or some similar thing. Then by being amicable to change out the BB to a different type, you open up many more choices of what crankset to get.

Otherwise, there aren't going to be any short term gains to changing a BB out. IMO

If you need to tinker, then take it out, clean it up. Assuming they are sealed bearings, if the seals can be removed on the bearing and you can see inside, then you'll probably see clean grease and wonder why you went to the trouble of taking it apart. But at least you'll now know how to remove and install that crankset and BB. Hopefully messing with it didn't cause it to have a shorter life.

icemilkcoffee 

The direct answer to the OP's question is yes. The current state of the art is external bottom bracket bearings, with hollow axle cranksets.

The external bottom bracket is better than the traditional internal bearings BB because they are more outboard, and support the crank axle better. They are also larger in diameter, so they are more durable. The larger diameter also allows you to run a hollow axle crankset. The larger diameter hollow axle crank is lighter and resists deflection better. The crankset is also easier to remove without the use of any pullers. The right crank arm is integrated with the axle, eliminating one failure point.

MyRedTrek

A desire to tinker is part of it but it's been in there unexamined since I got the bike. Won't be able to see how things look until I look at it. I've seen at least one YouTube video showing a sealed cart being disassembled and relubed. If nothing else I can take this one to the Trek place and get a replacement and have one refurbished and ready to put in a couple of years down the road, or maybe rotate them once a year. Two carts that are kept cleaned and lubed might last the life of the bike or me.

Bill Kapaun

They are a cartridge. Basically UNSERVICEABLE!
Labor to service would be several times the cost of the part.

Quite worrying about what if's and learn some basic skill/thought processed.

hokiefyd 

I think you have more to lose here than you have to gain, unless you're talking about replacing the crank with a 2-piece crank as suggested earlier. The more you remove and reinstall a square taper crank arm from its square taper spindle, the more chances you have to over-tighten and "egg out" the taper in the relatively soft aluminum arms. Every time you remove and reassemble moving components of a bike (like the cranks especially), you chance introducing a click or tick or other unwanted noise where there once wasn't any. The OEM VP bottom bracket is likely a pretty high quality item (relatively) and will very likely last many thousands of miles. The bearings are internal, they're sealed, and they're protected from the elements. They'll happily spin along encased in their cartridge housing inside that bottom bracket shell.

Unless you're getting noises already from the crank area, or feel grittiness that you can confidently attribute to the bottom bracket bearings and not to the pedal spindles (which are often too tight from the factory), I'd recommend not removing it.

MyRedTrek

Apparently not.

Bill Kapaun

You obviously have NO CLUE about what "Basically UNSERVICEABLE!" means.
IF you want to spend an inordinate amount of time on an "iffy" repair instead of $13-20 for a new one you certainly have my permission to be an idiot. I simply don't see YOU being successful considering the nature of your questions/apparent skill level.
IF you have the tools/ability to do THIS job, your time can be much better spent elsewhere.
Ignore list because you never seem to make an attempt to THINK.

Rolla

WTF is wrong with you? I don't know if I've ever seen you offer anything but criticism and insult here.

Please add me to your ignore list too, you contentious wanker.

John Valuk

I've seen that video, and that general style of BB was what my 1995 Trek hybrid came with.

I think you will find that fairly modern cartridge bottom brackets are not put together like that, but will instead have bearing cartridges.

Some of them (e.g., some of the models from Interloc Racing Development) can reportedly be serviced by replacing the bearing cartridges. I haven't tried doing that myself.

cyccommute 

Although I don’t agree with the way Bill Kapaun’s delivery, his message is correct. It’s just not worth the effort to disassemble and reassemble a cartridge bearing. They are just too cheap. Nor is there any reason to “service” one. They last roughly 90% of the life of the sun. Even at my local co-op, I’ve seen only a few truly buggered ones. The vast majority of them are reusable and we often use those to replace chewed up loose bearing bottom brackets.

Personally, I’ve only ever had one cartridge bottom bracket fail in 30+ years of using them. That one was recently and was actually a Chris King unit. It was easy enough to service and worth doing so. But it took a lot of miles (around 10,000) to get to that point and the unit is worth service. A $12 bottom bracket simply isn’t worth more than just replacement.

MyRedTrek

He seems like a jolly fellow - lol. Clearly a Dale Carnegie devotee.

Pity him - he's going to wake up as himself for the rest of his life.

3alarmer 

....everything you have written in this post is subject to some debate. Outboard bearing setups are certainly lighter.
But in actual practice, they often end up with a shorter service life than a high quality, sealed unit inboard bearing BB setup.

A lot of this depends on the quality of the original components/bearings, how well they are sealed, and individual usage. So it's not a real easy comparison to make.

But the idea that outboard bearing setups are inherently a "better design", because they support the crank spindle "farther out", is dubious, at best. Sorry, but you have been sold an idea that is more complex in actual practice. The biggest problem with outboard bearing setups is getting the bearing cups installed perfectly parallel. But there are other issues with them as well.

I have had this discussion before with someone who had strong opinions on the matter, and who no longer posts in the mechanics forum. He was absolutely convinced I was wrong on this as well, so I don't really expect to convince anyone. If I thought outboard bearings were inherently superior, I'd probably convert a couple of my bikes.

MyRedTrek

Yeah but now I *have* to do it just because I know it'll really, really bug old Bill.

But seriously, yeah, I like to tinker, I got the tools a long time ago when I first got the bike and want to take a look. If it looks obvious that it's in solid shape, spins smoothly and isn't as easily re-lubable as the one in the video I'll measure it, make note of the model and put it back in.

I re-lubed the brand-new Shimano hub I just put in with my new 36H rim because the transparent factory lube seemed sparse. Prior to that I cleaned and re-lubed the original rear and front bearings - they had factory lube but it was getting gray which means metal particles. I've also cleaned and lubed my aftermarket pedals - a couple of times. Used Park PL-1 for all of it.

ThermionicScott 

None of the UN26/55/300 bottom brackets in my collection can be taken apart like in your video. On the plus side, they all have some kind of additional seal outside of the cartridge bearing that helps longevity. I'd suggest that if the crank doesn't have any play or rumble when you manipulate it with the chain off, just leave it in until it develops symptoms.

John Valuk

You may already know this, but I'll add this comment for the amusement of those who might not.

The UN55 - and some other Shimano bottom brackets similar to it - have sort of an interesting construction. They don't use pressed-in / pressed on bearing cartridges like most modern designs, but they also don't have any adjustable cup-and-cone aspect to them. The magic is all in the bearing surfaces that are machined into the body and the spindle.

This thread - Repacking a Shimano BB-UN55 - has a PDF in the opening post that covers a teardown of one of these, with pictures.

This cutaway is not a picture that I took. It's one that I found online that someone claimed was a UN71:

cyccommute 

Shimano hubs and most pedals are different. Almost all Shimano hubs are meant to be rebuilt. Some aftermarket pedals are meant to be rebuilt (but don’t need to be all that often). Others pedals use cartridge bearing and don’t need to be rebuilt not really serviced.

Most anything with a cartridge bearing doesn’t need service. Ride it until it seizes and replace the cartridge. The interval between replacement of the bearings is going to be a very long time. All of my bikes (all 10 of them) have cartridge bearings in the hubs, headsets, and bottom bracket. I have seldom had a cartridge bearing fail. The Chris King above is one of maybe 5 bearings that I’ve had to replace or service in 25 to 30 years of using cartridge bearings.

I like to tinker as well but I’d rather upgrade the components of the bike over doing maintenance…especially maintenance for no reason…on my bikes. You have other threads about wheel building. That’s kind of the ultimate tinkering. Build wheels for your bike if you are unfortunate to have only one. Build winter wheels and summer wheels and wheels for your relatives. Become the zucchini guy of wheels. Build them and leave them on neighbors porches.

Or, better yet, find a co-op where you can tinker on other peoples’ bikes.

cyccommute 

Your argument is like the arguments about steel vs X, where X is any other material that will aspolde because it isn’t steel. Lots of people have said that the original cartridge type bearing like the ones Shimano uses failed “all the time” when they came out. They didn’t in my experience. The same people said the same thing about ISIS bearings. They were equally wrong in my experience. They have said the same about external bearings and, again, they are wrong. I have had dozens of both ISIS bearings, cartridge bearing from various manufacturers, and external bearings. With the exception of the Chris King (an external bearing), I have never had a cartridge bearing of any flavor fail even with 10,000s of thousands of miles on them. I still have 2 bikes that use ISIS bottom brackets that are spinning just fine. The rest have external bearings and have never had any issues despite the fact that I have done nothing extra to the frames to ensure how parallel the bearings are.

From the standpoint of external bearing cranksets, they are far simpler to install and remove than any other crankset. They use fewer tools and can be easily removed in the field. The same can’t be said about either ISIS or square taper.

3alarmer 

...it's difficult to say from this whether you are agreeing with me or disagreeing with me. Which is about what I have come to expect from you. Thank you for yet another opinion. We all have them.

hokiefyd 

Yes, I think you'll find this to be the case. Despite RJ's video title, that's not really a sealed cartridge bottom bracket. It's a low-end Tourney group bottom bracket that's sort of a hybrid of the old cup-and-cone and what ended up being the standard design for square taper -- a bottom bracket with true sealed cartridge bearings. These usually feature cartridge bearings that are pressed onto the spindle and/or into the steel housing, effectively making the thing one unit. You may be able to prize up the rubber seal on one or both cartridge bearings to squirt some oil or grease in there, but you almost certainly won't be able to disassemble it like in RJ's video.

Don't forget to grease the bottom bracket threads before reinstalling it, and don't over-torque the crank arms.

cyccommute 

It doesn’t matter what kind of bottom bracket is used. With the exception of loose bearing bottom brackets…of which, I have destroyed many…no bottom bracket type is better than any other one in my experience which includes 10 years of working on very marginal bikes at my local co-op. External bottom brackets are far better in that they are simpler to work on. They are a bit like threadless headsets…fewer steps, fewer tools, less that can go wrong.

Just to be clear, I disagree that there is a problem with external bottom brackets. They last as long…in my personal and co-op experience…as any other bottom bracket. I would…and have…use a used external bottom bracket for my own bikes.