External ”Hollowtech” bearings or square tapered cartridges?
 

Hi everyone!

As the title says, but I’m thinking about the durability factor.

A crankset/bottom bracket similar to my actual ones (currently SunRace FCM918 with Shimano UN-BB26, looking for a Shimano FC-T4060 with Shimano BB-SM52) is about 2.5x more expensive here in Brazil. Is it at least as durable as it costs?

I like that Hollowtech is easy to take apart for cleaning so ti gets cleaned.

Well, I've replaced a cheap cartridge (Chin Heur) after a few K miles with a UN55 that probably has 5K miles on it and running fine. I probably have 10K on an 105 BB5600 HTII bottom bracket that is running fine.

Either one should give years/miles of trouble free service unless you're riding in very extreme conditions.

I would forget the UN 26 and step up to a UN 55 for a few more $$

If you would post in your native language then respondents could understand you better and you would receive more useful replies.

For the numbers of external to shell bearings (Hollowtech) sold and their relative mid to better grades (as they are on more expensive bikes typically) I will say that we replace a lot. For the most part these are not really rebuildable and are regarded as disposable by the industry.

The tapered square BBs seem to be of better sealing in general and don't wear as rapidly. Especially since they are so much more common at the lower cost levels one might think their longevity should be less then external units. But our experience doesn't prove this assumption out.

I'm sure others will have their opinions, perhaps they can offer some ideas as to how many they see a year:) so we know the foundation their opinions are based on. Andy

Just curious, How do you know what their native language is?

After faffing around with a White Industries square taper BB (a good, but rather expensive one) for a couple of years, I went back to the $18 Shimano Ultegra BB, and it felt the way it does when I stop hitting myself in the head with a hammer.

@Andrew R Stewart: sample size = 1.0

Edit: I just remembered my Crampy square taper BB survived about 35 years of malignant neglect.

I have a Shimano SM-BBR60 here with +15k miles on it, installed on it's third frame. Bearings are still smooth.

And even though no one asked, a BB-UN26 square-taper is 355g, while the aforementioned BBR60 is 77 grams. That's over half a pound.

Not sure what your problem is, but everyone else understood it just fine.

I’ve multiple thousands of miles on Ultegra and 105 level HollowTech b-brackets. They are easy to install, the spacing is dead on with the matched derailer so the shifting is easier to setup and are generally a ton easier to install and/or service than a square taper.

maybe a Russian troll spreading negativism prior to the elections???

I'm with Andrew the external bearings, while they brace the BB spindle better, seem to have a shorter life.

It may be because they are not as well protected, particularly from front wheel splash in wet conditions.

Mark Petry
Bainbridge Island, WA USA

My experience with Shimano HTII external bottom brackets has been very good. I have two BB6700 (Ultegra level) bottom brackets mounting FC-5703 (105 level) triple cranks with over 25,000 miles each and still in excellent operating condition. These bikes aren't ridden in rain or snow if I can help it but they have gotten wet and splashed a number of times with no apparent problems.

Sample size = 2 but success = 100%

To make a fair comparison you would have to include the weight of the spindle, which the BBR60 does not have but which is part of the BB-UN26.

Not all those Campag sq tapers were created equal....the worse are Campagnolo AC-H units, they go to gravel inside fast. Just junk. Then again AC-H was the cheaper Campag.

An era-appropriate square-taper crankset, like an Ultegra 6500 or DuraAce 7400, would both be 650-670g including fixing bolts. An Ultegra 6800 is 677g, and a DuraAce 9000 is 615g. The net savings is well over 300g.

Even an economy crankset today will be at or under 800g, which with a ~80g BB is still lighter than a higher-end square taper crankset from 20 years ago.

Hambini says a poorly aligned BB shell will cause premature bearing wear. Does a square taper cartridge unit isolate from those imperfections?

To a degree yes. However the shell faces are also about getting the BB (whatever type) securely tightened. A shell with cockeyed faces won't allow the BB RH (usually the RH) side to fully snug up and thus might loosen during use more readily. The other possibility with really off faces is that if the BB cartridge is fully torqued down before the LH locating ring (what most will call a cup even though it's a cylinder) the LH end can drift off center and make installing that LH ring rather hard. This is one reason why I'll not tighten the RH side completely before the LH side is installed. Andy

Thanks everyone for the quick answers! I’ll try to answer each one individually.

Square tapered can’t be taken apart for cleaning, but they look more sealed too. The square BB I’m replacing is 10-year old with about 12000km on it and has no contamination visible, even after breaking it apart.

The reason I’m replacing it is because it’s got some play and misalignment. As I’m still overweight, with 114kg (down from 157kg, all 43kg lost on this BB), I’d thought about upgrading to Hollowtech, if the durability factor worth it.

Unfortunately, UN55 isn’t available here. Also, I’ve only found SM-BB52 Hollowtech, so my choices are limited.

I don’t ride extreme, but I guess my weight still makes it kinda “extreme-y”, so to speak...

I’d already posted on local sites/forums and, despite some useful replies, most of it was like “Hollowtech is better because it’s newer” or so.

BikeForums’s users have my respect on this regard, as I always got useful answers. That’s probably due to a broader audience, and to reach everyone the common ground is English, so be it.

Please, don’t read that in a rough tone, that’s not my intention. I just couldn’t think of a better way to write it.

Thanks for your advice! That’s exactly what I’m looking for. Now let’s look for a Hollowtech opinion...

I’ve told I’m from Brazil on the first post. But please, I don’t speak “brazilian” (or spanish, for that matter): we speak portuguese here. 😁

Geez.. 35 years? My old Shimano UN26 survived “just” 10 years and I’m already thinking that’s a lot!