yannisg

Has anyone have a rough estimate how long the DuraAce Hollowtech brgs last under normal usage and maintenance.
I remove, clean and apply anti-seize to the threads after riding in heavy downpour. Riding in a relative dry climate so the BB doesn't get soaked very often.
Noticed that left brg has a slight drag when rotated by hand, but I cannot feel any resistance once the crank is installed. New brgs run smooth by hand.
Since the BB set is not very expensive it wouldn't pay to replace the brgs even if that is possible. Shimano notes do not dis-assemble.

Any info is appreciated.
YannisG

FBinNY 

There's no easy answer except to say thousands of miles. User experience is all over the board, because there are so many variables.

OTOH you seem to be doing fine so far, so I'll guess it'll last un til it wears out.

yannisg

FBinNY
Thanks for yr response.
YannisG

HillRider

There is no reason to remove the bearing cups after every rain. If you grease or anti-seize treat the threads once that should last until the bearings themselves fail and that should be a long, long time. The slight bearing drag is very common and usually most of it is from the seals.

Enduro sells replacement bearing cartridges in various grades and the tools to press out the old and install the new cartridges. These tools and replacement cartridges are so expensive that I can see no justification for not just buying a complete Shimano bottom bracket set when the bearings do eventually go.

yannisg

HillRider,
Thanks. I didn't think it would be worth it replacing the brgs since the BB is not that expensive. However, there are equivalent BB with ceramic brgs on the market, but are very expensive. Are they worth it?
YannisG

HillRider

Yes, they are very expensive and, no, they are not worth it. The amount of power saved by ceramic bearings is trivial.

This issue used to come up often when ceramic bearings first appeared on the bicycle market. Their partisans (i.e. those who had spent an absurd amount for them and had to justify it) made ridiculous claims for their benefits. Reality finally had it's day and that debate has more or less gone away. So, yes ceramic bearing do offer reduced drag but the savings are so small that it takes delicate instruments to measure it and actual riders will never see any advantage.

Eric S.

It was only after reading all the responses to this thread (which we all should do before responding...) that I figured out what "brgs" meant.

Kimmo 

Hollowtech II hasn't been around all that long, but I've already seen quite a bit of HTII carnage... the longevity is often a fraction of square-taper.

Worst one was on a cheaper set with the aluminium spindle (oddly, it's the nicer ones with steel spindles), and the guy had ridden it pretty far with the pinch bolts loose... although I was able to get it to hold for a while by ditching the plastic bit from the pinch slot and cranking up the bolts until the gap was almost closed...

But far more common is fretting of the spindle where it sits in the bearings. Which seems a bit counterintuitive, since there's a plastic sleeve between the spindle and the bearing cartridge, so it's the plastic wearing the aluminium or even steel away... hard to imagine that happening, but I've seen the results plenty of times. I'm not sure this is inherent to HT II; it might just be that this is just a result of insufficient preload, and/or unfaced BB shells, when it isn't brought on by another 3000km on worn and sloppy bearings.

For whatever reason, the bearings can die fairly young - if you want to preserve the crank, replace those puppies as soon as you can feel play in the BB.

HillRider

Well, riding with the pinch bolts loose is like riding with the crank bolts loose on a square taper crank. Either one will ruin the crank.

Barrettscv 

I prefer to change out lower cost components before they become a problem.

Should a user just continue to use the Holletech II bottom bracket until it fails? what are indications of wear?

rmfnla

Yeah, but just think of all the vowels the OP saved...

Jamminatrix

What model Shimano Dura-Ace BB?

Shimano really has two versions of Hollowtech II BB's...the larger diameter (original) ones and the smaller (newer) diameter ones. The older style is still used on lower end models like Sora and Alivio.

Old:

New:



The older style larger diameter ones don't last very long because they are sealed like absolute crap. The bearing itself does not have a normal bearing shield pressed between the races, instead relying on a rubber shield sandwhiched between the plastic adapters aluminum cup.

Mentioned in a post above by HillRider, Enduro makes bearing kits. Enduro claims the extended life comes from larger diameter bearings withstanding load forces better, but that isn't the case (as Shimano went to even smaller bearings on the new BB's, which disproves this). The longer life with the Enduro kits actually comes from the fact the Enduro kit has real seals which do a much better job of keeping water/debris out.

The newer, smaller diameter Shimano BB's seem to be shielded slightly better than its predecessor.

Barrettscv 

What is the durability of the SM-FC6601 in wet conditions?

HillRider

What do you mean by "doesn't last very long"? I have two old style HTII bottom brackets (BB-6700) that have 9,000 and 10,000 miles on them so far and are still in perfect running condition. That isn't 50,000 miles (at least not yet) but it certainly isn't premature failure either.

andr0id

The Enduro stuff doesn't work with the latest generation of Shimano BB cartridge bearings.

But as OP stated, they're cheap, even the DA can be had for about $30. So just replace it if it gets rough or dry feeling.

Crankycrank

For anyone that has the Hollowtech BB. Instead of waiting for it to die you can pry off the seals, flush, re-grease and install seals. Should last almost forever. Hopefully the OP discovered this when he started the thread 2 yrs ago.