needing a new chainset and external BBs will be on the cards, but i can’t decide whether the external BB design is a good thing or bad thing. i’ve had sq. taper and octalink – both lasting a fair old bit but i keep hearing nightmarish stories of the external variety not lasting all that long due to bearings on the outside exposed to the elements etc.

can anybody with experience comment?

My external BB is the longest lasting BB I have ever had and to top it all the cranks are the stiffest I have ever had!

my two external BB’s are the longest lasting i’ve ever had, never had a square taper or octo/isis last me six months before they were fragged, i’ve never touched my Xt2 or Dura-ace sets and they are 2 years

Didnt say that mine is two years old too and has been on 3 frames.

As above

Mine has lasted a year of serious abuse. Just starting to get a little bit of play, but good for another 3/4 months i would say.

And this is a Truvativ one (which are renowned for being poor)

My HT2 are new to me but stiff. ISIS lasts 2 minutes unless made by SKF.

My square taper XT lasted ages, I only ever snapped one axle. My raceface isis went about 5 years before i replaced the bearings and it’s still going strong. My M970 is still sweet. The bottom brackets just do what bottom brackets do. However, each time the type has changed, the cranks/interface got stiffer.

Yes.

I have only heard bad things about them…I personally run square tapers, one of wich i had 6 years in one Ti frame and only that one cup had seized cause i forgot to grease them, was it then knackered. Now running Royce in both MTBs

Mine seem to have got a bit graunchy after a year or 18 months, but I’ll accept that for the increase in stiffness and security.

Used to kill cheaper square taper (un52) in under two months. Better ones (un72) would last a year or so. XT level Octalink (es71) also lasted a year or so. ISIS of any price, no more than a month. XT outboard, so far so good, just fine since last april – if it lasts a year, i’ll be happy and then up-grade to summit nicer. I’m not sure it matters wether it’s in board or outboard, it’s more to do with bearing quality and seal quality.

people seem to accept changing a £20 chain, but moan about a £20 BB. Its all wear and tear, I find external BBs better than any other type Ive used.

‘I have only heard bad things about them’

Not read every reply to this thread then!?

Whilst I don’t think they’re perfect, it’s definitely a great system, I changed my road b/b after 4 years and about 15000 miles! My MTB ones last 2 years on average. I’m not complaining! The cranks are not only stiffer as cited here, but also lighter.

Me too. Gone from changing bb every 3 months or so, to a quick bearing swap every 12-15 months.

been pleasantly surprised by the HT2 on mine

HT2 has been brill for me, no issues on a lot of daily commuting in the past in the wet and grime.

Don’t think Shimano XT last that well, but Hope seem excellent…so far! But there’s no doubt they’re stiffer that square taper etc.

Been running an HT2 for about 18 months and it is still spot on, but ran a Truvativ external BB before that and they didn’t last more than 6 months. Obviously I would recommend the HT2. There is a noticable increase in stiffness over a conventional set. I have old style XT with an octalink on another bike and you can tell the difference riding them back to back.