[Closed] how many miles from a bittom bracket is fair?

I find I get anything from 700km to 2500km out of xt bbs on the mtb, but the one on my road bike is now at 12000km and still feels ok.

xtr isn't worth the money imho, xt lasts as long but often is under 1/2 the price.

Edit: if your mechanical able most hollowtech bbs can be rebuilt and re-greased which can often extend their life quite a bit, but you'll find that if there's any play it's not worth bothering

CRC were doing XT for a tenner a shot recently.

My BB's seem to go more because water gets down the seat tube and into them than through the outer seals.

It's worth pulling them out every now and again and drying them all out and greasing the backs of the bearings and making sure the axle tube is sealed into the shells as well as you can.

But to answer you original question, 500 miles for a cheap BB used through the winter and not pampered wouldn;t disappoint me.

What did you do in the miles, time, spins and conditions matter much more with mountain bikes. And cheap shimano stuff is shit

Thanks for the feedback, at least it is not just me. XT at £10 sounds like the way to go.

I've been having a cracking sound on the bike recently and changed the BB to remedy it but I still have the noise so the change was pointless. Gonna regrease the headset bearings today and try some different pedals to try and pin point the offending component.

my new favourite BB is from uberbike, it's a little 'nicer' than the Gusset EXt24 in my commuter which has done over 10,000 km through all sorts of filth.

That's about what I get from the Shimano BBs. Worth also considering something like the Gusset BB which has replaceable bearing but I've come to the conclusion cost of ownership / faff is similar to the Shimano. Comes in shiny colours.

Also worth checking other parts of the bike. I had a nightmare creak on my full sus, cursed press fit BBs and could never get rid of it. Turned out it was the rear hub, it was a bonty cartridge hub and axle was ever so slightly out of tolerance and it creaked like nothing else. Could have sworn it was the BB. Also had similar "blame the BB" moments with creaking pedals, slightly loose chain ring bolts and all manor of pivoty things.

The very bottom end Shimano BBs are different from the XT/SLX ones, they have a shorter life at best but they're also much more vulnerable to water/mud leakage and damage. I killed a deore in a day at fort william frinstance. False economy really. But the XT/SLX BB is really pretty good, and good value.

(also- all Shimano BBs have no tolerance for overtightening. And mountain bikers overtighten everything)

Got Gusset EXT24s in all my bikes now, recommended. Good life and they use standard bearings, easy to fit, so cheaper to run than most servicable BBs. Just don't break the top hats.

The cheap square taper Shimano BB I installed on (in?) one of my bikes in 2007 is still going fine. No idea how far it's gone, but it's been my commuter on-and-off so a couple of thousand there and it was my main long-distance rides bike for a while too.

I've killed a HTII on one (wet) 50 mile MTB ride.

As above. External bb's are not very durable. Square taper bbs on my tourer going strong after 7 years plus and my wife's Isis bb on her old MTB was only every changed once and is now 9+ years old and stills ees some service.

As above. External bb's are not very durable.

I've just discovered that NDS bearing in the Ultegra BB in my tourer has given up on me. That's the one I installed when the bike was built - almost exactly 5 years ago. Dunno how many thousand miles that ones done.

clanton - Member

As above. External bb's are not very durable.

some are extremely durable.

That's about what I get from the Shimano BBs. Worth also considering something like the Gusset BB which has replaceable bearing but I've come to the conclusion cost of ownership / faff is similar to the Shimano. Comes in shiny colours.

This applies to Hope too. Disappointed with bearing life when compared to Shimmy XT.

As above. External bb's are not very durable.

On the whole, yes. It's a good design for a modern standard that's bolted into a smaller older standard; while it works, it's not an ideal solution.

Get the BB shell properly faced and chased - slight misalignment can make a huge difference to the life of external bearing BBs.

As above. External bb's are not very durable. Square taper bbs on my tourer going strong after 7 years plus and my wife's Isis bb on her old MTB was only every changed once and is now 9+ years old and stills ees some service.

The external one on my road bike's 10 years old if this is a pissing contest?

It's not how old it is, it's how it's been used, I used to get through a un72 every year, it invariably failed after the anual pilgrimage to mid wales. I not get through XTR BB's in about the same sort of timeframe.

I had a Chris King one for a while, maybe 4 years before it died. But £15 XTR BB's from Germany mean I just replace it when I strip the bike in the spring and make sure nothings siezed, stick a new one in and it's good for another 12 hastle free months.

Road - 5,000 miles and 9 months on the winter bike (external)

Mountain Bike - Too variable to comment really, think I killed one by just doing Mayhem a few years ago.

1724 dependent upon solar activity at the time of fitting.

As above. External bb's are not very durable.

Mountain Bike - Too variable to comment really

*entry level stuff almost universally seem to have crap seals, hub BBs headsets, keep away from water, great for UK then 🙄

reasonable* square tapers can be relied upon to last you a decent amount of time whatever the weather, so I'll stick with external BBs are not a patch (durability wise) on Sq taper

For me Hope did that with external BB's

Still think someone should make some with [i]external[/i] grease ports.

Hope aren't so much better than Shimano ime, and they use a nonstandard bearing so less servicable (you can find them from a couple of sources but not from quality manufacturers, unless you buy expensive ones from Hope or IIRC FSA). In the long term, Shimano is cheaper than Hope. Gusset much cheaper.

This is all assuming you can fit them right to be fair- Hope seem much better than Shimano with overtightening.

Mountain Bike - Too variable to comment really, think I killed one by just doing Mayhem a few years ago.

I tend to replace after every Dyfi Enduro. 🙁

Hope aren't so much better than Shimano ime...

I'd agree with that. I seemed to replace bearings more regularly than I would a decent Shimano BB, and a Shimano BB is usually cheaper to boot. A few friends got early Kings too and were disappointed - quite a shame, as personally I think the headsets and hubs I've had are nothing short of amazing.

reasonable* square tapers can be relied upon...

I'd agree with that too: the payoff is less stiffness. There was a surprisingly noticeable improvement when I switched from HT1 to HT2.

I am long term user of square taper bb's and they never die. In mh race bike i have an xtr bb and that has been in there since spetmener but it not used weekly but has seem some wet rides. I remeber the days of isis bb's and these where truely awful. I wore them out every couple of months and bit the bullet and switched to shimano external bbs the good ones mind. Been happy since. Token bb are decent and the bearing are repalacable so i fitted ina to one and that lasted along time.

I fitted a Hope stainless steel BB, its done over 3,500 miles and still like new.
Not like the bad old days of Isis BB's which would last about 6 weeks in North Yorkshire mud.

I have Hope SS and Chris kings that have done 6000km plus each.

Did have an xt that did 65km but turned out that shall was badly faced.

Bogs and river crossings and miles of gloppy grit tends to prematurely end bottom bracket life. But northern England is not California!

Just replaced the shimano ht2 bb that came with the tiagra-but-different-colour oem cranks on the wife's cx bike after a couple of thousand miles, suprised to find that they manufacture a ht2 bb with even poorer quality bearings and even less sealing than deore. 😯

A bittom bracket...?

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This is all assuming you can fit them right to be fair- Hope seem much better than Shimano with overtightening.

I read a lot of posts about bottom brackets of various makes not lasting very long but I find bottom brackets last donkeys years with no creaking or seizing or notable roughness.

Aye, overtightening cranks into the BB. I doubt overtightening into the bike has any ill effects other than maybe stripping the threads

I used to find htii bearings only lasted 6 to 9 months on the Quantocks, so tried a hope ceramic in 2008 and it's been there ever since, brilliant piece of kit. I just can 'to be doing with wonky cranks, chain rub all the time for the time it takes me to think, really, another bb already.

Chris King BB doing ok here so far, 1 1/2 years but lots of miles. Being able to flush with new grease every 4 months helps no end I think. Maybe try poping seals on cartridge bearing BBs and clean out + apply new grease, bet that would extend the life of most bearings.