How long should a bottom bracket last?

levad

Veteran
My bike has a Shimano Tiagra 4500 BB, I had to replace the first one after about 3,000 miles. The replacement is just showing signs of falling apart, cranks can be moved lateraly, this is after a further 4,000 miles. Is this an 'expected' mileage for this type of BB?

I commute most days all year round so the bike sees all types of weather.

If this is an expected mileage, is there a more robust (but light and easy rolling) BB that could be used?

Ta folks.
 

battered

Über Member
Mine on the MTB turned commuter last about this long. I bought a SH ex hire MTB with the dreaded Isis BB, that fell apart in short order.

I think it's a problem with modern sealed units, they last longer than the old ones assuming no maintenance but when they are done, that's it. No £2 packet of ball bearings, you need a new £30 unit.

You can indeed get better BBs. I've seen boutique jobs at £100. You'd want that to last. I've also seen plastic bushed affairs on BSOs, I suspect they last for 4 miles or 3 weeks, whichever comes first.
 

guitarpete247

Just about surviving
Location
Leicestershire
I still use traditional balls, cups and grease. Rebuild every so often when I think it needs it. Put in new balls and it has so far lasted 25 years in road bike and 20 years in MTB.
The more I read the less likely I am to go for sealed unit anytime soon. I'll keep with traditional unit until they stop making balls;).
 

Steve Austin

The Marmalade Kid
Location
Mlehworld
I'd be happy with 3/400 on a BB. I use XTR and Dura Ace on my bikes now. they cost more but last a lot longer and run smoother.

although i'm moving to Hope next as they come with replaceable bearings.
 
Location
Midlands
guitarpete247 said:
I still use traditional balls, cups and grease. Rebuild every so often when I think it needs it. Put in new balls and it has so far lasted 25 years in road bike and 20 years in MTB.
The more I read the less likely I am to go for sealed unit anytime soon. I'll keep with traditional unit until they stop making balls;).
In the day i used traditional balls, cups and grease it was a sort of 4 -6 month thing until one day I had not got the time/or the cup siezed (cannot remember which) and I took it to the bike shop for them to replace - sealed unit was cheaper than the traditional unit and I quickly discovered lasted at least a couple of years in all weathers.

However, the sealed units are too fit and forget - I was in Greece touring and the BB started to show signs of wear - by the time I got home the BB shell threads had been damaged - I had to have the BB sleeved - nowadays I inspect the BB regularly and will replace them at the first sign of wear or when they get to 20000km (pretty unlikely on my commuter bike before it gets nicked).

The tourer's BB is soon to be replaced with sorta XT quality - is it really worth going for something better? - assuming anyone does old fashioned shimano octolink
 

Steve Austin

The Marmalade Kid
Location
Mlehworld
psmiffy said:
The tourer's BB is soon to be replaced with sorta XT quality - is it really worth going for something better? - assuming anyone does old fashioned shimano octolink
You can still get octalink at CRC. very cheap too

the old Square taper Shimano BB (un53/54) were great. Lasted forever!!
 
Location
Midlands
Steve Austin said:
the old Square taper Shimano BB (un53/54) were great. Lasted forever!!
Yes but I have old school XT octolink cranks - they have done just under 40000km but must be good for a few more (makes mental note to start thread - how long do cranks last?) - The question in my mind is - is some posh Hope or Royce BB going to be a better bet than the Shimano in the long run
 

bauldbairn

New Member
Location
Falkirk
Industrial type sealed(non-servicable/fit and forget) Ball Bearings are designed/warrantied to last 18 months continuous service(24/7/365) or 18,000 hours in stop/start non-continuous use. Depending on environment/conditions etc.

I don't know how this compares to the life of bearings in bicycle bottom brackets?
 
Location
Midlands
Steve Austin said:
I don't think you can get anything other than Shimano Octalink now, so you are stuck with them. then again thats no bad thing
looks like I am stuck with changing the BB every 20000km or so - Merci Beucoup for that
 
OP
levad

levad

Veteran
bauldbairn said:
Industrial type sealed(non-servicable/fit and forget) Ball Bearings are designed/warrantied to last 18 months continuous service(24/7/365) or 18,000 hours in stop/start non-continuous use. Depending on environment/conditions etc.

I don't know how this compares to the life of bearings in bicycle bottom brackets?
Looking at my cycling logs, the bearings have been in use about 245 hours. I don't expect that it is the bearings themselves that are the problem, I think it is probably the plastic housing that the bearings are in. As you look at the bearing cups the bearing races and cups are metal but the sidewall is plastic. Certainly it was the platic sidewall that gave way on the first BB I replaced. I hope that description makes sense!
 

bauldbairn

New Member
Location
Falkirk
levad said:
Looking at my cycling logs, the bearings have been in use about 245 hours.
That doesn't seem long at all. Only about 10 days continuous use really. :sad:
I was just trying to give you a benchmark on how long ball bearings lasted in industry. As it was something I knew a bit about. If it is the housings/bushings that are giving way - the facts on bearing life in relatively stable/solid fittings won't be much use then, sorry! :rofl:

I must admit when I watched the Mark Beaumont documentary in the Americas I was surprised how quickly his bottom bracket gave in. :o)
 
Location
Midlands
Actually got me wondering now about my head set - Chris King - got about 40000km on it - been apart a couple of times and regreased - not noticed any play - but!
 
Location
Midlands
bauldbairn said:
Didn't Mark Beaumont's headset bearings go quite quickly as well??? :rofl:
Yes - makes the stuff I use a total bargain

makes you wonder what Koga fit - but as far as I know it is all good stuff - It is not as if it is easy to be rough on those components -unless of course the BBC took it off him every now and then and powerwashed it for filming
 
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