scop

I think I have worn out my second bottom bracket in a year! I bought my bike new a year ago and had to replace the bottom bracket (Sugino) last September after 900 miles. The bike shop fitted a Shimano UN51 and all has been fine until now when the familiar noises have returned. I'm pretty sure the noises are coming from the BB.

I have cycled 2000 miles over the last year and have gone through the winter. My commute is half on the road and half on a country cycle track which is wet and muddy all winter and dry and dusty during summer (or as much as it can be in the UK!).

Can anyone reccomend a decent upgrade? Surely a BB should last a long time? My bike is a bianchi axis cyclocross bike. I was thinking Shimano 105 but are these more for road bikes? I guess the BB needs to be really well sealed to keep the wet out. Or perhaps its me, should I be puttings lots of grease around the BB casing?

Many Thanks....

I_bRAD

Sounds like an installation issue to me. 900 miles is way too little, even for the cheapest bb

EatMyA**

Instead of a new BB. Get free bearings, BB cups, and a square tapered axle. They will last much longer under your conditions.

it'll feel like a downgrade but will last you much longer. Plus beariings are cheap if you do wear them out.

DieselDan

The shell may need to be faced.

tellyho

I like cup and loose ball bottom brackets, but even I think this advice is crazy. Sealed cartridges last forever. Except the OP's, apparently. I can't say that one brand is going to be better sealed than another. I'd suspect some other cause than your riding conditions. But I don't know what.

EatMyA**

For the average person yes. The average person rides like 10 miles per year, in smooth roads, with sunny fair weather conditions. then the bike is stored. So the sealed bearings would last longer because its sealed better. It doesnt dry as fast or come out of adjustment.

But if you ride in sandy and wet conditions even sealed bearings get screwed up FAST. The only difference is you cannot service them. well some BB you can, kinda like rollerbladers service their sealed bearings.

Sealed bearings on skates are not going to last you long at all in those conditions, without maintenance (think 50 miles), because they are closer to the ground and collect more dirt and water easyer. Its the same thing on a bike its just that you can get away with it for longer because the BB is higher off the ground and therefore collects less dust and moisture.

If you ride like that OP, you're going to need maintenace and its just easyer on a cup and loose bearing BB. Sealed bearing BB are not cosidered serviceable, you just buy another one. The name, "sealed bearing" is a bit misleading.

But thats just me.

scop

Thanks guys

I have checked a few UK forums and it seems that our climate destroys BBs with quite a few bikers reporting short life out of their BBs due to wet muddy conditions. When I embarked on cycling I never figured that I would end up replacing the BB once or twice per year. There was an upgrade available (UN73) which is Shimano XT level but I gather this has been discontinued, looks like I'll have to get handy with the spanners! To top it all I measured my chain at the weekend only to find that its stretched and I'll have to replace it, the brake blocks are also looking low! The LBS is going to love me!!

Doe anyone know whether theres a better BB available thats the same kind of fitting as a UN54 but an upgrade. Are there better manufacturers??

Cheers..

noglider 

Nonsense. Once or twice a year sounds insane, even in mud, unless copious amounts of mud somehow get in there. What caused the failure? Let us know when you disassemble it.

As DieselDan said, you may need to get your BB shell refaced. The outer surfaces may not be paralllel, which would put wear on the bearing surfaces.