Cheap but good square BB recommendations please

[Watchman]

My BB is creaking. Looks like a very run of the mill one by a company called RPM (fitted to a Whyte Portobello).

I can see a Shimano UN55 is all metal and cheap (8 and half quid from CRC). Their UN26 has a plastic cup on the non-drive side so I'm not interested in that.

Wondered if anyone had any experiences I should be aware of, or recommendations please?

[Fluffsri]

Had UN55s in a few bikes, last for ages, great value for money.

[Justin S]

UN55 is nearly all you can get now. UN72's or I think they are 73's now, maybe around, but the UN55 will be a sensible choice.

[Watchman]

Thanks Gents. UN55 from CRC on order.

Incidentally, other forums I checked out seemed to suggest an external BB is preferable. I have one on my other Whyte (901) which led me to question whether installing one on my Portobello would push the crank arms outward further and spoil the alignment. Any thoughts on this?

[Watchman]

For info, I've probably only done 3000 miles on the current BB - an RPM branded 7420. Another forum suggested they're generally rubbish and I ought to expect a longer life out of a Shimano. My experience with all Shimano products has been very positive in the past so I'm hopeful.

[gazza285]

You would need a new crank as well if you wanted external bearings. Stick with the UN55, it'll last you years.

[Watchman]

I wondered about that. Thanks for the info.

[Barchettaman]

Nothing wrong with square taper. Boonen won Paris-Roubaix using a Campagnolo square taper crankset as late as 2005. the current Japanese female cyclocross national champion uses Sugino square taper cranks.

It's old technology, but not outdated or obsolete.

Shimano square taper BBs will last a long time. SKF even longer (I have an SKF Isis BB in my CX bike and am not expecting to replace it for 60,000 miles)

http://www.lfgss.com/conversations/133893/

[Watchman]

Barchettaman said:

Nothing wrong with square taper. Boonen won Paris-Roubaix using a Campagnolo square taper crankset as late as 2005. the current Japanese female cyclocross national champion uses Sugino square taper cranks.

It's old technology, but not outdated or obsolete.

Shimano square taper BBs will last a long time. SKF even longer (I have an SKF Isis BB in my CX bike and am not expecting to replace it for 60,000 miles)

http://www.lfgss.com/conversations/133893/

Crikey, some of those are expensive. I wonder where the diminishing returns kicks in. If what people are telling me is right, I suspect the Shimano UN55 might be as high as you want to go unless weight saving is your objective.

I've never replaced a BB before. Never had to. I've only ever fitted a BB when I have built BMXs from new (sealed units with pressed-in cups) or serviced the older loose bearing type. It was quite a revelation to see the whole set (cups, shaft, bearings) come out in together. I groaned a little, expecting a wallet thrashing but for a tenner delivered, I can't complain really.

Oh... and 60,000 miles. I may not surpass that total until I'm 120 years old.

[Fastpedeller]

I ride my rigid MTB mostly on road (with some gritty Norfolk lanes though), and had a UN55 in it - only lasted a year! However since then (not to be deterred) I fitted another UN55 and that's still going good 4 years on (OOPS that statement's probably killed it!)
So, it can be the luck of the draw - But I'd certainly buy a UN55 again. Far, far superior to the old separate cups/cones from years ago!

[JEA1K]

Just junked a square taper from my winter bike in favour of hollowtech and a Tiagra chainset, raplacing the FSA vero. What an awful set up it was, none-stop creaking and flexing ... last BB lasted a week before it started making noises again so had enough. Total cost for replacement was £52 for brand new BB and chainset ... a better option!

[Watchman]

JEA1K said:

Just junked a square taper from my winter bike in favour of hollowtech and a Tiagra chainset, raplacing the FSA vero. What an awful set up it was, none-stop creaking and flexing ... last BB lasted a week before it started making noises again so had enough. Total cost for replacement was £52 for brand new BB and chainset ... a better option!

I am tempted to change to 1x9 setup because I rather like the simplicity of it. Checking them out last night, after I ordered the BB off CRC, I noted all 1x9 cranksets were of a non-tapered type. So if this BB doesn't work out, I may look at a bigger change.

As it stands though, I'm not unhappy with the compact double I have and when the BB works, the bike is near silent in operation. Anecdotal evidence suggests a UN55 should last well enough and at that price, I'll be happy with it.

[Fastpedeller]

Fastpedeller said:

I ride my rigid MTB mostly on road (with some gritty Norfolk lanes though), and had a UN55 in it - only lasted a year! However since then (not to be deterred) I fitted another UN55 and that's still going good 4 years on (OOPS that statement's probably killed it!)
So, it can be the luck of the draw - But I'd certainly buy a UN55 again. Far, far superior to the old separate cups/cones from years ago!

I will add.... I'm VERY fussy, and whilst I say the old UN55 only lasted a year, it probably would have kept going for some considerable while - It has a 'tick' at a specific point, but no discernible play as such (indeed I've kept it as a spare) I'd stick with a square taper BB, if nothing else it's a good, tried and tested system (though some, maybe for fashion reasons?, would reject it as being too old/outdated)

[Watchman]

I am in total agreement. I can't stand ticks and creaks. The current RPM-branded BB doesn't move adversely but creaks like my knees.

[richardxjr]

You'll want to change when you feel how heavy it is!

Remember to loosen (and re-tighten afterwards) the cable guide screw underneath

[Watchman]

richardxjr said:

You'll want to change when you feel how heavy it is!

Remember to loosen (and re-tighten afterwards) the cable guide screw underneath

I'm a fat knacker. The weight of my BB is inconsequential compared to that. In fact, having a lighter bike is somewhat counter productive in my search for (personal) lower weight and greater fitness.


However, beating my colleagues on a challenge on Endomondo is the most important thing, so I'll be looking for a full CF roadie for next year's challenge.