The humble BB fixes many ills
 

Interesting past few weeks for me. Friends were complaining about their bikes lacking in some area, looking to upgrade and all it took was Shimano's UN55 BB. Which cost all of $17 from REI.

Bike #1 . Bikes Direct Motobecane Mirage SLX. Bottom Bracket Flex: Owner is a big guy and complained the BB area was flexing. Sure enough, riding along side him when he was out of the saddle there was chain rub. Replaced this New VP BB English Square Bottom Bracket Set 68X 126mm VP BC73A Aluminum Cups | eBay and all problems gone.

Bike #2 . Diamondback Bikes - Road Bikes - Century Slow to accelerate and owner wanted a major wheel upgrade. Wheels weighted in at 1900 grams so not light but not super heavy either. Replaced the Chin Haur BB with the UN55 and no complaints.

The cheap BB in the first bike was a bit of a surprise given it cost $500, but the second bike cost close to $1000. Who puts a $8 BB instead of a $17 BB in a well speced bike?

So consider changing out your BB before upgrading other stuff. All it takes is 10 minutes and cost $20.

My guess is that to sell bikes at these low prices, you have to put in cheap components wherever you can. Most people are going to be looking at the gears, crankset and maybe brakes. Nobody pays attention to what BB they use.

The BB failed on my Diamondback bike after 350 miles, but that was BB30 so likely more about poor installation than the FSA branding.

So a cheap BB was slowing down guy number two? Look, I haven't run the numbers, so I am in no position to say authoritatively, but that just doesn't make sense. The force involved in turning a crank against no other resistance than its own bearings (even crappy ones) is minuscule compared to accelerating the whole mass of the bicycle and rider. Assuming competent installation of course. Unless the bearings were loose balls, mashed in so tight the crank couldn't turn, what you are saying makes no sense. There is some serious Kool-Aid guzzling going on here.

I personally find if I pour the kool-aid down the seat tube you can drink it directly from the bottom bracket. Very refreshing ...

Google Chin Haur BB and you'll see they are pretty junky in how they are put together.

I even noticed differences b/w Shimano's own UN26 and UN55.

Still amazed these companies would put a $8 part in a bike when a $17 part is so much better.


Chin Haur strikes again with injuries

Chin Haur strikes again

http://www.pardo.net/bike/pic/fail-001/FAIL-202.html

Don't forget to use ceramic bearings ftw :lol:

That's all fine, and I believe you installed a much better BB. But to say the effect is better acceleration like having better wheels isn't reasonable. Compare the power required to turn a crank (no chain attached) with your hand and to accelerate a bike from standing still. Is there any way the two could be comparable. That improving the BB could affect the feel of accelerating from a standing start just isn't reasonable.

Thing is, you don't need an excuse to put in a better BB. It justifies itself. But claiming some impossible effect from it isn't right.

I think you get what I am saying, eh?

My personal preference on BB is "good enough, not too good". For this reason I usually buy Shimano BBs and am happy.

Both my newest bikes have the Shimano BB-R60 Ultegra level BB on them, at a cost of $16 each. I figure a Chris King BB has likely more longevity, but I can go through 9 Shimanos before I regret not having paid the extra for the CK!

I haven't gone through 9 BBs in 32 years even including the ones I just got rid of when buying a new bike, ditching a bike or rebuilding it!

Exactly.

My record was going through 3 BBs in a year. The answer: ditch the BB30.

Same here. The only BB I had that was really useless was one I got off Ebay, that was a frozen solid cartridge. That one actually might have slowed me down if I tried using it.

otherwise, they last for years....... But I am still in English thread world, no BBxx on my old bikes.
:50:

What are some good and bad BB's?

All the major players make good BBs. Shimano, SRAM, Campy, FSA, etc. Then there are the big name independents like Chris King and Phil Wood.

Of course it is. Those Chin Haur BB didn't work perfectly for years and fail one day, they were inherently defective from the start and then broke after.

Earlier batches (not sure about the ones I changed over) would literally break off at the spindle leaving the rider with one leg clipped into a pedal which was not attached to the bike. Those spindles under stress must have been twisting and couldn't have been transmitting power particularly well.

Must have been eating up power, huh? CrMo spinde. Give me a break.

If your BB is broken, you don't say the bike feels sluggish. You say that you have this crazy noise coming from the BB. Besides you never said the BB was broken, just that it was crappy. Get a grip.

C&V BB Pro Tip-

If you're buying a frame and the seller offers to include a "free" titanium bottom bracket, It's probably frozen in the BB shell. Like puppies there is no such thing as a free titanium bottom bracket.

Good BBs:
old style..threaded square taper ball and cage. Rebuild every year - takes about 15 minutes to disassemble, clean, pack with new grease and put back back together. As long as you keep them greased and replace the ball bearings every so often, it'll last decades
external..unbolt the cranks (no puller needed), take the external cups off, replace with new ones, stick the crank back through and tighten it down.
Cartridge square taper bbs are ok
The damned:
Pressfit. Really. just **** em.