BB stands for “big bummer”

I give up.  After an out and about on a beautiful 100km (60 mile) tear through the rolling country roads beyond South Seattle, my T47 bottom bracket shit the bed.  Again.

I noodled with my original Token BB for ages.  It never stayed silent.  I blamed it on the BB30 Force crankset.  I blamed it on the bogus bearing compression spacer.  I blamed it on the BB itself.  It spun out a miserable life around 6000 km before the non driveside bearing imploded.  Lesson learned.

I decided to upgrade. A trusted mechanic suggested the tolerances on a 30mm axle were much tighter necessitating a higher quality BB.  I can’t afford to pay for something cheap twice, so I threw the coin down on the upgrade.

With under 1000 km (600 miles) on the upgrade, a BB cup sheared in half leaving me to limp the final 20 odd km (12 miles) home, head hung low.  I’ve never seen anything like this happen to a bottom bracket.  I was riding with the boyz from Tukwila Trek, who were equally stunned, but agreed with my hunch:  BB30 and the oversized axle standard is garbage.  Here are a quick three reasons why:

  1. Shimano lords over the patent for logical bearing compression, a screw that tightens the crank against the bearing face to get proper preload. This means other crank manufacturers have to rely on a compression spacer.  SRAM’s is a particularly awful piece of plastic prone to slipping, stripping and loosening.  Bummer.
  2. 30mm has benefits on paper, but in reality the bearing size introduces a lot of wiggle room for error.  Axle to bearing fit tolerances need to be much tighter. Power transfer from the crank spindle to the bearings is also much higher, meaning quicker wear and tear. Bummer.
  3. They are a non-standard standard.  T47 for instance has two different BB cup tools, 12 and 16 notch.  That’s if anyone has the tool to begin with.  BB30 is pricy as a result, compared to its smaller diameter through-axle brethren. All these reasons combine and create an experience of constant adjustment, parts replacement, and complete failure. Bummer.

For me, the next upgrade is a costly one.  First is the delightful task of trying to remove the ruined cup.  Then I’ll be putting in a replacement BB to retrofit a GXP version of my crankset. Then my grand experiment will conclude itself.  My foray into BB30 leaves me with one message for its engineers: Big bummer.

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