Manufactured to EXACTING specifications! The spindle taper on the Protype Bottom Bracket has been measured using computer coordinated measured machine (CMM) to ensure an exact fit for the Sugino 75. This is no cheap imitation like the BB Sugino has called out*** on their site to cause damage to your expensive crankset.
***Sugino recently released a bulletin (opens in new window) informing consumers of poor fit with aftermarket bottom brackets saying they are compatible with the Sugino 75 crankset that will cause damage to your Sugino 75 crank arms.
If you take a close look at the fogged out pic of the bb Sugino calls out you will see it has the Tange decal on it. We do not offer this bottom bracket. BUT; we did order one to see how the fit compared to the Sugino 75 BB and the Protype BB and it is significant.
If you look at the pic in the gallery you'll see the we slip fit a Sugino 75 crank arm onto each of the bottom bracket axles till each bottomed out and took the measurement from the axle end to the bolt head surface. From this you can see how each matches the crankarm's taper. You might think that 1.1mm isn't that great of a difference; but Sugino believes it is and so do we.
The number one question/email we get is..."Does anyone offer a reasonably priced sealed cartridge bottom bracket for the Sugino 75 track crankset, a true 109mm ISO taper bottom bracket?". The answer for a very long time was unfortunately "no".
Well, after searching high and low (for what seems like a millennium)we found a manufacturer!
We have a few local messengers riding them and they have been holding up superbly well. Granted it's no White Industries or Phil Wood with replaceable bearings; but it's also a fraction of the price.
Alloy Cups and Sleeve
Sealed Cartridge Bearings
Manufactured and verified by CMM to be a high quality sealed bearing replacement
Designed for use with the Sugino 75 crankset only