This video uploaded by youtuber Peak Torque shows a Hambini BB having it’s engineering tolerances judged. Some key points
- It’s a BB86 Shimano Racing Edition Bottom Bracket
- The bottom bracket tolerances are accurate to 0.005mm, that is less than the diameter of a human sperm cell.
- The eccentricity was found to be 0.010mm (0.0005inch), the recommended tolerance was 0.1mm. It was therefore 100 times more accurate than the specification allows.
How is .01mm 100x better than .1mm
it’s a tighter tolerance, it’s therefore more accurate
Not necessarily 100x better but with tighter tolerances there is more rigidity, less wear and tear. In engineering 0.1mm or 0.004” is quite a large tolerance and with current DNC or CNC Machines tolerances of 0.05mm are quite easily achieved with aluminium components of batches of 200 off or more just as easily as with components of greater tolerance. Paying £4K for a bicycle I’d only expect the best from the very few machined components included.