You are reading a single comment by @853Superfly and its replies.
Click here to read the full conversation.
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
Howard
Bearlegged
@853Superfly
@yetidamo A better picture of the stock BB, not an isis unit but a Truvativ Howitser Team.
Bigger external cups and bearings than shimano, let down by the bearings low quality and non marked size. Slight play in these but free spinning I would have to drift them out somehow and take one into a bearing specialist for correct replacement. Like shimano the cups are throw away and not user serviceable.
Brief history of bottom bracket.
Sealed cartridge square taper. As mountain biking grew, people rode harder and square tapers got snapped.
Shimano Octolink. An 8 spline interface using a larger diameter spindle than square taper. Downside is bearing size is smaller to accept the larger diameter spindle in the same space as a cartridge BB. Stronger but weaker bearings.
ISIS was an open platform patent free design to tackle Shimano patents on Octolink. This failed for the same issue of weaker bearings compounded by many attempts to make them but using low end bearings or poor Q/C also the race for the lightest BB didn't help matters.
By the time SKF had entered the game with a high quality BB the format was dead as Shimano had moved on.....
External Bearing cups. Game changer by Shimano, lets intergrate the spindle into the crank set, we can have a larger diameter spindle and lighter, and by moving the bearings into external cups you can run larger bearings and get round all the problems of the dimensions of a cartridge BB.
Plagued by Q/C and crap bearings and Shimanos plastic Top Hat inserts which others got round.
Never had issue with square taper. Burst an Octolink bearing and bent the chainset with it.
Isis would fail or bend the spindle to quick. I ruined one within hours of use.
Shimano and Raceface external bearings didn't last long but Shimanos where cheap. Both brands used same cup dimensions so aftermarket bearing kits soon appeared. The race face cups had a deeper insertion, tie that up with the Enduro Bearings and a really strong set up that lasted seasons of use and not ruined after a race weekend.
The Truvativ is kinda an inbetween lash up. It should be really strong (it is) let down by overweight to competition and poor bearings and you could only use it with Truvativ cranks which you had to be mad to buy aftermarket...… The Holzfella cranks are nice and the stems and bars.... but the steel spline BB would quickly chew out the crank interface if you didn't keep checking the crank bolts, then your crank would shake loose and fall off mid race run :)
1 Attachment