SHIMANO Bottom Bracket BBR60-68mm English Thread.

Product Information

The design comes about as a solution to the well documented creaking issues associated with oversized press-fit systems. While these issues are near always the result of poor tolerances, the T47 standard promises to fix the creaking issue without sacrificing the benefits of an oversized interface. However Shimano advertise that SM-BBR60 & BB-R9100 use 'small ball bearings'. This is not necessarily a good thing, in that smaller bearings are weaker. However there are more of them. Still it would be reasonable to assume that the RS500 will be DIFFERENT in durability from the other two, but not necessarily worse. The road standard has an 86.5mm shell width (hence BB86) whilst the mountain bike standard has a 91.5mm shell width. A number of other shell widths may also exist, though they all use the same bearing cups. Pros: Lighter weight; more resistant to axle twist; more heel clearance; larger-diameter shell and spindle; potential for narrower pedal stance width One of the earliest standards of crank interface, 'cottered cranks are now considered obsolete in developed countries, but are still in common use in developing nations. [ citation needed] The spindle is a cylinder and has a flat region across it (a land). The crank has a hole through it to fit onto the spindle, with a transverse hole for the cotter pin. The cotter pin is cylindrical with one side flattened at an angle to form a wedge to match the spindle land. When tightened, this produces a simple and effective interface. The problem is that normally the interface cannot be tightened enough without a cotter pin press, a highly specialized type of clamping tool, [19] though still produced and for sale. Cotters can also be installed with an improvised tool designed for another purpose, such as a ball joint splitter or hammer, with mixed results.

That extra 5mm can complicate crank compatibility, however. BB30-compatible cranks that feature axle spacers on the non-driveside (such as from Cannondale and SRAM) will work just fine because all you’ll have to do is remove spacers as needed to accommodate the extra width, but BB30 cranks without such spacers (such as from FSA and Specialized) won’t work.a b "Royal Enfield Revelation 1965". Archived from the original on 2013-10-15 . Retrieved 2013-08-26. Royal Enfield Revelation (retrieved 26 August 2013).

And here's where my problem is, I have no idea whether a BB I'm considering will fit the bike or not.

PF30 and OSBB bottom brackets

Table of BB standard and compatible cranksets of different standard (all the BBs accept the same standard cranksets, of course, others require an adapter, as is explained in chapter 3): BB standard The Threadfit T47 standard (no relation to Colnago’s ThreadFit system) was originally developed for Argonaut Cycles by Chris King. It uses an oversize, threaded alloy sleeve to house the bearings. Among its advantages touted by Argonaut are a reliable threaded interface and compatibility with all known crank standards. Other names PF41 (Hope – refers to BB shell diameter), PF24 (Chris King – refers to spindle diameter)