Essentially the tool presses the bearings into the frame. It's designed to do this squarely, though like any tool, if used incorrectly it can result in problems. In most cases it's a job for a professional mechanic, who'll have the tools and the experience.

How companies decide to go about that — and precisely what design features they want — is the real issue, because everyone seems to have their own ideas on how to achieve the same goals (less weight, more stiffness, and lower manufacturing costs). Cranksets with 24 mm spindle diameter are the most versatile and, with the right BB, or adapters, can fit almost any frame. Other names PF41 (Hope – refers to BB shell diameter), PF24 (Chris King – refers to spindle diameter)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

Table of crankset standards and compatible BBs (all the cranksets are compatible with the BBs of the same standard, of course, the others needing a special adapter): Crankset standard Compatibility Originally designed for 24mm spindles, but some BBs that fit a 30mm spindle are available A different approach than to move to threaded external bearings could be to standardize on one of the larger diameter press-fit BMX shell standards for all bicycles, or the press-fit BB30 standard [10] originally introduced by Cannondale. Instead of bearing pressed into aluminium cups that were then threaded into the frame, Trek pressed the bearings directly into the frame.Crank designs that will fit: BB386 EVO/BB392 EVO specific, standard 24mm external-type (can be adapted), BBRight, BB30 (axle width dependant), What amazes me most is that people seem to have good experiences with these very small bearings. They shouldn't last as long as normal 6805, hmm. Trek’s BB90 system uses the same bearings and bearing locations as a conventional threaded system, but eliminates the cups entirely. Bearings are pressed directly into precision-molded carbon seats Immediate Media 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.

As it stands, this new standard may just become the hot new thing among smaller manufacturers of metal bikes. From the outset, Cervélo introduced BBRight as an open standard that anyone could jump onto. While it seems to make good engineering sense, however, other bike companies have been slow to come on board. The granting of a best price is not combinable with other promotions (e.g. "free articles) from Bike-Discount. Previously referred to as 'cotterless', since this was the design that was introduced after cottered spindles, square taper was once the most popular (and only) style 'cotterless' crank. This interface consists of a spindle with square tapered ends that fit into square tapered holes in each crank. It is still manufactured in great numbers for bicycles and maintains popularity for such applications as bicycles. [20] This system has a number of different names depending on who you talk to. It is also called PF86, PF92, PF24 (Chris King) and PF41 (Hope).

In concept, at least, all of the standards we’ve covered are functionally sound. But the realities of relaxing tolerances can create other issues. The idea is simple, by moving the bearings outboard of the shell, you can then use a much larger spindle. Currently, 24mm is the accepted norm compared to square-taper’s relatively minuscule 17mm diameter. Chain reaction Cycles and CRC are trading names of Wiggle Ltd (In Administration) registered in the United Kingdom at 1000 Lakeside, Suite 310, Third Floor N E Wing, Portsmouth, Hampshire, PO6 3EN, Once obscure it’s now used by Trek across all its carbon road bikes, with the US brand making the switch due to the T47 ease of service as well as the system offering "extra stiffness and for better power transfer and pedaling efficiency". All the load is on one very small area of the cotter pin and the crank land, the cotter pin deforms plastically under normal use and must therefore be replaced regularly. If this is not done the crank and the spindle wear and must be replaced. The rider will get a warning through a characteristic creak sound that aging pins cause the cranks to make.

So it’s mostly eyeballing and trial and error. Some very rough guide (what I often try with first) would be:The bearings are normally open to the elements and easily contaminated, although this rarely causes failure. Ball retainers (caged bearings) are used to facilitate assembly and to reduce the number of balls required. [9] Thompson [ edit ] Because you have aluminium threads and surfaces, you can face the shell with a cutter and make it parallel if it is not. The bearing bores are usually round already, with aluminium cups, because it is a machined surface, and if the bearing bores are too tight you can sand them out and get the fit just right for the bearings before you thread them into the frame. You cannot use a facing or cutting tool that I know of in a carbon shell.” The picture shows a bbr60 without its dust cover/sleeve. That's one very slim bearing. Who makes them? What are the dimensions? Do they have a short lifespan? Curious... And here's where my problem is, I have no idea whether a BB I'm considering will fit the bike or not.