New crank lengths have been added to the Gear Calculator and Internal Gear Calculator, so they can calculate gain ratios for children’s bicycles with cranks down to 100 mm (less than 4 inches).
Tag: Sheldon Brown
More hubs in cable-pull cribsheet
Added information on four hubs to the internal-gear hub cable pull cribsheet:
Shimano Alfine 11-speed
SRAM G9
Sturmey-Archer S3X
Sturmey-Archer ASC
Thanks to Jeff Meredith and Michael Wilson for the measurements!
Measuring tricks

We have a new article on how to perform the precise measurements needed to determine whether bicycle parts fit each other, without expensive and fragile tools. There are a number of clever tricks — for example, you can test the width of the square taper of a cotterless crank with an ordinary open-end wrench!
Reorganization of headset tables

Our tables of headset sizes have been reorganized to make it easier to determine which headset can be made to fit which frame and fork. Fork crown race seats can be milled down and head tube race seats can be enlarged. The tables now are in order of head tube race seat size, as the frame is the more difficult and expensive to replace, followed by fork crown race seat size. The tables are used in the article on headsets and several other articles.
Shimano 4-speed hub gears

Expanded coverage of Shimano Nexus 4-speed hub gears — we now have rebuilding information, translated from manuals in German which are the only ones we could find online — complete instructions for both the freewheeling/Rollerbrake version and the coaster brake version. Thanks go to Patricia Morris for assistance with translation.
Shimmy, or speed wobble
A new article on shimmy, or speed wobble — what it is, why it happens, how to prevent it and how to recover from it.
More tire-sizing updates

http://sheldonbrown.com/650b.html : added more info on “27 five” tires, and a photo (thanks to Aaron Goss!).
http://sheldonbrown.com/tire-sizing.html : added several tire sizes
Sheldonbrown.com’s angle on the Trek quick-release recall
Sheldonbrown.com’s angle on the Trek quick-release recall. This addresses technical issues which we haven’t seen covered in news reports.

Update to the page on 26-inch tires
Update to the page on “26-inch” tires — there are actually 5 common tire sizes called 26-inch and if that isn’t enough one is also called “27.5” The updates cover new developments in availability, naming and tire widths.
New tire sizes in Gear Calculator
Several tire sizes have been added to the Gear Calculator:
Fatbike sizes: 26 inch tires, 26 x 3.8, 4.0, 4.25, 4.7
Wide 29ers: 29 x 2.7 and 3.0
32 inch and 36 inch (common on unicycles).