Q-factors for various cranksets

This is a list I have pieced together from various articles and postings on the internet.

Make Model BB Q-Factor Claimed/Real
FSA K-Force Light DoubleCeramic MegaExo168mm Claimed
KCNC K-Type XC2 Double 161mm Real
ShimanoXT 750 UN72 (110mm) 163mm Claimed
ShimanoXT 752ES71 (113mm)170.8mm Real
ShimanoXT 760HT2175.2mm Real
Shimano XT 770 HT2 176mm Real
Shimano XTR 952 M952 (68-112.5mm) 163mm Claimed
Shimano XTR 960 HT2 168mm Claimed
Shimano XTR 970 HT2 169mm Real
Sram XX 166 GXP 166mm Claimed
Sram XX 164 BB30 164mm Claimed
Sram XX 156 GXP 156mm Claimed
Sram XX 156 BB30 156mm Claimed

Related articles:

Short cranks for kids

Update 2021

Formula RX brakes

These are MY2012 versions and so feature the newer graphics as well as lever code numbers of FD532XX and caliper code numbers of FD520XX (last two digits denotes colour of master cylinder, caliper and/or annodized bore cap).

20" air forks for kids

There really is not much that's decent when it comes to 20" kids forks.  Most are heavy, oversprung and crappy performing el-cheapo forks. There are, however, a few good options:

Fork and shock oils

Just my quick notes on the fork and shock oils I have been using


There seems to be a surprising amount of interchangeability between the 32mm chassis forks from Rockshox, Fox and even Marzocchi. Here are some examples of frankenforks that people have put together:

XD driver bodies for various hubs

To run SRAM XX1 or XX0 11 speed you need a special XD driver body for your hub. A number of popular hubs have conversion driver/freehub bodies available: