# Pedal Spindle Diameter...



## MCF (Oct 12, 2006)

Ordering my wife a set of Sport Powergrip Pedals for her Trek Touring bike....want to make sure I order the correct spindle diameter - measure the actual spindle of stock pedals and not hole in crank I assume to determine 9/16 or 1/2 spindle? Obvious to me to measure actual pedal spindle diameter, but I have been wrong before...


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## JCavilia (Sep 12, 2005)

*They're 9/16"*

All modern 3-piece cranksets use 9/16". Half-inch are used only on the one-piece cranks (the two arms and the bottom bracket spindle are a single piece of metal, with two right-angle bends in it). Those are used now only on cheaper bikes. I don't believe any Trek ever used such cranks.
http://www.sheldonbrown.com/gloss_p.html#pedal

BTW, it's not the spindle diameter that the measurement refers to, but the thread diameter, specifically the outside diameter of the male thread (the part on the pedal spindle). You're correct that the measurement is taken on that part. The inside diameter of the female thread is slightly smaller. This is a general rule for measuring threads of all kinds.


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## Dave_Stohler (Jan 22, 2004)

Gee-any pedal available in 1/2" threading is either antediluvian or junk.


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