Bicycle Mechanics - Removing a freehub body, always 10mm allen?

So, i want to transplant a 9 speed freehub body to and older wheel, but I'm having issues taking it off. I've gotten to the part where you're supposed to use a 10mm allen key to unscrew it (following Sheldon brown's instructions) but it seems too small. Do different hubs need bigger Allen keys? My lbs didn't have bigger than a 10. Thanks for any help

Oh, it's a ritchey hub, if that makes any difference

D'oh, answered my own question, ritchey hubs need a 12mm Allen key

This raises a troubling question then, is the ritchey freehub body compatible with a shimano hub?

I have a Bontrager freehub and it uses an 11mm allen. I could not find a 11mm allen after searching high and low, but realized a 7/16 is very close and works. After I removed the freehub body and bought a new one from the LBS, it came with a 11mm allen in the bag.

Good question about the 12mm Ritchy fitting a 10mm Shimano. Realize the 12 / 10mm refer to the wrench size to fit the bolt head, but the threaded portion of the bolt may be the same thread diameter, pitch and length. I'm not sure, but there is some hope that it can fit (I'm an optimist at times). Let us know when you find out.

parktools make a 11 mm & 12 mm allen wrenches just for time like this. try going to a lbs and have them order one from their supplier.

Not all use a hex key. Old school Shimano FH bodies in some cases were press fit and others some funky Dura-ace specific tool that's no longer made.

you can find the Dura-ace tool at biketools&etc.com

Everyone who works on their own bike(s) should have BikeToolsEtc. bookmarked in their Favorites List:

http://www.biketoolsetc.com/index.cgi?id=180244260661&h=main&m=top_ten

They have just about all-things-bicycle at very friendly prices.