Dura Ace 7900 rear derailleur

[jpw]

I want to replace the bolt that holds the 7900 rear derailleur to the hanger with a brake away one, the kind made by SRP, either their standard bolt or the more complex 'Wreckdefier' bolt. I wonder if anyone knows the precise measurements of the original Shimano bolt, length and diameter? I want to be sure which one to get, and the Shimano exploded diagram isn't saying much about that.

http://techdocs.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/RD/EV-RD-7900-2871A_v1_m56577569830676546.pdf

http://www.srp-usa.com/category-s/40.htm

http://www.srp-usa.com/SearchResults.asp?Search=wreckdefier&Search.x=0&Search.y=0

Thanks, Jason.

[dogdriver]

For lack of a better answer, you can take the original bolt to a Lowe's, Home Depot, etc, and threat said bolt into the display sizers. Then you'll know thread pitch, diameter, etc, and only have to measure the length to know what you need.

Or, call a good bike shop...