For those interested, and I can't speak for other Dyna models or other years, but the wrench/socket size for the rear axle and axle nut for the 2008 Fat Bob are 28mm and 36mm. Just thought I'd throw that out there so others can avoid the search I just finished.

 

Thanks for the info. Always a good idea to buy the factory service manual for your bike.

 

I couldn't find the sizes there, maybe didn't look hard enough.