Topic: Rear drum specs... No one talks about it!!!

[firefighter_zach]

Hey guys,
I bought a 16" rim kit for my '74 550 project. I want to swap it but my only problem is that the inner diameter of my brake drum is about 183mm which is outside the 181mm oem tolerance. I've looked for a used replacement hub but most are already out of spec as well. Since I don't hear anyone talk much about whether or not their rear drum is within specs I assume that its ok to put in new bearings, pads, and lace up the new rim. Will I regret this later?
O ya, I found a brand new oem 550 hub, the guy wanted $600 bucks for it! Thats more than I spent on the bike! Anyone have a 550 hub that is within specs they are willing to sell? Or should I just go ahead and lace it up?
Thanks in advance for all replies!!!

[traveler]

Your only option is either to buy a new hub (about 300 bucks), or use what you have.  Most I imagine don't sweat it, as they rely on the front disc for 90% of the needed stopping power.

Converting the rear to disc is also an option.

~Joe

[firefighter_zach]

Thanks! Any threads on here showing the process of rear wheel disk conversion? Would I use the original hub or get a whole new wheel assembly? Probably something for the future as I think I've found a used hub within specs from MrOzz.

[traveler]

Google search Cycle Exchange or CycleX....they sell a conversion kit using the original rear wheel.

CB750's ('77-'78) F2's came from the factory with a rear disc.

Then of course, with some fabbing, a rear harley wheel with disc could be made to fit.  For a 550, that may be the route to go....also some other 70's Jap bikes had rear disc brakes that could be fabbed on.  There is just no "bolt on and go" setups for 550's.....gotta do some fabbing or live with what Honda gave you.

Or....just run the rear drum and live with it.  The front brake does the majority of the braking anyway....but rear brake is nice in corners, as it prevents the front wheel from washing out, if the front brake is hit and there is gravel on the road in a corner!

P.S.  Remember, rear disc, means hydralics, so you will have to come up with a rear master cylinder, and assorted bits.

~Joe

[verboten1]

I can measure my hub if you would be interested

I have a spare one sitting around... 2 actually with the sport bike wheel swap.

[firefighter_zach]

Well i bought another rear hub but it is just about out of spec too. I am doing a 16 inch wheel conversion. I'm building a bobber and wanted to go with no front brake, thats why i worried about it. but being a firefighter and seeing too many people bloody on the road after bike crashes has convinced me that a tacky front brake is better than a messed up face! I think I'll throw it together and hope for the best. with brand new brake pads and the decision to add front brakes i shouldn't have to worry for awhile.

[Flying J]

you could always build a wheel with a tiny drum up front just to have a little stopping power. Like a cb350 drum.