Topic: Rotor swap and bore questions

[JJbigshoe]

Does the center bore of a brake rotor need to fit snug to the ring of the hub? Does the hub ring share the load when braking or is that job done by the rotor bolts and the hub ring is there mostly to line the rotor up when mounting it? If the hub ring does share the braking load, would milling a washer-shaped spacer do the same job?

I am mounting GSXR rotors to a Harley wheel and the bore size is larger. I'm wondering if I could leave the gap, make a spacer or will I need to drop $400 on 320mm Harley oversized rotors from T.C. Bros. that will fit correctly (but don't have the gold carriers that I like).

Don't mind the poor drilling job, these rotors are only for mock up and won't be used.

[JJbigshoe]

I think I found the answer to my own questions. They make adapters to fit later year rotors to earlier Harleys that came with smaller bore rotors so an adapter ring is commonly used for this type of application. If I get a set made to 69mm O.D. to match the GSXR rotor bore and a 56mm center hole to match the Harley hub ring I'll be good.

[scottly]

The center hole of the rotor mostly centers the rotor on the hub, and technically is not needed after the rotor bolts are tightened, once centered. The stock Honda rotors have a somewhat loose fit on the hub, but only by a few thousandths of an inch. If your GSXR rotors are like Ducati and Yamaha, the center hole is 3mm larger than a Honda hub. 

[JJbigshoe]

I'm of the same mind that a gap isn't a problem and the bolts do the job of holding the rotor tight, but the parts guy at the Honda shop got me worried after talking to him. I actually dropped the HD and GSXR rotors at a local machine shop to have spacers made. Might be unnecessary but at the least they will tidy up the wheel.

[754]

Is that front or rear wheel ? I assume front as you said rotors. Did you check the calipers for spoke clearance ? The rotor often needs to be spaced out, if so you would want it one piece. IF Front what front end,  the standard 750 fork is not wide enough. 

[JJbigshoe]

It's a 1998 GSXR 600 front end, standard forks, not USD. I'm using a Harley mid-glide or super-glide or something like that front rim from I think a Dyna series bike. It came with 25mm bearings which fit the GSXR axle. Ends up it's a really easy conversion. The only special parts I had made were the spacers I mentioned in this post earlier and a centering puck my friend made for me with a 3D printer. It allowed me to stack a Harley rotor on top of the GSXR rotor and align it properly to drill the new bolt pattern.
I found the correct width axle spacers I needed from Lowbrow Customs to center the wheel on the axle. The calipers just kinda lined up great. I can go into more detail if anyone is interested once I get everything sorted a bit more.

[754]

Looks good , we had to go to Gold wing forks on my son's bike to get a 30 on the front.

[JJbigshoe]

My original plan was to use the stock GSXR front and a blacked out laced rim on the rear. Then I saw a pic of the Rusty Olive bike and decided I'd have chrome spoked rims front and rear no matter what. I had bought a black Goldwing hoop before I found the chrome Harley front, so I stripped the powder coat from the GW hoop  in an acetone bath and started polishing. Then decided I'd rather eat dryer lint than polish that rim (I had just finished polishing my engine cases. No mas...no mas) and found a 750 chrome hoop cheap enough and good enough to use.

Anyone need a half polished Goldwing rim?