So how do I buy aftermarket wheels

Do people even do this who own bikes? How do I do it? There isn't really a "bolt pattern". What do I need to know?

Hub, axle and widths would be my guess

It depends on what kind of wheel, are we talking spoked or solid? I know sport bike guys say a good set of lightweight wheels is the absolute best mod you can possibly do because they benefit handling, braking, and straight line performance. I recently read an article of back to back tests on a cbr600rr and the BST carbon fiber wheels dropped lap times more than all the other bolt ons they tried combined.

You call the shop and ask whats availible for you bike. If you ride a Ducati your in luck seems to be a bunch availible....but hold on to the check book..

With money.

/smartass

Slight, but relevant thread jack: I have a friend with a neglected CB900F like the one in this pic. I could probably get it for a song, but I just can't swallow the com-star wheels. I would love to some spoke wheels on it, but even a more modern oem mag wheel set would be the a huge improvement. Is there a data base of interchangeability?

I don't know of a data base, but there are a lot of variables with the wheels. You have diameter, rim width, rotor space in the front and rotor and sprocket spacing on the rear as well as axel diameters.

For that cb900, you could always get something like a cbr600 F3 front end and rear wheel for $400 to $600 and swap not only the wheels, but the forks and brakes. That will give you some nice looking 5 spoke wheels and it will be a huge improvement over the stock. You would have to do some fabricating of spacers in the rear. You can't go too new as I doubt your swingarm, could hold a 5" wide wheel.

Call the companies below, they will have something that fits. The wheels may cost more than your motorcycle.

http://www.marchesiniwheels.com/en/why-marchesini/Pages/Lightness.aspx

http://www.marvic.it/marv_esperienza_eng.php

http://www.forged-wheel.com/fw/products.php

http://www.hardracing.com/OZWHeels.htm

Andy CBR600 swaps abound at www.CB1100F.net tell em you know 79cb750f aka me.