Where can I get gears / chain&sprockets?

I`m looking to get a 16:1 ratio with bosch 750s & 16 inch wheels, can anyone give me some ideas on where to get some gears?
I could use chain drive instead so anything along these lines.
thanks

Technobots do both Spur gears and sprockets+ chains for what looks like a reasonable price. The spur gears do have hubs on which may or may not be a problem. I can't vouch for their quality as I've never bought them myself, but I'd imagine they'd be good. Plus Technobots usually ship quickly which is probably a bonus at the moment!
http://www.technobotsonline.com/mod-...pur-gears.html

http://www.gearsandsprockets.co.uk/ - this is the spin-off from Technobots. No really specialist stuff but perfect for our needs. Never ordered from them as the new site but Technobots were always fine.

I often use http://www.beltingonline.com/, typically a little pricier but they have a huge range, including nice timing belts. Good service, can recommend!

edit: and there's always Ebay.

I've used the technobots spur gears in the past. No issues at all and very reasonably priced.