Chainring help

Like tick.tick.tick said - make sure you get the right BCD (bolt circle diameter).

I'd like to move up to a 46/16 gearing. My LBS (Apex Cycles in Clapham) are very friendly, but don't seem to have a clue when it comes to fixed stuff, so I was thinking for something as simple as this I could swop chainring (+/- chain if absolutely necessary) myself.

You want to make your gear ratio bigger, so if you change your chainring to a larger size you will probably have to buy a new chain (the old one may be too short to go around the larger chainring).

But . . . why not increase your gear ratio by dropping the size of your rear cog ? Cogs tend to be cheaper than chainrings and you can use the chain you have (might need to shorten it).

Here is a gear calculator to work ratios out on . . . .

http://software.bareknucklebrigade.com/rabbit.applet.html

PS: sorry for jumping on your subcultural bandwagon/contributing to the death of the fixed-wheel phenomenon by buying a Langster/etc.

If you are that ashamed or self conscious of your Langster then simply don't mention what bike you have. No one here is really that bothered about what you ride.