I ride singlespeed from October to January. For several reasons as follows:

• It means I don’t have to clean my bike
• I re-learn how to spin a gear – I’m not tempted to push the big ring
• I have an excuse for being slow
• I love the purity
• My one speed bike is really comfortable (steel Condor)

Tips on the hardware…

Fix up an old frame
If you have an old steel frame you could consider haing it renovated and returned as a single speeder.
http://www.merciancycles.co.uk/renovation.htm

Use a 42×16 if you live in a flat area, 42×18 if it’s hilly. I know some people push bigger gears but it really doesn’t make that much difference on the flat, I can cruise at 22mph easily if I’m riding in a group. RPM goes a bit bananas after that. Ride a freewheel, unless you have experience of riding fixed – you should certainly try fixed but I don’t use it (my Sunday ride is always too lumpy).
Use a 1 1/8″ BMX chain and if you use a single chainring check the chain tension regularly.

Chainline
Buying a Single chainwheel and suitable size BB is the best option. This could cost a

RPM…
200 rpm is the most I’ve seen anyone do which was on a 38×16 downhill. Madness.

Bikes are rare with mudguard eyes etc. Condor, St John’s, Surly. Pure track bikes tend to be a bit twitchy for road use and you can’t get mudguards to fit. You can even get an old bike converted

Fixed

The winter is bad for your bikes. Gears and brakes need regular cleaning and
Fixed has the main advantage of maintaining momentum. The pedalling action is very smooth

Track riders always have good pedal actions

Many riders remove the lockring from the rear hub. This is

Advantages – smooth action. Great for hill climbing.
Disadvantages – crazy legs in hilly areas can be just as harmful if you are not up to it.

Freewheels
http://www.whiteind.com/ENO_web/freewheel.html

Bikes we like the look of…
Surly’s Steamroller is a stripped down street bike with horizontal dropouts and loads of clearance. No mudguard eyes. No frills.
http://www.surlybikes.com/steamroller.html
Their Karate Monkey is whatever you want it to be, take a look and you’ll see what I mean.
http://www.surlybikes.com/karatemonkey.html

St John’s Street do a great entry level cheap and cheerful single speed trainer. They are superb value.
http://www.sjscycles.com/store/vIndex.htm

A Mercian fixed winter bike has to be one of the classic road bikes of all time. Simple retro and beautifully made.
http://www.merciancycles.co.uk/frame_vigorelli.html

http://www.sheldonbrown.com/singlespeed.html

Gear conversion chart
http://www.campagnolo.com/sviluppo.php

http://www.roadcyclinguk.com/news/article/mps/UAN/293/v/1/sp/