Bicycle computers are electronic speedos that tell you a lot more than how fast you're going.

How They Work. In general they work via a sensor mounted on the fork which senses the passing of a magnet mounted on a spoke, sending a signal to the head, which has the wheel size programmed into it so it can calculate speed etc.

What They Tell You. Most computers will tell you your current speed, your maximum speed for this ride, your average speed for this ride, your distance for the ride, your total distance (odometer), your ride time and the time of day. Some will tell you less than this, some will have a variety of other functions ranging from calorie consumption to altitude.

Rear Wheel Mount. For use on a training stand (with a stationary front wheel) you'll need a rear wheel sensor and a long wire kit to suit. The cateye Astrale offers this, as well as cadence (the speed at which you're turning the pedals).

Wires and Transmitters. Some computers have tougher than usual wires in them to prevent damage from catching on bushes etc, and the next step in this direction is the cordless computer which sends the signal from the sensor to the head via a radio signal. No more broken wires, no more ugly wires hanging on the bike, and, in Cateye's case at least, no contacts between a handlebar bracket and the computer head to wear out after years of use on bumpy roads, or to give a poor connection during wet weather.

Cateye Padrone Computer

If you want to be able to read your computer without wearing your reading glasses - this is the one to buy! By a large margin, it's the biggest and easiest to read display we've come across.

Developed from CatEye customer feedback, the Padrone features the largest display available today. From the downhill mountain biker to the far-sighted cyclist, the Padrone is ideal for anyone who wants to enjoy a squint-free ride and a fast, simple set-up.

Shipping Weight: 90 g.

Echowell Computer U6 (Wired)

An economical cycle computer from the dependable Echowell factory. Large, easy to read display, with 6 functions including average speed.
Shipping Weight: 91g.

Echowell U4w Wireless Computer White

This very simple wireless computer tells you the essentials and otherwise lets you enjoy your ride. The top line of the display shows current speed, the bottom line shows the odometer reading. The middle line shows average speed and trip distance, alternating each 5 seconds.

 Dimensions: 48mm x 34mm x 13mm. Tool-free installation. Test button on speed sensor.

Shipping Weight: 101g.

Maxell Battery LR44 Pair

Pair of 1.5V (Alkaline) LR44 batteries.
Weight: 4g.

Sigma Cadence Power Magnet


Stronger magnet than the regular cadence magnet.

Magnet has double sided tape and zip ties for fixation to crank arm. works with all computers with cadence.

Shipping Weight: 12g

Sigma Cadence Sensor Kit Universal

Cadence sensor kit for wired Sigma Sport cycle computers.

Sigma Article Number 00425.

Shipping Weight: 28g.

Sigma Cadence Sensor Kit Wired

Fits wired Sigma Sport computers with cadence option.
Shipping Weight: 100g.

Sigma Sport Speed Power Magnet Tool Free

Sigma have redesigned their Power Magnet so you no longer need tools to fit it. It fits bladed or round spokes.

Length: 21mm. Width: 12mm.

Weight: 4g.

Sigma STS Speed Sensor

For bike 1 or bike 2,. 3 channels digital coded transmission system. Less power consumption. Faster actualisation of data.
Shipping Weight: 60g.

Spoke Magnet for Computer

A spoke magnet with a simple attachment system that will fit just about any spoke out there.

Made of plastic. Weight: 4g.

Topeak Bar X-Tender

Gain more room or find the perfect position for lights and computers on your bicycle handlebars with the Topeak Bar X-Tender. Attaches securely to handlebars or handlebar stems and adjusts for optimum positioning.
Weight: 100g.

Vinnic Battery Lithium CR2032 (ea)

Not a premium battery brand; quality unknown. But price is OK.
Weight: 3g.

Vinnic Battery L1028 12V Alkaline

Not a premium battery brand; quality unknown. But price is good. This battery fits the sensor of the O-Synce Mini Free computer.
Shipping Weight: 14g.