If you're an amateur and interested in speed, you might want to save your pennies and opt for something cheap.
Dr Groves' set up a trial to test whether his new, lightweight carbon-framed bicycle (which cost £1000) was any faster than his second-hand steel-framed bike bought for £50.
For six months he tossed a coin each morning to decide which bike to use - and then timed the journey.Dr Groves compared his commuting times on a heavy and a light bicycle
His study, published in the British Medical Journal, found that there was no measurable difference in commuting time over the 27 miles from Sheffield to his place of work and back.
The average journey time using his heavy, old bike was 1 hour 47 minutes and the average journey for the new, lighter new bike was 1 hour 48 minutes.
"A reduction in the weight of the cyclist rather than that of the bicycle may deliver great benefit at reduced cost," the study says.