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Bike speed

Posted: 19 Jun 2020, 8:52pm
by james.wiz
Bike power seems to be way higher than the speed that im going. Position and bike are decent. Any advice to help me get quicker?

Re: Bike speed

Posted: 20 Jun 2020, 2:08pm
by fastpedaller
james.wiz wrote:Bike power seems to be way higher than the speed that im going. Position and bike are decent. Any advice to help me get quicker?

Go with the wind instead of against it :lol:
Sorry I couldn't resist

Re: Bike speed

Posted: 20 Jun 2020, 3:50pm
by ANTONISH
james.wiz wrote:Bike power seems to be way higher than the speed that im going. Position and bike are decent. Any advice to help me get quicker?

Are you actually measuring the power?
I'm not sure what advice you are looking for.

Re: Bike speed

Posted: 20 Jun 2020, 7:04pm
by further
Don't bother about speed, just enjoy the ride.

Re: Bike speed

Posted: 20 Jun 2020, 7:40pm
by cycleruk

Re: Bike speed

Posted: 20 Jun 2020, 7:45pm
by richardfm
james.wiz wrote:Bike power seems to be way higher than the speed that im going. Position and bike are decent. Any advice to help me get quicker?

Pedal faster

Re: Bike speed

Posted: 20 Jun 2020, 7:57pm
by foxyrider
power is no indicator of speed

Often my highest power output will be when i'm going quite slow, say at traffic lights or a short sharp climb. There are so many things that can affect your speed, weather, the bike, your technique/position, road surface/terrain, clothing even. Its a whole can of worms and there are no wonder solutions but you have to start somewhere i guess so i'd make sure the bike is in tip top condition and assess your clothing, in terms of speed you need close fitting stuff, no baggy shorts or flappy jackets (and before someone comes in, yes i know you can ride at speed so dressed but those in pursuit of higher speed don't) and find a bit of road that you can do reliable comparisons on. There are a host of books on the subject of going fast on a bicycle, maybe its time to go back to basics and read up on the subject so you understand whats going on, the advice on this forum may or may not work for you and often is based on fag packet science so beware. :D

Re: Bike speed

Posted: 21 Jun 2020, 4:58pm
by Peter F
james.wiz wrote:Bike power seems to be way higher than the speed that im going. Position and bike are decent. Any advice to help me get quicker?

How are you measuring power?

Re: Bike speed

Posted: 22 Jun 2020, 3:02pm
by rmurphy195
Bike power (as in - motor) or your power?

Re: Bike speed

Posted: 22 Jun 2020, 3:36pm
by nigel8322
The article in the road bike link above is wrong. The air resistance increases as the square of the speed but the power required goes up with the cube of the speed (the article says it's the square). Eg doubling your speed (unlikely, but it makes the maths easier) quadruples the air resistance but gives x8 for the power (x4 air resistance then x2 because you work against the resistance for double the distance per second). This assumes that you are ignoring all other resistance (friction in the drivetrain, rolling resistance from the tyres, energy loss from 'bobbling' over rough tarmac etc.)
This explains why tootling along at 14mph average allows me to enjoy the countryside but 16mph average feels like a workout (the power required to overcome air resistance goes up by almost 50%).
Since I cycle for enjoyment (mainly) I tend to average 14mph! However, I do buy good tyres (losing 10W matters more when you're a bit short of Watts to begin with) and I keep the drivetrain lubricated- but that's because it sounds nicer when it's running smoothly). The key point seems to me to be 'forget the Watts; are you having FUN?'

Re: Bike speed

Posted: 22 Jun 2020, 4:23pm
by Yossarian
No substitute for working harder I'm afraid! Pick some long steadily downhill stretches and work hard all the way down, you'll get used to going faster.

Re: Bike speed

Posted: 22 Jun 2020, 4:47pm
by Jdsk
nigel8322 wrote:The air resistance increases as the square of the speed but the power required goes up with the cube of the speed (the article says it's the square). Eg doubling your speed (unlikely, but it makes the maths easier) quadruples the air resistance but gives x8 for the power (x4 air resistance then x2 because you work against the resistance for double the distance per second). This assumes that you are ignoring all other resistance (friction in the drivetrain, rolling resistance from the tyres, energy loss from 'bobbling' over rough tarmac etc.)

Yes.

Jonathan