Bike speed

Commuting, Day rides, Audax, Incidents, etc.
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james.wiz
Posts: 1
Joined: 19 Jun 2020, 8:48pm

Bike speed

Post 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?
fastpedaller
Posts: 2936
Joined: 10 Jul 2014, 1:12pm
Location: Norfolk

Re: Bike speed

Post 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
ANTONISH
Posts: 1998
Joined: 26 Mar 2009, 9:49am

Re: Bike speed

Post 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.
further
Posts: 37
Joined: 25 Apr 2016, 6:44pm
Location: South West

Re: Bike speed

Post by further »

Don't bother about speed, just enjoy the ride.
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cycleruk
Posts: 5607
Joined: 17 Jan 2009, 9:30pm
Location: Lancashire

Re: Bike speed

Post by cycleruk »

You'll never know if you don't try it.
richardfm
Posts: 422
Joined: 15 Apr 2018, 3:17pm
Location: Cardiff, Wales

Re: Bike speed

Post 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
Richard M
Cardiff
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foxyrider
Posts: 5360
Joined: 29 Aug 2011, 10:25am
Location: Sheffield, South Yorkshire

Re: Bike speed

Post 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
Convention? what's that then?
Airnimal Chameleon touring, Orbit Pro hack, Orbit Photon audax, Focus Mares AX tour, Peugeot Carbon sportive, Owen Blower vintage race - all running Tulio's finest!
Peter F
Posts: 143
Joined: 25 May 2020, 8:16am

Re: Bike speed

Post 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?
rmurphy195
Posts: 2054
Joined: 20 May 2011, 11:23am
Location: South Birmingham

Re: Bike speed

Post by rmurphy195 »

Bike power (as in - motor) or your power?
Brompton, Condor Heritage, creaky joints and thinning white (formerly grey) hair
""You know you're getting old when it's easier to ride a bike than to get on and off it" - quote from observant jogger !
nigel8322
Posts: 13
Joined: 5 Feb 2015, 8:53am

Re: Bike speed

Post 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?'
Yossarian
Posts: 18
Joined: 21 Dec 2015, 4:24pm

Re: Bike speed

Post 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.
Jdsk
Posts: 8187
Joined: 5 Mar 2019, 5:42pm

Re: Bike speed

Post 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
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