Looking on the bright side!
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It’s not just cyclists that the general population resent.
With people not driving as much and a higher increase in people going out and about on foot...
They’ve decided they hate joggers now. Consistent complaint on vox pops is of runners passing too closely and breathing heavily.
A close passing jogger is now the parklife equivalent of a cycling red light jumper.
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Should make them wear helmets!morstar said:It’s not just cyclists that the general population resent.
With people not driving as much and a higher increase in people going out and about on foot...
They’ve decided they hate joggers now. Consistent complaint on vox pops is of runners passing too closely and breathing heavily.
A close passing jogger is now the parklife equivalent of a cycling red light jumper.0 -
My last say on this. Imagine if there had been scientific research into the impact of vehicle speeds on emission levels and that as a result 20mph zones were being used as a means to reduce air pollution. What's that you say? It's already been done? Oh!
http://www.20splenty.org/emission_reductions
https://www.nice.org.uk/guidance/ng70/chapter/Recommendations#smooth-driving-and-speed-reduction
The proviso is that driving is kept smooth so you need to avoid speed bumps etc. that lead to braking and acceleration but other than that low speeds (20mph in this case) reduce emissions and pollution.1 -
Bahahahahahahaha.Wheelspinner said:rick_chasey said:
Do you cycle? How much more effort is it to ride at 40kph versus 30kph?
Why do you think that is?
Yes, I ride. Not enough, and not that quick, but still fun.
You are correct it takes more power to ride at 40 kph than it does at 30. That's overcoming aero and mechanical drag primarily on a bike. Give you are both the motor and mostly the sole resistance load causing thing on a bike, the relationship is as Pinno noted fairly linear (assuming you don't change gear!)
So what?
If you ride at those speeds for the SAME time duration, you will go further doing 40 than 30, so your work done is actually greater. Work is the energy consumption total amount, the FUEL BURNED bit... That particular calculation includes variables such as force, distance, and velocity.
It's NOT the rate at which you produce it - that's the Power bit.
If you burned the exact same amount of total energy and rode your bike at 30 instead of 40 (using the same gear ratio and riding position to minimise the comparison variables), you will go the pretty roughly the same distance in the end, it will just take you longer (time) to get there. You burn fuel (work) at a lower rate because less power is required to overcome the resistance at the lower speed.
Believe it or not, this is what bike racing is partly about, at least TT and straight speed stuff like pursuit on the track etc. Who can do the same amount of work in the least amount of time?
Put another way, if you decide to commute to work (a distance of 30 km) at a constant speed of 30 kph on your bike. You have two choices of bike to do it on:
- One is your really short geared, but lightweight fixie where you must spin at 140 rpm to keep the speed up. You are wearing chinos, trainers and an anorak, on flat pedals.
- Other is your slick carbon roadie with 24 gears, aero bars, deep rim wheels. You are wearing a teardrop helmet and a skin suit. You can pick whichever gear suits your particular physiology for most efficient pedalling.
The combined weight of rider and bike is the same for this example.
Which one will require more total energy (work, fuel burned) on your part to ride at that constant 30 kph for the 1 hour it takes?
For a clue, remember Sir Bradley Wiggins did not set the hour distance record riding a Boris bike.
The astonishing achievement he made was not really the actual distance he travelled. It was the sheer amount of work (power he maintained for the whole hour) that he could produce before failing. If he *had* ridden the Boris bike in the attempt, the odds of some other rider also riding that same Boris bike any further are pretty low, because there isn't anyone else who can produce that much power for that length of time.
Brad's team simply maximised his conversion efficiency in converting that work into distance travelled, by minimising the amount of wasted energy on aero, mechanical and bio-mechanical drag.
So for the same wiggins bike, does he travel 30km burning fewer calories at 30kph or 50kph?
I think you're confusing advocating everyone drive light small engined efficient cars which have low drag with advocating for higher speed limits.
I can pretty much guarantee that across pretty much all cars you will burn less fuel travelling a given distance at a lower speed than a faster speed, because of how drag and friction works.
The bit I've put in italics misses the drag component, which is easily the biggest factor in all of this. That's before you get to BB's point that decelerating and accelerating from higher speeds is also materially less efficient.0 -
Mass cycle in Turkmenistan 2 days ago to celebrate day of health
https://www.bbc.co.uk/news/world-asia-52186521- Genesis Croix de Fer
- Dolan Tuono0 -
That is a scary bright side, heckkingstongraham said:0 -
True, I was not really positioning it as a 'Stevo top tip', more of a personal observationmorstar said:
"I spent most of my money on birds, booze and fast cars: the rest of it I just squandered." [George Best]0 -
Hey wheel, here's the bit in power on drag that you've missed. Funnily enough, at A-level you don't cover drag in your mechanics paper, but that's why you don't have A level students designing things to be used in the real world.
Lucky for you, Wikipedia is your friend on this one.
Power
Under the assumption that the fluid is not moving relative to the currently used reference system, the power required to overcome the aerodynamic drag is given by:
Note that the power needed to push an object through a fluid increases as the cube of the velocity. A car cruising on a highway at 50 mph (80 km/h) may require only 10 horsepower (7.5 kW) to overcome aerodynamic drag, but that same car at 100 mph (160 km/h) requires 80 hp (60 kW).[17] With a doubling of speed the drag (force) quadruples per the formula.Exerting 4 times the force over a fixed distance produces 4 times as much work.
At twice the speed the work (resulting in displacement over a fixed distance) is done twice as fast. Since power is the rate of doing work, 4 times the work done in half the time requires 8 times the power.
When the fluid is moving relative to the reference system (e.g. a car driving into headwind) the power required to overcome the aerodynamic drag is given by:
Where v(w) is the wind speed and v(o) is the object speed (both relative to the ground).
But I did appreciate the facepalm pic.0 -
I immediately scroll past anything more than 4 lines. See above. Interesting? I wouldn’t know. It’s the modern now, now, now way. 😉pinno said:
You must read them before classing them as boringpblakeney said:Having the ability to scroll past boring posts cheers me up.
Think I'll use some unallocated funds towards booze. Good plan.
The above may be fact, or fiction, I may be serious, I may be jesting.
I am not sure. You have no chance.Veronese68 wrote:PB is the most sensible person on here.0 -
FFS give it rest or find another thread.rick_chasey said:Hey wheel, here's the bit in power on drag that you've missed. Funnily enough, at A-level you don't cover drag in your mechanics paper, but that's why you don't have A level students designing things to be used in the real world.
Lucky for you, Wikipedia is your friend on this one.
Power
Under the assumption that the fluid is not moving relative to the currently used reference system, the power required to overcome the aerodynamic drag is given by:
Note that the power needed to push an object through a fluid increases as the cube of the velocity. A car cruising on a highway at 50 mph (80 km/h) may require only 10 horsepower (7.5 kW) to overcome aerodynamic drag, but that same car at 100 mph (160 km/h) requires 80 hp (60 kW).[17] With a doubling of speed the drag (force) quadruples per the formula.Exerting 4 times the force over a fixed distance produces 4 times as much work.
At twice the speed the work (resulting in displacement over a fixed distance) is done twice as fast. Since power is the rate of doing work, 4 times the work done in half the time requires 8 times the power.
When the fluid is moving relative to the reference system (e.g. a car driving into headwind) the power required to overcome the aerodynamic drag is given by:
Where v(w) is the wind speed and v(o) is the object speed (both relative to the ground).
But I did appreciate the facepalm pic.
The older I get, the better I was.0 -
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Thanks Pross, I appreciate the effort to post that link. It's cleared up a whole pile of things for me. I accept that I am wrong. And boring, and probably barking too. Sorry.Pross said:My last say on this. Imagine if there had been scientific research into the impact of vehicle speeds on emission levels and that as a result 20mph zones were being used as a means to reduce air pollution. What's that you say? It's already been done? Oh!
http://www.20splenty.org/emission_reductions
https://www.nice.org.uk/guidance/ng70/chapter/Recommendations#smooth-driving-and-speed-reduction
The proviso is that driving is kept smooth so you need to avoid speed bumps etc. that lead to braking and acceleration but other than that low speeds (20mph in this case) reduce emissions and pollution.
But, still.... I am a little confused on a couple things. Imagine if scientific research was done that showed driving a (petrol engined) car at a lower speed actually generated increased emissions for each km driven.
What's that you say? It's already been done? Oh...
It's in the links you posted.
See other thread that @rjsterry started. Open One+ BMC TE29 Seven 622SL On One Scandal Cervelo RS0 -
I think some people need to re-read the title of the thread.0
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Things to be grateful for. Being in a happy relationship. You wouldn’t want to be single at this time now would you?The above may be fact, or fiction, I may be serious, I may be jesting.
I am not sure. You have no chance.Veronese68 wrote:PB is the most sensible person on here.0 -
Not so bad now the toilet paper shortage has ended.0
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I was wondering what had happened to Tinder during the lockdown.0
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pblakeney said:
Things to be grateful for. Being in a happy relationship. You wouldn’t want to be single at this time now would you?
Having more than one person in the house increases the chance of a virus making its way into the household...
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...and not necessarily C-19.briantrumpet said:pblakeney said:Things to be grateful for. Being in a happy relationship. You wouldn’t want to be single at this time now would you?
Having more than one person in the house increases the chance of a virus making its way into the household...
Probably doubles the chances. 😉
The above may be fact, or fiction, I may be serious, I may be jesting.
I am not sure. You have no chance.Veronese68 wrote:PB is the most sensible person on here.0 -
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Enjoying the Friday night West End musicals and a chance for a bit of a singalong0
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It was our little boys first birthday today. He still managed to love the day.2
