Wednesday, 27 November 2019

The extraordinary efficiency of bicycles, the potential of active modes, and the role of active travel in transport poverty

Last month my eldest daughter ran the Amsterdam marathon. She achieved her aim of running the 26.2 miles (42.2 km) in under her target of four and a half hours. A marathon is something you need to train for. The race was won by the spectacular Eliud Kipchoge, an extraordinary athlete and the world record holder, who has won nearly every race he's ever entered and who finished with a time of just over 2 hour and 5 minutes, but I'm still also very impressed with Eliza's achievement. It takes a lot of effort to run that far without stopping. I certainly couldn't do it.
One of several stops on our route through the countryside. We
weren't in a hurry today.

Twice as fast using a quarter of the energy
Like many people these days Eliza uses an electronic device linked to her mobile phone which monitors heart rate and speed and can calculate her energy usage. To run the marathon required about 2800 kcal.

Two weeks later I went for a bike ride with my daughter. It just so happened that this was also over 42.2 km and as she carries the same device for all exercise we could make a comparison. On the bike ride the energy consumption was just 700 kcal (about the same as one home made pizza). What's more, though we weren't in anything remotely like a hurry (we stopped for refreshments, for coffee, to buy bread from a baker and vegetables from a farm), our time was still several seconds better than Kipchoge's best ever marathon time and remember that Kipchoge's faster time over the marathon distance required him to expend somewhat more energy than Eliza had to.

A sack of onions joined us for the second half of the ride.
Running or even walking 20 km doesn't really work with a load
The difference in efficiency between running and cycling is extraordinary: On a bicycle an average person can easily travel faster than a world champion can run. We can use a quarter of the energy to travel at twice the speed. Because it takes so much less effort to cycle than it does to run we need no special nutrition or training before setting off to travel the same distance as a marathon. There's no expectation of damage to your body from a bicycle ride of marathon length. What's more, we can do all this while carrying far more than it is practical to transport if running or walking.

The potential of walking as a mode of transport
My cargo bike loaded up with parcels full of bicycle parts.
I ride this to the city centre often. If it were not possible to do
this by bicycle then I'd have to use a motor vehicle.
Both walking and cycling, the two really practical active travel modes, should be encouraged. But there is far more potential to cycling than there is to walking. Walking is of course a lot less tiring than running, but this comes at the expense of even lower speed. Speed is not everything, but the distance we can travel by any given mode is dictated more by available time than it is by the distance itself. That's why many everyday distances are are longer than is practical to walk. A relatively fast walking pace is only around 5 km/h (3 mph). This works only for the shortest journeys because the time taken out of the day is just too long if we try to walk for longer journeys. What's more, it's not possible to carry much when walking. All these things limit the potential of walking as a mode of transport. Children who live really near their school can practically walk to it, but even most of those who live within the same suburb as their school will need to use a faster mode of transport. Similarly, people who live in a city centre may be able to reach nearby shops by walking, or those who live in a suburb can reach some local facilities by walking, but it doesn't work over a larger radius.

A successful pedestrianized city centre, accessible to all.
Conflict is avoided by obvious demarcation of where cyclists
should ride by use of different colours and kerbs (forgiving).
The two hours that it took to make the leisurely 40 km recreational ride around the countryside described above are about the same amount of time as it would take us to make a reasonably brisk walk to the city centre and return again. We have done this occasionally, on a Sunday just for the novelty of it, but it's not something that we do on a regular basis. On the other hand, we cycle there almost daily for one reason or another. Cycling to the centre takes less than 10 minutes, which makes cycling a highly competitive mode with driving a car the same distance. Also, by using a bicycle we can transport almost anything and do so with far more ease than by carrying it while walking. So that's how we make those journeys.

Pedestrianization projects in city centres are not generally intended to be used by people who have walked to the city centre because almost no-one does that. They are instead used by people who have travelled by motorized vehicle to reach the city centre. Pedestrianization projects which exclude cyclists actually work against active travel.

Walking and cycling policy need to be different because walking and cycling are different.
If someone runs through a crowded area for pedestrians it's likely be seen as an anti-social act. Yet many places combine cycling and walking policy and even the infrastructure for both modes as if this is reasonable. It's not.

A few weeks ago Judy and I brought home a new floor for
our home by bicycle. Two 10 km round trips were required.
This would not have been possible by walking.
Cycling and walking are not the same. A bicycle allows anyone to travel at twice the speed of a world champion runner, to cover marathon distances without any great difficulty and a bicycle also allows people to transport loads which are well beyond what they can lift, let alone practically carry over a distance of kilometres.

Unfortunately this potential is often not understood. Through a non-cyclist's eye, cycling is often perceived as being much like walking. This is one of the reasons why it is common to hear that it's "not possible" to carry home grocery shopping by bike, that it's "too far" or "too sweaty" to cycle to work or "impossible" to cycle in winter. None of these things are true, of course. They're just the ideas that people have because they've not actually tried and experienced for themselves how easy and convenient it is to do those things by bike.

The objection to shopping by bike can be due to a misunderstanding of how convenient it is to carry items on a well equipped bicycle designed for everyday use. The concerns about commuting are often based on overestimation of average commuting distances combined with perceptions that cycling is no quicker than walking or that it will take as much effort as running and therefore result in sweating a lot. The objection to winter is often due again to a lack of familiarity, or perhaps also to having seen people on less well equipped bicycles struggling.

In this photo my other daughter, Alice, and her dog demonstrate
parallel cycling and walking infrastructure in Groningen.
Pedestrians and cyclists shouldn't be mixed on through routes.
In places where which lack well designed cycling infrastructure, any trip by bike will likely be seen as akin to an extreme sport. Indeed, it may well be both difficult and dangerous if the infrastructure is lacking and that is a good part of what prevents people from even trying to cycle in many parts of the world.

Cycling can be made very inconvenient indeed if cyclists are required to behave as pedestrians or weave through motorized traffic. Indeed where bicycle riders are given a choice of either not taking advantage of the efficiency of the bike or riding in conditions which cause danger, the whole point of the bicycle as a practical and safe means of transport is lost. Not cycling where conditions are poor is in many cases actually quite a rational decision.

The importance of cycling policy
It's of vital importance that we reduce climate changing emissions.
Cycling is the best way to reduce the emissions of transport.
But cycling policy is important, especially now, because bicycles are the most efficient vehicles in existence. Unlike other low or "zero emission" vehicles, bicycles in most cases genuinely have zero emissions. After all, we all need half an hour of exercise a day to be healthy and drivers eat too so in most cases the carbon cost of the "fuel" for cycling is zero. But even if we forget about our actually needing to eat and count the full carbon cost of food, we can eat in such a way that our "emissions" are still less than a tenth of even the most efficient motorized transport modes. Also remember that the embedded energy in even a sophisticated bicycle is unlikely to be greater than 1% of the embedded energy of a car. This wonderful machine avoids the many problems caused by motorized transport while giving us competitive travel times. Cycling is almost always quicker than taking a bus, often quicker than a car within towns. And let's not forget that while other transport modes cause health problems, there are many health benefits to cycling.

Cycling is so obviously a good idea, but it's still being overlooked in most places on the planet. This is something that we really have to change. We are living in a climate emergency. The most efficient transport mode on earth should be getting the highest degree of public support from world governments.

How to make every bicycle efficient
Let's continue with a short piece of advice about making any bicycle efficient. While some bicycles have more potential efficiency than others, all of them, no matter how old, no matter how inexpensive, are amongst the most efficient vehicles on earth. It doesn't cost anything to set up a bicycle for maximum efficiency. That's just a matter of quite simple maintenance:
  1. With any bicycle, start by setting the saddle height so that you can extend your legs properly. We pedal with the ball of our feet but can approximate the correct distance from saddle to pedal by straightening our legs so that the heel just rests on the pedal). If the saddle is too low it costs a lot of extra effort.
  2. Pump up your tyres to something approaching the maximum recommended pressure written on their sidewall. Note that in most cases bicycle tyres need to be pumped to far higher pressures than car tyres so a car pump isn't ideal. Under-inflated tyres consume a lot more energy from the rider than correctly inflated tyres.
  3. Make sure the chain isn't worn or dry. Each link should be exactly half an inch long. 1% wear is enough that you should replace the chain to avoid wearing other components unduly (measure over many links or use a specifically designed measuring device). The chain also needs to be oiled (WD40 falls off, grease is horrible on a chain and thick oils are not ideal, but any thin oil including proprietary bicycle chain oils will work) so that the internal links are wet (the outside need not be). A dirty/rusty chain often makes an unpleasant noise as well as consuming more energy.
Also see my guide to the features of everyday bicycles.
Taking care of those things is enough to optimise the efficiency of any bicycle and any bicycle combined with its rider is more efficient than any other machine that exists.

While many bicycles, especially outside the Netherlands, are sold with no means of transporting cargo, almost all bikes can be fitted with an inexpensive luggage rack which makes transporting goods more easy.

Please note that this is not a complete guide to safe cycling - also ensure such things as that your brakes and gearing work correctly and that you have fitted any equipment that is required to cycle legally in your country (e.g. bellslights).

I'm a hopeless runner. The furthest I ever ran was just short of a quarter marathon more than 30 years ago and that was more than enough. I can still cycle 200 km in a day without a problem but running any distance at all results in knee pain.

We make our living by selling bicycle components so if you order something we will of course supply it. But to make your bicycle more efficient you need only to follow the steps above. Do that before buying anything else, including from us.

8 comments:

Unknown said...

Your tyre inflation recommendation is not up to date, see:
https://www.renehersecycles.com/myth-16-higher-tire-pressure-is-faster/

David Hembrow said...

Unknown: I've long advised people to use wider tyres because they are both comfortable and efficient at lower pressures than are required in very narrow tyres and I ride myself do most of my riding on tyres which are considerably wider than any of those referred to in your article, though I actually do find that I still ride very close to the maximum pressure for the best efficiency with those tyres (we have very smooth cycle-paths here and most of my riding is on them). But the advice above isn't really aimed at people who are focused on performance who already keep their tyres well inflated and their chain well oiled, but at those who are riding on tyres so under-inflated that they absorb a lot of energy, with chains so dirty and rusty that they also absorb energy and a saddle so low that they can't extend their legs properly. For those people, any increase in pressure will result in better efficiency. While if they actually follow my advice they may lose just a few percentage points by being over-pressure relative to the most efficient point immediately after inflating their tyres, over a few weeks or months as the tyres slowly deflate they'll likely go through whatever the best pressure might happen to be and back out the other side to rather too soft before the problem is again addressed and the tyres are re-inflated. That many people simply don't check the pressure often is in itself a good reason for most people to pump their tyres to just about as hard as is allowed on the sidewall. It's far better than running under-inflated.

marmotte27 said...

Just a little clarification regarding tire widths. In the blogpost referenced by Unknown, Jan Heine recalls his initial testing from 12 years ago with performance tyres that were then considered normal or wide (i.e. up to 32mms!). Based on this and the research conducted since today his company offers tyres as wide as 54mms.
As I said, he's talking about performance tyres, i.e. tyres with supple sidewalls. Of course tyres this wide have existed before, but they were stiff and/or knobby tires that per se roll slower. Such tyres flex so much internally you won't get any benefit from running lower pressures.
But as you say, all this is outside the scope of your article and it's intended public (technically and financially, a pair of Rene Herse tyres cost as much as most people will ever pay for a whole bike).

David Hembrow said...

Marmotte27: I am not in any way disagreeing with Jan's conclusions, but I can assure you that wide smooth tyres with supple sidewalls have existed for very much longer than 12 years and their advantages have long been understood amongst riders of recumbent bicycles. For instance, following other people's tests of rolling resistance (almost certainly including this set of tests from between 1993 and 2002), I personally rode on Tioga Comp Pool tyres starting around 2000. Indeed, the photo at the top of this web page was taken in September 2000 and is of my bike fitted with those very same tyres. The Comp Pool's are long out of production, but were about 47 mm wide, slick and had a soft sidewall. Judy definitely still had one of these on her bike for the study tour we organised in 2006 - it was memorable because she had more than one puncture due to the tyre. And that's one of the reasons why we stopped using that particular tyre - the other being an almost total lack of grip in the wet. These days there are better options than the Comp Pool. It's certainly still not necessary to spend a fortune to buy an efficient tyre. However for most people there's really nothing that works any better than a Schwalbe Marathon. They're not expensive, they're very long lasting, they have exceptional puncture resistance and they're also pretty quick.

Unknown said...

Schwalbe Marathon *Plus* if you live in a big nasty city. In central London on Marathons I still get punctures occasionally, but on the Marathon Plus variant I never do.

--Richard

Unknown said...

40 km in less than 2h? How do you do that? My route to work is about 10 km, I ride through the city, with 3 high overpasses on the way, most of the cycle path is rough sidewalk bricks or old broken asphalt, lots of traffic lights, and the ride takes me a whole hour. After riding I'm so tired that I barely stand on my legs, my wrists hurt badly and I need to replace my tshirt because of the sweat.

David Hembrow said...

Richard: The Marathon Plus is my other favourite tyre. I have them on my town bike. They're fantastically puncture proof.

Unknown: 40 km in 2 hours is really not fast. We didn't break a sweat at that speed. The cycling infrastructure here simply allows a cyclist to keep moving and its that ability to continuously move which makes cycling efficient. Overall speed when cycling depends a lot on the conditions which are faced by a cyclist. For example, a few years back I wrote a piece comparing my Dutch commute to work in which I covered 30 km in 50 minutes with a previous commute in the UK took just as long to go 20 km. The UK example included bad surfaces, dangerous conditions and far more stops, which overall resulted in a much lower speed. In conditions which were even worse than my experience in the UK then I also would ride at lower average speed.

It's vitally important that cycling infrastructure is built to a high standard, minimising the need to stop and maximising how quickly cyclists can ride safely because otherwise the potential of cycling as a mode of transport is again lost.

Kevin Love said...

I am another satisfied owner of the Marathon Plus tyres. Until the year 2006, I rode a Chicago Schwinn bicycle that I bought in 1978 at the age of 16. That bike worked perfectly, but it was a bit small for me, as I am 205 cm tall. In 2006 I bought the large frame Pashley Roadster Sovereign because it is a better fit for my height.

Marathon Plus tyres came as factory standard equipment on the Pashley. Suddenly I never, ever got a puncture again. Before then, I would be getting a puncture every 1-2 months. I grew quite proficient in patching punctures without removing the wheel from the bike, but it was always quite a nuisance. And the puncture would always happen at the most inconvenient time, such as when I was going to an important meeting.

Over the years, people had sold me various things to eliminate punctures. Heavy duty tyres, gels/liquids to put in the tube, etc. All of which had a lot of marketing hype, which was nothing but a lot of bovine effluent. None of them worked. So when I bought the Pashley, at first I put the claims of the Marathon Plus tyre into the same category. But these tyres actually worked!

A note to Marmotte27: The Pashley Roadster has always used 28 X 1.5" tyres. That is a 38mm width. Since this tyre was used on the Flying Pidgeon (over 500 million bikes made), it is the most common type of tyre ever manufactured. And for good reason too. It achieves the best compromise amongst all the factors that make tyres useful.