Wednesday 10 May 2017

Come hill or high headwind

One of the many ideas which is proposed as an argument against making it safe and pleasant to cycle in the UK is that it's too hilly.

Speaking as someone who dismounts every day for the last 100 metres up my hill, I have some sympathy with this argument. I have heard people argue that the Netherlands, being flat, suffers from much higher winds than more bumpy places, and these are an equal problem. I was very skeptical until I cycled home in gale force winds one afternoon.

So here is my attempt to decide if I'd rather have hills or headwinds.



Headwinds

The wind is unpredictable. You set off expecting a quick journey, and for some reason your legs don't seem to be working. Then as you come to a gap between buildings, your bike jumps sideways and you realise you've been cycling into the wind this whole time.

(I would like to register a personal complaint against whichever architect designed the buildings around the south end of Blackfriars Bridge. Why did they include a wind tunnel round the base? I could do without the sideways jump when I'm in a group of a few dozen cyclists at rush hour, almost all of whom want to overtake me...)

At this time of year, I also have a particular grudge against the London Plane and its seeds, or whatever it is that gets in my eyes when it's windy.

High winds are another reason for separating bicycles from motor vehicles: many drivers don't seem to realise quite how much a bicycle can act like a sail when there's a sudden gust, catching the wind and propelling its rider sideways. There's not much a cyclist can do to prevent invisible shoves from the air!

Hills

By contrast, hills are permanent. Home is uphill every. single. day. But I know how to avoid it by approaching from a different direction, and journey times are predictable.

It's possible to create a network of cycle tracks in London which avoid unnecessary hills. Unfortunately, if you look at a contour map, you will see that our ancestors had exactly the same idea! So the main roads which now carry lorries and buses take all the flat routes, leaving anyone wanting a quiet cycle to go over multiple unnecessary hills. Bring on protected cycle tracks on main roads!

The technological solution to hills is the ever-more-popular electric assist bike. The battery gives you the extra oomph needed to get uphill without sweating over it. I've not been able to justify the cost of one yet, but if the day ever comes when I think "I need a car", I intend to take that money and run to the shop that sells electric cargo bikes, cackling the whole way.

The electric assist would help with headwinds, but not with sideways gusts and dust. And freewheeling downhill is one of life's great joys.

So in the end, I think I'll take the hills. Of course, I live in a mostly flat river valley, so residents of Snowdonia might feel differently...

A table of wind speeds

Adapted from the Wikipedia article on the Beaufort scale to be useful for cycling.

Beaufort number Description Wind speed (kph) (mph) Conditions
0 Calm < 1 Calm. Smoke rises vertically.
1 Light air 1–5        Smoke drift indicates wind direction. Leaves are stationary.
2 Light breeze 6–11 ~5 Annual mean wind speed in London.
3 Gentle breeze 12–19 ~10  Good dinghy sailing weather.
4 Moderate breeze 20–28 Dust and seeds in your eyes
5 Fresh breeze 29–38 ~20  Gusts this strong push you sideways
6 Strong breeze 39–49
7 High wind, near gale 50–61 ~35  Difficult to get anywhere. Effort needed to walk against the wind.
8 Gale, fresh gale 62–74 ~40 Cars veer on road. Cycling definitely not advised.
9 Strong/severe gale 75–88 ~50 Some branches break off trees, and some small trees blow over. 

1 comment:

  1. Actually, more and more residents of Snowdonia are finding out that cycling up the hills can be quite pleasurable, as long as you have a Dutch bike! No electrics needed, just enough gears. Perhaps it's time for you to get yourself another (second hand) bike again? See Beics Berno on Facebook.

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