Radio 4 go out with London Cycle Police

[punkedmonkey]

An interesting article on Radio 4's 'BH' programme about cycling with London's cycle police - it's in the last 10m http://www.bbc.co.uk...rammes/b006qnj3 from the programme on 13 March.

Some interesting advice given on road riding by the police to the presenter. Including 'cycling on the brakes' - apparently applying your brakes while pedalling in a slow/tight space gives you better balance and control. A new one on me (anyone know anything more about this?) - will have to try it out sometime (hopefully with more success than the radio presenter!).

It was interesting to hear them talking about 'setting the standard' for cyclists... given the comments on "Velo-plod" on this forum earlier this week!

 

[summerdays]

Some interesting advice given on road riding by the police to the presenter. Including 'cycling on the brakes' - apparently applying your brakes while pedalling in a slow/tight space gives you better balance and control. A new one on me (anyone know anything more about this?) - will have to try it out sometime (hopefully with more success than the radio presenter!).

I don't know how I know it but it is something that I do a lot of ... from my gate to the shed involves a number of 90 deg bends and a sharp 60 deg turn ... each one only a meter or two apart on a path that is about 70 cm wide but narrows to 40 cm at one point which I aim to do without putting my foot down each day. And also the gear has to be right ... not too low or high either seems to be best. It occasionally goes wrong ... most often because a pannier strap catches on the gate latch mechanism

 

[deptfordmarmoset]

Some interesting advice given on road riding by the police to the presenter. Including 'cycling on the brakes' - apparently applying your brakes while pedalling in a slow/tight space gives you better balance and control. A new one on me (anyone know anything more about this?) - will have to try it out sometime (hopefully with more success than the radio presenter!).

I wasn't fully awake when I heard that this morning so I may have got it wrong but didn't the officer say something about it helping you keep your centre of gravity low? I'll have to have another listen because I've got no idea how applying the brakes would make the slightest difference to your centre of gravity. Maybe it'll make more sense once I've had a couple of cups of tea.

EDIT: I just listened to it again - it starts around 0:54:00 - and I still don't understand how braking lowers your centre of gravity.

 

[shunter]

Dragging the rear brake whilst doing tight turns and twists as well as when travelling very slow is a well known motorcycle technique. I am sure I have used it on the bicycle without thinking too much about it.

 

[yello]

Including 'cycling on the brakes' - apparently applying your brakes while pedalling in a slow/tight space gives you better balance and control.

I'm more used to doing it on the motorbike but have done it on the pushie too. It does give a better precision control (if you know what I mean) at slow speed. Try it, easy enough to master.

Re the programme, I heard it and thought more should have been made of the reporter going up the inside of traffic. The bike police mentioned it to each other but not to the reporter. Missed opportunity I thought. An interesting, if light, programme though.

 

[atbman]

We teach the kids this in slow bike races.

1. Stand up on pedals
2. Strong foot above horizontal (say, 10 o'clock)
3. Push down to horizontal (not below) while dragging rear brake only
4. Push rear foot down to raise leading foot to 10 o'clock (ish)
5. Repeat until last across the line

 

[MrHappyCyclist]

This riding under braking for stability is mentioned by John Franklin in Cyclecraft, and I was rather puzzled when I read it in there. I, too, can see no reason why this technique would give better lateral control.

The lower centre of gravity point just doesn't make sense. First, braking whilst pedalling will make no difference to the centre of gravity. Even if it did, lowering the C of G increases maneouverability but decreases stability, making it harder to control the bike at low speeds, not easier. This is because a higher C of G causes the bike to "fall" sideways more slowly at any given deflection, allowing more time for correction. (This is different to the effect when stationary, whereby a higher centre of gravity would make the bike harder to hold up.)

I can imagine that there may be an apparent increase in the stability of the steering column itself if the front wheel is braked whilst pedalling because this would create a backward force at the point where the tyre contacts the road, reducing the effective "trail" of the steering and bringing the total force at the contact point more into line with the steering head. However, I think that would be unlikely to affect the actual ability of the riser to control the bike's lateral movement.

My own feeling is that this cycling under braking thing is a myth, but I'm interested to hear if there is a rationale that supports it.

 

[summerdays]

There is no way that I can explain it in any technical terms... physics just wasn't my subject ... but I guess for me it seems to make sense that I can make a tighter turn at a lower speed - so that if I take a normal corner at too high a speed I end up crossing the central line of the road - so the slower I go the tighter the turn?

I guess it is easier to go slow pushing against the brakes because the bike tends to want to roll... err that is probably the limit to my theorising ... I just know it works for me.

 

[Dan B]

I do it sometimes because, um, actually I don't know why. But I agree that it cannot possibly change the bike CoG (assuming an unsprung bike, haven't thought about the compression effects if you have boingy bits).

summerdays probably has got the actual explanation as well as anyone: most people can probably control bike speed more easily using their right hand than they can by careful modulation of how hard they push the pedal - especially as the force exerted by pedalling will vary depending on pedal position.

 

[Ste T.]

I posted this last year but I think it's relevant to this.


I had a very interesting conversation with a PCSO yesterday. I was riding through a local town with loads of parked cars and narrow streets, and was getting the usual comments and filthy looks for riding in the primary and staying out of the door zone, when I spotted two PCSOs on bikes coming out of a park so I stopped for a chat.
I asked them what their training was on the subject of riding primary and her answer was that they get two days training so that the can go out on the bikes but the passing of parked cars wasn't covered. She then went on
"It's an awkward one that isn't it? You see, if you ride far enough out so that the door won't hit you, you'd be too far out and holding up the traffic. That's why I ride next to the cars and if they open the door they are in the wrong."

So there you have it.



I don't know what they teach them about the door zone in your neck of the woods but I think it is an opportunity missed if coppers aren't seen riding a full metre away from parked cars. It would be a good example to other cyclists but more importantly it might get the point across to motorists, most of whom haven't a clue why we are doing it, and think we are just being peanuts.
A shame if they didn't cover it on BH.

 

[jugglingphil]

I heard the radio 4 program over the weekend.

I was a bit disappointed that the BBC go to the trouble to go out with 2 cycling cops (there must be a good name for them), but send a presenter who hasn't ridden a bike in years.

Or am I missing the point?

 

[pshore]

To answer the braking-whilst-going slowly technique ......

Balancing is a mix of: Steering, centrifugal force, and position of weight relative to tyres.

When making a slow tight turn:

If you are falling into the turn too much, you can accelerate to (1) steer the bike underneath you quicker, and (2) it pushes your weight towards the outside of the turn (increase centrifugal force) and you become more upright.

If the opposite is happening, and you are rising to towards the outside of the turn (perhaps due to an over correction), you can use the back brake to lose speed and centrifugal force (opposite of 2 above) which will help you fall back into the turn. With only the back brake applied, the front wheel can still steer to maintain balance.

If off the saddle, you can change your weight position to also change balance.

Put all the above together and you'll be doing track stands in no time.


In addition to this, and whilst making faster turns, the back brake has the effect of making you fall into a turn, but the front back will often sit the bike up and make it want to go straight. I'm not exactly sure why though.

Re, the low centre of gravity, I am not sure it applies here. Ever tried balancing a broom on your hand ? It's easier with the weight at the top. In a fast turn it is useful to push your weight into the pedal on the outside/upper pedal as this puts more weight over the tyre for increased grip.

 

[MrHappyCyclist]

To answer the braking-whilst-going slowly technique ...... etc.

Thank you. I like this analysis. It seems to make sense (but will need to think about it a bit more).

 

[Simon_m]

Update:

http://www.bbc.co.uk/news/uk-scotland-north-east-orkney-shetland-12745313