Safe Speed Forums

So, on my 14 mile cycle through London I average about 14mph (I.e. it takes me about an hour to go 14 miles).

Now in clear road I cruise at about 20mph, sometimes hit 25 or 30, and go slower when filtering in traffic.

Of the hour I spend on my cycle about 10 minutes is spent stopped (sitting at lights, junctions, stuck in amongst a load of cars etc...).

My question is, in the grand scheme of things, if I travel at a maximum 14 mph, given all the variables involved, will it still take me an hour to get to work, or would I be quicker, or slower overall?

It will depend on the timing of the lights.

If you arrive slower and still get stopped, it will take longer.

I learned these things in school - usually it was made more complicated by their being more than one traveller, going at different speeds, and we had to say who would arrive first.
They NEVER allowed for lights or stopping off at the paper shop and finding a queue!

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Time to take responsibility for our actions.. and don't be afraid of speaking out!

It will, at absolute best, take you the same length of time.

As 14mph is currently your average speed, ie 14 miles travelled in one hour, time stopped/delayed is taken into account. To take the same length of time at a maximum of 14mph you would, of course, have to maintain that maximum for the whole hour. Since there are parts of your journey that you currently travel at less than 14mph, regardless of stops for lights etc, I would suggest that this would be unsafe.

In a nutshell, in all but the most exceptional of circumstances, its going to take you longer. I've a feeling you knew this, however, since its pretty simple logic, so can only assume that you have some ulterior motive for asking the question, so please do enlighten us.

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Regulation without education merely creates more criminals.

No serious question, I've often wondered this.

Interesting. So clearly you vary your speed according to the conditions. I do too, and not just when I’m the engine.

I'll put aside how I know you generally feel about anything going faster because I'd like to address your question as though it came from someone who asked it without any hidden agenda. (I apologise in advance if that's wrong or unfair but I'm sure you understand why someone/anyone here might think that.) So then..

As someone who does a similar journey around England's second largest city every working day in all weather conditions, I have a slightly different angle which is health and safety related rather than speed. I see this as much more important than a snap-shot numerical speed or overall average speed. Sound familiar?

I cycle every working day and can travel at ~15 mph without too much heavy breathing but of course it depends on the gradient, traffic and conditions.

At one point, I am going downhill as mothers are walking their children to school. They're like ants all around the nearby pavements; pretty little flowers that I don't want to bump into.

So although I could make time up at this point I’m on the brakes the whole length of the road until the danger is passed.

I try to cycle at a rate where I do not have to breathe heavily and ingest the fumes of slow moving or stationary traffic, especially when I stop at a red light. (Yes, I'm one of those who do stop at a red)

So my advice would be to go at a speed based on your environment such that you are not putting yourself or others at risk while protecting your own health - but I'm sure you do this anyway weepej.


BTW, “No serious question” is different to “No! Serious question.”

(Eats shoots and leaves)

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

Oh, me too, but sometimes I'm tired and like to slow up a bit, but brain still unconciously nags that this means I'll get home/to work slower and I tend to push myself when I shouldn't; just questioning the "common sense" (which is more often than not totally and diametrically wrong).

Like I've said before, in and around ped heavy areas I travel at a much lower speed, so I could ask why do I see cars whizzing by me?

I know a cycle is a little different than a car, peds only often use ears to detect movement, so can easily step out in front of a silent bike as opposed to a noisier car. I've said this before but when we're all driving electric practically everybody is going to have to learn how to drive again.



I've read that it's better to breathe more heavily as it helps rid your lungs of all the dirt, rather than a partial exchange that get's to sit and absorb; although I've scant idea of the mechanisms, better out than in in this case IIRC.

You do more miles than me on your journey and possibly more traffic lights etc. So I'm not sure if the same applies to you as it does for me but if I cycle quicker I get back sooner.


I have to agree with your there, it's a source of concern for me too. I think, in general, there's something in the drivers psyche' who thinks "It's a cyclist, I must get past", even when we're doing the speed limit.


Interesting that you put the onus on the driver and not the pedestrian. I would say when we’re all driving electric that it is the pedestrians whom will have to be re-educated. They need to be anyway IMO. I hope you're not suggesting 10 mph limits everywhere because peds won't be able to cope with the quietness of cars?


I’ve read that somewhere too, or was told, but I don’t believe it. If I ride slow enough I can continue to breath just through my nose which has a better filter than my mouth, but I’ll acquiesce to anyone with proof to the contrary. I would say it has to filter out particulates to some extent even if it can't do anything about the carbon monoxide etc. (I don't 'do' masks)

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

I'm sorry, I'm not wishing to sound glib, but I think I've missed your point, weepej.

If you raise your maximum travelling speed from, say, 14 mph to 25 mph, even if you only achieve this for short periods, by definition you must cover the ground in less time (barring random intervention of lights etc.).

One caveat is pacing yourself: I'm working on the assumption that you do not adversely affect your stamina by short periods of high speed if you then have enforced rest periods at lights. Is this the case?

This reminds me of an ex work colleague who used to say - usually after I'd just overtaken someone - "There's no use going faster, it'll take just as long to get there." I used to ignore this, until one day I took it to heart, went home and found an old text book on Newtonian mechanics and left it on his desk with a note suggesting he read it!

By the way, weepej: 14 miles across London. I salute you sir! A friend of mine used to do Chiswick to London Zoo and back each day and that impressed me; I never had to do worse than Putney to South Kensington (I hated Putney Bridge in the evening, it seemed like a mountain, and a windy one at that...).

I know where weepej’s coming from, I think, but don't let me put words in your mouth.

Start from A - stop at B - end at C = 10mins
Start slowly from A - pass through B without stopping - end at C = 8mins

So it’s possible to get from A to C quicker by going slower but that’s just down to the luck of the lights.

So, as JTB said, all things being equal faster will mean getting there sooner and you can't defy the laws of physics. Or was that Scottie?

BTW With regard to your journey across London, I salute you too

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

I find a steady cadence and appropriate choice of gear helps a lot - especially on the up hills. The old "heavies" did drain - but the current breed of roadies/hybrids do help the cyclist to keep in tune with a bicycle.

As to whether or not 14 mph constant will take the same hour?

Weepsy cannot guarantee not being stopped for the same 10 minutes at the lights.

One trick I find so how I am travelling is to take a long look ahead at the lights. If they've been on "red" for a while - likely they will change to green as I reach them (on clear-ish) road. If a lot of cars stopped - then it's likely not all will make the lights on the green .. so again I would decide on pace and judge how safe to filter up to the start line to get the "early gets-aways" (If a ruddy great lorry there or a bus - then I wait behind these as much safer. to let them get out of the way.

If we all ride bikes tomorrow though - we would still have to abide by similar rules of red lights etc as - let's face it - most of the current codes of practice are designed to allow us all to get along in relative harmonised co-operation out there

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Take with a chuckle or a grain of salt
Drive without COAST and it's all your own fault!

A SMILE is a curve that sets everything straight (P Diller).

A Smiley Per post
FINES USfor our COAST!

Approach love and cooking with reckless abandon - but driving with a smile and a COAST calm mind.

Cheers guys; 14 miles sometimes isn't long enough frankly, and I really feel like riding straight on past work!



Ah, yes that's easy, 25 mph vs 14 mph along a road with no stops will obviously get you there quicker in but it is the lights, slow downs and stops that I'm interested in.

Guess I'm sort of trying to work out what the "cadence" of the system is, I.e. you can try to "fight" the system, but in the end it might be pointless and you might as well hang back.

Not saying that sometimes I don't hit 20-25 on the bike knowing full well I'm going to have to stop before long anyway, and I might've well have pootled along at 14mph.

Only if you assume that the faster you go, the more lights etc. you will be stopped by. I'm not sure what law other than Murphy's covers this.

Yes, if you average 14mph with stops, then you will achieve the same journey duration at exactly 14mph the whole way. As soon as you have to slow or stop though, you can no longer maintain 14mph as an average, even if you cycle at 14mph for the rest of time, and thus the journey will take longer.

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Regulation without education merely creates more criminals.

Well, some of them, but the really dangerous ones, the ones so small that they can get stuck in and fiddle around with cellular operations, are going to get in anyway, hell these guys might even get in through your skin!

Have to say I think one day we're going to be utterly amazed that we allowed such nasties to be generated in urban environments.

Sods law you mean.

Murphys law was "if it can go wrong it will go wrong", attributed to an incredibly sentient engineer that I thikn we owe a lot to. Sods law is "Anything that can go wrong, will—at the worst possible moment" .

Subtle, but very important difference!

It certainly does seem that some rides are more red light heavy that others, don't know if this is speed, luck or general day to day attitude (i.e. just a perception depending on my mood!).

Oh yes, do this a lot, change down gear to maintain candence, but go slower so light is green when I get to it, no cyclist (or car driver I figure) really ever needs to stop at a red light

However, there is a light at the top of a very big hill I ride up that I will slow down for to make sure it is red when I get to it. Sometimes I think it's best to stop here rather than seeing my heart jumping out of my mouth as it surely feels it's about to.

I know what you mean, although I feel like a failure if I don't power over the top every day.

Slightly off topic but just a quickie you may relate to and I'm curious if others do the same..

I sometimes filter down the outside of stationary traffic which occasionally freaks-out an unweary driver coming towards me. The reason is because if the wind is blowing in the wrong direction I'm literally stuck in a channel of fumes on the inside whereas I'm not if I cycle past their driver doors. There's not much traffic coming towards me so I have fresher air doing this. Know what I mean?

You just have to be careful of someone doing a quick right turn in front of you from the line of stationary traffic on your side. Nearly came a cropper last week if fact; no signal, he just decided to turn into a driveway and pulled right in front of me. (Although the same can happen on the inside if they suddenly decide to do a left.)

_________________
The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

Oh and while I'm here can someone, a 'techi', answer a question for me please? (Sorry. I'm terrible, I know)

When I was watching the Tour de France yesterday I heard Phil Liggett, (I think it was him), say of a cyclist who was pounding up a hill "He'll be generating 800 watts at this point".

Now, as a techi myself, I know that one horsepower is 746 Watts

So a man is producing more than one HP?

_________________
The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

go fast.
it's better.

800W sounds right ball park for peak power, not a power expert but...
http://www.analyticcycling.com/ForcesSpeed_Page.html

e.g. on that calculator a 30minute 10mile time trial (average 8.8m/s) needs 330W constant power output.
746W gives you 31mph (13.78m/s) and a 19min 10mile TT which would have put you top 10 at this years national 10mile champs
(http://www.bikeradar.com/road/news/arti ... ship-16643)

But more dangerous.