Quick question about measuring average speed

Jamey

When you stop at traffic lights or junctions do you stop the timer on your cycle computer (or use an auto-pause feature, if it has one)?

Or do you leave it running?

And do you time training runs differently to commutes?

I tend to leave mine running for the whole journey regardless of whether I have to stop often or not but it never occurred to me until today that the rest of you may calculate your average speeds completely differently and only run the timer when actually moving.

Denny69

If you've got the auto pause feature on you cycle computer activate it as this will affect your Avg speed. Most cycle computers stop when they don't sense the magnet after a second or two.

Leave this feature active even for your training runs to get a moving average speed.

CanterburyTailwind

My cycle computer automatically stops/pauses. I think if it didn't my average speed would be down to about 5mph...

Jamey

Part of the reason I don't use auto-pause is because on my computer (Garmin) it's a bit flaky and there are a lot of reports of it failing to start up again after a pause, so I'd rather play safe.

GeorgeShaw

Never had a problem with my 305 failing to start up after an auto-pause. The only problem I find is, because of calculation errors, you may find yourself "moving" slightly. This means that the calculated pause time may be less than the real pause time and the output can also include mythical enormous gradients ("move" by 1 metre, "height" changes by 1 metre). The effect is worse when stopping under tree cover, when I guess the calculations can be more error-prone.

DavidBelcher

CanterburyTailwind wrote:

My cycle computer automatically stops/pauses. I think if it didn't my average speed would be down to about 5mph...

Mine too, and it's only a cheapish one (Sigma BC600) which doesn't even work out the average for you [1] - I'm assuming all models in the Sigma range have auto start/stop. Certainly better than the Cateye one I had yonks ago, which inolved much fiddling with the stopclock on/off button!

David

[1] Meaning some quick post-ride sums if I do want the value.

doyler78

Like most others here I use my autostart/stop function on my cycle computer. It makes more sense to me to do it that way. Why should my average be affected because I'm stuck at traffic lights.

My cycle computer gives me so much information I could write a book on each ride if only I knew what the half of it meant

W5454

doyler78 wrote:

My cycle computer gives me so much information I could write a book on each ride if only I knew what the half of it meant

I'm perfectly happy with my 20+ years old Cateye Mity2 even though it only has 6 Functions, thats all I need.It's only let me down once when it stopped working for about 20 mins in a torrential downpour.
I use the auto stop/start function.

Mudcp

doyler78 wrote:

Why should my average be affected because I'm stuck at traffic lights.

Because the recovery time you are getting is going to boost your speed over the next section.

Ok it will never be as quick as a smooth ride with no stops, but it will certainly be quicker than pretending you didn't stop at all, IYSWIM....

Denny69

I've just got a 205 and you can set the speed at which the auto pause kicks in...I got mine set at 3mph and it's never let me down yet.

Lagavulin

What are most people's policies regards taking readings from their computers? From door to door or once their "proper" ride starts? I take mine from leaving the house to entering the drive but I find that I rarely average over 16-17 on say a 40-50 miler.
I not so sure the traffic lights, junctions and roundabouts affect my average speed to the extent the warm-up and warm down do.

Jamey

So are people in cars allowed to discount their speed when they're stuck at lights too?

oldwelshman

Lagavulin wrote:

What are most people's policies regards taking readings from their computers? From door to door or once their "proper" ride starts? I take mine from leaving the house to entering the drive but I find that I rarely average over 16-17 on say a 40-50 miler.
I not so sure the traffic lights, junctions and roundabouts affect my average speed to the extent the warm-up and warm down do.

Traffic lights and junctions have an impact on av speed.
You cannot accelrate from junction to 17mph in zero seconds so it takes several seconds to get back up to speed.
Av speed is really only a guide anyway.

Lagavulin

oldwelshman wrote:

Traffic lights and junctions have an impact on av speed.
You cannot accelrate from junction to 17mph in zero seconds so it takes several seconds to get back up to speed.

Perhaps you'd like to read my last sentence again.

on the road

Mudcp wrote:

doyler78 wrote:

Why should my average be affected because I'm stuck at traffic lights.

Because the recovery time you are getting is going to boost your speed over the next section.

Ok it will never be as quick as a smooth ride with no stops, but it will certainly be quicker than pretending you didn't stop at all, IYSWIM....

But on the other hand, stopping at traffic light etc slows down your average speed anyway.

I usually get an average speed of about just under 18 mph with all the start stops, you might think that by stopping and getting breathers I'm getting a boost, but stopping and starting is actually slowing me down, if I didn't stop then I would probably get an average speed of about 20 or 21 mph.

doyler78

Mudcp wrote:

doyler78 wrote:

Why should my average be affected because I'm stuck at traffic lights.

Because the recovery time you are getting is going to boost your speed over the next section.

Ok it will never be as quick as a smooth ride with no stops, but it will certainly be quicker than pretending you didn't stop at all, IYSWIM....

I don't understand your point. If it is quicker to maintain a smooth ride then how can you argue that the average speed is artifiically high because of the breather. My view is that the slowing down and starting up again do disrupt my flow and as such lower my average speed. The only circumstances that I can see where a breather may provide an advantage would if you were working anaerobically and if that is the case then you are likely not to be going too far anyway and if you are doing say intervals then doing them in an urban setting seems a strange choice of place to do that as you can't plan traffic lights therefore you are not going to be able to properly manage your efforts as these will be dictated by where the lights are.

Jamey

I tried my commute with auto-pause turned on yesterday and my average speed hardly changed.

Yesterday, with auto pause on = 14.5mph
Personal best (auto pause off) = 15.5mph
Usual average (auto pause off) = 14 - 15mph

CrookedCucumber

There's a really simple answer to this question:

If it actually matters whether you average over the whole ride, or only over the moving bits, then the average speed you measure will not be comparable to anything else.

Therefore there's simply no point measuring it.

I am reminded of a Dilbert strip, where the conversation was something like this...

Boss: These figures are terribe! Are they the best figures you've got?
Dilbert: They're the right figures. I've got any number of wrong figures.
Boss: Well keep them in your back pocket, we may need them!

In short, the fact that you can assign a number to something does not mean that the number tells you anything of value. If you want to record your average speed for training purposes, then you need to ensure that your rides are more-or-less identical, so far as conditions, number of stops, etc.,, are concerned.

If you can't do that -- and you can't control the weather -- then the best that an average speed will tell you is a long-term trend. And in the long term it won't make any difference whether you record the average for total or moving times, so far as the trend is concerned.

Jamey

Good answer, A+, would read again.

ta.

Mettan

My bike computer (cheap) carries on timing (for 2 minutes) , even when the bike is at a stop - this brings my Avg down - although I tend to go out very early in the morning so I don't stop too often - if anyone hasn't gone out training at 5.00 in the morning, try it - there's virtually no traffic (only a few Taxi's typically) - makes for a fast (and enjoyable) training ride.

on the road

I like my bed too much :oops:

dennisn

GeorgeShaw wrote:

Never had a problem with my 305 failing to start up after an auto-pause. The only problem I find is, because of calculation errors, you may find yourself "moving" slightly. This means that the calculated pause time may be less than the real pause time and the output can also include mythical enormous gradients ("move" by 1 metre, "height" changes by 1 metre). The effect is worse when stopping under tree cover, when I guess the calculations can be more error-prone.

Tell me you're joking. Please tell me you're just kidding. Of all the things in life to worry
about this takes the cake. Sorry, didn't mean to get overly sarcastic but I really can't
imagine something like this having any real meaning in the scheme of things.

Dennis Noward

doyler78

Jamey wrote:

I tried my commute with auto-pause turned on yesterday and my average speed hardly changed.

Yesterday, with auto pause on = 14.5mph
Personal best (auto pause off) = 15.5mph
Usual average (auto pause off) = 14 - 15mph

Well if my commute takes 5 mins more including stops than when autostop is used then over a 45 min ride then that is a significant difference in the average speed. It may be that you have a commute that has little in the way of traffic lights whereas I do have to put with 5 min waits in total on average.

doyler78

CrookedCucumber wrote:

There's a really simple answer to this question:

If it actually matters whether you average over the whole ride, or only over the moving bits, then the average speed you measure will not be comparable to anything else.

Therefore there's simply no point measuring it.

I am reminded of a Dilbert strip, where the conversation was something like this...

Boss: These figures are terribe! Are they the best figures you've got?
Dilbert: They're the right figures. I've got any number of wrong figures.
Boss: Well keep them in your back pocket, we may need them!

In short, the fact that you can assign a number to something does not mean that the number tells you anything of value. If you want to record your average speed for training purposes, then you need to ensure that your rides are more-or-less identical, so far as conditions, number of stops, etc.,, are concerned.

If you can't do that -- and you can't control the weather -- then the best that an average speed will tell you is a long-term trend. And in the long term it won't make any difference whether you record the average for total or moving times, so far as the trend is concerned.

Training Diaries. Great thing. It allows you to add environmental information to any ride therefore when used in conjunction with average speed then relevant information can be had. If you have a cycle computer which records altitude then yet more information can be gleaned. If you are lucky enough to have access to heart rate and power data then average speed in the context of all that can be very relevant as well the information that all data provides in itself.

How much all this applies to each of us in our rides is down to each of us to decide however from my own non race based riding and generally commute only I can tell you that average speed has been very relevant to me as it helps me push on if I think I am on for a record. Recently I got an average speed of 19.8mph on my commute. I am really determined to get that 20mph average. Who cares if it is wind assisted that's not the important point to me - it is the mere fact that I have a target that makes the ride fun. Just because the target measure may be flawed doesn't make the target worthless.

CrookedCucumber

doyler78 wrote:

Recently I got an average speed of 19.8mph on my commute. I am really determined to get that 20mph average. Who cares if it is wind assisted that's not the important point to me - it is the mere fact that I have a target that makes the ride fun. Just because the target measure may be flawed doesn't make the target worthless.

I'm afraid I'm reminded of another Dilbert strip. Dilbert is standing at the front of a room full of people next to a fliipchart...

Dilbert: And next week, a gynaecologist with a flashlight explains where sales targets come from!

To be fair, I do the same thing when I have my GPS on my bike -- if I'm approaching the end of a ride and the speed or time is very close to the `best' I have achieved, I feel motivated to work a bit harder to break the `record'.

That probably isn't a bad thing for training purposes, I suppose; but it's still a gynaecologist-with-flashlight situation, because a number is just a number. If you were measuring in kilometres per hour, maybe you'd be trying to beat the 31.68 km/hr barrier. Doesn't have the same ring to it, does it?

What's more, if my record-breaking performance is actually due to a stronger tailwind or something, then I'm going to miss it badly next time, which will irritate me.

I'm certainly not averse to measuring average speeds. I'm only saying that, so long as you do the measurement in a consistent way, it doesn't matter enormously what that way is.

doyler78

Yep agree with that and I do get annoyed when its a strong headwind I am only doing 15mph in which case I switch my motivation to hrm and try and turn it into a hard effort ride. Always find something to try and keep me interested. The ride itself just isn't enough for me.

oldwelshman

Lagavulin wrote:

oldwelshman wrote:

Traffic lights and junctions have an impact on av speed.
You cannot accelrate from junction to 17mph in zero seconds so it takes several seconds to get back up to speed.

Perhaps you'd like to read my last sentence again.

You mean this? :
I not so sure the traffic lights, junctions and roundabouts affect my average speed to the extent the warm-up and warm down do.

I did read it.
I read it to mean you did not think that junctions and roundabouts make much difference to av speed compared to warm up and warm downs?

Unless you do a warm up at 12mph which is a waste of time then the junctions and lights will have similar affect on av speed. Unless of course you train up and down a dual carriage way and go round large roundabouts and encounter no lights or junctions, then there would be negligable affect.

Fed up with this boring thread who cares what affects it just enjoy the ride.