Campaign for real averages

[mjr]

Anybody who uses "real" averages must be completely off their chump. What happens if you stop for half an hour for lunch or to fix a breakdown or whatever? The meaning of average speed is lost.

No it isn't. I don't know about you, but I eat fairly consistently and breakdowns have a probability, so if you average over enough journeys, then your planning for similar journeys takes them into account as it should. It's like windspeed... that eventually factors out to an average based on the probabilities of different wind directions and so on. Of course, it's worth looking at the deciles as well as the median if you need to be somewhere at a certain time.

My cycling buddy is faster than me up hills so sometimes has to stop and wait for me so when we cycle for an hour on a Wednesday evening he averages 17 mph and I average 16.8. This is a true and accurate measure of our relative speeds.

No it's not. You're both averaging 16.8mph over that journey. The 17mph might be interesting if he's planning a ride without you, but the 16.8 is the key figure for planning a similar ride for both of you.

 

[Tim Hall]

Anybody who uses "real" averages must be completely off their chump. What happens if you stop for half an hour for lunch or to fix a breakdown or whatever? The meaning of average speed is lost. You can only compare your speeds on different trips by comparing the average speed at which you moved. My cycling buddy is faster than me up hills so sometimes has to stop and wait for me so when we cycle for an hour on a Wednesday evening he averages 17 mph and I average 16.8. This is a true and accurate measure of our relative speeds.

Anybody who uses "real" averages must be riding an Audax. You have a start time and a time by which you must be home, based on a "real" average. No deductions for cake, punctures, mechanicals, buying cable ties, taking pictures.

 

[huwsparky]

Anybody who uses "real" averages must be riding an Audax. You have a start time and a time by which you must be home, based on a "real" average. No deductions for cake, punctures, mechanicals, buying cable ties, taking pictures.

Correct, 'real' average as it's been put is pretty much useless data for anything else as it has no meaning.

 

[Red17]

Went out last night with my Garmin and Strava on the phone just out of interest and Garmin gave me a 14.8mph overall average, 15.0mph moving average and 39.4mph max (freewheeling down a steep hill).

Strava gave me a 15.5mph average (moving) and a max speed of 42.1mph.

As the phone with Strava was in my back pocket and the Garmin was on the stem does this mean that the back of the bike was catching up with the front?

 

[PhilDawson8270]

Differences in GPS unit, and accuracy. Plus the processing of raw GPS data doesn't give the same results across multiple platforms, as different companies will process the data differently

 

[Red17]

Or could be that back of the bike is picking up a slipstream?

 

[mjr]

This is normal. The back wheel is the drive wheel, so the bike is gradually getting shorter when ridden at high speeds, or rather, high power outputs (it doesn't happen from freewheeling downhill). This is why manufacturers recommend buying new road bikes every few years and why ordinary bikes with front wheel drive died out because the front wheel pulled away and stretched the frames until they snapped.

I promise I've not had a beer yet.

 

[Globalti]

No it's not. You're both averaging 16.8mph over that journey. The 17mph might be interesting if he's planning a ride without you, but the 16.8 is the key figure for planning a similar ride for both of you.

Yes in terms of the overall time for the trip but no in terms of our speeds.

My head hurts.

 

[Dogtrousers]

Well, it's been a fun thread. The answer is, of course, that both kinds of average are useful in different ways for different purposes. This just highlights the evilness of the conspiracy that sees real average not represented on RWGPS and Strava.

I'll finish with a story. I've just got back from an pretty bad (if picturesque) ride. It was meant to be a hilly 100k, but my legs just wouldn't work and I found myself grinding in bottom gear up the smallest of hills, pulling Tommy Voeckler faces. So half way, with the worst hills yet to come, I cut my losses and re-routed to a station (which was the other side of an effing big hill). I made numerous stops: to eat, to have a rest, to navigate, to have another rest, to seek inspiration, pray for teleportation and so on. I ended up with 73k, 1,000m climbed, and two average speeds:

Moving: 18.9km/h (Not quick but hey, it was hilly)
Real: 15.4 (Aaargh! Crash and burn!)

Which do you think gives an accurate picture of the ride? (hint, it's not the first one).

 

[Hacienda71]

I went out for a ride the other day.

My moving time was 1:04:01 for 23.6 miles
My elapsed time was 1:04:01 for 23.6 miles

That tells me I didn't stop for a coffee break.

 

[jarlrmai]

Average moving speed gives you a decent reflection of your fitness/cycling ability, average "real" speed tells you how unlucky you got with the junctions/lights. Unless you stopped for any length of time because you were knackered and even then you could probably have kept on going

 

[400bhp]

My yearly average speed, calculated any way you want, shows that on half my rides ~I'm below average.

Wow, someone who has a median average calculating cycle computer. Impressive.