Looking at my mapmyride info I noticed an interesting result.

I typically do two types of ride. One where I'll take off in the morning and ride for 6-8 hours (i.e. a century) with the other being when I only have 1 or 2 hours.

Of course I treat both rides differently, with the former I'll pace myself (i.e. not attack rolling hills_ and try to ride so I have plenty left in the tank. With the later, I know I only have a short period of time so I got all out.

So I was surprised to see my average speed for the first ride being 14.0 mph and for the later rides being 16.0 mph. All that effort only translates to a 15% improvement in speed! In both case terrain is similar: windy pancake.

I'm curious if other people have a larger difference in their averages than mine?

I'm also curious what this says about me and my bikes? Me being a newbie rider (but rides a lot) and my bike being a Breezer Venturi (steel racier bike)

It sounds like you are always in endurance mode. If you are interested in getting faster you need to do some short intense anaerobic intervals. That said average speed is a vague metric but it is something.

If you ride varied terrain and length and mix solo and group rides, you'll see a bigger difference. In the same year, I've had a 19.5mph average on a totally flat, windless 40 mile ride and a 14.5mph average on a hilly (10,000+ ft of elevation gain), headwind-y 143 mile ride on the same bike. Still not a massive difference considering how different the rides were. Goes to show how big of a drag air resistance is.

I don't think that 2 mph is an insignificant difference. Perhaps the use of a power meter would support this, but think about riding 16 mph when it's calm, and how much more effort it would take to maintain 16 mph when pedalling into a 10-15 mph headwind.

I thought you lived somewhere in SoCal? Isn't the terrain there fairly hilly?

Also, are you tracking anything other than speed on these rides? If you use HR, how is your average HR varying between those two types of rides? If I'm "cruising", my average HR for 3-4 hours would probably be ~130, while if I'm going for a sub 1 hr kill myself ride, my average HR would be ~165. The average speed difference between generic examples of those two rides would maybe be about 3-4 mph for me, assuming similar terrain and no other riders or crazy wind.

You need another bike for those shorter rides. Something more aero. At least some deep carbon wheels. That should get your average to 19 ​at least.

Yes, but I don't ride the same sort of terrain on short and long rides.

Since I live about 15 miles from good riding roads, all my weekday rides are dead flat but involve stops for traffic and time accelerating/decelerating.

With good riding roads running through the Santa Cruz or Diablo mountains, all my long rides include sustained climbs, and an hour at 7 MPH is not good for average speed.

It says you need to ride hard (as fast as you can for 10 minutes) intervals and forget about trying to be fast for an hour or two at a time. The shorter intervals will lift your VO2max and lactate threshold by applying more stress than a long hard ride could, and produce bigger improvements in your speed over durations past an hour.

Your expectations may also be unrealistic. On flatter terrain speed is essentially proportional to the cube root of power because aerodynamic drag increases with the square of velocity and you're covering ground faster. With all-day power 60-70% of one hour power you'd be at best 18% faster if you spent no time slowing or otherwise not pedaling.

I've done a number of hard 20-mile efforts with Strava averages in the ~20mph ballpark.

On Saturday I did a century ride with a Strava average of 19mph.

That was mostly in a paceline versus my 20-mile efforts being solo. But, also had more hills than my 20mph solo rides.

Obviously I need to spend a day riding 100 miles up and down the remote sections of the local nearly-flat MUP and see what happens.

¯\_(ツ)_/¯

Yes. On a short ride you are (or should be) trying to hold a very low aero position the whole time, since the ride isn't long enough to exhaust your postural muscles. On long rides staying low the whole ride could lead to major back pain. So a fast ride may require less than a cube of the speed increase but still a significant increase in power.

Personally I ride 19.5-20 on short (2 hour or less) rides, and 18.5-19 after that. Same hills. Also faster solo, riding with a group means slowing down to chat and regroup.

If you have any stop signs or traffic lights, that's going to have a huge effect on your average.

Since when is 6-8hrs all day?

After consulting veloviewer here's some numbers for me:

Median average speed: 24.1kmh (14.96mph)
Best average speed (not in a race/group): 28.8kmh (17.89mph) over 1h47m

It's interesting to look at Strava's estimated power curve for that ride. Note how Strava thinks I can hold 250W for only 4 minutes but I can do 180W for an hour and three quarters. By that graph the difference between the power I can hold for say 30 minutes verses an 1 hour and 3/4 is only about 25 watts.



Which is typical really. For most sports a 1-2 hour effort and a 6-8 hour effort would both be considered endurance efforts. It's only when you get into very short time frames (say 5-10 minutes) that you can start to get significant boosts in your power output and thus your speed.

Here is an interesting comparison.

The world record for the 5km running race is 23.77kmh ( for 12m 37 sec) while the 42.21km marathon is 20.59kmh ( for 2h 3min). The 5km run is only one eighth the distance but the average speed is only 15% better. The 800m is run at 28.5kmh (over 1 min 41 sec) which is a significant increase on the 5km pace but it is only less than 2 minutes that the runners can hold that power and pace.

God that is depressing. These guys can RUN a marathon just a bit slower than I can ride a marathon .... and they are not even in an aero position.

You said your rides are "windy pancake (flat)". Those average speed differences sound reasonable. And any changes in wind speeds, small hills, or number of traffic lights will affect the average a lot.

It takes a lot more power to go just a little faster. Wind resistance goes way up as speed increases.

For instance, see this speed/power calculator. (These calculators are good for a general idea of power requirements. Other online calculators will likely have different results, but they'll be fairly close.)

Taking the defaults, but changing to a 1% grade to lower the calculated speeds a little:

Column A: 135 watts is 14 mph.
Column B: 175 watts is 16 mph.

That's 30% more power to go 2 mph (14%) faster. Which sounds about right for a hard 1-2 hour effort compared to pacing for a century ride. And the speed increase on the shorter ride is partly due to pushing harder on the small climbs and into the wind. That saves the most time, since those are the slowest sections.

And check out this post on wind resistance and transmission & tire loss as speeds go up.

[MENTION=408786]smarkinson[/MENTION] is very insightful regarding how short "short" rides would need to be in order to notice a significant difference in performance over longer rides. However, what I have found, unsurprisingly, is that in circuit races (typically 45 - 90 minutes), I can sustain average speeds about 6 mph faster than in group rides generally (which are anywhere from 2-6 hours), and in group rides, generally 2-3 mph faster than solo, regardless of duration; I rarely ride fast when I ride by myself.

All I know is that the difference between my FTP and my 70% intensity on flat, even ground is a whopping 2mph. Because that last 2mph is over 20mph, and maintaining it rakes a whole lot of energy. Given enough time and base miles, anything at or under 18mph is just Z2 stuff. Each MPH above that just takes more and more gas, as aero drag gets worse and worse.

...but has been said before, avg. speed is a virtually meaningless metric, unless viewed as a trend over long periods of time. Only power matters. Difference between short intense power and all day power-- that's something. My power drop (drawn from the power curve average) from 1 hour power (measured) to 2 hour only drops about 5%. But the drop from hour 1 to hour 5? Almost 20%. After that it's like the graph falls off of a table.

The difference between 14 and 16 mph is a LOT: 14 minutes for a short 25-mi ride, and almost an hour (53 min) for a century.