20mph moving avg a natural hurdle?

[Yojimbo_]

If it's not due to slowdowns and stoppages that drag your average down (and I bet it does regardless of what your device does - after all, it takes time for the device to decide you are at 0 mph), then all that's left is your engine.

I've seen cubic equations fit to speed / power curves that look reasonable. That means losses (primarily due to wind drag) go up as the cube of the speed. So you need a whole lot more power to go from 20 to 21 than you need to go from 14 to 15.

And not many people can sustain 20 mph averages btw despite what they tell others.

 

[sitzmark]

^^^^^
Your point about taking time to figure out when I'm at zero is valid. I might be getting dinged for actually moving a little longer than I am. But on the flip side, I'm probably putting in some distance before the devicwe rolls it up correctly. Same with slowing/accelerating. So net-net maybe these discrepancies offset each other and I just suffer the actual decrease in speed to make the direction changes.

My interest isn't so much making sure I'm averaging 20+, just that I have a controlled metric to measure improvement. If I ride into slowdowns and away from them in a reasonably consistent manner from ride to ride, then my metric of average moving speed is a valid indicator of performance progression.

To your points - one or a combination of three things probably needs to happen before I make another "breakthrough".

1. I need enough engine to push above my existing flatland speed
2. Need to carry more speed uphill for 3-5% grades (typical grade on routes)
3. Might benefit from opportunities to be more aerodynamic - either through body position or mechanicals.

The non-linear effects of air resistance will play a bigger and bigger role as I work on #1, which will require a combination of #3 and an exponentially "bigger engine". #2 benefits from a bigger engine, but more effectively, so #2 has a quicker return.

Maybe my engine isn't quite as wimpy as I think ... but it needs a lot of work. :grin:

Off to work on this interval thing ......

 

[limerickman]

All the advice given thus far is good.

20mph is a good average speed.
If you can hold that average for longer distances, that's even better cycling.

When I raced - raced- years ago, the average race speed was 22mph.
And that was over distances between 60 and 100 mile distances.

So to be touring/charity rides at 20mph is pretty good going, I would suggest.

To increase your average speed, as swampy says, you need to be able to sustain power for an extended period.
And the only way to do this is by interval training.

 

[alienator]

I've seen cubic equations fit to speed / power curves that look reasonable. That means losses (primarily due to wind drag) go up as the cube of the speed.

Those cubic equations should look reasonable because the science says that power needed to overcome drag increase with the cube of the velocity. In fact, this is how iBike determines power: a calibration is done to establish coefficients for drag and for drivetrain losses, as well as a constant offset, and power is calculated from the cubic defined by those three calculated constants. The calibration process is a best fit. Once again, science and math win.

 

[gman0482]

My primary concern is the extened plateau that I've hit on all my courses (all have similar topography - about 500ft of vert for every 10 miles). Previously I've experienced sporadic "breakout days" in the mix that indicated progress was possible. Over time my breakout would slowly become my new norm.

Was just wondering if there was something around the 20 mark that made for a natural hurdle. Something I could blame it on other than my engine. ... it's the engine.

That indeed is a great average to keep. As far as hitting a plateau, I think that when one's averaging 20 and above, it just gets that much more difficult, and so it feels like there's no progress.

I found that the best way to get that average above 20+ mph, is to get into a fast paceline. Just a few days ago, I jumped into one, and that average came out to be 20.8 mph, and that's with a very hilly route. On other routes they averaged 21+ mph (can't wait for those). After that ride I was beat, and I've never pushed myself as hard before. My next solo ride, I felt much better, feeling a little stronger than before that group ride.

Try to find that group ride where there's a nice paceline heading out of it, and I'm sure your averages will go up.

 

[sitzmark]

Try to find that group ride where there's a nice paceline heading out of it, and I'm sure your averages will go up.

I've ridden two "real" pacelines with CRW and some quasi-paceline in more casual CRW rides. The first with the Friday eve group out of Bedford in April or May before I had my road bike. And a second in June with the Saturday morning fitness ride out of Newton (Nahanton Park).

In both cases the paceline environment definitely made a difference. I was a solid 18-18.5 solo on the mtb and recorded a 20+ for the Bedford ride. Messed up my tracking by switching to "do course" mode on the Newton ride, so don't know what moving avg I had on that ride. It was definitely the most demanding ride I've done to date. I pulled a few times and got a "nice work" shoutout after a couple, so hopefully I pulled some of my weight.

Does require some "deep digging" to keep the line moving when it's your turn to pull, but not sure that alone is enough to build up my solo performance level. Have been reading a lot of the great training/interval threads on this forum and started to think about how to layout some interval courses. Rode with my wife this weekend and she's not too interested in interval training. I'll have to do that on my own time.

 

[gman0482]

Yea that's why I like both paceline as well as solo rides.

With a fast paceline you'll get that extra effort in, and go well above your normal pain barriers. It's the best feeling when you can pull and finish while dropping some riders in the process.

With solo rides, you can really focus on what you want to do, break your ride down into detailed intervals/routes, where others would probably not want to do.

Now I'm hooked on paceline riding, and today is the best one of the week. It's gonna hurt.

Maybe someday we'll be riding in one together.

 

[sitzmark]

...Maybe someday we'll be riding in one together.

Do you ride with CRW? If so, any suggestions for particularly good reoccurring rides or special events?

Enjoy your ride today!

 

[Yojimbo_]

Those cubic equations should look reasonable because the science says that power needed to overcome drag increase with the cube of the velocity. In fact, this is how iBike determines power: a calibration is done to establish coefficients for drag and for drivetrain losses, as well as a constant offset, and power is calculated from the cubic defined by those three calculated constants. The calibration process is a best fit. Once again, science and math win.

Yes, thank-you. I'm a engineer - just didn't want to get into a bunch of technical stuff in my post.

 

[alienator]

Yes, thank-you. I'm a engineer - just didn't want to get into a bunch of technical stuff in my post.

Don't be afraid to go technical. Tech is good and sorely needed, at least here in the US, where Reader's Digest is as technical as things get.

 

[sitzmark]

... In fact, this is how iBike determines power: a calibration is done to establish coefficients for drag and for drivetrain losses, as well as a constant offset, and power is calculated from the cubic defined by those three calculated constants. The calibration process is a best fit. Once again, science and math win.

Do you know if the calibration is performed with generic assumptions or are specific rider/bike parameters programmed into the base model iBike units?

Considering for a quick easy way to track approximate power output. I'm not at a point where getting overly exact is going to matter that much - just need something reasonably precise ... accurate would be even better.

 

[alienator]

Do you know if the calibration is performed with generic assumptions or are specific rider/bike parameters programmed into the base model iBike units?

Considering for a quick easy way to track approximate power output. I'm not at a point where getting overly exact is going to matter that much - just need something reasonably precise ... accurate would be even better.

The rider inputs his weight and bike weight. The calibration process determines everything else needed to calculate power.

 

[sitzmark]

The rider inputs his weight and bike weight. The calibration process determines everything else needed to calculate power.

Thank you. Sounds like a fairly generic (but workable) assumption of frontal surface area tied to weight. If that's true, then I question the accuracy, but as long as ride position and other drag factors remain relatively constant ride to ride, then precision should be acceptable for performance tracking over time.

Will have to research to see if side by side comparisons of iBike with direct power systems have been done.

edit- yes .. a quick search of threads in this forum confirmed my suspicions. (and a few more)

 

[alienator]

Thank you. Sounds like a fairly generic (but workable) assumption of frontal surface area tied to weight. If that's true, then I question the accuracy, but as long as ride position and other drag factors remain relatively constant ride to ride, then precision should be acceptable for performance tracking over time.

Will have to research to see if side by side comparisons of iBike with direct power systems have been done.

edit- yes .. a quick search of threads in this forum confirmed my suspicions. (and a few more)

Actually, there's no assumption about frontal area. Power output on a bike follows an equation of this form: P=a*(v^2) + b*v + c, where v is velocity and a, b, and c are characteristic constants for a bike/rider system and power meter. By doing a series of coast-down calibrations, the iBike calculates a, b, and c. Once that's done, iBike can calculate the power output at any given moment just by knowing the velocity. iBike can also detect head winds and factors that in correctly. iBike is, as you might guess, sensitive to calibration. Also, the calibration is done for one position on the bike (the one you most often ride in), so there is a small measurement error when you change positions. Likewise, a change in road surface quality from the surface on which calibrations were done results in another small measurement error. The system can be pretty darned accurate and precise.

 

[sitzmark]

Actually, there's no assumption about frontal area. Power output on a bike follows an equation of this form: P=a*(v^2) + b*v + c, where v is velocity and a, b, and c are characteristic constants for a bike/rider system and power meter. By doing a series of coast-down calibrations, the iBike calculates a, b, and c. Once that's done, iBike can calculate the power output at any given moment just by knowing the velocity. iBike can also detect head winds and factors that in correctly. iBike is, as you might guess, sensitive to calibration. Also, the calibration is done for one position on the bike (the one you most often ride in), so there is a small measurement error when you change positions. Likewise, a change in road surface quality from the surface on which calibrations were done results in another small measurement error. The system can be pretty darned accurate and precise.

Great info - thanks. So a specific calibration IS performed for rider/bike. That makes a big difference. The position changes could be somewhat significant depending on how dramatic the position change, but good enough for my needs. Based on your description, concerns about shielded riding in pacelines and group riding may not have as much effect as some posters were opining. i.e. headwind is an adjustment to calculations and not the basis for calculations.

 

[gman0482]

Do you ride with CRW? If so, any suggestions for particularly good reoccurring rides or special events?

Enjoy your ride today!

No I ride with NSCYC most of the time. I actually do mostly solo rides, but now I join the Monday 6:30 evening ride for the paceline.

I kinda look at it as an event, so I do some solo training all week, and go all out on Monday, which is great, but like Felt Rider said, sometimes group rides and fast hammerfest pacelines are not the best vehicle for training purposes, just cause they are not as structured and you can't 'personalize' the ride as much. Once or twice per week is good to add to the week.

Let me know if you're up in the northshore sometime. (that reminds me, Cyber, where have you been ?)