Author Topic: Training – the next step after just riding your bike?  (Read 13039 times)

Re: Training – the next step after just riding your bike?
« Reply #50 on: 09 October, 2016, 08:11:06 pm »
yes, that thought had occurred, but thats where having a proper measurement is so useful, I can see exactly what effect it is having

TimC

  • Old blerk sometimes onabike.
Re: Training – the next step after just riding your bike?
« Reply #51 on: 10 October, 2016, 02:57:29 am »
Sam, the Mk 2 Stages does seem to get better reports from people like DCRainmaker. But Ray liked version 1 too, so maybe I've got the better end of the powermeter product market!! I'm perhaps being unfair; Stages have a very good reputation for customer service and the battery issue is something they're aware of and have tried all sorts of things to solve. It just hasn't worked for me. When it does work, the results are comprehensive, credible and repeatable. And are backed up by Wattbike sessions so I can have some faith in the accuracy. And it's all fascinating stuff; I'm no athlete, but I have to admit I'm a sucker for the data - and gathering data is a motivation in itself.

zigzag

  • unfuckwithable
Re: Training – the next step after just riding your bike?
« Reply #52 on: 10 October, 2016, 09:55:04 am »
i personally don't trust pedal based power meters

Why not? Is it the existing products or the idea you don’t like?

pedals wear out, and require to be tightened to cranks at a precise torque to give consistent readings, which is a problem if you fly with your bike. battery life isn't great either, from what i've read. the need to use specific cleats however is the biggest inconvenience. if you accept the compromise (which every power meter system has), then they are ok.

jiberjaber

  • ... Fancy Pants \o/ ...
  • ACME S&M^2
Re: Training – the next step after just riding your bike?
« Reply #53 on: 10 October, 2016, 02:31:07 pm »
If you can live with a HRM, and Strava I have found the estimated power on Strava to not be that far out from my measured power.  You only get that after the event through, alternatively, there are some ConnectIQ (garmin apps) which allow a virtual power reading from HRM.  Problem is HR lags power by quite a bit for the same effort plus is effected by other things (heat etc)... and you did say you didn't want to turn your rides in to a data fest :)

Perhaps RPE is where it's at with the suggested hill reps etc from some of the earlier posts ?

ETA: You need to ensure your weight and your bike weight are fairly correct on Strava for the power to work I think
Regards,

Joergen

Kim

  • Timelord
    • Fediverse
Re: Training – the next step after just riding your bike?
« Reply #54 on: 10 October, 2016, 03:18:55 pm »
If you can live with a HRM, and Strava I have found the estimated power on Strava to not be that far out from my measured power.

I expect that's mostly down to luck, in that your aerodynamic profile is pretty close to their model.  I find it gives hilariously inconsistent results, presumably because my bikes have little aero similarity to their tiny selection of bike types.  I'd love to see what my actual power looked like.


Quote
ETA: You need to ensure your weight and your bike weight are fairly correct on Strava for the power to work I think

I've complained about this before, but it frustratingly lacks a per-ride luggage correction factor.  Sure, touring and utility cyclists aren't really what Strava is about, but it's not uncommon for serious cyclists to commute...

Karla

  • car(e) free
    • Lost Byway - around the world by bike
Re: Training – the next step after just riding your bike?
« Reply #55 on: 10 October, 2016, 03:26:33 pm »
I find it gives hilariously inconsistent results

I've posted them before, but to show the comic unreliability of Strava powers, here are two TTs I did on the same course, on the same bike, i.e. near as dammit as similar as they come:

The first time

The second time

That's right, the slower ride was supposedly 130 W more powerful  ::-)

Kim

  • Timelord
    • Fediverse
Re: Training – the next step after just riding your bike?
« Reply #56 on: 10 October, 2016, 03:33:05 pm »
Does Strava include wind data?

*googles*

Apparently not:  https://support.strava.com/hc/en-us/articles/216917107-How-Strava-measures-Power

That's a shame really, as Strava's in a better position to include a fudge factor for that than a bike computer would be.

Karla

  • car(e) free
    • Lost Byway - around the world by bike
Re: Training – the next step after just riding your bike?
« Reply #57 on: 10 October, 2016, 03:49:30 pm »
Another thing to point out: my heart rate was about 10 beats higher on the faster ride where I supposedly produced less power - and Strava had that data the activity pages.  Based on speed and heart rate but not wind, I have no idea how they got that figure.  Well, I do: either they plucked it out of thin air, or they changed their algorithm between the two rides.

[ EDIT: Actually, thinking about it, do know what caused the difference: the first (slower) ride had a stronger wind blowing up the course, so I went slower in the first half and faster in the second - as you can see if you follow the link.  Strava say (your link) that they assume no wind when calculating power, so my slow speed in the first half has dropped my estimated power, but the cubic speed/P(aero) relationship has given me a massively inflated power reading in the second half: Wiggo's hour power to win the Tour de France is less than I supposedly put out in the second hour of my ride. ]

Samuel D

Re: Training – the next step after just riding your bike?
« Reply #58 on: 10 October, 2016, 08:34:16 pm »
I’m convinced I’m more aero than most people and only able to ride with fast groups by cheating in this way. Plus, proper wind management when drafting and drafting closer than many other people do. I’m light so the hills are comparatively easy for me (not that I’m a great climber, mind you).

When I do a big effort to close a gap or tow the group, I get very low, often in the ‘invisible aero-bar’ position.

I do wonder how much power I put out. Not much, I suspect, but I use what I have wisely. It would be fascinating to see how I compare in speed-per-watt, so to speak.

zigzag

  • unfuckwithable
Re: Training – the next step after just riding your bike?
« Reply #59 on: 10 October, 2016, 09:27:48 pm »
^^ you can test your w/kg in a gym that has a wattbike or similar for a tenner or so - no need to buy a power meter just for that.

simonp

Re: Training – the next step after just riding your bike?
« Reply #60 on: 13 October, 2016, 03:18:43 pm »
Strava's power model for climbing Cheddar Gorge is wildly out due to the profile being broken (steep sided twisty gorge with terrain interpolation makes the profile have steep rises and falls where in reality it is continuously uphill). Pretty much useless IMO. On the flat, you have the issue of wind conditions, so riding on the A38 10 mile TT course into a headwind the power estimated is way too low, and then on the way back it's way too high.

I've got a pair of P1s and the only issue I've had is reading zero at very low cadences, which is problematic for steep climbs on fixed.


Re: Training – the next step after just riding your bike?
« Reply #61 on: 24 October, 2016, 04:39:59 pm »
i personally don't trust pedal based power meters

Why not? Is it the existing products or the idea you don’t like?

pedals wear out, and require to be tightened to cranks at a precise torque to give consistent readings, which is a problem if you fly with your bike. battery life isn't great either, from what i've read. the need to use specific cleats however is the biggest inconvenience. if you accept the compromise (which every power meter system has), then they are ok.
I don't know about the others, but the Bepro doesn't require a specific torque. and is simple enough to set up that I can do it. I use look keo cleats anyway, which are Bepro compatable, so there was no issue there for me.
I think the battery life quoted was 30 + hours and they seem to hold charge reasonably well. Recharging is easy with a usb charger. I haven't yet tried putting them on the tourer and recharging using the dynamo!
My only wish is that I'd sprung for the double pedal system initially as I think I have a significant L/R imbalance. I'm waiting for the pedal upgrade to convert to a double sided system.
Audax Ecosse - always going too far

simonp

Re: Training – the next step after just riding your bike?
« Reply #62 on: 25 October, 2016, 10:16:26 am »
AIUI, the Garmin Vector pedals do need a specific torque, but the PowerTap P1 seem to require no special fitting - the instructions just say to use the torque setting specified by your crank manufacturer.

It would be interesting to experiment with using them on the KickR to see how the measurements compare. OTOH, life is too short.

LMT

Re: Training – the next step after just riding your bike?
« Reply #63 on: 25 October, 2016, 12:09:03 pm »
P1 pedals don't need to be torqued and the battery life is about 55-60 hours as per Powertap. They are good pedals ime, very easy to set up, calibrate and swap between the df and the recumbent.

Having said that my next power meter will be a crank based system, probably Power2max as I do like the free float of Speedplay pedals when riding the recumbent.

Re: Training – the next step after just riding your bike?
« Reply #64 on: 18 November, 2016, 09:22:48 pm »
The right pedal arrived yesterday, allowing me to convert to the double sided system. The process was very straightforward, although due to stupidity, I omitted one key stage.

This had the amusing result of the right pedal grossly overreading. It appeared that my right side was putting out 4 times as much power as the left. I pedalled along effortlessly at 250watts, without even breaking sweat. Once I was finished it was time to face up to the truth.

I performed another dynamic calibration, but the results were the same.

I emailed Bepro and was very surprised to have a response within an hour, which very gently pointed out that I had failed to do the static calibration. 2 minutes later, calibration completed and power meter working perfectly.

Very impressed with the tech support, and pleasantly surprised by the ease of setup
Audax Ecosse - always going too far