The Wattage Thread
Discussion
BMWBen said:
upsidedownmark said:
Funny thing this power stuff.
Did a threshold test on the trainer (...)
Trainers can be quite hard to put out the same power on - I believe due to the issue you have with heat (your body, not the trainer). I thought it might just be a motivation thing, but then I rode a bit in Croatia earlier this year when it was 30 degrees, and just like on the trainer my threshold seemed to be 20-30w lower than I can do on a chilly English morning.Did a threshold test on the trainer (...)
okgo said:
Yeh, not a bad ride. So close at the sharp but not razor sharp end of things. 17 seconds from 16th to 8th!!
I think I went well but always wonder if I could have gone harder on the way out..hopefully a bit more power and a few aero tweeks and on the regular course I should be good for a short 18. And on a freak day I won't rule out a 17 tbh with a few more watts.
Will you go public with your data ? Be interested in seeing avg speed / power ... I know the avg power figure it took for 1 of the riders to go under 18min .I think I went well but always wonder if I could have gone harder on the way out..hopefully a bit more power and a few aero tweeks and on the regular course I should be good for a short 18. And on a freak day I won't rule out a 17 tbh with a few more watts.
All on Strava!
384w average , 386 normalised, which is a best on TT bike since I swapped to a new Qaurq with round rings. I suspect with q rings it would report it as near 400 due to the way they inflate power. Still some way down on road watts though, before the RAS I did 385w for nearly half an hour in a solo training effort!
So my position is ever so slightly less aero than Andy Jacksons, he is shorter and less broad than me though, he did 410w for 18.02 to my 18.46. I've worked out that with his position and the same watts I would have done 18.33. And of I could manage that with 400w I would be around 18.15, which makes sense as he then had another 10w to knock another 10 secs off. So for me 1w is about 1 second.
I guess it's Russ's data you have, he put 44 seconds into me at h10/8 with him doing 385w and me 373w. So I would imagine given he put about same amount of time give or take into me that he probably did around 400w?
384w average , 386 normalised, which is a best on TT bike since I swapped to a new Qaurq with round rings. I suspect with q rings it would report it as near 400 due to the way they inflate power. Still some way down on road watts though, before the RAS I did 385w for nearly half an hour in a solo training effort!
So my position is ever so slightly less aero than Andy Jacksons, he is shorter and less broad than me though, he did 410w for 18.02 to my 18.46. I've worked out that with his position and the same watts I would have done 18.33. And of I could manage that with 400w I would be around 18.15, which makes sense as he then had another 10w to knock another 10 secs off. So for me 1w is about 1 second.
I guess it's Russ's data you have, he put 44 seconds into me at h10/8 with him doing 385w and me 373w. So I would imagine given he put about same amount of time give or take into me that he probably did around 400w?
upsidedownmark said:
yonex said:
I have a P2M one of the Type S ones and it is great. It compares very well with the Powertap and in my case was a good deal as I already had compatible cranks which dropped the overall cost. I wouldn't personally go for with Stages but I know people who use them and they're happy enough. The P2M was reliable at altitude in Tenerife, it's pretty compact. The one downside is it seems to be a bit laggy with cadence, you get used to it but it's not as instant as some. The deal on the classic is very good, I might have to go for one and flog the PT finally.
Same goes for the vectors - Far as I can tell all accelerometer based cadence sensing is the same.FWIW I'd also go for the p2max at the 'entry' price point right now. I went powertap->vector due to having various wheels making powertap a pain - otherwise it's a great solution.
Having vector, I do get L/R balance, and (for me) it is very inconsistent. Consequently left only seems rather pointless.
Having done a little reading, P2M and a few others base left/right power on power produced between 12 and 6 o'clock (right) and 6 and 12 o'clock (left). From what I gather it's still estimating left/right as it doesn't know what is produced on the opposing up stroke. Is that really much better than just doubling left?
Starting to consider P2M as a bit more bang for my buck but I'm still trying to get to grips with the details.
You can work on technique, but generally I'd say don't worry about it - nobody seems to have figured out what the power balance really means, or if it matters..
The p2max and other crank spider based systems are estimating L/R balance, you're correct - they assume the power generated on the right (say) is from pushing down when the right crank is between 12 and 6, and assign that to the 'right' bucket. It is possible that some of that power is actually coming from lifting the left - so the L/R balance may be inaccurate (I sincerely doubt many folks generate any meaningful power on the upstroke however).
What it is NOT ESTIMATING however is total power. However and wherever it is generated, all the input from your legs is measured between the cranks and the rings.
Left only power meters are assuming a 50/50 balance and doubling the left - estimating total power. If your balance is 60/40, it over-reads by 20%, if it's 40/60, it under-reads by 20%. If your balance shifts around, it will be inconsistent, which seems to be the big argument against.
The p2max and other crank spider based systems are estimating L/R balance, you're correct - they assume the power generated on the right (say) is from pushing down when the right crank is between 12 and 6, and assign that to the 'right' bucket. It is possible that some of that power is actually coming from lifting the left - so the L/R balance may be inaccurate (I sincerely doubt many folks generate any meaningful power on the upstroke however).
What it is NOT ESTIMATING however is total power. However and wherever it is generated, all the input from your legs is measured between the cranks and the rings.
Left only power meters are assuming a 50/50 balance and doubling the left - estimating total power. If your balance is 60/40, it over-reads by 20%, if it's 40/60, it under-reads by 20%. If your balance shifts around, it will be inconsistent, which seems to be the big argument against.
upsidedownmark said:
You can work on technique, but generally I'd say don't worry about it - nobody seems to have figured out what the power balance really means, or if it matters..
The p2max and other crank spider based systems are estimating L/R balance, you're correct - they assume the power generated on the right (say) is from pushing down when the right crank is between 12 and 6, and assign that to the 'right' bucket. It is possible that some of that power is actually coming from lifting the left - so the L/R balance may be inaccurate (I sincerely doubt many folks generate any meaningful power on the upstroke however).
What it is NOT ESTIMATING however is total power. However and wherever it is generated, all the input from your legs is measured between the cranks and the rings.
Left only power meters are assuming a 50/50 balance and doubling the left - estimating total power. If your balance is 60/40, it over-reads by 20%, if it's 40/60, it under-reads by 20%. If your balance shifts around, it will be inconsistent, which seems to be the big argument against.
Ahhhh gotcha! I see your point now. The p2max and other crank spider based systems are estimating L/R balance, you're correct - they assume the power generated on the right (say) is from pushing down when the right crank is between 12 and 6, and assign that to the 'right' bucket. It is possible that some of that power is actually coming from lifting the left - so the L/R balance may be inaccurate (I sincerely doubt many folks generate any meaningful power on the upstroke however).
What it is NOT ESTIMATING however is total power. However and wherever it is generated, all the input from your legs is measured between the cranks and the rings.
Left only power meters are assuming a 50/50 balance and doubling the left - estimating total power. If your balance is 60/40, it over-reads by 20%, if it's 40/60, it under-reads by 20%. If your balance shifts around, it will be inconsistent, which seems to be the big argument against.
okgo said:
Rocksteadyeddie said:
I have it on good authority that Wiggins did 472W yesterday.
What authority is that?I don't think he meant that he averaged 47-480 for the entire TT, rather the last section?
He has also broken Bobridge's 4k record in training recently.
Rocksteadyeddie said:
okgo said:
Rocksteadyeddie said:
I have it on good authority that Wiggins did 472W yesterday.
What authority is that?I don't think he meant that he averaged 47-480 for the entire TT, rather the last section?
He has also broken Bobridge's 4k record in training recently.
In his book he claimed to be doing about 460w for the hour in the TdF time trials and the Olympics. He could of course be well aware his rivals will read it (or their team staff will) so what better way to demoralise them than to claim a really high power output.
Boardman was putting out around 450-460w for his 1996 hour record, which I suspect will be Wiggins target for his hour record attempt.
ALawson said:
Stupid question but how accurate is the Strava estimated power against those who use Power Meters?
My experience has been that it's generally sort of rightish over the period of a whole 2-3 hour out and back ride, but for anything shorter than that it's not accurate at all.Rocksteadyeddie said:
Apparently for the full ride. On good authority.
He has also broken Bobridge's 4k record in training recently.
The Bobridge 4K record in training is pretty much not true im afraid .. The main reason Brad didnt ride the IP at the comms was that he wasnt going quick enough to get a gold... He was close but not close enough . He was probably riding at WR pace without a issue, but as for doing a standing start full WR effort there is a high chance this didnt happen. As good as he is (and thats pretty mega IMO) pulling off a 4.10 in training isnt something that happens in training, even if you are a Knight of the realm !He has also broken Bobridge's 4k record in training recently.
BMWBen said:
ALawson said:
Stupid question but how accurate is the Strava estimated power against those who use Power Meters?
My experience has been that it's generally sort of rightish over the period of a whole 2-3 hour out and back ride, but for anything shorter than that it's not accurate at all.These are some of my efforts with / without power up a local climb:
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