Author Topic: Wattage Required to do 40k for one hour.  (Read 3624 times)

Wattage Required to do 40k for one hour.
« on: January 29, 2018, 03:05:20 pm »
I have just invested in a Wattbike Atom and would like to see what I can do with some proper training when it arrives in about two months. I have done many 40k p/hr + TT rides of up to 80k about 45 yrs ago but I would like to know if it is feasible to do so again even if only for 15k or 40k rides. Does anyone know how many watts I would need to achieve this again? I appreciate there are so many variables but think there must be a vague rule of thumb.

simonp

  • Omnomnomnipotent.
Re: Wattage Required to do 40k for one hour.
« Reply #1 on: January 29, 2018, 03:11:58 pm »
http://forums.roadbikereview.com/racing-training-nutrition-triathlons/average-power-do-sub-1hr-40k-time-trial-326408.html

I guessed 250w for a TT bike, seems right sort of ball-park if this thread is to be believed.

Tests that estimate your FTP using shorter efforts will over-estimate your hour power, so add 10-15% margin to that.

Samuel D

Re: Wattage Required to do 40k for one hour.
« Reply #2 on: January 29, 2018, 03:12:16 pm »
Very roughly 250 watts with aerobars. You would have needed more power 45 years ago without those.

Re: Wattage Required to do 40k for one hour.
« Reply #3 on: January 29, 2018, 03:14:21 pm »
40kph, 40km. But you do need to type more letters though.

Re: Wattage Required to do 40k for one hour.
« Reply #4 on: January 29, 2018, 03:14:38 pm »
I was going to say about 260-270w.  That's from personal experience on a Wattbike-type trainer, but I wouldn't be able to maintain that for a whole hour, sadly.

Re: Wattage Required to do 40k for one hour.
« Reply #5 on: January 29, 2018, 03:24:06 pm »
I don't know what wattage is required for a given speed - the variables of bike/position/course are so large as to give a large margin for error anyway.
One thing to be aware of is that you will need a decent size fan (or 2) if you want to run the same power as you do outside for any duration. Lack of cooling can seriously restrict your power.

Re: Wattage Required to do 40k for one hour.
« Reply #6 on: January 29, 2018, 03:38:30 pm »
Many thanks for these replies. I can see I will have to do a bit of work. I have started doing 5 x 3 min intervals at the gym and am doing over 200 watts going over 300 for the last minute but know I could not hope to maintain this for one hour. I do not have a TT bike and do not intend to purchase one until I see that my goals are achievable so will content myself with adding aerobars to a road bike after a few rides without them to give a base level.

Re: Wattage Required to do 40k for one hour.
« Reply #7 on: January 29, 2018, 03:56:16 pm »
That sounds like a sensible plan.  I don't have a power meter on any of my rod bikes but find the gym trainer very useful for monitoring wattage as there are no variables so you can directly compare performances over time (particularly if I can nab the same bike each session as they do vary a little even if the same model/age/etc).

Having a Wattbike at home sounds great.  Good luck!

Re: Wattage Required to do 40k for one hour.
« Reply #8 on: January 29, 2018, 04:34:12 pm »
Indoors on a Wattbike or similar you probably wouldn't need so many watts. The data for the last hour-long spin class I did shows 215W average and 42kph average speed (though that was intervals and stuff rather than just trying to maintain the same power for an hour). Wouldn't get anywhere near that average speed for the same power outside, though. :'(

simonp

  • Omnomnomnipotent.
Re: Wattage Required to do 40k for one hour.
« Reply #9 on: January 29, 2018, 04:35:21 pm »
I'll be interested in hearing how you get on with the Atom.

Re: Wattage Required to do 40k for one hour.
« Reply #10 on: January 29, 2018, 04:59:15 pm »
The data for the last hour-long spin class I did shows 215W average and 42kph average speed (though that was intervals and stuff rather than just trying to maintain the same power for an hour).

Those figures don't add up.  You can't generate 42kph (av.) at 215w (av.) on any trainer or spin bike I've ever used.  The better bikes I've been using are pretty accurate and 215w (av.) will give you 33kph (av.) tops.  Much different than that and your bike's not calibrated correctly.

Samuel D

Re: Wattage Required to do 40k for one hour.
« Reply #11 on: January 29, 2018, 05:02:27 pm »
The concept of speed on a stationary contraption is too ridiculous to consider in the first place.

Re: Wattage Required to do 40k for one hour.
« Reply #12 on: January 29, 2018, 05:04:23 pm »
The concept of speed on a stationary contraption is too ridiculous to consider in the first place.

True, but wattage can be very accurately tracked.

Samuel D

Re: Wattage Required to do 40k for one hour.
« Reply #13 on: January 29, 2018, 05:08:13 pm »
It can, and that seems adequate to gauge performance on these machines without adding an imaginary speed.

Zwift takes the imaginary speed a bit further, of course. There is a market for imagined bicycle rides. I’d rather just do them. Luckily I live in a part of the world that allows cycling all year around.

Re: Wattage Required to do 40k for one hour.
« Reply #14 on: January 29, 2018, 06:00:38 pm »
In general, my experience is that 40 km in 1 hour needs an average in the low 200’s Watts on a Wattbike.

A Wattbike is probably one of the few calibrated machines, other devices use algorithms etc.

However, in the real world watts/kg is what really matters. A 100kg rider could ride 40 km on a Wattbike, but would be slower than a 60 kg rider.  In hilly country the gap increases of course.

Re: Wattage Required to do 40k for one hour.
« Reply #15 on: January 29, 2018, 06:26:06 pm »
In general, my experience is that 40 km in 1 hour needs an average in the low 200’s Watts on a Wattbike.


That tallies with my experience - I'm used to Matrix IC7s rather than Wattbikes, but they're also power meter-equipped. It also tallies with data I have from using Zwift (using a Stages power meter).

The concept of speed on a stationary contraption is too ridiculous to consider in the first place.

Of course. It's not something I've ever even looked at before before this thread prompted me to look at past data. (I'd also love it if Strava could discount indoor "miles" automatically, but that's veering off-topic!)

Re: Wattage Required to do 40k for one hour.
« Reply #16 on: January 29, 2018, 07:18:55 pm »
It can, and that seems adequate to gauge performance on these machines without adding an imaginary speed.


As a Wattbike user and instructor I agree. Power and pulse are the key parameters.

However, sometimes someone comes up with a charity “ how far can you go in an hour?” sort of event - like I got talked into last Saturday!

Re: Wattage Required to do 40k for one hour.
« Reply #17 on: January 29, 2018, 07:36:22 pm »
I do not have a TT bike and do not intend to purchase one until I see that my goals are achievable so will content myself with adding aerobars to a road bike after a few rides without them to give a base level.

You may also find that you can generate the required power on a Wattbike as it has a much more relaxed postion, but when you move to a road bike with aerobars you may find you're unable to generate that same power in a different position.

TT-ing is a lot about adapting positions on the bike such that the aerodynamic gain is more than the subsequent loss of power it causes.

That being said, there's nothing stopping you building up your power with some structured training until you think you are getting close, and then giving it a go.
"Yes please" said Squirrel "biscuits are our favourite things."

dim

Re: Wattage Required to do 40k for one hour.
« Reply #18 on: January 29, 2018, 07:37:54 pm »
I'd love to know how many Watts Chris Froome produces ...

this was his weekend ride in South Africa:

https://www.strava.com/activities/1379317668

271.65km .... 3,485m .... and his average speed was 44.8km/h
“No great mind has ever existed without a touch of madness.” - Aristotle

Samuel D

Re: Wattage Required to do 40k for one hour.
« Reply #19 on: January 29, 2018, 07:45:56 pm »
I’m curious despite myself how these machines estimate speed from power. Do you give them your weight and they simply read a speed off a curve in firmware for the applicable weight?

I have noticed on the road that I am more aerodynamic than almost all others (talking road bikes). On the other hand, I’m light and don’t have a lot of power. This combination reveals that speed estimates from weight and power can be inaccurate, because bigger guys often out-climb me and I often outrun them on the flat despite having nothing like their power output.

Re: Wattage Required to do 40k for one hour.
« Reply #20 on: January 29, 2018, 07:48:59 pm »
I'd love to know how many Watts Chris Froome produces ...

Reasonably public knowledge.

http://www.cyclist.co.uk/news/691/chris-froome-s-numbers-what-do-they-really-mean

An FTP of 419W (although he probably wouldn't be able to put out 419W for an hour in a TT position for the reasons I posted above.)
"Yes please" said Squirrel "biscuits are our favourite things."

zigzag

  • unfuckwithable
Re: Wattage Required to do 40k for one hour.
« Reply #21 on: January 29, 2018, 07:49:23 pm »
for what it's worth, checked the stats of my first 40km of the 24hr tt (the only proper tt i've done so far, on a tt bike):

speed - 36.2kph
power - 178w
heart rate - 147bpm
cadence - 89rpm
temp - 29deg

i reckon 230w should be enough to ride 40km in 1hr.

Re: Wattage Required to do 40k for one hour.
« Reply #22 on: January 29, 2018, 07:59:07 pm »
for what it's worth, checked the stats of my first 40km of the 24hr tt (the only proper tt i've done so far, on a tt bike):

And to compare what weight (88kg, it wasn't a pan-flat TT) and a non-aero position do, here's my stats for the first 40km of that very same TT (on a non-TT bike but with aerobars but I hadn't trained on the aerobars so I wasn't able to stay in them for long periods):-

speed: 28.0kph
power: 166W
HR: 154bpm
cadence: 88rpm
"Yes please" said Squirrel "biscuits are our favourite things."

dim

Re: Wattage Required to do 40k for one hour.
« Reply #23 on: January 29, 2018, 08:14:50 pm »
for what it's worth, checked the stats of my first 40km of the 24hr tt (the only proper tt i've done so far, on a tt bike):

speed - 36.2kph
power - 178w
heart rate - 147bpm
cadence - 89rpm
temp - 29deg

i reckon 230w should be enough to ride 40km in 1hr.

and which way was the wind blowing, and how strong was it?
“No great mind has ever existed without a touch of madness.” - Aristotle

zigzag

  • unfuckwithable
Re: Wattage Required to do 40k for one hour.
« Reply #24 on: January 29, 2018, 08:19:05 pm »
the wind wasn't much of a factor that day, iirc