Mont Ventoux Power calculation
- Thread starter 2laps
- Start date
2laps, it's worth bearing in mind that your Tacx may not be accurate for the purposes of power output. While i have *never* used a Tacx Flow, i have used several other Tacx trainer (Elite, Grand Elite and another) and the power they reported was somewhat different to my PT and SRM. Additionally, each one reported different power values when riding at a constant PT/SRM power. In other words one unit reported higher figures, another reported lower figures, etc.
Ric
Ric
In belgium we had a great weekend of the 21 july so i could not reply sooner.
I did calculate the power needed for the Km sections starting from Bedoin.
The first time i tried it, i had to stop just before Km 10. Was very dissapointed. Next day tried again and went the whole way. Triumph! or not?!
The thing is at the higher power settings 250W - 270W i had to keep a cadence of at least 70rpm otherwise my trainer couldnot prevent my wheel from slipping. Now i am worried that with the higher rpm it felt a little bit better than it would if i was riding at a cadence of 60rpm like i was supposed to do. Anyway i will try to insert my settings here:
Each section of 1Km had a timeframe of 5m30s
Km slope% height m power W
1 3 311 84
2 2.5 338 73
3 3.5 375 96
4 5 426 131
5 5.5 482 143
6 4.5 527 120
7 6.5 592 166
8 10 690 248
9 9 781 225
10 10.5 884 260
11 9.5 977 236
12 10 1076 248
13 9.5 1172 236
14 9.5 1266 236
15 9 1356 225
16 7.5 1429 190
17 7 1500 178
18 6.5 1564 166
19 7 1635 178
20 8 1712 201
21 8.5 1799 213
22 11 1909 272
I did calculate the power needed for the Km sections starting from Bedoin.
The first time i tried it, i had to stop just before Km 10. Was very dissapointed. Next day tried again and went the whole way. Triumph! or not?!
The thing is at the higher power settings 250W - 270W i had to keep a cadence of at least 70rpm otherwise my trainer couldnot prevent my wheel from slipping. Now i am worried that with the higher rpm it felt a little bit better than it would if i was riding at a cadence of 60rpm like i was supposed to do. Anyway i will try to insert my settings here:
Each section of 1Km had a timeframe of 5m30s
Km slope% height m power W
1 3 311 84
2 2.5 338 73
3 3.5 375 96
4 5 426 131
5 5.5 482 143
6 4.5 527 120
7 6.5 592 166
8 10 690 248
9 9 781 225
10 10.5 884 260
11 9.5 977 236
12 10 1076 248
13 9.5 1172 236
14 9.5 1266 236
15 9 1356 225
16 7.5 1429 190
17 7 1500 178
18 6.5 1564 166
19 7 1635 178
20 8 1712 201
21 8.5 1799 213
22 11 1909 272
2laps said:
I have both a Tacx Flow and Power-Tap Pro (which I've check the calibration of) and to be quite honest, the figure shown on the Wattage figure shown on the flow is so far out it's not even usable. I've calibrate the Flow as described in the manual, however, this still produces wild readings.
Also, FWIW (old news here), producing 200W on the trainer feels about 50% harder than producing that same wattage out on the open road.
tomUK said:
tomUK, this comes as a shock
to me. You are now telling me that i will not be able to simulate the montoux on my Flow because i can not rely on the Wattage figures it gives me. So my trainer is practically useless for this kind of stuff. I'm stunned. You think the Power-Tap is accurate? (i will have to get one, but i dont know much about it). You also say that the trainer feels harder than the same thing on the road? Do you mean it just 'feels' like it or is it actually harder (more wattage)?And i thought i climbed the mountain
2laps said:tomUK, this comes as a shock
And i thought i climbed the mountain
2laps, as i suggested in my previous post, it's unlikely that your Flow will be accurate.
The Power Tap is as accurate (if not more so) than the SRM Pro, as has been discussed in quite a few threads previously. The SRM Amateur is less accurate.
Some people find riding a trainer at the same power harder than the road. On the other hand i find it considerably easier than the road (and can generate ~10% more power in a 1-hr TT on the trainer)
Ric
ric_stern/RST said:
Yes, you did tell me the flow was not accurate enough but still i had some hope (could live with a 10% deviation) but the way tomUK presented it, there does not even seem to be any logic in it not being accurate.
If i would to calculate the speed outcome for the given power settings on a flat road, and then train on the flat road for the given speeds, would that give me a good training for the ventoux? Suppose not because my cadence would be much higher?
I just spend money on new gipiemme wheels with campa gears (9s veloce), not even sure if i could still use them if i'm going to buy a power-tap. Ohoh what a setback, i keep spending money and i'm not getting anywhere.
2laps said:
As i mentioned earlier i have *no* experience of a Flow, but have used and own a Tacx Basic and Excel (or Grand Excel). These units are not accurate. I do not know if they are the same flywheel, and computers as the Flow.
However, on the Wattage list, someone, maybe a year ago reported that the Flow was not accurate and was possibly less accurate than the Basic and Excel units in comparison to an SRM unit.
Environmental conditions will affect your velocity/power relationship to, too much extent.
The Power Tap gets built into an entire wheel, so some or all of your new Gipiemme wheels would be redundant if you purchased a PT.
However, it is possible to train (well) without the use of a power meter (although having a power meter makes your training much more accurate and specific, and cuts down on wasted time). Good coaching (and training) will improve your fitness, which is what you need to aim to do (increase fitness) if you want to ride up Ventoux or other climbs either at a faster pace or at the same pace as before and feel more comfortable.
You need to concentrate on building your sustainable power output, and maximal aerobic power. This can be done in several ways from longish, quality rides, to flat out time trialling, to short (~4-min) nasty intervals. This will help you increase your fitness, and thus travel at a faster rate up Ventoux (or any other climb, and of course on flat roads). In the training section of this forum, there's quite a lot of threads on these subjects. Additionally, our coaching group (RST; www.cyclecoach.com) who sponsors the forum can help you with these issues if you so desire, and of course there's several other coaches on this forum who would also be able to help.
I see you're in Belgium, do you read "Het Nieuwsblad"? I'm trying to translate an interview i did with them... If you are able to help, i'd be most grateful,
cheers
ric
ric_stern/RST said:
Ok ric, thanks for the info, i think i will visit your coaching group, remind you i'm not a pro
And yes i live in Belgium but no i do not read "Het Nieuwsblad" BUT if you give me some more details for that specific interview (date) maybe i can still get a copy and help you with translation. Or if you have a copy, just send it to me and i will help.
2laps said:Ok ric, thanks for the info, i think i will visit your coaching group, remind you i'm not a pro
just to clarify, we coach a wide range of people from recreational/fitness, sportif riders, amateur racers, elite racers, and pro cyclists, as well as other sports such as triathletes, and paralympians. so, please don't worry that you're not a pro.
And yes i live in Belgium but no i do not read "Het Nieuwsblad" BUT if you give me some more details for that specific interview (date) maybe i can still get a copy and help you with translation. Or if you have a copy, just send it to me and i will help.
it's from the 30th june. i can scan the paper and email the image (if you email me your email addy)
cheers
ric
ric_stern/RST said:
You can send your paper to this email
btw went to your site and i suppose i would fit the recreational/fitness, sportif riders profile for which you provide a team coaching(?) but as an individual. Still i'm not quite sure if this is my cup of tea. have to think about it
greets
peter
Well, as someone who does not have a power meter but trained this year on a trainer (Cardgirus), I can guess that you should get quite low gearing.
I rode an organized century in June that climbed Mont Ventoux from Bedoin and then again from Sault (longer, but easier) for about 106 miles and 12,500 feet of climbing. I rode the climb in somewhere around 1:35 (where in Bedoin do you start the clock?) and rode a few days later in 1:29. I used a 34X23/26 for most of the steep section from the first hairpin after St. Esteve to Chalet Reynard, and did not hesitate to use a 34X29 on some occassions.
When you are fresh it is not so bad since the climb never hits more than about 12% but it is relentless after St. Esteve for 10km, and then gets steep again after Chalet Reynard. Also, I was lucky enough to miss the mistral that was prevalent that week. Good luck!
I rode an organized century in June that climbed Mont Ventoux from Bedoin and then again from Sault (longer, but easier) for about 106 miles and 12,500 feet of climbing. I rode the climb in somewhere around 1:35 (where in Bedoin do you start the clock?) and rode a few days later in 1:29. I used a 34X23/26 for most of the steep section from the first hairpin after St. Esteve to Chalet Reynard, and did not hesitate to use a 34X29 on some occassions.
When you are fresh it is not so bad since the climb never hits more than about 12% but it is relentless after St. Esteve for 10km, and then gets steep again after Chalet Reynard. Also, I was lucky enough to miss the mistral that was prevalent that week. Good luck!
Watoni said:
Hi Watoni, i'm wondering if your trainer (Cardgirus) gives you some power values? You say you use a 34x(23-29) is that a tripple? I don't have a tripple, so i was thinking of using a 39x(23-29) in the hope of getting there.
Watoni said:
I still have to do my first climb. The goal is to climb from Bedoin, from other peoples journals there is supposed to be a fountain with a start line on the road that would be my starting point for the clock.
Watoni said:
It is not so bad since the climb never hits more than 12% your joking right!?
Fear creeps in my legs. By the way, congrats on your time 1:29, hope i can do it in 2:00
2laps said:
Hi 2laps
I'd like to ask you some questions on you Tacx Flow.
I've just purchased mine on Friday I've always had the tacx speedmatic, but wanted to add power training into my training as my road bike has it but doesnt work on my trainer.
Firstly tonight I'll start playing around with it and from tommorrow use it for training. So sorry if my questions sound stupid.
1. Do you simply start riding and then it automatically start to record the data or do you have to "start it" somewhere.
2. Do you leave the power connection on the whole night or do you disconnect the power after your sessions.
Thanks
franco,
You only have to plug in the power and you are ready to ride.
However, it does not record data for later use (there is no connection for a computer ) it does show you the current speed, cadence, watts etc.
I always disconnect the power after my sessions. There is no reason why you should leave the power on (data is not stored so you can not loose it)
franco1 said:
You only have to plug in the power and you are ready to ride.
However, it does not record data for later use (there is no connection for a computer ) it does show you the current speed, cadence, watts etc.
franco1 said:
I always disconnect the power after my sessions. There is no reason why you should leave the power on (data is not stored so you can not loose it)
If you want the Ventoux experience we have it as a Real life video http://www.tacx-video.com/DV2004Ventoux.htm Its the Sault & Malaucéne side (they were laying new tarmac on the Bedoin side which joins the Sault road about 6km from the cloudy top). There is a little bit of low res wmv video on the Tacx site (VR trainers).
You would need to upgrade the flow with a USB adapter to turn it into an i-magic. Once you have that you can calibrate it with a Powertap or SRM to make it more accurate.
We use virtual speed which is calculated from your total mass (you & bike), power & grade so your time will be close to real life if your power is calibrated, even though your wheel speed could be much higher then what you see on the PC.
The actual profile is hard linked to the video so as you grovel along those steep sections the video slows down with you. This is the only ride Ive not been able to finish yet .
As for the flow's accuracy make sure its had a really good warm up before doing the calibration test with it. I can say the new Fortius & Cosmos when calibrated will match the SRM spot on at all power outputs.
Rick you can always email me with anything you want translated I live in Belgium also.
Regards
You would need to upgrade the flow with a USB adapter to turn it into an i-magic. Once you have that you can calibrate it with a Powertap or SRM to make it more accurate.
We use virtual speed which is calculated from your total mass (you & bike), power & grade so your time will be close to real life if your power is calibrated, even though your wheel speed could be much higher then what you see on the PC.
The actual profile is hard linked to the video so as you grovel along those steep sections the video slows down with you. This is the only ride Ive not been able to finish yet
. As for the flow's accuracy make sure its had a really good warm up before doing the calibration test with it. I can say the new Fortius & Cosmos when calibrated will match the SRM spot on at all power outputs.
Rick you can always email me with anything you want translated I live in Belgium also.
Regards
2laps said:
Thanks for the reply.
Last night I used my "flow" for the first time and I've got another few questions to ask you if you dont mind.
Firstly I when I switched it on and went to set up I could'nt see my weight. I only saw the last digit.
And I didnt see the "km" sign either did see the Mile one.
Also when I started training and tried to alternate between Gradient and Power I couldn't see the power,only saw the last two numbers. Saw +90 not 190W or 290W
And lastly where do you see the number of Kcal or Kjoules burnt during the session?
What I've done is I've returned it to the shop where I've purchased it as I think there is a problem on the head unit.
Thanks
Appreciate the help.
hi franco, some more questions hé
If you plug in the power you should see the following:
left top corner: frequency(50/60hz) next to it voltage(110/220V)
next rule below:software version number ( p28 or something like that)
next : scale factor (default 100)
next : body weight ( 75 Kg)
bottom line : speed unit (Km or Mi) ont the right Kjoules or Kcal
if you want to see the speed in Mi you should press the SET and MODE buttons until SETUP appears on the screen with the arrow buttons you should be able to alter the weight in steps of 1 Kilo. Press MODE to enter the value (Kg is the only weight unit). After this you should see the speed blinking, again press the arrow button to change this in Mi. MODE to enter.
Next you should see the Kcal/Kjoules. repeat the same procedure.
If you only can see the last digit of your weight you've got a problem.
-check: you can only enter weight between 40 - 120 Kg
-check: are your cable contacts not corroded
-check: temperature should be between: 5 - 35 C or 40 - 95F
Well, eh, i think you do have a problem with your display
You can only see your Kcal burnt if you are wearing a hartrate belt. If you press the MODE button the first line should show you the right numbers.
Did the shop gave any comment on your head unit
If you plug in the power you should see the following:
left top corner: frequency(50/60hz) next to it voltage(110/220V)
next rule below:software version number ( p28 or something like that)
next : scale factor (default 100)
next : body weight ( 75 Kg)
bottom line : speed unit (Km or Mi) ont the right Kjoules or Kcal
if you want to see the speed in Mi you should press the SET and MODE buttons until SETUP appears on the screen with the arrow buttons you should be able to alter the weight in steps of 1 Kilo. Press MODE to enter the value (Kg is the only weight unit). After this you should see the speed blinking, again press the arrow button to change this in Mi. MODE to enter.
Next you should see the Kcal/Kjoules. repeat the same procedure.
If you only can see the last digit of your weight you've got a problem.
-check: you can only enter weight between 40 - 120 Kg
-check: are your cable contacts not corroded
-check: temperature should be between: 5 - 35 C or 40 - 95F
Well, eh, i think you do have a problem with your display
You can only see your Kcal burnt if you are wearing a hartrate belt. If you press the MODE button the first line should show you the right numbers.
Did the shop gave any comment on your head unit
2laps said:hi franco, some more questions hé
If you plug in the power you should see the following:
left top corner: frequency(50/60hz) next to it voltage(110/220V)
next rule below:software version number ( p28 or something like that)
next : scale factor (default 100)
next : body weight ( 75 Kg)
bottom line : speed unit (Km or Mi) ont the right Kjoules or Kcal
if you want to see the speed in Mi you should press the SET and MODE buttons until SETUP appears on the screen with the arrow buttons you should be able to alter the weight in steps of 1 Kilo. Press MODE to enter the value (Kg is the only weight unit). After this you should see the speed blinking, again press the arrow button to change this in Mi. MODE to enter.
Next you should see the Kcal/Kjoules. repeat the same procedure.
If you only can see the last digit of your weight you've got a problem.
-check: you can only enter weight between 40 - 120 Kg
-check: are your cable contacts not corroded
-check: temperature should be between: 5 - 35 C or 40 - 95F
Well, eh, i think you do have a problem with your display
You can only see your Kcal burnt if you are wearing a hartrate belt. If you press the MODE button the first line should show you the right numbers.
Did the shop gave any comment on your head unit
Thanks for your response.
I brought back the head unit yesterday and they lent me one which was there "demo" unit. I can see everything on this unit which means the LCD display must have been damaged.
I'll get my original back next week I hope.
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