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Trying to understand efficiency / TT numbers
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Please help me to read these numbers of my last TT test.

After an hour of activation, did a 20min. TT test:

Weight: 160 lbs
Distance: 13.09km
Time: 20min.
Avg power: 291w
NP: 292w
Avg speed: 39.2k/h
Flat road
Aero position the whole test.
Bike/gear: TT with racing kit, aero helmet, etc.

How do I know if this is efficient of not ?

Cheers !
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Re: Trying to understand efficiency / TT numbers [Hoodoo] [ In reply to ]
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Firstly, what do you mean by efficient?
Are you looking for a single number to combine aerodynamic drag, drivetrain losses and rolling resistance losses?

Next, there are a load of other variables that stop this from being an easy derivation.
Was this an out and back course, a loop, a single direction, or something else and what was the wind speed and direction? Flat terrain and calm wind are relative terms! It's never totally flat or totally calm, best you can hope for is negligible.
What was the temperature and atmospheric pressure?
What was the road surface? Tarmac/Ashphalt? How smooth and flat?

I think you're better off looking up your tyre's test results if Tom A or someone else has done good testing with them. Then maybe use Chung testing and/or BestBikeSplit aero tool to do some analysis of your aerodynamics to see how your position , helmet and clothing might be impacting you. Others may be able to chime in on a general idea of where your figures stand relative to typical cyclists at similar speeds or powers over a similar course. I don't think you'll get an actual efficiency figure.
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Re: Trying to understand efficiency / TT numbers [Hoodoo] [ In reply to ]
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I agree with Ai_1...lots of ways we could interpret this.

To give any meaningful analysis we really need to have a better idea about the atmospheric pressure, wind direction, wind speed, type of road and smoothness, was this a loop/straight shot, or out and back, etc, etc, etc.

If you care about getting into the nitty-gritty I'd suggest searching ST for the "platypus thread."

If you just want to measure up against other people, then look at the "post your time/watts from your last race" thread. Find someone of similiar weight and/or watts and see how they did compared to you. Again, take this with a grain of salt without more info about the riding conditions for either effort.

Without knowing anything else about your test,13.09km is 8.07 miles and you were traveling at a speed of 2:27 per mile which would put your 10TT time at around 24:35. That's not too bad, but at 291 average watts I think you could probably be faster. Of course based on the riding conditions this could change and perhaps a good time, just goes back to the first point of needing more info. Excellent job pacing yourself. 1 watt difference between average and NP can be difficult to achieve. Did you feel you had anything left at the end?
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Re: Trying to understand efficiency / TT numbers [Hoodoo] [ In reply to ]
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I cannot speak about efficiency, but I can give you two points of reference in conditions similar to yours. I did a 12.6km out and back TT with a friend yesterday, mostly flat (60m elevation), average quality asphalt, light wind (about 10km/h).

I'm 136 lbs, and my 20' power is about 275w (I didn't race with power yesterday). My position is good, but not great. My friend is 175 lbs, and averaged 277w yesterday. His position is ok. I did 43.3 km/h avg, and my friend 40.2.

So, my uneducated guess is that you have quite a lot left on the table considering your values...
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Re: Trying to understand efficiency / TT numbers [Hoodoo] [ In reply to ]
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Hoodoo wrote:
Please help me to read these numbers of my last TT test.

After an hour of activation, did a 20min. TT test:

Weight: 160 lbs
Distance: 13.09km
Time: 20min.
Avg power: 291w
NP: 292w
Avg speed: 39.2k/h
Flat road
Aero position the whole test.
Bike/gear: TT with racing kit, aero helmet, etc.

How do I know if this is efficient of not ?

Cheers !

First, congrats! Nice test, especially the pacing. A 1w difference between average and normalized power is as good as it gets. Looks like you were just over 4w/kg, which is outstanding. Your warmup was a bit long for a traditional 20min test. Multiplying 291 by .95 yields 276 for an FTP.

If by "efficiency", you mean velocity per watt, then I think you have a great deal of improvement to make in either your equipment or position.

Here are my number from my last 40k. I'm a marginal Cat4 cyclist. I was 7th out of 22 in the 55-64 age group in this race.

Conditions: Very flat road, little wind, overcast, mid 70's.

Weight: 182
Distance: 40k (measured)
Time: 57:33
Speed: 41.7 kph
AP: 281 (3.4w/kg)
NP: 282

My FTP was 265 at the time of this race. For some reason, I can always go a bit harder in a race than I can in a test.

While it's not appropriate to draw a conclusion from such little data, I outweigh you by 10kg and you're 10w stronger. That's why I *think* you have opportunities for improvement in either position, equipment, or both.

hth
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Re: Trying to understand efficiency / TT numbers [racehd] [ In reply to ]
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racehd wrote:
I agree with Ai_1...lots of ways we could interpret this.

To give any meaningful analysis we really need to have a better idea about the atmospheric pressure, wind direction, wind speed, type of road and smoothness, was this a loop/straight shot, or out and back, etc, etc, etc.

If you care about getting into the nitty-gritty I'd suggest searching ST for the "platypus thread."

If you just want to measure up against other people, then look at the "post your time/watts from your last race" thread. Find someone of similiar weight and/or watts and see how they did compared to you. Again, take this with a grain of salt without more info about the riding conditions for either effort.

Without knowing anything else about your test,13.09km is 8.07 miles and you were traveling at a speed of 2:27 per mile which would put your 10TT time at around 24:35. That's not too bad, but at 291 average watts I think you could probably be faster. Of course based on the riding conditions this could change and perhaps a good time, just goes back to the first point of needing more info. Excellent job pacing yourself. 1 watt difference between average and NP can be difficult to achieve. Did you feel you had anything left at the end?[/quo

Yes, I was at the end of something... quite exhausted. ;)
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Re: Trying to understand efficiency / TT numbers [FatandSlow] [ In reply to ]
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FatandSlow wrote:
Hoodoo wrote:
Please help me to read these numbers of my last TT test.

After an hour of activation, did a 20min. TT test:

Weight: 160 lbs
Distance: 13.09km
Time: 20min.
Avg power: 291w
NP: 292w
Avg speed: 39.2k/h
Flat road
Aero position the whole test.
Bike/gear: TT with racing kit, aero helmet, etc.

How do I know if this is efficient of not ?

Cheers !


First, congrats! Nice test, especially the pacing. A 1w difference between average and normalized power is as good as it gets. Looks like you were just over 4w/kg, which is outstanding. Your warmup was a bit long for a traditional 20min test. Multiplying 291 by .95 yields 276 for an FTP.

If by "efficiency", you mean velocity per watt, then I think you have a great deal of improvement to make in either your equipment or position.

Here are my number from my last 40k. I'm a marginal Cat4 cyclist. I was 7th out of 22 in the 55-64 age group in this race.

Conditions: Very flat road, little wind, overcast, mid 70's.

Weight: 182
Distance: 40k (measured)
Time: 57:33
Speed: 41.7 kph
AP: 281 (3.4w/kg)
NP: 282

My FTP was 265 at the time of this race. For some reason, I can always go a bit harder in a race than I can in a test.

While it's not appropriate to draw a conclusion from such little data, I outweigh you by 10kg and you're 10w stronger. That's why I *think* you have opportunities for improvement in either position, equipment, or both.

hth

Thanks, that's what I meant by efficiency. I have a good bike, good helmet, great wheels, etc. I think my position needs tweaking ! I'm french, so maybe I wasn't so clear !
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Re: Trying to understand efficiency / TT numbers [Hoodoo] [ In reply to ]
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Hoodoo wrote:
FatandSlow wrote:
Hoodoo wrote:
Please help me to read these numbers of my last TT test.

After an hour of activation, did a 20min. TT test:

Weight: 160 lbs
Distance: 13.09km
Time: 20min.
Avg power: 291w
NP: 292w
Avg speed: 39.2k/h
Flat road
Aero position the whole test.
Bike/gear: TT with racing kit, aero helmet, etc.

How do I know if this is efficient of not ?

Cheers !


First, congrats! Nice test, especially the pacing. A 1w difference between average and normalized power is as good as it gets. Looks like you were just over 4w/kg, which is outstanding. Your warmup was a bit long for a traditional 20min test. Multiplying 291 by .95 yields 276 for an FTP.

If by "efficiency", you mean velocity per watt, then I think you have a great deal of improvement to make in either your equipment or position.

Here are my number from my last 40k. I'm a marginal Cat4 cyclist. I was 7th out of 22 in the 55-64 age group in this race.

Conditions: Very flat road, little wind, overcast, mid 70's.

Weight: 182
Distance: 40k (measured)
Time: 57:33
Speed: 41.7 kph
AP: 281 (3.4w/kg)
NP: 282

My FTP was 265 at the time of this race. For some reason, I can always go a bit harder in a race than I can in a test.

While it's not appropriate to draw a conclusion from such little data, I outweigh you by 10kg and you're 10w stronger. That's why I *think* you have opportunities for improvement in either position, equipment, or both.

hth


Thanks, that's what I meant by efficiency. I have a good bike, good helmet, great wheels, etc. I think my position needs tweaking ! I'm french, so maybe I wasn't so clear !

Do you have a picture of you in aero position? a side-shot during a race preferred or on the trainer would also help. I'm not very good at analyzing these pictures but the rest of the ST community is good at being able pick out areas of improvement.
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Re: Trying to understand efficiency / TT numbers [Hoodoo] [ In reply to ]
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If you just looking for some reference points take a look here:

http://forum.slowtwitch.com/...r_last_race_P3499977
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Re: Trying to understand efficiency / TT numbers [Hoodoo] [ In reply to ]
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hth[/quote]

Thanks, that's what I meant by efficiency. I have a good bike, good helmet, great wheels, etc. I think my position needs tweaking ! I'm french, so maybe I wasn't so clear ![/quote]
You were clear. I was confirming that I understood. I'm a southerner. We barely speak English!

There can be a huge difference between good equipment and great equipment. When you post a picture from the side, also list your equipment. Many here can tell you what you can change inexpensively.
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Re: Trying to understand efficiency / TT numbers [Hoodoo] [ In reply to ]
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I'd suggest playing around with Bestbikesplit.com. You can input your course and weather to see predictions. Putting in a competed workout can give your some idea on how aero your whole setup was for the ride. Multiple runs on the same course can help drill down a little.

I think their beta aero calculator is premium only and still rough, but the free edition gives you a lot to play with.
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