Triban 520: Update :)

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dude7691

Well-Known Member
As I said earlier: data error.
The Pembrokeshire climb (which I've ridden en route from Newport to Saundersfoot) rises from 21m to 98m (77m climb) over a distance of 1.6km (one mile) so an average gradient of less than 5%. Pump those data into your chosen 'power calculators' and get a more realistic guesstimate.
As others have said, though, you're getting out there and beasting it. Just keep a note of you best times up that and other local hills (the one above Gelli, for example) and that is the best evidence of the rise in your strength and fitness. If you feel the need to compare yourself with others, I understand there is an app called Strava which enables this.
I understand that yeah, as I say the total gradient change for my ride is only 0.4% but it's tricky for me to accurately calculate. For example some of the hills I'm doing 6-7mph going up them but only 20-25 going down as I can't make the most out of the momentum because the surface is so dangerous if you go above that speed, so I have to use the brakes which wastes energy. The total climb on that hill I showed is 100m in 0.7mi which gives a 13% gradient, and definitely the most challenging hill on the whole ride. Honestly I think going to the gym and just doing a 20 minute power test would be the best option.
 
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dude7691

Well-Known Member
The calculator is rubbish I'm afraid. If generating 2.5w/kg, you'd be doing a far quicker ride. 7 plus w/kg is loads.
I've ridden on smooth roads and because of my 25mm tires they make a huge difference to my speed. In the town on the flat I could do 17mph vs just 11mph on some of the backroads, at what felt to me like the same effort... I think my average speed of just 12.8mph is partly caused by that, plus the fact the roads are all 1 way pretty much so if I car comes behind me or towards me I have to slow to a stop and let them past, I probably lose 5-10 minutes each way because of that for example. I don't know, I think my weight biases my W/kg a lot because 51kg is stupidly light for anyone not just a cyclist (and we tend to be lighter), and I'm in very good shape for my weight, hard to say really. Gym it is :biggrin:
 
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dude7691

Well-Known Member
Speak to a cycling coach and not a personal trainer. I can let you have the details of mine if you like.
That would be great very much appreciated :smile: Thank you. Do you need my email to send it across.

My philosophy goes something like this:

If I weigh 50kg at the moment, I'm probably around 30kg of muscle (although that is a wild guess)
Adding just 10kg of muscle would increase my muscle mass by 33%, thus increasing my power by a similar amount
However my weight increase (10kg) added to my 51kg weight would result in an increased weight of just 20% more.

33% more power for 20% more weight = higher power/weight surely?
 
plus the fact the roads are all 1 way pretty much so if I car comes behind me or towards me I have to slow to a stop and let them past



if all the roads are one way and you have cars coming towards you then either you or the motorists shouldn't be going in the direction that you are
 
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dude7691

Well-Known Member
plus the fact the roads are all 1 way pretty much so if I car comes behind me or towards me I have to slow to a stop and let them past



if all the roads are one way and you have cars coming towards you then either you or the motorists shouldn't be going in the direction that you are
Oh I don't mean it like that haha I mean as in the roads are backroads so really really narrow they're 2 way roads but like only 1 vehicle can fit through them at a time unless there's a passing point :biggrin:
 

mattobrien

Guru
Location
Sunny Suffolk
What was my power?

According to that calculator roughly 160W average? That's really impressive just from looking at it, 19mph is really fast. I think this calculator is very poorly done actually looking at it because 19mph on my bike requires a tonne more effort than around 14mph which is where it feels most sustainable. Is elevation the height above sea level or your total altitude gain?[/QUOTE]

Average power was 196w and normalised power was 236w, so the calculator was 22% to 47% different depending on whether you work on average or normalised power numbers.

My PM is +/- 1.5%, but trying to calculate the figure without using a PM is too far away from reality to be of any use.
 
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dude7691

Well-Known Member
Average power was 196w and normalised power was 236w, so the calculator was 22% to 47% different depending on whether you work on average or normalised power numbers.


My PM is +/- 1.5%, but trying to calculate the figure without using a PM is too far away from reality to be of any use.[/QUOTE]
Thank you for that, it's kind of reassuring to know it's probably under reading if anything :biggrin: There's so many factors it doesn't take into account, thank you for that insight :smile:
 

mattobrien

Guru
Location
Sunny Suffolk
There are just too many variables when cycling outside to try to calculate power.

The calculation might be under for my example, but I might be over in others. Had I had a tail wind or been riding in a group then I would have required less power. As it stand there was no riding behind anyone and there appeared to be a headwind in all directions.

Personally I prefer to ride with power, but that’s because I time trial and most rides are training as opposed to just cycling. A power meter is pretty pointless unless you are going to specifically use the data it provides. If you’re not going to do this then you may as well save a load of cash and just use a heart rate monitor.
 

ColinJ

Puzzle game procrastinator!
Well done on your progress so far. :bravo:

I think this calculator is very poorly done actually looking at it because 19mph on my bike requires a tonne more effort than around 14mph which is where it feels most sustainable.
That is exactly how it is!

At any significant speed, nearly all of your power goes into overcoming drag/air resistance and that is proportional to the square of velocity so instead of needing 19/14 (36%) more power, you actually need about (19/14) x (19/14) (84%) more power. The physics of it is explained HERE. CORRECTION - @Ajax Bay correctly pointed out that the force needs to be multiplied by the velocity to get the power requirement so it is even worse - you'd need to put in 2.5 times the power!

As for small cyclists piling on muscle - Chris Froome is 1.86 m (6'1") tall but only weighs about 68 kg. Note his entirely NON-massive legs!

Chris_Froome_Tour_2012.jpg


Picture from HERE.

Attribution: Igs165 [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)]
 
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Smokin Joe

Legendary Member
Well done on your progress so far. :bravo:


That is exactly how it is!

At any significant speed, nearly all of your power goes into overcoming drag/air resistance and that is proportional to the square of velocity so instead of needing 19/14 (36%) more power, you actually need about (19/14) x (19/14) (84%) more power. The physics of it is explained HERE.

As for small cyclists piling on muscle - Chris Froome is 1.86 m (6'1") tall but only weighs about 68 kg. Note his entirely NON-massive legs!

View attachment 459164

Picture from HERE.

Attribution: Igs165 [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)]
He's exactly the same build as me. Where the feck did I go wrong? :sad::sad::sad:
 

Ajax Bay

Guru
Location
East Devon
At any significant speed, nearly all of your power goes into overcoming drag/air resistance and that is proportional to the square of velocity
I may have got this wrong but the force on the rider of air drag is proportional to the square of velocity (through the air).
The power needed to overcome air drag is proportional to the square of velocity through the air and then multiplied by the actual velocity of the rider. So in still conditions: power needed to overcome air drag is proportional to the cube of velocity.
https://www.gribble.org/cycling/power_v_speed.html
"One of the scary implications of this equation is that at high speed, the power you have to produce is proportional to the cube of your velocity. So, to increase your speed by 25%, you need to nearly double your wattage!" [1.25^3]
 

ColinJ

Puzzle game procrastinator!
I may have got this wrong but the force on the rider of air drag is proportional to the square of velocity (through the air).
The power needed to overcome air drag is proportional to the square of velocity through the air and then multiplied by the actual velocity of the rider. So in still conditions: power needed to overcome air drag is proportional to the cube of velocity.
https://www.gribble.org/cycling/power_v_speed.html
"One of the scary implications of this equation is that at high speed, the power you have to produce is proportional to the cube of your velocity. So, to increase your speed by 25%, you need to nearly double your wattage!" [1.25^3]
Ah, I thought that I remembered it being a cube law but I did a quick search and found that article on drag and didn't think any more about it!

So 14mph -> 19 mph needs almost exactly 2.5 times the power.
 
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