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Postby mikesbytes » Tue Nov 27, 2007 12:50 pm

Another factor is feel. If it feels good, you feel good and ride faster.
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by BNA » Tue Nov 27, 2007 1:01 pm

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Postby sogood » Tue Nov 27, 2007 1:01 pm

artemidorus wrote:Noone said that 0.2% wasn't significant at an elite level, or even if you're sprinting uphill against your mate. It's not only going to increase the steady state workload uphill, but it is going to increase the wattage required for a given acceleration, slightly. Nothing to doubt.

Well, the question is how much, hence the doubt. 0.2% is probably something a rider can make up if the situation calls for it. But what if it's 1%? Does that become very significant in a chase situation? Does a fraction of a second missed in the acceleration make a difference to one's ability to catch a wheel? At 30km/h, a second missed equates to 8m in separation. A loss of 1/8th of second equals to a meter of separation. How much more energy would one need to close that meter gap in a hurry? These are my questions.

To the extent that many well versed forum participants pushing the line that weight makes ignorable difference while basing their arguments primarily on static state calculations. I think there's some more to the story.

I wonder if a decent power meter has the necessary resolution to differentiate?
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Postby artemidorus » Tue Nov 27, 2007 1:12 pm

sogood wrote:
artemidorus wrote:Noone said that 0.2% wasn't significant at an elite level, or even if you're sprinting uphill against your mate. It's not only going to increase the steady state workload uphill, but it is going to increase the wattage required for a given acceleration, slightly. Nothing to doubt.

Well, the question is how much, hence the doubt. 0.2% is probably something a rider can make up if the situation calls for it. But what if it's 1%? Does that become very significant in a chase situation? Does a fraction of a second missed in the acceleration make a difference to one's ability to catch a wheel? At 30km/h, a second missed equates to 8m in separation. A loss of 1/8th of second equals to a meter of separation. How much more energy would one need to close that meter gap in a hurry? These are my questions.

To the extent that many well versed forum participants pushing the line that weight makes ignorable difference while basing their arguments primarily on static state calculations. I think there's some more to the story.

I wonder if a decent power meter has the necessary resolution to differentiate?

You're not happy with a=F/m? Increase m by 0.2% and F has to increase by 0.2% to maintain a. (I'm still happy to ignore rotational inertia as being 2 or more orders of magnitude less important).
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Postby artemidorus » Tue Nov 27, 2007 1:15 pm

sogood wrote:I wonder if a decent power meter has the necessary resolution to differentiate?

I really doubt it. You'd need two, cross-calibrated to measure less than a watt's difference beyond the predictable 0.2% difference.
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Postby mikesbytes » Tue Nov 27, 2007 1:30 pm

sogood wrote:Where should we stick that age variable in the equation? I am sure it'll significantly affect the calculation. :wink:


Poorer aerodynamics, things hang out more as you get older :(
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Postby toolonglegs » Tue Nov 27, 2007 1:42 pm

mikesbytes wrote:
sogood wrote:Where should we stick that age variable in the equation? I am sure it'll significantly affect the calculation. :wink:


Poorer aerodynamics, things hang out more as you get older :(


Poorer aerodynamics but a more devious cunning mind
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Postby sogood » Tue Nov 27, 2007 2:07 pm

artemidorus wrote:You're not happy with a=F/m? Increase m by 0.2% and F has to increase by 0.2% to maintain a. (I'm still happy to ignore rotational inertia as being 2 or more orders of magnitude less important).

If you read my earlier posts, I was referring to total bike weight rather than dwelling on the much smaller impact of inertial issue.

F=ma is without doubt real. But the question is how much does 0.2%, or 0.2+x% (where x could be a multiple of 0.2) in an uphill acceleration, make to one's ability to catch a passing attacker?
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Postby sogood » Tue Nov 27, 2007 2:11 pm

artemidorus wrote:I really doubt it. You'd need two, cross-calibrated to measure less than a watt's difference beyond the predictable 0.2% difference.

Not sure of the need to have two PMs. With two and calibration, it's still likely to have greater variance than measuring it using a single unit. Given the best power meter has an error band of 3%, the difference may truly be hiding in the noise. Yet again, could the x in the (0.2+x)% be equal or greater than 3?
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Postby sogood » Tue Nov 27, 2007 2:12 pm

toolonglegs wrote:Poorer aerodynamics but a more devious cunning mind :twisted:

Nasty, nasty! :roll:
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Postby Bnej » Tue Nov 27, 2007 2:21 pm

sogood wrote:F=ma is without doubt real. But the question is how much does 0.2%, or 0.2+x% (where x could be a multiple of 0.2) in an uphill acceleration, make to one's ability to catch a passing attacker?


All I know is every time I lose someone on a hill, it's because they have a lighter, more expensive bike. That's my story and I'm sticking to it! ;)
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Postby sogood » Tue Nov 27, 2007 2:31 pm

Bnej wrote:All I know is every time I lose someone on a hill, it's because they have a lighter, more expensive bike. That's my story and I'm sticking to it! ;)

You have to be truly objective about all these. The real reason was because that Record and DA had a superior and faster shift action and that's where you really lost time! :P
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Postby toolonglegs » Tue Nov 27, 2007 3:12 pm

sogood wrote:
Bnej wrote:All I know is every time I lose someone on a hill, it's because they have a lighter, more expensive bike. That's my story and I'm sticking to it! ;)

You have to be truly objective about all these. The real reason was because that Record and DA had a superior and faster shift action and that's where you really lost time! :P


The only time i lose time to anyone on a hill is when my hand slips off the tow car :D
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Postby sogood » Tue Nov 27, 2007 3:17 pm

toolonglegs wrote:The only time i lose time to anyone on a hill is when my hand slips off the tow car :D

Serve you right for picking up those non-grippy and non-aero gloves off the back of that tow car. :wink:
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Postby toolonglegs » Tue Nov 27, 2007 3:25 pm

sogood wrote:
toolonglegs wrote:The only time i lose time to anyone on a hill is when my hand slips off the tow car :D

Serve you right for picking up those non-grippy and non-aero gloves off the back of that tow car. :wink:


Did I say tow car!...i meant chair lift :roll:
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Postby MichaelB » Tue Nov 27, 2007 4:30 pm

Bnej wrote:
sogood wrote:F=ma is without doubt real. But the question is how much does 0.2%, or 0.2+x% (where x could be a multiple of 0.2) in an uphill acceleration, make to one's ability to catch a passing attacker?


All I know is every time I lose someone on a hill, it's because they have a lighter, more expensive bike. That's my story and I'm sticking to it! ;)


Yeah, but gravity works with you downhill.

I have passed my mate many a time downhill. About the only place though :?
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Postby Bnej » Tue Nov 27, 2007 5:47 pm

MichaelB wrote:Yeah, but gravity works with you downhill.

I have passed my mate many a time downhill. About the only place though :?


People on dual suspension bikes always leave me for dead on any rough downhill.

When I was coming back from Jenolan with two others ages ago, they both had dual suspension MTBs (Anthem 0 and Top Fuel) and I was on my road bike, and this long downhill on caves road they got waaay ahead of me. I had to keep my speed down to save my wrists & body from the pitted and cracked road surface, while they did it at speed in plush suspended comfort.
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Postby mikesbytes » Tue Nov 27, 2007 5:52 pm

Bnej wrote:
MichaelB wrote:Yeah, but gravity works with you downhill.

I have passed my mate many a time downhill. About the only place though :?


People on dual suspension bikes always leave me for dead on any rough downhill.

When I was coming back from Jenolan with two others ages ago, they both had dual suspension MTBs (Anthem 0 and Top Fuel) and I was on my road bike, and this long downhill on caves road they got waaay ahead of me. I had to keep my speed down to save my wrists & body from the pitted and cracked road surface, while they did it at speed in plush suspended comfort.


Yeh, but once you reach the bottom your bike is the better option.
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Postby sogood » Tue Nov 27, 2007 6:25 pm

I have similar experiences where the heavier riders would gradually move ahead of me on those down-hills during our RNP rides. The annoying part was that I couldn't make up by peddling at those speeds. Most frustrating. Just had to do the catch ups on the up-hill... Painful!
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Postby mikesbytes » Tue Nov 27, 2007 7:25 pm

sogood wrote:I have similar experiences where the heavier riders would gradually move ahead of me on those down-hills during our RNP rides. The annoying part was that I couldn't make up by peddling at those speeds. Most frustrating. Just had to do the catch ups on the up-hill... Painful!


I'm peddling downhill. Years of experience and a motorcycling background make me a bit braver.
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Postby toolonglegs » Tue Nov 27, 2007 7:54 pm

mikesbytes wrote:
sogood wrote:I have similar experiences where the heavier riders would gradually move ahead of me on those down-hills during our RNP rides. The annoying part was that I couldn't make up by peddling at those speeds. Most frustrating. Just had to do the catch ups on the up-hill... Painful!


I'm peddling downhill. Years of experience and a motorcycling background make me a bit braver.


went riding with my mate bubbles on the way to and from eastern creek on sunday...he is about 8 kilos heavier than me and it was the first time i have had to pedal downhill to keep up with some one :D
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Postby Bnej » Tue Nov 27, 2007 8:31 pm

sogood wrote:I have similar experiences where the heavier riders would gradually move ahead of me on those down-hills during our RNP rides.


Tried using a really flat aero tuck to go faster? Of course they can counter by doing the same thing. You could try a ski tuck where you sit on the top tube. :shock:

Downhills is all mass & power vs drag, uphill is all power vs weight. Unless it's off-road in which case downhill is all confidence vs terror.
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Postby artemidorus » Tue Nov 27, 2007 8:34 pm

sogood wrote:
artemidorus wrote:I really doubt it. You'd need two, cross-calibrated to measure less than a watt's difference beyond the predictable 0.2% difference.

Not sure of the need to have two PMs. With two and calibration, it's still likely to have greater variance than measuring it using a single unit. Given the best power meter has an error band of 3%, the difference may truly be hiding in the noise. Yet again, could the x in the (0.2+x)% be equal or greater than 3?

Sorry, I'm really not sure where your mysterious x is coming from. Do you mean that the rims weigh more than 100g above the competition? I'm not sure that we're getting anywhere.

You couldn't use a single PM as you need to have two bicycles accelerating at exactly the same rate, side by side.
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Postby sogood » Tue Nov 27, 2007 8:50 pm

Bnej wrote:Tried using a really flat aero tuck to go faster? Of course they can counter by doing the same thing. You could try a ski tuck where you sit on the top tube. :shock:

Downhills is all mass & power vs drag, uphill is all power vs weight. Unless it's off-road in which case downhill is all confidence vs terror.

They are in as much a conventional tuck as I was in. As for superman position, well, I'll endure the up-hill catch ups than becoming a statistic. :roll:

With some of the roads in RNP, down-hill is also confidence vs terror.
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Postby toolonglegs » Tue Nov 27, 2007 8:55 pm

sogood wrote:
Bnej wrote:Tried using a really flat aero tuck to go faster? Of course they can counter by doing the same thing. You could try a ski tuck where you sit on the top tube. :shock:

Downhills is all mass & power vs drag, uphill is all power vs weight. Unless it's off-road in which case downhill is all confidence vs terror.

They are in as much a conventional tuck as I was in. As for superman position, well, I'll endure the up-hill catch ups than becoming a statistic. :roll:

With some of the roads in RNP, down-hill is also confidence vs terror.


You can always tell me in the bunch,I am the one sitting straight up trying to catch as much wind as possible so i dont have to hit the brakes :D ...will miss all that soon
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Postby sogood » Tue Nov 27, 2007 8:59 pm

artemidorus wrote:Sorry, I'm really not sure where your mysterious x is coming from. Do you mean that the rims weigh more than 100g above the competition? I'm not sure that we're getting anywhere.

You couldn't use a single PM as you need to have two bicycles accelerating at exactly the same rate, side by side.

Sorry if I didn't make it clear. The x refers to the additional efforts required for an acceleration to catch another rider. So with 0.2% being the effective difference caused by the weight difference under steady state (constant velocity) while it acted against a constant deceleration force (gravity). With an additional acceleration, the total difference would be 0.2 plus another amount attributable to the effort required for the additional acceleration (to catch the attacking rider).

The reason you don't need two PMs is that this really is an intrinsic test, one that determines at what level of weight difference would there be a significant change in the ability of the same rider in latching on.
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