'Bent Legs

DIscuss anything relating to non-standard cycles and their equipment.
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pjclinch
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Re: 'Bent Legs

Postby pjclinch » 13 Sep 2018, 12:45pm

belgiangoth wrote:
pjclinch wrote:
NATURAL ANKLING wrote:Hi,

Ignoring aero effects?


(a) I don't know the answer but...
(b) why would you ignore the aero effects?


Because there are conditions (say uphill) where you aren't going fast enough for aero to be an advantage?


Fair point!

And also up steep hills you'll probably run in to extra issues of weight, especially if you've gone to all the trouble of adding a fairing.

For a long trip I think it's worth remembering that despite all the excited talk of a new LEJoG record recently on a Luddites-of-Lausanne-approved bike, the pedal-power record is still held by a faired recumbent trike. I've not done a LEJoG but I understand some hills are dotted along the route.

Pete.
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NATURAL ANKLING
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Re: 'Bent Legs

Postby NATURAL ANKLING » 14 Sep 2018, 12:02am

Hi,
Records say Faired recumbent bicycle.

Its faired in so super low drag, cant really be in same class as unfaired upright.

Some records are corroborated, because non standard bike and course not confirmed by authority of any type.

Recumbents are more aero efficient no argument, but this obviously masks the differences in actual ergo body position, muscles used and gravity.

https://en.wikipedia.org/wiki/List_of_c ... n_O'Groats
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Re: 'Bent Legs

Postby pjclinch » 14 Sep 2018, 11:42am

NATURAL ANKLING wrote:Recumbents are more aero efficient no argument, but this obviously masks the differences in actual ergo body position, muscles used and gravity.


Of course it does, so you need to look at the bottom line, which isn't how much power you can put out but how fast you can go and/or for how long.
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belgiangoth
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Re: 'Bent Legs

Postby belgiangoth » 14 Sep 2018, 9:14pm

Bam!

... though not always true. For example for a short commute it's irrelevant how long you can ride and maximum speed is probably not important either in stop-start traffic. What is important is how fast you accelerate, which is down to power. ... I think.

Very much a horses for courses argument.
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[XAP]Bob
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Re: 'Bent Legs

Postby [XAP]Bob » 15 Sep 2018, 9:35am

Of course it’s horses for courses. I used to take an up wrong to church some weekends...
It was easier to prop up in the back of the building, and for the three mile journey (at a deliberately relaxed pace) it made little odds what I used for transport.

The longer the journey the more it favours a ‘bent, in general.
Similarly very short journeys are better covered by walking...
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
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Re: 'Bent Legs

Postby Stradageek » 15 Sep 2018, 9:45am

So recumbents are indisputably faster on the flat/downhill.

Personally, uphill, I'm a little slower than some uprights but the lighter the recumbent I ride and the stiffer the recumbent frame the smaller the disadvantage (comparing my different machines).

I'm pretty sure I can put more power into the recumbent than a DF as I have a rigid seat to push against and I've broken chains on my recumbents which I've never done on an upright.

But the full science still seems to be missing. Has anyone put a power meter on the cranks and rear wheel and measured heart rate/breathing etc.

If at the same effort (heart rate etc.) and crank and rear wheel power (i.e. identical transmission losses to a DF) a recumbent was still slower you could conclude that recumbent legs can't output the power that DF legs can. That is until you find someone with better recumbent legs!

Or did I miss something?

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Re: 'Bent Legs

Postby NATURAL ANKLING » 16 Sep 2018, 1:15am

Hi,
Not read it yet but I have seen other reports too-

https://pdfs.semanticscholar.org/c2d3/9 ... bd41b9.pdf
If You Don't Try You Don't Do.....Don't Do You Don't Get...I'm Still Trying....Well Very..
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Re: 'Bent Legs

Postby NATURAL ANKLING » 16 Sep 2018, 1:20am

Hi
NATURAL ANKLING wrote:Hi,
Not read it yet but I have seen other reports too-

https://pdfs.semanticscholar.org/c2d3/9 ... bd41b9.pdf

Sorry :oops: Wrong report, compares aero with upright on same std bike.
Its late, I did read a report the other day on my other computer will try and find tomorrow.
Edited-
Should of gone to bed earlier :)
Not what I was looking for......confused myself again :lol:
http://www.unm.edu/~rrobergs/478SS1.pdf
Still looking.....
Last edited by NATURAL ANKLING on 16 Sep 2018, 1:08pm, edited 2 times in total.
If You Don't Try You Don't Do.....Don't Do You Don't Get...I'm Still Trying....Well Very..
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Re: 'Bent Legs

Postby [XAP]Bob » 16 Sep 2018, 8:09am

Stradageek wrote:So recumbents are indisputably faster on the flat/downhill.

Personally, uphill, I'm a little slower than some uprights but the lighter the recumbent I ride and the stiffer the recumbent frame the smaller the disadvantage (comparing my different machines).

I'm pretty sure I can put more power into the recumbent than a DF as I have a rigid seat to push against and I've broken chains on my recumbents which I've never done on an upright.

But the full science still seems to be missing. Has anyone put a power meter on the cranks and rear wheel and measured heart rate/breathing etc.

If at the same effort (heart rate etc.) and crank and rear wheel power (i.e. identical transmission losses to a DF) a recumbent was still slower you could conclude that recumbent legs can't output the power that DF legs can. That is until you find someone with better recumbent legs!

Or did I miss something?


I believe the general consensus is that the max power output is lower. Dave McCraw did some power meter testing between his bikes...
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.

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pjclinch
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Re: 'Bent Legs

Postby pjclinch » 16 Sep 2018, 9:21am

You can have a similar non-argument about the merits of an upright riding position vs. a crouch on an upwrong. The upright position enables cleaner breathing which, in an aerobic activity, is going to be a Good Thing, but racers crouch because getting out of the wind is more important at their usual speeds: when you've given your all and exploded they don't just say you've sat up as a metaphor.... The faster you're going the more aerodynamics is the significant factor.

Related to this, you can probably breathe more easily on a good selection of 'bents than you can in the positions used for aero efficiency on a racing bike, and that will affect things on longer courses too.

In summary: there are so many caveats and issues you'll need to ask very specific questions to get answers, and they won't tell you that much outside of your tightly defined situation.

Pete.
Often seen riding a bike around Dundee...

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NUKe
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Re: 'Bent Legs

Postby NUKe » 17 Sep 2018, 10:11pm

Stradageek wrote:So recumbents are indisputably faster on the flat/downhill.

Personally, uphill, I'm a little slower than some uprights but the lighter the recumbent I ride and the stiffer the recumbent frame the smaller the disadvantage (comparing my different machines).

I'm pretty sure I can put more power into the recumbent than a DF as I have a rigid seat to push against and I've broken chains on my recumbents which I've never done on an upright.

But the full science still seems to be missing. Has anyone put a power meter on the cranks and rear wheel and measured heart rate/breathing etc.

If at the same effort (heart rate etc.) and crank and rear wheel power (i.e. identical transmission losses to a DF) a recumbent was still slower you could conclude that recumbent legs can't output the power that DF legs can. That is until you find someone with better recumbent legs!

Or did I miss something?

Dave McGraw did some power meter tests,he has posted here before now, but all the details are in his own web pages accessible from Laidback bikes site.
NUKe
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