Optimum Cycling Position

General cycling advice ( NOT technical ! )
bjlabuk
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Re: Optimum Cycling Position

Post by bjlabuk »

Yes, Hinault/Genzling use a factor of 0.885.

However Hilary Stone, the writer of the Cycling Plus Special Report preferred somewhere between 1.05 and 1.09 x inside leg measurement. According to the article you need to take 7 measurements:- Height, Inside leg measurement, Thigh Length, Lower leg length, Trunk length, Arm length and Lower Arm length. From this information you can work out various body ratios, eg trunk/inside leg ratio. There are no detailed formula - this is not an academic or scientific paper! - but there is thereafter a Table in which are stated the saddle setback range, handlebar reach range, handlebar height range (relative to saddle) and crank length range for different ranges of inside leg measurement, ie from 72-75cm up to 91-94cm.

I certainly found it interesting to take the measurements and use the Table to adjust my cycling position.
Jdsk
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Re: Optimum Cycling Position

Post by Jdsk »

531colin wrote: 14 Jul 2021, 8:19pm I have no doubt that an experienced observer can help a rider get a better/more efficient/more comfortable position....and even a position less likely to cause injury.
Yes. The formulae and algorithms aren't absolutes, they're helpful starting positions from which an individual rider can, and should, experiment.

Jonathan
Jdsk
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Re: Optimum Cycling Position

Post by Jdsk »

531colin wrote: 14 Jul 2021, 8:19pmInteresting stuff about pedal extenders. I have been struggling for a few years in that my (left) heel moves out at an exaggerated angle when I get tired. Oddly, this doesn't seem to hurt the knee, but I get cramp in the calf because I'm working against the limit of the cleat float. I fitted a pedal extender just to the left pedal on a couple of bikes, and it helps, I guess by putting the leg where it wants to be without the comedy foot angle. I'm aware I tilt the bike to the left when riding, and always have done; I am now finding that if I deliberately keep the bike upright then I'm comfortable at least for a short ride without the pedal extender...I must gather the courage to try a longer ride "un-extended".
Exactly: observe and experiment and repeat.

Jonathan
Mike Sales
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Re: Optimum Cycling Position

Post by Mike Sales »

My legs differ in length by one and a quarter inches.
Where does that put my saddle height?
My right knee moves not in a nice, vertical up and down plane, but in an outward arc as it lifts.
My leather saddle has been moulded into a lopsided shape.
I get along fairly well on my bike, so my conclusion is that the body can adapt well to less than theoretically ideal movements.
It's the same the whole world over
It's the poor what gets the blame
It's the rich what gets the pleasure
Isn't it a blooming shame?
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[XAP]Bob
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Re: Optimum Cycling Position

Post by [XAP]Bob »

Mick F wrote: 14 Jul 2021, 11:17am Yep.

Some of us are "apes" with long arms. My arm-span is five inches longer than my height.
I'm like that, but not very strong in the upper body. Never ever been able to more than two or three press-ups for instance.
My bum is happy on any saddle, and the harder ones suit me fine.
I have strong legs, and cannot "spin" for the life of me.
CJ once said, that any experienced cyclist can ride at 80rpm all day. I doubt I could get more than a mile at 80rpm.

We are all different.
You cannot dictate the correct bike fit based on your dimensions.
I am an orangutan as well. Even in my wheelchair I can reach stuff off the top shelf at the supermarket - and have done so to aid various people who couldn't reach standing on their feet.

OTOH I comfortably spin at over 100rpm, my average for a ride tends to be ~95-115rpm, topping out just shy of 160.

If we were all the same the world would be very boring indeed.
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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Mick F
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Re: Optimum Cycling Position

Post by Mick F »

[XAP]Bob wrote: 15 Jul 2021, 4:38pm If we were all the same the world would be very boring indeed.
Absolutely :D
Mick F. Cornwall
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Mick F
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Re: Optimum Cycling Position

Post by Mick F »

................. also ..............

Having swapped from road cleats and Campag Pro Fit road pedals to Speedplay Frogs (on both bikes) I had to lower the saddles by half an inch due to the low stack-hight of the Frogs.

Pedals and shoes come into the mix for bike fit, not just your physical dimensions.
Mick F. Cornwall
Syd
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Re: Optimum Cycling Position

Post by Syd »

I had to do something similar when I changed from Look Keo to Speedplay Zero to accommodate for the difference in stack height.
Blondie
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Re: Optimum Cycling Position

Post by Blondie »

[XAP]Bob wrote: 12 Jul 2021, 12:27pm One should recline on a comfortable seat, preferably with a neck/head rest. :lol:
A recumbent 😁
mattheus
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Re: Optimum Cycling Position

Post by mattheus »

rogerzilla wrote: 14 Jul 2021, 7:38am Bike fits are snake oil, in my opinion. People are too different in flexibility and riding style.
If they're just done by the numbers - sure.

But like a physio, some can look at individuals. The guy I paid spent more time analysing me OFF the bike than on it; looking at assymmetry, muscle strenght, medical history etc etc. It was a bit longer than 2 hours!

He'd gone through a lot of training, and invested in keeping his knowledge current (with a professional body, and other sources).
Jdsk
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Re: Optimum Cycling Position

Post by Jdsk »

mattheus wrote: 16 Jul 2021, 10:57am... with a professional body...
: - )

Jonathan
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pjclinch
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Re: Optimum Cycling Position

Post by pjclinch »

As noted above, there aren't absolutes but that doesn't mean you can't improve things... but if you want something better you need to start by defining "better".

Take, for example, the pro peloton, where obviously the best bike is the fastest legal bike on the day... though on a TT with flat bits and steep bits some riders change between bikes with radically different positions in order to get the best time, so even with a very limited range of requirements you can get obviously different answers. Regarding personal differences, Graeme Obree's first super-aero tuck was (before the Luddites of Lausanne banned it) remarkably efficient, but even in the limited context of individual pursuit on a track hardly anyone but him could ride that way.

There are simple "this is better" things, so if your seat is so low you can scarcely bend your knees enough to pedal then it needs to go higher, but optimums will be down to the personal physiology and the particular job you want doing better.
Often seen riding a bike around Dundee...
st599_uk
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Re: Optimum Cycling Position

Post by st599_uk »

There's a bike fitter on YouTube who claims that 90% of his clients have their seat too high (buy say 15mm) and that by dropping it stress on the quads and knees is reduced, blood flow in the saddle regions is improved and you can ride in more comfort.

This does seem to then require lots of other tweaks though looking at his videos.
A novice learning...
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bjlabuk
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Re: Optimum Cycling Position

Post by bjlabuk »

"No improvement can be made without change, but not all change leads to improvement"

It is all about trial and error, but it is handy to have somewhere to start, hence the guides that are produced. The pedals turn in a circular motion. The diameter of that circle can be measured reasonably accurately. Your knees go up and down (and side to side to varying degrees) as the pedals turn. There is a certain place in this motion when the knee is in a 'better' place relative to the pedal if the saddle is moved fore or aft. etc etc. No guide is going to cater for all body types or sizes, but that does not mean they should all be dismissed as nonsense.
mattheus
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Re: Optimum Cycling Position

Post by mattheus »

Jdsk wrote: 16 Jul 2021, 10:58am
mattheus wrote: 16 Jul 2021, 10:57am... with a professional body...
: - )

Jonathan
Stop sniggering at the back, boy.
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