On Mon, 07 Aug 2006 09:37:00 GMT,
[email protected] wrote:
>
>"Ron Ruff" <[email protected]> wrote:
>>If your seat is positioned rearward you will be more balanced, and the
>>action of pushing down with the legs (pedaling) will naturally help to
>>lift your torso at the lower back and glutes. The weight is supported
>>by the seat and pedals, and only a little by the hands. When you ride
>>up an average hill at a good pace, the weight on your hands should
>>naturally drop to ~zero. If the seat is forward you have to hold up
>>your upper body with your arms, plus there is a tendency for the
>>pedaling action to push you forward, rather than being neutral
>>fore/aft... which is best.
>>
>>Level to slightly nose-up saddle, and a couple cm behind KOPS is a good
>>starting point. BB center to top-middle of saddle about 0.88 x inseam.
>>
>>If you watch any of the pro stage races, you'll see that most of the
>>riders sit pretty far back, with their arms stretched out. A similar
>>position with the bars raised to a comfortable height works well for
>>recreational riders.
>
>Thanks Ron. I've checked out the KOPS using a plumb bob and
>found that the bump below each knee (tibial tuberosity) is directly
>above the pedal spindle (with the seat post reversed).
>
>Do most people recommend that it's a couple of cm further back ?
>I haven't seen this mentioned on Sheldon Brown's web site and
>other sites I've looked at.
>
>http://www.sheldonbrown.com/gloss_i-k.html#kops
>
>In any case don't you think it's more logical for me to adjust
>my saddle's horizontal position according to my torso length
>and stem length ?
Nope. The crank spindle and it's relationship to the wheelbase is the truly
fixed part of the program, nothing you can do about that. The crank length isn't
fixed, but isn't a part that lends itself to adjustment. Most people can ride
most cranks without trouble, so let's just leave those there.
Given that - you want the saddle and bars a comfortable distance apart
horizontally and vertically. That distance will change a bit depending on how
you're riding. You also want your position balanced fore/aft on the bike for
stability in the saddle, and here's an important part, so that the relationship
between your shoulders and upper body, and hands on the bars and the contact
patch of the front tire are conducive to strong stable riding out of the saddle
and when driving hard in the saddle. Now, back to how far over that fixed crank
position you are: The saddle/handlebar position can be seen as rotating about
the crank spindle. Your ability to apply power to the pedals is affected by how
far over or back you are. There's also a difference in whether you're pounding
up hills, spinning madly, riding casual or time trialing.
So the saddle goes in place relative to the crank - this is the engine, it's
important. The handlebar goes in place to give you balance, control and position
in and out of the saddle. The frame size is selected to allow the previous
criteria to make the bike have the correct front/back weight balance and have
the tire patch inline with your hands and shoulders when standing.
You have excess weight on your front tire. I can't imagine how a short arm/torso
will get over the bars to work efficiently out of the saddle.
By all means ride and enjoy. Don't futz and fuss, but I'd keep an eye out for a
frame that really fits you. Like someone else suggested, a compact frame could
help get the bars up where you want them. If you still want them there after
doing more riding.
Ron
