Bike Setup (Positioning, Biomechanics)

A light bike doesn't replace good fitness.

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Posts: 1117
Joined: Mon Jul 26, 2004 1:06 pm

by grover

Hey Guys,

I'm just wondering what the general consensus with saddle for/aft positioning and how to work it out is? I've heard pedals at 3/9 o clock, drop a plumb bob from the knee and you want it lining up with the centre of the pedal spindle.

Now my question is, which part of the knee? I've read the centre, the knee cap and the little bumbs just below (tuborosity of the fibula), which is it?

Next thing is, I'm about to buy a new Syntace F99. I've just put a new seatpost on and it has taken my saddle position back about 25mm. Should I buy the stem 25mm shorter than my old one so that the reach is the same?

NOTE that with the saddle back 25mm, when a plumb bob is dropped from the bumps just below the knee cap it goes straight through the centre of the pedal spindle.

Your quick and helpful replies will be greatly appreciated, gotta decide on length within the next 40 hours.

Cya, John.

by Weenie

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the Repeater
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Joined: Wed Dec 15, 2004 5:06 pm
Location: Burlington, VT

by the Repeater

Positioning via this method is an old standby for fitting. It is really just an approximation and not a guarantee on a "perfect fit." Outdated, antiquated.

It sounds like you're happy with your position as is. If it gives you no discomfort and it feels effective, I wouldn't change a thing. Usually, set back seatposts are for femur length, compared to overall leg length, but plenty of short riders use them.

Usually the only change you should make when going to a setback post is to drop the saddle a couple mm's to compensate for saddle to pedal distance change.

big fellow
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Joined: Thu Nov 04, 2004 4:05 pm

by big fellow

the bump you're referring to is the tibial tuberosity....

i'd also be careful about making too many radical changes as it will catch up with you and you'll end up getting injured...

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