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Seat positioning

Old 07-07-12, 08:00 AM
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Seat positioning

Is there a simple or convenient way to move my seat 10-20 mm forward toward the handle bars? My seat position now is as far forward as it will go, and I need about 10-20 mm more forward positioning. Fuji road bike, carbon frame, light as a feather, but my legs are not positioned correctly unless I move forward almost off the seat.
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Old 07-07-12, 08:02 AM
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Assuming you currently have a setback seatpost, replace it with a zero-setback post.
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Old 07-07-12, 08:09 AM
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Originally Posted by nrsmd
Is there a simple or convenient way to move my seat 10-20 mm forward toward the handle bars? My seat position now is as far forward as it will go, and I need about 10-20 mm more forward positioning. Fuji road bike, carbon frame, light as a feather, but my legs are not positioned correctly unless I move forward almost off the seat.
The important question here is why you need more forward positioning. If it's to get proper fore-aft position of the saddle (and where that is constitutes a whole other subject) then go for it. If it's to get closer to the handlebars you need to change the stem or the bike, or risk knee damage as well as less efficient pedaling.

Last edited by cny-bikeman; 07-07-12 at 08:41 AM.
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Old 07-07-12, 08:45 AM
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+1 you want be sure why.
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Old 07-07-12, 08:45 AM
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Plain seat post and a saddle clip.. clip can go in the front of the post or back..

Why? folding bikes, like Brompton , adapt the bike, to the rider..
many ways, since they make just 1 size frame..
so offer the best of the saddle clips..

shorter femur would be a reasonable Why.. to shorten setback..
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Old 07-07-12, 08:47 AM
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Originally Posted by fietsbob
Plain seat post and a saddle clip
This is the perfect solution if the concept of 'bike porn' could never make any sense to you.
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Old 07-07-12, 08:59 AM
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Originally Posted by fietsbob
Plain seat post and a saddle clip.. clip can go in the front of the post or back..

Why? folding bikes, like Brompton , adapt the bike, to the rider..
many ways, since they make just 1 size frame..
so offer the best of the saddle clips..

shorter femur would be a reasonable Why.. to shorten setback..
Yes, that's all true - but to just tell the OP how to move the seat forward when we don't know the reason is a disservice.
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Old 07-07-12, 09:37 AM
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Brompton's 'penta clip' is good enough to be called the best of it's type part.

I find them F ing brilliant [as Bono(U2) would say]..

friction developed by multiple plates, so, stepless,
hold tight with reasonable bolt torque..
and being mostly Aluminum, still light..

Riv Bike brings Nitto's 27.2 plain posts in, their finish quality
puts them above Kalloy..

Last edited by fietsbob; 07-07-12 at 09:41 AM.
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Old 07-07-12, 09:40 AM
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The recommendations are to have your right knee over the ball of the foot when the left foot is at its low pedaling point. Mine 10-20 mm behind that marking, so moving the seat a little forward I thought will provide the textbook "correct fit."
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Old 07-07-12, 10:30 AM
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Originally Posted by nrsmd
The recommendations are to have your right knee over the ball of the foot."
Where are you measuring on your knee?

Back when I worked in manufacturing we used to joke about "measure with a micrometer, mark it with a piece of chalk, and cut it with an ax." Bicycle fit systems might be the poster child for that.
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Old 07-07-12, 10:40 AM
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if you tape a string with a weight on it, to your kneecap/patella..

plumbline with crank at 9: & 3: o'clock. to pedal axis..
measure both, bones are not identical.
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Old 07-07-12, 11:00 AM
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Originally Posted by nrsmd
The recommendations are to have your right knee over the ball of the foot when the left foot is at its low pedaling point. Mine 10-20 mm behind that marking, so moving the seat a little forward I thought will provide the textbook "correct fit."
I've never seen it put that way - generally cranks are to be level and you check with the crank that is forward. Secondly, that's more tradition than textbook. KOPS as it's called is just a starting point, but certainly if you're really that far back it's OK to move forward a bit.
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Old 07-07-12, 11:11 AM
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Originally Posted by nrsmd
but my legs are not positioned correctly unless I move forward almost off the seat.
Based on what? Frame geometry is such that the vast majority of people are properly positioned within the range offered by posts and saddle rails. Moving forward, puts you more above the Bottom bracket and will generally cost you power, and tire you more quickly over long distances.

Even track bikes built for sprinters do not position riders much more forward than rod bikes do. Just about the only riders who ride in a more forward position are Tri-athletes using aero bars, and the jury's still out whether this radical, nearly over the BB, saddle position is actually better.
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Old 07-07-12, 12:53 PM
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I am going to defend the OP's desire to move his saddle forward. There may be a good reason for it.

I am tall with long legs out of proportion to my torso. After plugging my numbers into The Comp Cyclist fit calculator, it told me my saddle was too far back. After experimenting with jamming the saddle all the way forward, I swapped out the seatpost for a zero-setback model. It made a *huge* difference in comfort! Now I no longer feel like I am folded into a "pike" position; I can breathe better; And I can lift off the saddle to sprint, and sit back down, w/o needing to shift my hips forward to stand and back when I sit down again. It also improves the front/rear weight distribution on a large frame where the saddle is nearly above the rear axle.
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Old 07-07-12, 01:08 PM
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You have to start posting a picture of the bike plus a picture of you in the bike because ask such a thing is just useless w/o a picture.

Asking for the picture because :

1- you can have a frame too big

2 - the saddle is too high

3- you are just being anal with something that doesnt apply to everybody. More than a rule is a suggestion.

4 - if 1 and 2 are right then you have a serious problem in the fitting.

5 - if 1 and 2 are right and you are trying to reach aero bars in the bike then dont bother, we dont like aero guys that can't handle the bike or have no idea what they are doing hehehe

6 - you are a phenomenon that has super short femurs and super long tibia to the point that even being all the way to the front it is still short.

7 - The super light bike you have has a seat tube angle of 50 degrees, in such case no seatpost will do what u want. Im not going to look into the fuji catalogs the bike you have, and pretty much nobody here will do either

8 - post pictures man.
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Old 07-07-12, 01:55 PM
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Before you send out the Sopranos to do me in for this consideration, let me ask:
What about turning the seat post 180 degrees which would bring me about 20 mm closer to the handlebar? I read that the stem, which has a slight angle bend, could be reversed to raise the handle bar. Why not use the same principle for the seat post, and then I would be moving the seat a little back as needed for correct geometry (KOPS).

Am I brilliant or am I deranged with this idea?
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Old 07-07-12, 02:07 PM
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Most posts have a limited tilt range which won't accomodate that, but you can give it a shot.
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Old 07-07-12, 02:14 PM
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Nrsmd, having your knee over the ball of your foot is only a starting point. Everyone is gonna have a slightly different preference. I prefer my knee to be slightly behind, this makes it easier for me to grab the bar ends and push my pedals giving me lot's of accelerating power.
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Old 07-07-12, 02:23 PM
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Originally Posted by nrsmd
The recommendations are to have your right knee over the ball of the foot when the left foot is at its low pedaling point. Mine 10-20 mm behind that marking, so moving the seat a little forward I thought will provide the textbook "correct fit."
Something is very wrong with this picture.

I'm not criticizing your desire to change saddle position, that's yours to set wherever you want. But this makes absolutely zero sense, so you may wish to recheck your methodology.

If the left foot is at it's lowest position that means the pedal is at 6 o'clock directly under the BB, or slightly forward of there. That puts your right foot directly above the bottom bracket, or slightly behind that. For your knee to then be above that on any bike, you'd need an extremely short femur.

As I said, it's not my lookout either way, but if you're going to follow some scientific method, you should make sure you're reading it correctly.
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Old 07-07-12, 02:28 PM
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Originally Posted by ben4345
Nrsmd, having your knee over the ball of your foot is only a starting point.
+ 1

Google "knee over pedal spindle" esp look at the first few results.
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Old 07-07-12, 03:33 PM
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Originally Posted by nrsmd
The recommendations are to have your right knee over the ball of the foot when the left foot is at its low pedaling point. Mine 10-20 mm behind that marking, so moving the seat a little forward I thought will provide the textbook "correct fit."
I think you are not interpreting the usual fitting suggestion correctly.

This link https://www.jimlangley.net/crank/bikefit.html (item 4) shows the usual 9 o'clock - 3 o'clock pedal position for setting fore/aft saddle position. N.B. it's also important that the ball of the foot rest above the pedal axle (item 3).
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Old 07-07-12, 04:16 PM
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FBinNY I thought in the same thing.. .thats why I asked for pictures to know exactly what he was doing And I'm the one who doesnt know english
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Old 07-07-12, 04:33 PM
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Originally Posted by nrsmd
The recommendations are to have your right knee over the ball of the foot when the left foot is at its low pedaling point. Mine 10-20 mm behind that marking, so moving the seat a little forward I thought will provide the textbook "correct fit."
While that's how people traditionally positioned themselves on bikes Knee-Over-Pedal-Spindle has no basis in physiology or physics.

Stand on the balls of your feet with heels and butt against the wall and lean forwards. You fall over. Stand on the balls of your feet in the middle of the room and lean forward. Notice how your rear end moves back to counter balance your torso weight.

The same thing happens on your bike.

You want to get your rear end back far enough that you aren't putting too much weight on your hands.

Here's Keith Bontrager's classic article on the subject:

https://sheldonbrown.com/kops.html

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Old 07-08-12, 05:08 PM
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For an article that is a little less heavy on the details, one can read Peter White's: https://www.peterwhitecycles.com/fitting.htm. I think he basically says the same things
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Old 07-08-12, 09:04 PM
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KOPS refers to the patella (kneecap) being positioned directly over the pedal spindle when the pedals are at 9:00 and 3:00 - the crank arms are both horizontal. Not at the bottom of pedal rotation.
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