Counterintuitive saddle adjustment idea

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nirakaro
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Counterintuitive saddle adjustment idea

Postby nirakaro » 21 Dec 2017, 3:18pm

Can't remember where I read it, but someone said, if you keep slipping forward on your saddle, try moving it further back. Sounds implausible and daft, I thought, but gave it a try, and it seems (still early days) to help. Any idea why?

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Heltor Chasca
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Re: Counterintuitive saddle adjustment idea

Postby Heltor Chasca » 21 Dec 2017, 3:26pm

I think this is back to front. I was told on here that if you keep have to shuffle your bum back, you need to move your saddle forwards. And that to me makes sense, because your body is trying to settle into it’s natural placement.

Do you perhaps mean rake it back? In other words, tilt the nose up. Wait for the bike fitting document that’s about to be posted. :wink:

You will soon find out if it’s wrong (after a long ride) as there will be too much weight on your sit bones and the steering will be light.

Roadster
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Re: Counterintuitive saddle adjustment idea

Postby Roadster » 21 Dec 2017, 3:30pm

I don't know about that but if you keep slipping forward on your saddle, it usually needs to be tilted up at the nose slightly rather than moved back.

nirakaro
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Re: Counterintuitive saddle adjustment idea

Postby nirakaro » 21 Dec 2017, 3:51pm

Heltor Chasca wrote: if you keep have to shuffle your bum back, you need to move your saddle forwards. And that to me makes sense

Of course, that's the obvious solution - that's why I said counterintuitive. I took the saddle forward as far as it would go, and still had the issue. Moving it further back does seem to improve the feel of it.

nirakaro
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Re: Counterintuitive saddle adjustment idea

Postby nirakaro » 21 Dec 2017, 3:58pm

Roadster wrote:I don't know about that but if you keep slipping forward on your saddle, it usually needs to be tilted up at the nose slightly rather than moved back.

I'm working on that one. My seatpost only allowed me to change the tilt in increments of three or four degrees, which was ludicrously uncomfortable. I've changed it, and am experimenting with tiny adjustments, but more upward tilt seems to shift the weight from the sitbones onto the perineum, which ain't nice.

Brucey
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Re: Counterintuitive saddle adjustment idea

Postby Brucey » 21 Dec 2017, 5:00pm

nirakaro wrote:Can't remember where I read it, but someone said, if you keep slipping forward on your saddle, try moving it further back. Sounds implausible and daft, I thought, but gave it a try, and it seems (still early days) to help. Any idea why?


it is to do with weight distribution. Get the saddle far enough back, and you will be pulling on the handlebars even when you are sat in the saddle.

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Si
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Re: Counterintuitive saddle adjustment idea

Postby Si » 21 Dec 2017, 7:13pm

Id have thought that if the saddle is above the bb then when you push on the powerstroke your bum is pushed upwards, neither backwards now forwards. But if you move your saddle back then the power stroke is in a slightly more forwards direction, pushing your bum back a bit (as well as up).

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NATURAL ANKLING
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Re: Counterintuitive saddle adjustment idea

Postby NATURAL ANKLING » 21 Dec 2017, 7:37pm

Hi,
Roadster wrote:I don't know about that but if you keep slipping forward on your saddle, it usually needs to be tilted up at the nose slightly rather than moved back.

Or Up.
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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531colin
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Re: Counterintuitive saddle adjustment idea

Postby 531colin » 24 Dec 2017, 4:20pm

Intuition is misplaced. Logic is more likely to succeed.
The first thing to think about is why you keep shuffling back on your saddle.
Too long a reach to the bars can make you slip forward on the saddle as you ride, so you keep shuffling back in order to sit on the right bit of the saddle
Or you might have too short a reach, so you shuffle back to get a better reach. This happens to me if I set a bike up with insufficient reach, I will find myself sitting on the back of the saddle even though the saddle is set up the right distance behind the bottom bracket.
Brucey is, of course, right, you should set up your saddle position (front/back) with regard to weight distribution; to paraphrase Si, if your bum is directly over the bracket, then leaning forward to hold the bars will put a lot of weight on your hands. (If you don't believe me, try standing upright and leaning forward to hold an imaginary pair of bars.....you can lean much further forward if you stick your bum out the back.) So that's a third reason to shuffle back; to take some weight off your hands.
If you're racing, a forward saddle position can help you hold an aerodynamic position, and pushing down hard on the pedals helps support your torso (the "equal and opposite reaction" of Newtonian physics.) More leisurely cyclists are likely to be more comfortable with the saddle further back.....I find I am pulling back on the bars as soon as I put a bit of effort into my pedalling, because pedalling pushes me back as well as up.

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Gattonero
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Re: Counterintuitive saddle adjustment idea

Postby Gattonero » 25 Dec 2017, 10:22am

nirakaro wrote:Can't remember where I read it, but someone said, if you keep slipping forward on your saddle, try moving it further back. Sounds implausible and daft, I thought, but gave it a try, and it seems (still early days) to help. Any idea why?


Assuming the saddle is level, the obvious answer to me would be that there is some reduced flexibility of the upper body, so when cycling one would start to move (not "slip") forward in the saddle to compensate what is perceived as a long reach. The latter, implies that the bike is set correct to the rider's measurements, yet not taking in accounts the level of body flexibility and strength of the back&arms
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531colin
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Re: Counterintuitive saddle adjustment idea

Postby 531colin » 26 Dec 2017, 8:31pm

Gattonero wrote:.......... the bike is set correct to the rider's measurements,..........

Have a look at Steve Hogg here....https://www.stevehoggbikefitting.com/bikefit/2011/05/seat-set-back-for-road-bikes/
The riders' measurements and shape of the bike they are comfortable riding are only loosely related.
If anybody tries to sell you a bike fit which is based on taking some body dimension(s) and multiplying by a magic number in order to get to your "perfect" fit, I suggest you walk away. At best, all they will do is to fit you into some sort of average position, or some pre-conceived idea of the "perfect" position.
There is a thread here https://forum.cyclinguk.org/viewtopic.php?f=5&t=113772&hilit=laugh&start=30 where four forum members compared inside leg measurement against saddle height......even for such a "basic" measurement there was no agreement amongst four experienced riders.

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Re: Counterintuitive saddle adjustment idea

Postby Brucey » 26 Dec 2017, 11:07pm

531colin wrote: ....There is a thread here https://forum.cyclinguk.org/viewtopic.php?f=5&t=113772&hilit=laugh&start=30 where four forum members compared inside leg measurement against saddle height......even for such a "basic" measurement there was no agreement amongst four experienced riders.


I have done an experiment where four different people measured the same person and got four different answers. Add in four different pedals/shoes/preferences for saddle height and you can have a wide variation!

However I think it is fair to say that if you use the right 'magic number approach' it can

a) give you an upper limit for the saddle height
b) a sensible saddle setback
b) a sensible reach

which makes for a good starting point for those who have (as many do) vaguely sporting intent when they start out cycling. Given that some folk decide to go touring and others go racing, setting your starting point as somewhere inbetween, as many audax bikes and training bikes are set up makes sense. You ought to see if you have some leeway (in any given machine) for further adjustments in the most likely direction.

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531colin
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Re: Counterintuitive saddle adjustment idea

Postby 531colin » 27 Dec 2017, 5:01pm

OK, to keep it simple, lets just look at saddle height.
From the thread I linked, here are the four contributors ranked in ascending order for inseam (all by the "book and crotch" method, as far as I'm aware) ;
82.5 Gattonero
84 Natural Ankling
84.5 Colin
87 Samuel

And again, ranked by bottom bracket axle to saddle top, measured along the seat tube;
70 Colin
73 Samuel
74/74.5 Gattonero
76 Natural Ankling

I can't see any relationship at all between inseam and saddle height in those individuals, so I can't see how any "magic number" can predict saddle height from inseam.

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Re: Counterintuitive saddle adjustment idea

Postby Brucey » 27 Dec 2017, 6:38pm

you have made no allowance for crank length, pedal height, shoe sole thickness, saddle shape, seat angle, saddle flexibility, leave alone personal preference, or the possibility that the folk concerned may be happy but their riding position is all wrong (because they started out that way, for want of decent advice) and that it would be the first thing that anyone coaching them seriously would change.

What I am taking about is a method of making sure that beginners start out with the right size bike and a vaguely sensible position, not the last word in bike fit. The latter takes a lot more effort. Blind application of formulae without attention to detail can result in errors for sure but is still way better than nothing which is the usual alternative on offer.....

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531colin
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Re: Counterintuitive saddle adjustment idea

Postby 531colin » 27 Dec 2017, 8:40pm

Brucey wrote:you have made no allowance for crank length, pedal height, shoe sole thickness, saddle shape, seat angle, saddle flexibility, ........

Am I alone in that? Do all the people who say saddle height should be your leg measurement times a magic number account for those factors?
Lemond's formula measures from the bum bones' position, which does take account of saddle setback.
Brucey wrote:.......... What I am taking about is a method of making sure that beginners start out with the right size bike and a vaguely sensible position, .............

I hope you will share it with us?
Brucey wrote:..... Blind application of formulae without attention to detail can result in errors for sure but is still way better than nothing which is the usual alternative on offer.....

It was the lack of suitable advice that made me undertake to write my own poor effort. The very fact that one or two people have said they found it useful serves to underline how poor the general standard of provision is.
I still feel that setting your saddle height with reference to how it feels to ride is likely to be better than a body dimension times a magic number, then having to factor in crank length, pedal height, shoe sole thickness, saddle shape, saddle flexibility, saddle setback, cleat position, heel dropping/toe dipping, tightness of hamstrings, pelvic tilt........