Seat Tube Angle
seanorawe
Posts: 950
Apologies for the long winded post.
My bike seat post angle is 73.5 degrees according to the Geo on the bianchi website. Is this considered a steep seat post? I have read a bit in to it and have copied the following from a website.
Frame angles
Seat tube angles range from about 70-75 degrees. A steeper angle moves the saddle forward while a shallower angle moves it back. Steep is fine for racers. It allows them to ride hard in an aero crouch, as the more open hip angle doesn't constrain breathing or power transfer. It's not so good for more relaxed riding as it transfers more of your weight from your backside to your hands, which can cause aches and pains.
You can change the effective seat tube angle by sliding the saddle forward or back in the seat post clamp, or by fitting a different seat post with more or less 'layback' (the distance the clamp is behind the seat post centreline).
If I slide my saddle forward will my bike become more relaxed? I do feel pressure on my hands after making all relative adjustments that should take it away.
My bike seat post angle is 73.5 degrees according to the Geo on the bianchi website. Is this considered a steep seat post? I have read a bit in to it and have copied the following from a website.
Frame angles
Seat tube angles range from about 70-75 degrees. A steeper angle moves the saddle forward while a shallower angle moves it back. Steep is fine for racers. It allows them to ride hard in an aero crouch, as the more open hip angle doesn't constrain breathing or power transfer. It's not so good for more relaxed riding as it transfers more of your weight from your backside to your hands, which can cause aches and pains.
You can change the effective seat tube angle by sliding the saddle forward or back in the seat post clamp, or by fitting a different seat post with more or less 'layback' (the distance the clamp is behind the seat post centreline).
If I slide my saddle forward will my bike become more relaxed? I do feel pressure on my hands after making all relative adjustments that should take it away.
Cube Attain SL Disc
Giant CRS 2.0
Giant CRS 2.0
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Comments
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moving the saddle should be about getting your position over the pedals right not a frame size adjustment (as it were). If you want a bit less pressure on your hands then look at stem height or length
Its a 55cm bike with a 110mm stem using all spacers. I don't like flipping the stem as it gives me a sore back when I do. It was really just a thought, and I was thinking if I moved the saddle back it would reverse the effect of having an aggressive seat tube angle. On the flip side someone in work mentioned moving the saddle more forward to get an imaginary plumb line from my knee to be further forward than the pedal axle.Cube Attain SL Disc
Giant CRS 2.00 -
sliding saddle forwards makes an effective steeper seat post angle and hence less relaxed.
However you should only really be moving the saddle to get your butt in the right place for effective pedalling, by looking at leg angles and knee in relation to pedal etc. you then adjust reach with the stem etc.
start point is saddle height, then fore / aft on saddle, then look at bar height with spacers and then stem length for reach.
all of the above are a bit subjective as there are no definite answers in bike fitting. Its what works for you.
The Via Nirone, whilst in Bianchi's C2C range is slightly "relaxed" geometry but in truth not that relaxed (compared to a 'dale synapse or Giant defy or Spec' Roubaix.Bianchi Infinito CV
Bianchi Via Nirone 7 Ultegra
Brompton S Type
Carrera Vengeance Ultimate Ltd
Gary Fisher Aquila '98
Front half of a Viking Saratoga Tandem0 -
A good way of thinking of it is always to completely ignore the bike, pretend it is invisible. You are trying to get your saddle in the right position relative to the bottom bracket (the bb never moves as it can't), then get the bars in position only after the saddle position is definitely perfect both in height and fore/aft.
Never compromise that saddle position, and if you don't know how to get the saddle position close to right, then read up a lot or go to someone who knows. That's a very basic run down.0 -
sliding saddle forwards makes an effective steeper seat post angle and hence less relaxed.
However you should only really be moving the saddle to get your butt in the right place for effective pedalling, by looking at leg angles and knee in relation to pedal etc. you then adjust reach with the stem etc.
start point is saddle height, then fore / aft on saddle, then look at bar height with spacers and then stem length for reach.
all of the above are a bit subjective as there are no definite answers in bike fitting. Its what works for you.
The Via Nirone, whilst in Bianchi's C2C range is slightly "relaxed" geometry but in truth not that relaxed (compared to a 'dale synapse or Giant defy or Spec' Roubaix.
All in all I guess what you are saying is the seat tube angle wont really effect me greatly. I don't mind the positioning on the bike, its less relaxed than my old Spesh Sectuer, but not overly harsh. My saddle could do with coming forward a touch , so I think I will go ahead and move it.Cube Attain SL Disc
Giant CRS 2.00 -
Moving the saddle forward, backwards, up or down will change your leg position at different parts of the pedal stroke. It will also effect how much weight is taken by the saddle and how much on your hands. Thirdly it will change the reach and drop to the bars . It should not be used to achieve number 3. You get whatever reach and drop you get as a result of the existing geometry of the bike and if you want to change it you should use the stem and bars to do so, not the saddle.sliding saddle forwards makes an effective steeper seat post angle and hence less relaxed.
However you should only really be moving the saddle to get your butt in the right place for effective pedalling, by looking at leg angles and knee in relation to pedal etc. you then adjust reach with the stem etc.
start point is saddle height, then fore / aft on saddle, then look at bar height with spacers and then stem length for reach.
all of the above are a bit subjective as there are no definite answers in bike fitting. Its what works for you.
The Via Nirone, whilst in Bianchi's C2C range is slightly "relaxed" geometry but in truth not that relaxed (compared to a 'dale synapse or Giant defy or Spec' Roubaix.
All in all I guess what you are saying is the seat tube angle wont really effect me greatly. I don't mind the positioning on the bike, its less relaxed than my old Spesh Sectuer, but not overly harsh. My saddle could do with coming forward a touch , so I think I will go ahead and move it.
Moving the saddle forwards puts your feet further back relative to your centre of mass meaning that essentially your lower body is "leaning" further forward. This will mean you legs can't support as much of your weight and your hands will have more work to do. Conversely if you move the saddle back your hands will take less of the load. As above, the bar position shouldn't be part of this equation, you adjust for the desired reach and drop separately.0
