Saddle height calculation help

Quoted post said:

Originally posted by gregk
What is the preferred method to calculate saddle height? I know there are a million theories out there, and some say that it is all personal preference. I've heard that the general rule was to do .883 x your inseam length in centimeters. That gives the distance from the center of the bottom bracket to the top of the seat. I am 6'1" tall, with a 91 cm inseam. Using the formula, that tells me that the top of my saddle should be 80.4 cm from the center of the bottom bracket. That seems like it is a bit much! I had it set too low at about 75.5 cm and was getting some knee pain. I just raised it to 78 cm, and I'm hoping that it is enough. Any suggestions? I don't want to pay $150 for a complete bike fit!

I've pondered this and my first piece of advice is to keep your calculator in your pocket where saddle height is concerned.

Get yourself a goniometer. This is a little device that measures joint angles. They pop up on Ebay from time to time and typically sell for around $10: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3248714798&category=15911 Any orthopaedic physician probably has them laying around his office and has one he can give to you (drug sales reps give them away like candy).

Get someone to help you with this:
Sit on your saddle in riding position with your hands placed comfortably on the bars and lock into the pedals (you'll have to lean against something). Extend one pedal downward such that the crank of that pedal is going downward at a slight angle, precisely following the angle of the seat tube. If you look at the bike from the side, it should look like the crank is a downward extension of the seat tube. This is the furthest distance your foot will be from the seat and the farthest your leg is extended in its range of motion. Adjust the saddle height such than the angle between your femur and tibia (knee angle) at this position to be 150 degrees. This is 30 degrees short of a fully extended leg when your foot is farthest from the seat. This angle will situate you such that your range of pedaling motion matches the optimum range of movement to get the most power from your thigh muscles. Try to have the fore/aft positioning of your saddle adjusted before you do this.

I got this tip from Chris Carmichael's book (Lance's trainer). It certainly seems to work better than static calculations, and the rationale is scientifically sound.

I hope this helps!

I remember reading this awhile back and its worked for me: Put your bike on a training stand. Get on the bike and place your heels on the pedals. Start pedaling backwards. If your hips start to rock while you're pedaling, the saddle is too high. Lower the saddle in small (1cm) increments until your hips remain stable.

I was once told by a coach that the best way to work this out is "have the seat as high as u can without losing power across the bottom of the pedal stroke.....it is a feeling, not a formula" but a good starting point is usually around the 109% of inseam length. Good Luck.

Quoted post said:

Originally posted by drewjc
I was once told by a coach that the best way to work this out is "have the seat as high as u can without losing power across the bottom of the pedal stroke.....it is a feeling, not a formula" but a good starting point is usually around the 109% of inseam length. Good Luck.

109% of inseam length - are you sure?

Quoted post said:

Originally posted by Spider1977
109% of inseam length - are you sure?

That's 109% of inseam ... including the length of crank! :-)

Quoted post said:

Originally posted by smurfbike
That's 109% of inseam ... including the length of crank! :-)

Thanks Smurf - now I understand.

Quoted post said:

Originally posted by gregk
What is the preferred method to calculate saddle height? I know there are a million theories out there, and some say that it is all personal preference. I've heard that the general rule was to do .883 x your inseam length in centimeters. That gives the distance from the center of the bottom bracket to the top of the seat. I am 6'1" tall, with a 91 cm inseam. Using the formula, that tells me that the top of my saddle should be 80.4 cm from the center of the bottom bracket. That seems like it is a bit much! I had it set too low at about 75.5 cm and was getting some knee pain. I just raised it to 78 cm, and I'm hoping that it is enough. Any suggestions? I don't want to pay $150 for a complete bike fit!

I don't know if there are a million but at URL:
http://www.cyclemetrics.com/ and click on the right side where it says "FIT LINKS" there are quite a few.
I suggest that you get some feedback from a cycling pofessional coach. You need to get the fit according to your anatomy, crank length, frame angles, saddle setback and other factors.
Height is only part of the issue.

sorry Spider. I always measure the seat height including the crank length to save time when changing bikes (road-long, track-short etc.)

Quoted post said:

Originally posted by Ted B
I've pondered this and my first piece of advice is to keep your calculator in your pocket where saddle height is concerned.

Get yourself a goniometer. This is a little device that measures joint angles. They pop up on Ebay from time to time and typically sell for around $10: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3248714798&category=15911 Any orthopaedic physician probably has them laying around his office and has one he can give to you (drug sales reps give them away like candy).

Get someone to help you with this:
Sit on your saddle in riding position with your hands placed comfortably on the bars and lock into the pedals (you'll have to lean against something). Extend one pedal downward such that the crank of that pedal is going downward at a slight angle, precisely following the angle of the seat tube. If you look at the bike from the side, it should look like the crank is a downward extension of the seat tube. This is the furthest distance your foot will be from the seat and the farthest your leg is extended in its range of motion. Adjust the saddle height such than the angle between your femur and tibia (knee angle) at this position to be 150 degrees. This is 30 degrees short of a fully extended leg when your foot is farthest from the seat. This angle will situate you such that your range of pedaling motion matches the optimum range of movement to get the most power from your thigh muscles. Try to have the fore/aft positioning of your saddle adjusted before you do this.

I got this tip from Chris Carmichael's book (Lance's trainer). It certainly seems to work better than static calculations, and the rationale is scientifically sound.

I hope this helps!

Ted B. is right, the best way adjust seat height is with a protractor or goniometer. If you have trouble finding a goniometer, Home Depot sells a plastic protractor, Made by Quint { www.quintmeasuringsystems.com } It will serve the same purpose.

Quoted post said:

Originally posted by bobobg
Ted B. is right, the best way adjust seat height is with a protractor or goniometer. If you have trouble finding a goniometer, Home Depot sells a plastic protractor, Made by Quint { www.quintmeasuringsystems.com } It will serve the same purpose.

Sorry url is www.quintmeasuring.com