Bicycle Mechanics - Seat Height?

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Court Jester
10-03-07, 05:00 PM
What’s a proper seat height?
I’m 6’ 1” and when on the bike my toes barely touch the ground. As much as some folks get into cycling I would think there has to be some type of formula to get the “proper” seat height.
jpbrew814
10-03-07, 05:01 PM
i can never get mine right, im constantly adjusting
ninjaman
10-03-07, 05:05 PM
Most cyclists would agree, you absolutely don't want your feet to touch the ground when you're seated! If you're doing any more than literally a stroll around the block, you risk lower back injury and unnecessary strain that could be easily avoided if you raise your saddle. If on a road bike, your knee should have a very slight bend when the ball of your root is pushing the pedal to the very bottom of its rotation.
twobikes
10-03-07, 05:27 PM
Formulae for seat height get you into the ballpark. From there you tweak it until it is right. In the 1960s the British did a study in which they concluded correct seat height is 109 percent of your inseam. To measure your inseam, stand by a wall in stocking feet with your feet about ten inches apart. Pull a thin book or a board up tight against your crotch. Measure from the spline of the book (as defining the bottom of your crotch) to the floor. That is your inseam. Place one crank down and on a straight line with the seat tube. Measure from the top of the pedal to the top of the seat. According to the British, this gives optimum torque from your legs. Some measure knee angles, etc. You may often see a figure of 0.883 multiplied by something or other, but that figure pertained to a particular characteristic of Greg LeMond's legs. It was never intended to be a universal figure. Some say to raise the seat until your heel just clears the pedal when you swing it front to back. This figure changes with shoes, etc. The usual advice is to tweak adjustments only a couple of millimeters and then ride for several days to see how it feels after you get used to it. At minimum, your hips should not rock when pedaling. Chafing of your genitalia from your clothing also indicates the seat is too high.
Court Jester
10-03-07, 05:35 PM
Thank you all very much
skanking biker
10-03-07, 07:55 PM
I've had a 12 people tell me 12 different ways to determine this. By far the most useful method I have found is the sit on your bike by a wall, turn the cranks to 12 and 6. The heel of your foot should touch the 6 o clock pedal with your leg straight.
Another preferred method (ala sheldon) is to keep raising it in small increments until your knee starts to hurt. At that point, you know it is too high.,
Having your saddle too low can mess up your knees and is also less efficient, as you are not able to apply maximum force throughought your spin and can't engage all the muscle groups.
tellyho
10-04-07, 07:26 AM
+1 to heel on 6 o'clock pedal.
masiman
10-04-07, 08:45 AM
+1 to heel on 6 o'clock pedal.
Do the heel method without reaching for the pedals, i.e. your hips should be parallel to the ground, not canted trying to reach a little farther for the pedal.
ultraman6970
10-04-07, 12:05 PM
with the cycling shoes on, measure your crotch starting obviously from the floor. Take the number u get an multiplied them by 1.90 or by 1.887 depends from you, then u are all set. The number u get should be the lenght from the center of the BB up to the top of the seat, Please follow the seat tube line ok?
I agree with ninja man, but always use the cicling shoes...
the other methods work also, always u can try the other methods and compare with the formula ones
I use heel on pedal at 6:00 should yield a slight bend in the knee. There's a lot of wiggle room in the "slightly bent" description; so it depends from there on riding style. Higher seat facilitates more leverage for power while a slightly lower saddle facilitated faster spinning. I also protect my knees byverifying that my knee cap is directly over the pedal spindle in the 3:00 position.
Road Fan
10-05-07, 08:06 AM
with the cycling shoes on, measure your crotch starting obviously from the floor. Take the number u get an multiplied them by 1.90 or by 1.887 depends from you, then u are all set. The number u get should be the lenght from the center of the BB up to the top of the seat, Please follow the seat tube line ok?
I agree with ninja man, but always use the cicling shoes...
the other methods work also, always u can try the other methods and compare with the formula ones
I like this method, without the cycling shoes, but Ultra's numbers are wrong. You multiply the inseam by 1.09 (NOT 1.90!) to get the distance from the axis of the pedal to the saddle top at the middle of the saddle. It this case the crank arms are aligned with the seat tube.
OR, you multiply the inseam by 0.887 (NOT 1.887!!) to get the distance from the BB center to the saddle top as above.
For 170 mm cranks the two calcs are really really close, but for other crank lengths there may be slight differences.
You also need to get the saddle fore/aft position where you need it. The classic starting point here is to get good sit-bone support when your knee is over the pedal spindle when the pedal is at the 3:00 position. Google KOPS for more info on this. It's only a starting point, but it is a standard starting point. You may want to adjust back and forth between saddle height and saddle fore/aft and saddle angle (classically it's level) to get all three right at the same time. Depends on how particular you are.
Then as you ride, see if the saddle pressure is good (on the sitbones and not on the boys), your hips are not rocking and causing abrasion, you don't have pain in front of your knees (saddle too low) or behind your knees (saddle too high). If you can ever get all these things right for a 100 mile ride, I think you're home. I'm not home yet!
Note that touching the ground with your feet does not enter into the picture. Presumably after you've ridden enough to get this far, you can stop without falling over.
The most critical part, though is saddle height, and most people have it way too low.
Road Fan
Road Fan
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