Saddle height is measured from the centre bb to the top of the saddle.

The formula most use is 0.883 X inseam lengh. Let's say I have inseam of 85cm. By the formula I get 75cm. OK now there's the crank lengh. The common sizes is 165mm, 170mm, 180mm. The lengh from the pedals to the saddle top is 75cm + 17cm. Wouldn't that make 92cm which is way higher than the inseam lengh?? Maybe my calculations or measurement or thinking is wrong. But please correct me if there is.

TQ.

The measurement is from the bb center to the seat top in a line parrallel with the seat tube. If you add the crank then the measurement is from the top of the pedal to the seat top.
This is only a guide, adjusted to meet your personal preference.

that's right berny..if I measure from the pedal to the saddle top I'll get 92cm(higher than my inseam lengh) using the formula. So is the formula something wrong?

There is a guy on RBR forum c-40 that has this explanation down.....maybe you can check over therre

you are using the formula correctly, inseam is measured from the heel, you pedal on the ball of the foot so you can't direftly compare the two numbers. Also you have cleats and shoes on which add height to your overall position.

Your femur attaches to your hip, that's where you pedal from, I suppose that's why the measurement seems strange. Like apples and oranges.

inseam x 1.09 is the other basic formula

That's for the distance from the saddle top, to the top of the lowest point the pedal can reach, measured generally along the length of the seat tube - no?

My inseam is only 67 cm but if I measure from the top of my saddle to the bottom of the pedal when inline with the seat tube it' measure about 74 cm. I don't feel that my saddle is too high but that's just the way it is.

Regard, Anthony

yep.

67cm x 1.09 = 73.03cm. Pretty close to 74cm, especially when considering the potential for small discrepancies in measurement.

Yes my measurements weren't that spot on so it's pretty close to the formula.

Regards, Anthony

Wow I didn't even know there was a formula. I've used the following method for 25 years: Put my racing kit on (including shoes) sit on the bike, clip into the pedals, move the cranks round until they are at '12:30' and adjust the saddle up or down until there is just a slight bend in my leg, at this point my knee should be directly over the ball of my foot, which in turn should be over the middle of the peddle.
It takes a few goes of getting on and off the bike, but it's always worked for me.
If the formula version works for you go with it, it's just the maths would give me a headache before I turned a peddle

I would go for a little more than a "slight bend". At least 25 degrees, maybe 30 degrees. I think knee angle is a lot more useful than formulas based on leg length.

Old school-put your cycling gear on and place heels on pedals and pedal backwards with heels barely keeping contact with pedals and like mentioned before adjust to your needs.