Good with bikecad or math?

[tuscanyswe]

Can someone tell me what .15 degree of less sta would do to a saddle at 78.5 cm? How much further back would it be than with an sta at 73 degrees?

[ergott]

2mm more

[tuscanyswe]

2mm more

Thank you! A little Less than i was thinking. Thats good :)

[zennmotion]

Yeah, for bike seat tube purposes I've always just estimated 1 degree = 1 cm setback. Math is hard.

[staggerwing]

FWIW, I agree, ~2mm, which is also less than the thickness of two stacked quarters.

[PacNW2Ford]

Can someone tell me what .15 degree of less sta would do to a saddle at 78.5 cm? How much further back would it be than with an sta at 73 degrees?

0.15 degrees or 1.5?

[BdaGhisallo]

Setback is pretty easy to calculate with a little trig:

cos(STA) * height = setback

Height being the straightline distance (the hypotenuse in the right angle triangle) to the point at which you want to measure the setback.

In this case - setback difference at 78.5cm of 0.15 difference in STA, starting with STA of 73 deg.

Cos 73 * 78.5cm = 22.9511cm

Cos 72.85 * 78.5cm = 23.1476cm

Effect of slackening STA by 0.15 deg from 73 deg at 78.5 cm is 0.1965 cm.

[tuscanyswe]

0.15 degrees or 1.5?

0.15

So its been cleared. Thanks to all that chimed in.

Yeah i also have the back of my mind that 1 degree is approx 1cm in my size but wanted a more specific number this time.

Cheers