Effective seat angle

mxh

When manufacturers quote this figure, is there some sort of standard for how high/low the seat is at the time.

Obviously with the 'actual seat angle' (for those bikes where this is still valid) the angle never changes, but with the 'Effective SA' the value will vary, getting slacker as the seat is moved from being fully down to it being fully up.

I get that trying a bike is better than relying on figures etc etc, but just from a purely technical viewpoint, if there are no standards behind measuring it then it would seem to be pretty a arbitary (or useless!) measurement.

Maybe if the manufacturers stated a range for the ESA it would have more meaning eg from 72 degrees (seat down) to 70 degrees (seat fully up). At least that way you would have an idea of what it is for your seat height (eg my seat is about 1/2 way up therefore the SA is approx 71).

Sorry - bored at work!

cooldad

Seeing as you do most of the interesting stuff standing, I would say it's not particularly important.
Especially as you can adjust bits to have your saddle wherever you want.

The Rookie

mxh wrote:

Obviously with the 'actual seat angle' (for those bikes where this is still valid) the angle never changes.!

Not forgetting that anything other than an inline seatpost will give you a difference between actual and effective seat tube angle which changes depending on saddle height.

mxh

Yes, both are valid points.

So why do manufacturers keep giving out an irrelevant measurement, and bike reviews keep quoting it?

The Rookie

Because, like top tube length, it's an indication, no more, of how a bike behaves.

I'd disagree with cooldad, where seat tube angle is important is on climbing in the saddle.