Effect of crankarm length on saddle height?

Luigi de Guzman <[email hidden]> wrote in news:GPGgi.652324$2Q1.241147
@newsfe16.lga:

Quoted message said:

All else being equal--frame, rider, etc--would mounting shorter (say by
5mm? 10mm?) cranks mean a corresponding decrease in saddle height to get
the same amount of total leg extension?

You would need to raise your seat if you got shorter crankarms, right?

Luigi de Guzman said:

A stupid question for you guys:

All else being equal--frame, rider, etc--would mounting shorter (say
by 5mm? 10mm?) cranks mean a corresponding decrease in saddle height
to get the same amount of total leg extension?

Actually, you'd /increase/ the seatpost height to keep the same
pedal-to-saddle distance.

Quoted message said:

I'm riding 175mm cranks now; my old bike was a bit big, but ran with
170mm cranks. I'm debating whether or not I should go to shorter
cranks.

No real reason to if current set-up is comfortable. You likely wouldn't be
able to tell the difference once saddle height is adjusted (slightly).

Bill Sornson said:

Luigi de Guzman said:

A stupid question for you guys:

All else being equal--frame, rider, etc--would mounting shorter (say
by 5mm? 10mm?) cranks mean a corresponding decrease in saddle height
to get the same amount of total leg extension?

Actually, you'd /increase/ the seatpost height to keep the same
pedal-to-saddle distance.

Quoted message said:

I'm riding 175mm cranks now; my old bike was a bit big, but ran with
170mm cranks. I'm debating whether or not I should go to shorter
cranks.

No real reason to if current set-up is comfortable. You likely wouldn't be
able to tell the difference once saddle height is adjusted (slightly).

This is all good news. Yay!

When this summer is out, I'm thinking about going to shorter cranks on my
main bike--mainly to try and solve an annoying toeclip/fender overlap.

-Luigi

--
Luigi de Guzman
http://ouij.livejournal.com

Bill Sornson said:

Luigi de Guzman said:

A stupid question for you guys:

Quoted message said:

All else being equal--frame, rider, etc--would mounting shorter (say
by 5mm? 10mm?) cranks mean a corresponding decrease in saddle height
to get the same amount of total leg extension?

Actually, you'd /increase/ the seatpost height to keep the same
pedal-to-saddle distance.

One formula in use for determining seat height is to use inseam x 1.09
to get the seat height from the bottom bracket + the crank length.
This means that longer crank arms would result in a lower seat
relative to the bb. In other words as you say if you swap to shorter
crank arms, you would raise the seat.

Quoted message said:

Quoted message said:

I'm riding 175mm cranks now; my old bike was a bit big, but ran with
170mm cranks. I'm debating whether or not I should go to shorter
cranks.

No real reason to if current set-up is comfortable. You likely wouldn't be
able to tell the difference once saddle height is adjusted (slightly).

I ride 165's, 170's, 175's, 180's and 195's. And occasionally 172.5's
and 177.5's. Each of these bikes has the seat adjusted to compensate
more or less for the different lengths. I can hardly tell the
difference between 165 and 175, and the jump to 195 is only really
noticable in that it encourages a much lower cadence and has more
aerobelly interference.

OP, In other words go for shorter cranks if you want, and maybe bump
the seat up a corresponding amount.

Joseph