- Why is seat angle so important
and how can changing the position of our saddles
affect how our whole bike feels
when we're sat down pedalling?
Well, I hope to be able to shed some light
on that very question today.
(whoosh)
- There is a huge conversation going on in regards to our
seat tube angles on our trail and enduro bikes.
So, how we ended up on seat tube angle
as something to change.
Well, as bikes have gotten longer reach,
it means that we can get our weight more central
by steepening the seat tube angle,
and it makes our seated position a bit more comfortable
on those long bikes.
When it moves your weight forward,
not only does it position your weight
closer to the front wheel,
but it can also deliver more grip on the rear wheel.
When we talk about seat tube angle,
there are two main measurements that we discuss.
There's effective and actual.
Now effective is the line from the bottom bracket,
the center of it,
to the center of your saddle rails.
And actual follows the exact angle of
the metal tubing there.
Now, how do these different measurements have an effect
on the feel of our bike?
Well effective is in some ways the really important one,
because that really does change where your weight sits.
But actual is a vital measurement too.
People that run lots of seat posts
exposed outside of the bike will find that
effective seating position is drastically effected
by your actual angle.
Because that means the higher our saddle is,
the further it is moving backwards.
Now imagine if you had a very, very slack
actual seat tube angle,
it would mean that your seat post
would be coming really far out,
so the higher you have your saddle,
the slacker the effective seat tube angle is becoming.
I hope that makes sense.
So, how would we measure this?
How are we going to measure it today?
Well, I have measured between the two extreme marks
on this saddle,
right in the center of the rails there.
And I have positioned that
right in the center of the seat post.
We measure from the center of the bottom bracket,
straight up through until it dissects that mark
and we take a measurement.
Now a way we can drastically effect our effective seat tube,
is by sliding the saddle forward and back on its rails.
Let's take some measures then
and find out the overall effect we can have
on our seat tube angles.
So what if you want to run either a slacker
or steeper effective seat tube angle,
what can you do?
Now you might find yourself in this position due to
a limitation of bike design,
or because you have a bike
where you run a lot of seat post,
and exaggerates some of those angles.
Well you can of course move it on the seat rail,
but how much room do we have to play with
and what does it effect in terms of the numbers?
So this is actually Blake's bike
and he's got the saddle at full extension
and with the saddle in its most neutral position,
he is running an effective seat tube angle
of about 76 degrees.
So here I have this saddle slammed as far forward as it can
in its most extreme forward position.
That is sitting about 77.5 degrees.
So it's added a huge amount in terms of the effective,
it's made it a lot lot steeper.
Let's slam it back and see what the difference is
on the other end of the spectrum.
(funky music)
- There it is, that's 75.5 in its most rearward position.
So three simple readings there.
In its steepest position, it was 77.5,
in its most neutral position, it is 76.5,
and when this effective seat tube angle was at its slackest,
thanks to slamming it back on the rails,
it was 75.5.
So that's really interesting.
We talk a lot about frame design
and people are up in arms and going crazy
because a frame might have got a degree steeper
in the seat tube angle,
but we already have a lot of use
and a lot of adjustment in our saddle rail.
Now bike fit is something really, really, really important.
And I'm not telling you to slam your saddle forward
on the rails like there's no tomorrow.
What I am suggesting is have an experiment.
It's also really important to know
that having the correct saddle height
is always going to be king to a comfortable ride.
I don't expect you to put up with pain
just to be keeping up with the Joneses
in terms of effective seat tube.
If you're getting any discomfort,
then trust that and change something.
I personally find that having a steeper seat tube angle,
it basically alleviates some of the discomfort I have
when riding my bike.
But, if I go too steep,
it gives me a different set of problems.
So it's a real sweet spot
and it's about getting it just right.
In terms of saddle height, you want to be riding
with a slight bend in the knee.
And, as you can imagine,
as we are effecting where the saddle position is,
it will also have a consequential effect
on our effective saddle height
because as we're moving it more over the bottom bracket,
we're effectively reducing it.
So, that's another thing to think about.
Like I said, a slight bend in the knee,
and I find in my experience,
it's always better to err on the side of caution.
When you have your saddle a bit too high,
you feel so powerful, you feel odd,
just so you smash the gears
but that doesn't necessarily mean
you're using your body in the best way.
Now, as you can imagine,
as we move our saddle position forward or back,
it's going to have an effect on all of our contact points.
Suddenly, a change in the saddle position,
can effect your comfort if you're riding clicks.
It can also effect things like your wrists.
You'd be amazed at such a small difference here
could potentially be putting too much pressure
on your wrists in your seated position.
Which is obviously no good.
What I'm trying to get at,
it's really important to listen to your bodies
and understand that a small change in one part of the bike
that effects one particular area of your body
is not isolated to there,
and if you changed your saddle position,
and then the next day you go riding
and your feet hurt like never before,
well, they're quite probably linked.
So there we have it guys,
there's over two degrees of movement
just in our saddle rails alone.
Which is pretty cool when we're talking about
progressive geometry.
Now if you want to stick with geometry,
click down here to see the Dodster's geometry 101
and click down here to see how we get on
when we start messing about
with different offsets for our forks.
As always, don't forget to like and subscribe
and we'll see you next time.
Cheers guys!