Talking about wheel path is probably not where we should
start.

But I feel good about this topic. It’s easy enough for anybody to understand,
but there’s some technical info in here that even the internet suspension gurus
are probably going to be interested in.
And we’re definitely going to start busting some heads.

We start here because wheel path has got to be the biggest topic of bullshit ever
created by bicycle suspension marketers.
Talk to some people and you will be convinced you’d be winning world cup
DH’s if you could just get the optimum wheel path. Rearward.
“Vertical”. I hope the guy who
thought of “near vertical” is a millionaire because of it. Thankfully, this seems to be slowly
changing. Santa Cruz has been setting
people straight for years, and even Specialized is coming around to telling
people not to worry about it.

**Single Pivots**

We’re going to start by looking at the simplest bikes to
understand, single pivots. Nobody needs
to be told that the wheel path on a single pivot is an arc centered at the
pivot point. You know this. You learned it in elementary school or college
or something, depending on whether or not you were schooled in the British Columbia public education system.

Here we have 8 theoretical 6 inch travel bikes, with 8
different theoretical pivot locations and 8 corresponding theoretical wheel
paths. Let’s zoom in (I’ve also sketched
in a 32 tooth middle ring and a 20 tooth cog for perspective).

From here, we can start to see some patterns. Pivots 1 and 2 are our high pivot
locations. Notice that swingarm length
doesn’t have much impact at all. These
pivots offer the most rearward swinging arcs, which is theoretically what
everybody wants, and why we get bikes like this:

Pivots 3 and 4 correspond with a medium pivot, roughly in
line with a middle chainring. Once
again, swingarm length has little input.
The path looks pretty damn close to "near vertical" to me.

Pivots 5 and 6 are extremely low, 6 being concentrically
around the bottom bracket and 5 at some imaginary point directly in front of
the bottom bracket. We’re starting to
see some spread due to swingarm length and a some forward arc. We notice that a shorter swingarm leads to
more forward arc.

Taking things to an extreme, we have 7 and 8, way below the
bottom bracket. We get a lot of spread
due to swingarm length and start to see some extreme forward arc.

So great, Dave. You
showed us a bunch of single pivot wheel paths, many of them in impossible
locations for bikes that don’t exist. So let’s start to overlay some real bikes over this
diagram (shown in red). We’ll start with
the Santa Cruz Bronson.

Which pretty much overlays our single pivot 3 and 4
examples.

Then the Ghost.

Which pretty much overlays our single pivot 3 and 4
examples.

And the Heckler.

Which....ahhh...pretty much overlays our single pivot 3 and
4 examples.

Three totally different bikes. Three totally similar wheel paths.

Let’s throw them all on one diagram, just for kicks. I’m not even going to bother labelling them,
because there’s no point.

They all look so similar, I should probably come to the
conclusion that I’ve doing something wrong.
In fact, they’re way more similar than even I expected, causing me to go
back and double check everything yet again.
But there isn’t a mistake. This
is what wheel paths look like. Even the
fanciest bikes with “complex” wheel paths are really only deviating a few
millimeters here and there from simple arcs (and there are reasons for this that we will talk about later...oh...nice teaser Dave!).
There’s other things going on...but dramatically different wheel paths
are not one of them. Especially in
shorter travel lengths. Those diagrams
they’re showing on their website? Gross exaggerations
of the actual curve.

And you shouldn’t worry about wheel path.

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