read this often, but don’t know exactly what it is….

is it basically a curb?

I’d say it’s hitting something with a square edge. No?

basically a curb?

yes, or trail obstacle that matches that shape like a newly fallen branch.

so there’s no soil or anything lessening the angle of impact.

Square edge is were your suspension is reacting to a large and quick change of terrain. Kerbs, potholes, tree roots can all be termed as square edge hits where the suspension needs to compress at high speed. Too much damping on the high speed compression can cause kick back.

What about ‘a sizable drop’. That pops up from time to time in conjunction with square edged hit. To me there are nothing drops (less than the height of the bar), small (bar to head height), medium (head height to 10′), large (10-15′), big! (15 to 20′) and finally stoopid (20-40′). Where does sizable fit into my chart?

What about ‘a sizable drop’. That pops up from time to time in conjunction with square edged hit. To me there are nothing drops (less than the height of the bar), small (bar to head height), medium (head height to 10′), large (10-15′), big! (15 to 20′) and finally stoopid (20-40′). Where does sizable fit into my chart?

Must be relative, ‘too big’ to me is bar height!

Possibly. I’m happy to hit up to medium if im in the mood and i’ve dabbled in large a few times but that’s as far as i’m prepared to go. I’ve had a look at a couple of bigs and thought ‘not for me thanks’. There’s even the remains of a stoopid (presumably left over from when hucks were in) beside a local DH run. I’ve heard a few guys used to hit it, but to me, there’s no way you could ride off it and not die. The landing alone would be a challenge to ride down.

I thought it was just nonsense that Guy Kesteven likes to write 🙂

I’m sure there are better examples, but these just came up on google:

Medium sized repeated hits, square edges, big drops and the secondary aftershock debris that’ll often kick a standard shock into space as it tries to recover from full travel – none of it seems a problem for the Trek.

Add the ultra supple suspension, which swings back to suck up square edges before they affect momentum but then tightens under power for a decent kick, and altitude gain is never an issue.

Square edged = a step up basically.

Other impacts might well be similar – big roots, rocks, etc – essentially it means a sharp upwards force on the bike. Unless you’re talking about an impact higher than the mid point of the front wheel in which case you’re talking about an endo 🙂

a single hit in the trail that immediately compresses the full travel of your forks, and makes you go oooofff as your wrists are pushed back, your shoulder blades kiss and you scrape your teeth on your top cap.

so would a 6′ wall be classed as a (bit too big for the suspension to handle) square edged hit?

What about ‘a sizable drop’

Actually I think this scales quite well with rider ability, a drop I can comfortably manage on my FSer other riders could do on a hardtail or rigid bike, others may need a DH bike to even attempt it. I’d guess a sizeable drop would anybody’s own definition of medium

a 6 FOOT wall? yeah, that would be a pretty big hit on your front forks!

😉

The impact of the drop largely depends on the landing (transition).

As far as square edge, anything that accelerates the suspension extremely quickly… like a large rock.

errrm, isn’t the square edge hit the bit you go up, not the bit you go down again afterwards?

Surely anything that gets even close to front axle height is likely to lead to an undignified otb or if your fork manages to compress enough to the front of the bike over it your chainring’s going to get a bit of a smack?

A drop to flat, even a decline, could be considered a ‘SEH’ – as the forks are compressing very quickly, which is contrast to compression due to braking.

(If you see the term “high speed compression” it’s the same thing)

To me it is basically something shaped like a curb I wouldn’t consider a flat landing as one.

What’s the difference? A short, sharp compression of the forks/shock is the result of both – a curb, and heavy landing to flat (I’m not talking about dropping off the curb here, a good 1m+ height)

A speed bump would be an example of LSC.

A speed bump would be an example of LSC.

normally yeah, but just wondering…if you hit a speed bump fast enough would it become a HSC?

Actually speed bump maybe a bit small for a bike wheel, so lets say something same shape but twice the size of a speed bump

so does LSC become HSC if you add more speed? I assume yes but happy to be corrected.

A drop off won’t impede forward momentum…
A seh will

To me that’s the difference, as different suspension designs will influence how the wheel will move forwards of the se, particular relevance to rear wheel IMO

for a flat landing the impact is in the vertical plane (up), for a square edged hit it’s both vertical and horizontal (up and back)

I thought the idea of square edged hits was primarily to justify the superiority of any rear suspension axle path with an initial backwards (or back and up) element as opposed to a simple upwards (or up and forwards) path.

SEH is an obstacle that impedes forward momentum, a drop isn’t as the bike can still roll forward.

with square edge hits you also run the risk of pinch flats and dings because of the sudden sharp impact at one spot on your wheel.

for a flat landing the impact is in the vertical plane (up), for a square edged hit it’s both horizontal and vertical (up and back)

which is why rearward axle paths are sometimes mentioned – more relevant on hitting an edge than a drop.

It would be interesting to see graphed suspension travel vs various obstacles

SEH is an obstacle that impedes forward momentum, a drop isn’t as the bike can still roll forward.

This is how I understand it. Casing a double or step up is a Square edged hit.

A big drop to flat where the suspension fully compresses is a G-out.

To the average rider (myself included) I don’t think this kind of stuff isn’t really that important. For guys racing downhill, i’m sure it becomes more relevant.

A big drop to flat where the suspension fully compresses is a G-out.

I don’t think it’s that simple. it’s more like when you hit a dip in a bombhole, you’re momentum continues to drive you down as you fully compress at the bottom and you’re still moving downwards as you start to go up the other side.