Pedal Feedback Through Suspension Stroke Comparison

A lot of times on our blog and videos we’re working to illustrate something with a clear point, ie your drivetrain wears as a group, brake feel is in part a condition of lever setup and thus leverage ratio, etc, etc. Well, this one I haven’t fully decided on the “what” of what we see here – simply that ya, there’s something to see here. A lot of content is coming out right now about suspension, chain growth and thus pedal feedback or whatever.

Without getting into what’s good, bad or indifferent let’s take a quick look at this tidbit from it: Depending on the wheel’s condition (free, held via brake or ground, or spinning) and chainline (based on location on cassette) the same suspension travel creates various pedal “feedback” or movement.

Here’s a quick look and you can read more on the blog below!

Pedal Feedback Through Suspension Stroke Comparison

So, why does this matter? Well we’ve seen a lot of content recently chattering on a handful of design considerations of suspension. Which is great. Frankly it’s one of the things I love about this industry – it respects your entertainment dollar. A huge amount of investment goes into finding designs that work better so your ride is better. Kudos to everyone.

Buuuuuuut, we’re seeing kind of a singular theme illustrating “the next thing” – I’d say the next big thing but I think that was plus tires and we all know where that went. I’d say something about the next mountain biking must have but that city in Arkansas probably already copyrighted it or whatever.

So, next time you see the teaser telling you why the next thing is the next thing remember that there are moving pieces involved.

Wheels on Ground (or brakes applied)

So this is kind of what gets me. A LOT of that content I’m talking about is visuals of aired down suspension being compressed and how the chain stretch does this or that or the other (again, not getting into the what’s and whys of different designs right now).

When the wheel is planted on the ground, or held with a brake, the cassette can only rotate backwards to freewheel. Since a working chain isn’t going to “push” a cassette back over it only can “pull” on the chainring and move the cranks.

This is true and accurate of this condition.

This condition tends to create the most  drastic images – but, is it really a fair assessment? (life’s not fair so does it matter? or is that too philosophical for now?)

Well I started to wonder how dramatic the images would be in a situation that might mimic more of a true riding condition.

No brakes applied.

Now the cassette is free to “drive” forward during suspension stroke. This tends to produce a less dramatic visual as some of the chain change is taken by the chainring, moving the cranks, while some is taken by the cassette slightly driving the wheel forward.

Since the chain is relatively close to the wheel center it doesn’t have a ton of mechanical advantage to drive the wheel, but it can move it some.

Well – now, not sure about you, but my bike is moving nearly all of the time I care about the suspension’s performance. So, what happens if we spin the wheel?

Wheel Spinning

I think this is kind of the most realistic condition if you’re looking for chain growth effects.

Now, in all three conditions shown in the photos I could easily hold the crank in place, typically with my pinky and keep it in the same place. The movement doesn’t cross many of the 5mm boxes on the graphic behind the cranks. Between the small movement and light load I can’t see a TON of actual feedback coming into my body from this.

That said, if you watch the video there are some other conditions that create way more crank motion depending  on what gear you’re in, etc.

Concluding without a Conclusion

Ya. Not going out on this limb just yet. But wanted to put something out that kind of shows how variables can change the effect, sometimes really dramatically.

So is chain growth good?

Well, Ibis’s DW and Yeti’s Switch Infinity both will show a bit of it – but its typically used to create a bit of a pedaling platform for efficiency. As shown, when ripping down trail in the proper gear range you’re not likely to be tossed off the pedals like some of the other brand’s marketing may be insinuating. Let’s be square – you’re hard pressed to find better riding bikes than Ibis or Yeti offerings…

On the other hand we also have the Mondraker Zero suspension which is designed to eliminate the chain working the cassette, freehub and chainrings through suspension stroke. Zero is race proven in everything from DH to Enduro to XC by a wide range of riders. It’s a comfortable and confident platform.

So either way BikeCo has you covered right?

eeeeee, Almost Done: eMTB Suspension

eMTB bikes see power applied, and with the assists they see more power applied, through a wider range of the suspension curve. They also see it applied in more up and downhill conditions.

Since eBikes are pushing more power, in more conditions, chain growth is more of an issue (like how I did more with more there?).

Suspension like the Mondraker Zero on the Crafty and the modified Yeti design on the 160E are designed to minimize chain growth and thus decrease wear to drivetrains, freehubs and hub bodies. So, I will stand on my limb and say if you’re shopping eMTB not only are you concerned about the suspension’s on trail feel but also how it effects your parts service life and longevity.

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