Opinion: It's Time to Recalibrate Our Ideas About Chainstay Length
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'Cause I gotta know how shorter chain-stays, bringing the rear axle _closer_ to the center of gravity, takes weight _off_ the rear wheel.
This goes directly against conventional wisdom that short rear center makes for easy manuals: if it's easier (read: don't have to get waaaay back and over-stretch your arms) to get your CG behind the rear wheel and let the rear wheel take _all_ the weight, then it corresponds that you shouldn't have to move back towards the rear axle very much at all to transfer some weight to the rear wheel. And with _relatively_ shorter chain-stays, that shift back is free: you're already closer to the rear axle, adding weight to the rear wheel.
The movement of the rider induced from forces acting on the rear wheel is also reduced (in the same way wider bars calm the effect of deflections of the front wheel at the hands) reducing unintended weight shifts which also contributes to making the rear feel more planted.
It's a game of balancing the center of mass between the axles. But like everything geometry-related, it is a compromise. Seeking better balance by making the rear end longer makes any type of manoeuvre that requires getting your weight over or beyond the rear axle - a manual for example - that much harder. That longer rear center and better balance are almost certainly better for going fast. Whether they make better mountain bikes for most people's use cases is debatable, IMO, and I personally don't have enough experience to even know what works best for me.
They also mentioned not enough weight on the back wheel when exiting corners, where there is going to be little front brake so again, not a ton of the front axle fulcrum effect happening then.
"Seeking better balance by making the rear end longer makes any type of manoeuvre that requires getting your weight over or beyond the rear axle - a manual for example - that much harder."
That's what I'm saying, too: longer rear center biases weight away from the rear axle; but they are saying that short chainstays also manifest as less weight on the rear axle, which doesn't make sense.
Maybe his experience has to do with excessive side leverage on the back wheel? Bringing the back wheel in closer means it has a relatively larger job to do in anchoring the bike to change direction. That should be offset by the additional weight that would actually be on the wheel though.
But what’s really REALLY strange is that neither the author nor the editors paused to recognize that they were directly contradicting intuition and conventional wisdom and that maybe they should pause for a paragraph and try to square it up. If you want to tell us we’re all goofy in the head and that we need to rethink a subject then I’m down. But to say the opposite of what everyone believes while apparently being unaware of the conventional viewpoint throws up huge red flags that the writer may be straight up uninformed.
That UCI quote is vaguely talking about wheelbase, and where the BB is centered between the axles. Short WB is less stable. Long WB being "unmaneuverable" has turned out to be a vast overstatement.
The community has noticed the effect of taking existing geo, but stretching the CS to fit bigger wheels or w/e, making handling feel off (like steering a bus). There is too much weight on the front, urging riders to adapt by getting their weight back. New geo has seemingly corrected this, by pushing the front wheel out further, to take weight off the front and allow the rider to stay centered. Some have taken this further (short rear-center, long front-center), forcing riders to basically ride the fork (e.g. Doctahawk).
The ratio between reach and CS length is a weird "recalibration" PB has brought up in the past. What's going on is that a person's bodyweight is being distributed between the front and rear. To get the wheels up off the ground, it helps to get your body's weight out of the way (e.g. reducing the downward pressure/weight on the pedals).
I dunno about understeer, but I know a lot of riders speak as if they prefer oversteer (the rear wheel being more likely to lose traction first in a corner). Maybe people are uncomfortable with the lack of oversteer, or are habitually getting weight back on a bike that doesn't call for it, and need to recalibrate themselves to a modern bike's balance. If they aren't, they are causing understeer through bad/subconscious positioning habits.
It would be nice if bikes were calibrated to people, but it's difficult to make a single mass-market bike design fit people who are different in dimensions, weight, and preferences. Paywall not letting me read the article, so unless you're saying that we should recalibrate our judging, in terms of choosing a bike based off its specs on paper (geo, susp kinematics, chassis stiffness/burliness, rider impressions/reviews, etc.) to be less overly simplified, being picky about angles, CS length, reach...