Why aren’t saddles made to tilt on the “roll” axis?
Just putting this out into the ether in case there are any makers who think this is a good idea.
I’d like to try a saddle / seatpost combo that:
1) Has air suspension.
Has slight vertical suspension that works like real air suspension, not maxed out at the top. But actually something that automatically sets sag to 20-30% where it puts me at the right saddle height, on average.
2) Rocks along the roll axis.
I’d like rock/tilt along the roll axis almost akin to the for-aft tilting mechanism of the old P5 seat post clamps. It would almost make the saddle “get out of the way” of the rider. There might be some anatomically / biomechanically better axis along which it should tilt, but I bet it’s close to pure roll axis. I’d like it to be spring loaded or some other progressive resistance to extreme roll positions.
I suspect that with those two features, folks would see increased efficiency and decreased saddle sores.
I think the reason this doesn’t exist yet is because people just don’t know they need it yet. (could also totally suck, but I’d like to try it.)
The rocking motion on a stationary saddle allows compression and decompression of the soft tissue as your weight cycles from side to side. It’s quite visible on saddle pressure mapping and is beneficial for the blood flow to the skin and underlying tissue.
A rocking system would likely lower peak pressures as it moves in connection with the body and not the bike. However, this would also raise minimum pressures; creating a relative flat pressure profile. This is similar to what is seen in overly soft saddles and can lead to discomfort as there is limited opportunity for refilling of blood into the tissue.
Interestingly this is opposite the effect of the rocker platform for a trainer. By allowing movement, the rocker platform allows a greater magnitude of pressure difference as the bike and connected saddle sway beneath the rider, resulting in less discomfort.
I was born about 18 months before they launched. So… nope.
That is a wee bit more suspension than I desire. I have ridden a cheapo commuter bike from REI that had a long-suspension seat post and it was awful.
What I envision liking to try is is 15-30mm of total travel, set pretty firm with a high ramp rate (like having several tokens in a front fork). And set the sag at about 20% compression depth so that it doesn’t take getting all the way “out of the saddle” to shift position.
A rocking system would likely lower peak pressures as it moves in connection with the body and not the bike. However, this would also raise minimum pressures; creating a relative flat pressure profile. This is similar to what is seen in overly soft saddles and can lead to discomfort as there is limited opportunity for refilling of blood into the tissue.
In addition to this, if there is sag, a suspended saddle system will also work to maintain a consistent upward saddle pressure on the rider as the rider load on the saddle decreases in concert with increased force on the pedals.
I’d suspect that at the end of the day, most suspension mechanisms constrained to about the practical 5-10mm displacements that you’d look for in a road saddle will be functionally indistinguishable from a saddle with about as much padding on it. After all, if you compress one side of a saddle’s pads, you have some roll degree of freedom with progressive resistance. “Air†suspensions are really suspensions that rely on the strain of whatever membrane is keeping the air in place, like a tire’s carcass or a balloon, but are kinda gimmicky, since they imply “what could be softer than air?â€
I’d bet that in practice you don’t really want to have a significant amount of displacement on the saddle before it feels unsupportive or unstable.
In essence we want saddles that distribute load evenly to minimize pressure variation or eliminate it altogether in some areas, but even if we have such a perfect fit, jounce will spike pressure over potholes or bad pavement, and the problem is like trying to achieve a tightly controlled attitude (narrow displacements) while allowing for comfort (allowing significant displacements) which are contradictory.
Maybe if we had something like magnetic active suspensions from modern cars on seatposts it would make a big difference, with programmable presets for aero, climbing, descending, etc…
