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<span style="font-size: 0.8rem;">I used to have a L Soul with 19" ST, so a lot of exposed Thomson post. Given that leverage, the post flexed back and forth disconcertingly whenever my pedalling rythm became a bit mashy (i.e most of the time).</span>
My current and previous XL bikes have 21" ST so 2" more support for the post. Rock solid, no problem.
I see that current XL bikes almost all have 19" ST, which means a lot of leverage on the post for taller riders.
Are modern droppers much more flex resistant than old rigid alloy posts?
It’s not really something I’ve thought about but a quick common sense appraisal would suggest they should be, a regular 420x31.6 post being in the ballpark of 250g and the lightest possible Reverb being more than double that. Common sense can often be misleading though. That said, I’ve seen people argue that a regular seat post is more comfortable than a dropper for long spinney rides so maybe?
Out of interest, how much post do you consider ‘a lot’? On my dropper equipped Soul I’ve got 260mm from clamp to rails and it doesn’t feel wobbly...
Out of interest, how much post do you consider ‘a lot’? On my dropper equipped Soul I’ve got 260mm from clamp to rails and it doesn’t feel wobbly…
I have 26cm from clamp to rails on my 21" ST bikes and agree it's rock solid.
However on the 19" ST I was up at 31cm, which with a 27.2mm seat post was very boingy, even moreso on a setback post.
Maybe the typically increased post diameter and the internal structure of modern droppers solve this problem?
Ah. If you’re talking about bikes with 27.2 posts, there’s more going on then just the post. The seat tube itself on a bike accommodating a 31.6 post is noticeably stiffer which directly affects perceived ‘boinginess’ guitar a lot. This is most of the ‘feel’ difference between a Mk2 and Mk3 Soul, for instance. The dropper itself is just the icing on the cake in that scenario, I think...