Originally Posted by
Oakesje
Really appreciate everyone's feedback,.
Quill post - if i found a shorter quill post would it clear the retention mechanism? What is the retention mechanism you're referring to? I've been using the bike wearing thicker soled hiking boots to get a little bit higher over the top tube. Definitely riding the bike every day has helped get a better idea of what we could compromise on - so its not a perfect fit but it still rides beautifully and i can reach the peddles, would be alot easier on my knees if i could lower the seat - is there a clamping system other than the quill post that takes up less space than the super clamp that is currently used - like a snail clamp? but still allows the post to clear the retention mechanism?
The quill posts were a short-lived "aero" invention from the 80's, I think. A nifty idea, but probably not the most practical.
Ok, for the Suntour Quill that I have, see the marked up image. There is a nut at the bottom, and a cam lock at the top. That cam lock must be accessible for it to work, and thus limits how far the post can be inserted.
Seatpost_Marked.jpg
As
fietsbob mentions, some quills may have a bolt straight through, or you could make one, although installation could be a pain unless you had a seat with a center hole, and a seatpost that also was also open on top. Vintage Campy Post?
Looking at your seat cluster:
Seatpost Mod.jpg
If you cut just above the top of the locking mechanism (A), you'll gain a little bit, and that would be easiest if it is enough. No harm just cutting at (A) now before you do anything else. Perhaps some touch-up paint?
If you cut just above the top tube (B), you gain the most, but you loose the lock. And, thus the "quill" post. However, you should be able to move the lock below either the chainstays or the top tube (blue circles). My guess is that hitting somewhere in the middle of the seatpost would be just fine.
I have never seen a seatpost locked like that, but I can only guess what I would put inside of the tube. A nifty idea. It should make it easy enough to move, although I'd probably make a spacer, then ream or hone the locks inside the seat tube to the proper radii for the final tube mounting position.
If you slam the seat to near the lowest possible point, you may choose to also lower the top tube as you've thought about to aid with getting on to the bike, getting off, and stopping. But, it all depends on what the "captain" and passenger are comfortable with.
I don't know about knees and seat adjustment. I have always adjusted the seat on a road bike so that if I put my heel on the pedal then the leg should be 100% extended, or nearly so at about the 7:00 position forward. And then I get pretty full motion of the knees with a forward posture. I currently have the boom a little long on my trike, and it still seems rideable. I do use cleats for foot/shoe placement on the pedals. I assume I could ride a seat a little high. Actually, the seat on my funny bike is, or was a little high, and I have been angling the seat nose down a little to compensate, but that is also a pretty unique bike. Anyway, it sounds like you're pretty close on the seat height.
Nonetheless, the bike needs to be comfortable to ride.