Does anyone have an opinion about how much of the sleeve has to be left to successfully hold the seat post so it won’t twist?
I have trimmed the seat post and the sleeve for the seat post, but it didn’t quite get me to the lower position I need.
I have been able to successfully mount and ride a older Coker for years, but now that I need to upgrade I am finding some difficulties as every new part seems to increase the distance from the bottom of the pedal stroke to the seat. I have a 26 inch inseam so I don’t have much room to adjust.
The newer unis have wider seat posts, wider hubs and the more advanced seat handles seem to require additional post space. I’m getting a bit frustrated with the process. Even my 26 inch wheel took new seat that pushed me up to the limit of my short (but very shapely, though deeply scarred) legs.
The answer I recall is that you want 2" of minimum overlap between the seat post and the frame. If the connection is very solid I might go to 1.5" or so, but I would start getting paranoid.
Only the part where the clamp is does the anti-twisting part. But you need more than that for a safe, secure structural connection between the frame and seatpost. But this should leave some room to cut down the seat tube. Just make sure you extend the slot so it goes down below your clamp.
Watch out for tapering tubing though I don’t have a Coker frame handy to look, but if it gets wider toward the bottom (on the inside), that means it’s not gripping the seatpost there. You want a minimum of 1.5" or so below your clamp, if possible.
Do you have room to go to shorter cranks? That’s some easy savings if you are comfortable with it.
Handles:
KH T-bar and Coker Pi Bar don’t have any effect on seat height. If I remember correctly, on older Coker frames the Pi Bar clamps to the seat tube, not the seatpost, so that might work for you.
The Nimbus Shadow handle is built into the seatpost, so I’m pretty sure it doesn’t allow the seat to go as low as with a traditional post. Same for T-7.
I cut a KH down for my wife “elk-e” and she had no problems, it works very well.
but as I know there exsist some customer frames, you are not the only one with this problem.
If you don´t find a solution or someone who build you a frame, we could build you a Triton short neck frame. I did some of them for people with similar problems
