It is the seat post that concerns me. I don't want to have to remove it each time. I think I will have to get a non quick release seat post bolt but the ones I have seen are designed for flat surfaces rather than the curved surface of the Dahon clamp that the quick release lever pivots in.

I Have heard about someone who drillesd a small hole towards the end of the seatpost. They locked their bike by pushing the seatpost down then putting a small padlock through hole to stop it being lifted out of frame.
You could also get type of saddle with a with a central hole if rails too tight.else ther are locking seatpost qr I seem to remember.
Personaly I use a ubus d clamp and fold the bike. Wher I can putting it through front and back wheel and rear triangle. Then I use seperate cheap combination lock through wheel and through seat rails.

But I have not had to lock my bike for aat least 2 years.

This is a great idea!

Locked my birdie up today with a cheap combination lock and didnot remove /secure seatpost.

Its a cheap secoundhand bike and it is insured new for old.

It was in an area of low pedestrain traffic were thiefs would stand out.
I would not leave the customised mezzos like this. As I do not want to do the work again !!

>> how about fabricating ? creativity..

you take out the BB and drill a hole . say just above it..

tie a cable up inside your seatpost.. plain ones. that can be the top of it ..

you pull the cable out the hole in the BB area , and tighten it with a screw .



then the seat post will only come out as far as the cable will allow.

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It was a consideration easily done with a Brompton Telescoping seat post , because the main post is flared at the bottom.


and the rubber bung in the bottom uses a screw wedge to tighten it. and the upper post is a standard straight one .

I use a combination lock carabiner clamp under the seat and put the cable through it when the bike is folded.

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Perhapes this is a thread designers need to consider!
I have owed a cargo tricycle that had a built in lock through rear wheel spokes but also had a chain lock operate from the same key.

I have a cheap folder so a U-lock is good enough for me. I don't bother to go through my wheels becuase they are not quick release. Just one more benefit of a cheap folder.

Same here and the local Walmart has Bell U-locks on clearance for $7, good enough.