Singlespeed & Fixed Gear - "threaded" seatpost

anyone ever come across these at all? they're not threaded as such, but they expand in the tube to set their position in the same manner that a quill stem does. the tube itself doesn't come cut to allow a clamp to function. reason i ask is because i came across an old Bridgestone frame that is designed this way (and can't be cut because of the stay/seattube interface). short of drilling right through the seattube and a conventional seatpost and bolting through that i'm going to have to find one of these seatposts, and i'd never even heard of one until i got this frame. (thanks austin, btw)

expanding wedge seatposts are very hard to come by. i actually passed up a super nice peugeot made of vitus because it required one. i've seen them go for ~100 on ebay. i wish you the best of luck!

schwinn road bikes also had those posts at one point. I had a 434 with one.

thanks shants. figured they were rare since i'd never even seen one. was thinking about building the frame into a daily beater (since it has absolutely gorgeous lugs) so a $100 seatpost is out of the question. there's always this solution though:

http://www.bikeforums.net/archive/index.php/t-77201.html

depending on the size you could also glue/epoxy or braze/weld a slotted tube that fits into the seat tube and then get a smaller seatpost and collar/hoseclamp

i am not a number....im a free man!

The same pins were used on moser frames, chateau d'ax team frames that Bugno used to ride. Depending on how much extension there is on your seat tube you could get a clamp as used on a lot of alloy frames and use that if you cut a small slot in the rear of your seat tube?

nah there's no extension and as i said in the original post nor is there room to cut a slot cause of how the stays attach. i'll pick up the frame later and post pics tonight. it's a good looking frame. sexy lugs.

I have one of the afore mentioned peugoets with Vitus tubing. The previous owner drilled through the seatpost. To insert a screw. I need to find a local builder to see if the frame can be saved. Until then it sits in my garage.

I'd love to see pics of these seatposts. I have a wedge seatpost collar for my road bike, guess that a different deal.

I have one of the afore mentioned peugoets with Vitus tubing. The previous owner drilled through the seatpost. To insert a screw. I need to find a local builder to see if the frame can be saved. Until then it sits in my garage.


you mean the seattube, right? you think the frame is f*cked now? how will it be "saved?"

I want to see if possible to braze a seatpost clamp somehow. You are right, I meant the seat tube has been drilled. I assume the hole he drilled can be covered.

ok. i was thinking you meant that the frame was somehow unsafe or something because of the drill-hole.

i don't know that a clamp could be brazed on. the act of clamping it, minus a slot in the seattube, would probably be enough to break the braze, i think.

i think i'm just gonna have to go with the drill-hole option too, to be honest.

I rode it for a year like that, but it always felt sketchy. the seatpost never moved, but I was alwys afraid it would.

don't know why it would be any more sketchy than a conventional seatpost clamp (unless you used a crappy little screw and it sheared). the expanding seatpost sounds like a sacking waiting to happen lol. i'll just have to take it easy on the dirtjumps…

eddie, what's the seatpost diameter on that bridgestone. i may have a lead on an affordable expanding wedge post.

dunno. i grabbed it from the yard sale next to time's up saturday morning and threw it in my buddy's store on elizabeth cause i was heading away for the weekend. gonna pick it up on the way home tonight. i'll measure it and let you know.

http://www.mosercycles.com/moser_leader_ax.html

contact them to find out how much the pin is on this


http://www.mosercycles.com/images/co_leader_a.jpg

what u mean bro?

if its a steel frame a framebuilder should be able to put some kind of extension/binder on it for you.