HELP! Triangular Seat Post Wedge?

[augraff]

Hi everyone,

Hoping for some advice here.
I recently had my saddle and seatpost stolen off my bike after leaving it locked outside for about 10 minutes.
Tragic but easily preventable, and I've learned my lesson.
While the saddle and seatpost are a loss, they are replaceable. Unfortunately they also stole this very specific seatpost wedge and cover that keeps the seatpost in place and I'm having a lot of trouble figuring out what part I need as a replacement.

I've been to about 7 different bike shops around London and they've all thrown up their hands so hopefully someone here can help sleuth this out with me.

The main problem with identifying the part is that the frame is un-branded.
I got it second hand from a friend back when I was in Canada. He can't recall any brand name associated with it when he bought it - though he thinks it may have been custom-welded by a guy with a shop near the Mirabel airport in Montreal... I kind of doubt this but either way- not very helpful.
Here's what it looks like in case anyone recognizes the frame:


Here's a top down view of the triangular frame. The seatpost that slides in the would be a standard 27.2 mm, I just confirmed this by measuring the hole below at it's widest point. Lengthwise, I got a measurement of 59mm.



The piece I'm looking for looks something like this - though this one is for a Specialized STP MY19 Venge, so pretty sure that ain't it.



I'm dying to ride again, life is shittier and more expensive without a bike so I would be so grateful to anyone with ideas on what I should do here (other than buy a new bike). Happy to post more info if anyone has questions.

Thanks in advance,

A

[Ugly]

I'm afraid I have no idea what the frame is, but you could try local small engineering shops and have a simplified version of the clamp made. If you have a local model engineering club they may well be able to help. Engineers love solving problems.

[Norman H]

I assume you've checked that the missing seat post wedge hasn't dropped down inside the seat post.

[Chris Jeggo]

You have probably already thought of this, but here goes. Why not phone around until you find a bike shop that has the Specialized part in stock, then go and look at it. It might do the job, or it might be adaptable to fit, or the shop might have a good suggestion.
All the best!
Chris

[augraff]

You have probably already thought of this, but here goes. Why not phone around until you find a bike shop that has the Specialized part in stock, then go and look at it. It might do the job, or it might be adaptable to fit, or the shop might have a good suggestion.
All the best!
Chris

I've taken a look at a few parts, though not this specific specialized one - good shout, though I'm close to 100% this isn't the same part.

I assume you've checked that the missing seat post wedge hasn't dropped down inside the seat post.

I've checked, left it for a bit and checked again a few times now :'( It's very gone.

I'm afraid I have no idea what the frame is, but you could try local small engineering shops and have a simplified version of the clamp made. If you have a local model engineering club they may well be able to help. Engineers love solving problems.

I like this idea a lot, I'll get a quote though I expect custom designing the part from scratch and then CNC milling it might be a little pricey - at least I'd have the designs for next time...

[rjb]

If mine i would experiment with a few designs. Experiment with a synthetic wine bottle cork. Whittle it to an approx fit, then drill a vertical hole and use a bolt with a couple of washers top and bottom so you can compress it, to clamp your seat pin in tightly. just an idea, to get you thinking.

[Paulatic]

Have you compared and tried a Giant wedge clamp in it ? Doesn’t look too dissimilar.

[Tigerbiten]

If the Specialized part is oversized, could a local engineering firm mill it to the right size.
Or use it as a template to make one the right size.

Luck ..........

[Jdsk]

I'm afraid I have no idea what the frame is, but you could try local small engineering shops and have a simplified version of the clamp made. If you have a local model engineering club they may well be able to help. Engineers love solving problems.

The simplest way to do this might be to buy a wedge type clamp and then make a new top piece to fit the frame tube. It might not be necessary to make a new bottom piece.

If there isn't anywhere local then it's now quite easy to have pieces made in response to emailed specifications: either sketches or CAD files.

Jonathan

[Jdsk]

Have you compared and tried a Giant wedge clamp in it ? Doesn’t look too dissimilar.

Yes. These spacers look similar to that frame tube:
https://www.ebay.com/itm/353793392831

Jonathan

[Chris Jeggo]

If mine i would experiment with a few designs. Experiment with a synthetic wine bottle cork. Whittle it to an approx fit, then drill a vertical hole and use a bolt with a couple of washers top and bottom so you can compress it, to clamp your seat pin in tightly. just an idea, to get you thinking.

Whatever you use has to do two jobs, stop the seat post slipping down and keep the weather out. The cork idea might struggle to do the first. If so, a seat collar could be used as well. These are designed to clamp on the seat tube, so to clamp it on the seat post you would also need some packing, a strip of metal or hard plastic of the same thickness as the seat tube - maybe 0.7mm.
Another thought - are there any aero seat posts that would fit straight into the seat tube?

[augraff]

If the Specialized part is oversized, could a local engineering firm mill it to the right size.
Or use it as a template to make one the right size.

Luck ..........

I that shaving shaving down an oversized part to size is probably gonna be my best chance, barring finding the right piece.

Have you compared and tried a Giant wedge clamp in it ? Doesn’t look too dissimilar.

Yes. These spacers look similar to that frame tube:
https://www.ebay.com/itm/353793392831

Jonathan

The spacers do look like they'd fit my frame, though from what I've seen of the Giant ones they actually clamp the seatpost from the front not the back, like mine. May just be the pics I've seen (see below) but given how similar those spacers look I'll give the Giant clamps another go - I did call the Giant store in London and the guy told me not to bother coming in if it wasn't a Giant frame, but worth a shot tbh.



Really appreciate everyone's feedback here. Re: cork/ washer method - I'll give it a go in the meantime just for posterity's sake and report back my results

[Jdsk]

Have you compared and tried a Giant wedge clamp in it ? Doesn’t look too dissimilar.

Yes. These spacers look similar to that frame tube:
https://www.ebay.com/itm/353793392831

The spacers do look like they'd fit my frame, though from what I've seen of the Giant ones they actually clamp the seatpost from the front not the back, like mine. May just be the pics I've seen (see below) but given how similar those spacers look I'll give the Giant clamps another go - I did call the Giant store in London and the guy told me not to bother coming in if it wasn't a Giant frame, but worth a shot tbh.

When I was looking for what yours might be it became apparent that there were several different Giant types, including some where you needed to know the year...

Good luck

Jonathan

[augraff]

Hi everyone,

Just posting a final update here.
After much searching, trying unsuccessfully to lobby hobby-tinkerers to build a custom part and waves of general despair, I have solved the issue!

Just want to put the answer in the annals of the forum on the off chance some other poor soul has a similarly specific inconvenience.

After much searching the frame - is an Aventon Mataro frame pre- 2018.

The part is this: https://www.aventon.com/products/replac ... ton-mataro

I discovered all this yesterday, emailed customer support and after a year of not being in stock - Aventon re-stocked the little [rude word removed] this morning so I'm on my way to salvation now.

Thanks all for your help and suggestions.

Best,

A

[Jdsk]

Thanks for adding the answer.

Jonathan