Suggestion for super thin shim on a 31.6 post?

[54ny77]

I have a 31.6 aluminum post that I'm maxing out on torque spec and general comfort level, but it can still move if I romp on it. Normally not a big deal if it were just me on a road bike, but the problem is it's a tandem and a stoker bar is affixed to it, so that's additional torque.

Is there anyone out there who makes a super thin (1-2mm) thin shim on a 31.6?

Otherwise I was gonna use an aluminum can and get creative, along with some carbon paste.

Thanks for any tips.

[RoosterCogset]

Random google search, there's a 31.6 to 33.9 option

https://www.amazon.com/GANOPPER-Seat.../dp/B08XPGJK2J

[54ny77]

Thanks, ordered!

[AustinHorse]

Carbon paste should be your next step.

[Flinch]

Depending on how precious your post is, you can also dimple the contact surface with a sharp punch. One punch every 5mm or so, cover the entire surface. A lot of effort, but increases the effective diameter about 1mm.

[54ny77]

it's not precious, it's just a spec'd cannondale c2 alu post that comes with the bike.

Originally Posted by Flinch

Depending on how precious your post is, you can also dimple the contact surface with a sharp punch. One punch every 5mm or so, cover the entire surface. A lot of effort, but increases the effective diameter about 1mm.

[54ny77]

i glopped a ton of it on (park tool paste) and that helped a tad, but not meaningfully more grippy.

Originally Posted by AustinHorse

Carbon paste should be your next step.

[gbcoupe]

If it's the proper sized post that came stock with the frame, you shouldn't need much. 1-2mm ain't going to fit. Carbon paste wasn't enough. Coke can it is. You probably won't need too much. I'd be surprised if you could get a full wrap.

[Peter P.]

Originally Posted by RoosterCogset

Random google search, there's a 31.6 to 33.9 option

https://www.amazon.com/GANOPPER-Seat.../dp/B08XPGJK2J

I know I'm late to the dance, but what is it with everyone's knee jerk response to seek out the junk from Amazon?! If I had a nickel for every time someone responded to me with "I got it on Amazon" I could afford a full Campy Richard Sachs in one week!

Get a seatpost adapter with class.

[Peter P.]

Originally Posted by RoosterCogset

Random google search, there's a 31.6 to 33.9 option

https://www.amazon.com/GANOPPER-Seat.../dp/B08XPGJK2J

I know I'm late to the dance, but what is it with everyone's knee jerk response to seek out the junk from Amazon?! It's also killing the economy.

If I had a nickel for every time someone responded to me with "I got it on Amazon", after one week I'd be able to afford a full Campy Richard Sachs!

Get a seatpost adapter with class.

I own a bike with a Cane Creek adapter and I approve this message.

[RoosterCogset]

Originally Posted by Peter P.

I know I'm late to the dance, but what is it with everyone's knee jerk response to seek out the junk from Amazon?! It's also killing the economy.

If I had a nickel for every time someone responded to me with "I got it on Amazon", after one week I'd be able to afford a full Campy Richard Sachs!

Get a seatpost adapter with class.

And... they don't have anything too close to what was asked for.

[cmbicycles]

Have you measured your post to actually be 31.6, or the seat tube? If both of those are within spec, is the clamp bottoming out when tightened? Any grease on the clamp itself, as well as the bolt?

You can have someone knurl an aluminum post if they have a tool to do so, that will take up some of a loose fit and add grip, or the coke can shim. Anything more than a couple tenths of a mm would likely be too much if everything is pretty close to spec.

[zmudshark]

I’ve used an old spark plug feeler gauge, the blade type.