Does 0.2mm really matters (re. seatpost clamp)

[phcollard]

So I need a 29.8mm seatpost clamp for my upcoming frame. I know Thomson makes one but I was looking for something more minimalist and boy that's a rare size!

I found a couple 30.0mm and 29.6mm so does 0.2mm really makes a difference?

Thanks for your thoughts!

[gemship]

Did you measure the frame where the clamp will fit? I mean I wouldn't just go by catalog specs.

To be safe the 30.0mm maybe your best bet, you may have to torque it down a little bit extra but this is all just an educated guess.

[phcollard]

Not measured yet because the frame is still at the builder's waiting for paint

[dogdriver]

Yes. I made the mistake of putting a 27.0 seat post into a 27.2 frame once. It slipped, and a 27.2 wouldn't fit until I pried the clamp back open. total freshman mistake. Use the correct size post...

[alancw3]

Originally Posted by dogdriver

Yes. I made the mistake of putting a 27.0 seat post into a 27.2 frame once. It slipped, and a 27.2 wouldn't fit until I pried the clamp back open. total freshman mistake. Use the correct size post...

+1. get the right diameter. SIZE DOES MATTER! it's diameter not length from what i am told. go figure!

[Rada]

Cane Creek makes a number of different size shims. I've used them and they work fine for me.

[phcollard]

I'm talking about seatpost clamp. Not seatpost itself

[Tony T]

Originally Posted by dogdriver

Yes. I made the mistake of putting a 27.0 seat post into a 27.2 frame once. It slipped, and a 27.2 wouldn't fit until I pried the clamp back open. total freshman mistake. Use the correct size post...

OP is asking about the size of the clamp, not the post.
Based on the cost of the 30.0mm and 29.6mm clamps, I would try both.

It's gonna be clamp this, clamp that. Bada-climp, bada-clamp!

[vqdriver]

the clamp itself?
i suppose if it's a type that doesn't actually touch the post (and acts on the seattube only) it might be ok. check out the gap size between the ends cuz you'll either be squeezing it or stretching out that much more. if it were mine, i'd go with the 30.0 that had enough of a "gap" so that i didn't feel like i was turning the ends in when tightened.

[cmg]

If you buy the 30 be willing to grind the inside faces of the opening to give you more room to clamp. try this http://orbeastore.com/29_8mm_Seatpos...p-details.aspx

[phcollard]

Originally Posted by cmg

If you buy the 30 be willing to grind the inside faces of the opening to give you more room to clamp. try this http://orbeastore.com/29_8mm_Seatpos...p-details.aspx

Hey Carlos!

I would be very interested in this one. But they don't ship to Canada

[jds108]

Not having dealt with this specific situation, I would have to think that either of those clamps that are +/- 0.2mm will be fine. All of these clamps of course see a change in diameter as they're being tightened around the post, obviously. I have one clamp that won't just fit over the frame unless I spread it just a tiny bit with finger pressure.

So that's the route that I'd go, go with the undersized clamp and put it on with a little finger pressure.

[buddybikes]

Why not have the builder supply it?

[phcollard]

Holy molly!!! I still don't believe it. My first bike here in Montreal was a steel Kona Lavadome that I got used like 12 years ago. I sold it 3 or 4 years after to get a road bike but I kept the seatpost clamp as a souvenir, 'cause I found it pretty and I like the bike.

Now this afternoon I had a flash about this and I found the Kona clamp in my parts box, measured it frantically with my calipers and bingo! It fits! 29.8mm!

Who doesn't believe in fate?

[akelman]

This is the most disappointingly on-topic thread I've ever seen.