# Where to clamp seatpost collar?



## golden boy (Oct 29, 2008)

Frame #3 is being built with a TT RC2ST seat tube with a reinforcing sleeve of 1.25" x .058 cromoly. I've seen a number of custom frames lately where the tube extends up above the sleeve. Is this extension to accommodate the seatpost collar? Or is it a bad idea to clamp only to the tube? Better to buy a larger collar and clamp to the reinforcing sleeve?


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## Feldybikes (Feb 17, 2004)

I just use a 1.25" clamp in that scenario. I'm not sure why to have the tube extend above the sleeve. Maybe aesthetics since the weight savings would be minimal. My guess is it's okay from a durability standpoint since most of the ovalization would happen below that point, where the TT and SS meet the ST, but why risk it if you're bothering to put a sleeve on in the first place?


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## golden boy (Oct 29, 2008)

Thanks Feldybikes. Anyone else have an explanation as to why some builders extend the tube above the sleeve?


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## Walt (Jan 23, 2004)

I've done it to make the seat clamp/seat tube transition a little smoother. So, vanity, I guess? There's not much/anything there in terms of weight savings but that certainly doesn't stop people from doing much dumber things to make their bikes lighter, so that could be a reason too.

-Walt


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## golden boy (Oct 29, 2008)

Walt, I wouldn't call it vanity. You're a custom framebuilder. Details matter. It's allowed to look pretty. ;-)


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## golden boy (Oct 29, 2008)

I decided to run the sleeve flush at the top of the seat tube, so I'll buy a 32.0mm collar to snug down the seatpost. Might as well get the full strength benefit of the sleeve. I'll start a post soon on frame #3.


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