Have some dimensional questions about TT S3 tubing

Howdy,
I've been lurking around absorbing information and have built a couple lugged and one fillet brazed frames at this point. I picked up a medium set of S3 tubing complete that I'm not ready to build with anytime soon, but have a question about the seat tube dimensions that I'm hoping a builder who has made some of those frames can answer. The butting is a little funny, due to the nature of this tubing. One end is .61 with a 32mm butt and one is .51 with a 136mm butt, if I'm reading the specs I can find correctly. Am I wrong to believe the .61 end is the post end? Seems like 32mm is a very short butt for the post end of things. Also, it doesn't come out to the standard 27.4 id for a 27.2 post, but I would think the .51 end with the longer butt is the end for the BB cut?
Thanks for the help,
Joe

sounds like a top tube

It does sound that way, but the top tube on this set is a teardrop shape. This is definitely the seat tube. Thanks for the reply.

It is a seat tube: https://web.archive.org/web/20140522...eat-tubes.html

Yes, the .61 wall side is the seat post side. Don't cut any of it off :) You'll want to reinforce the area with a sleeve or a lug.

Great, thanks for the information.
Joe

Quote:

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Originally Posted by niknak

It is a seat tube: https://web.archive.org/web/20140522...eat-tubes.html

Yes, the .61 wall side is the seat post side. Don't cut any of it off :) You'll want to reinforce the area with a sleeve or a lug.

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I definitely wouldn't be cutting anything off the 32mm butt end apart from your cope, you will need a sleeve on the top end of the seat tube for top tube, stay junction. This is why they make the tube in three lengths, you could get away with about 80mm of the top .61 butt length. Maybe pm Steve Garro, he has used heaps of this stuff.

Quote:

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Originally Posted by progetto

Maybe pm Steve Garro, he has used heaps of this stuff.

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Sorry, but never touched any, but .6mm wall x 28.6mm OD is consistent with many TT seat tubes
- Garro.