Framebuilders - Downtube or seat tube for adding bottle cage rivnuts
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Hi All: I am planning on drilling into a frame to add bottle cage rivnuts and am wondering, all other things equal, whether the seat tube or the down tube is better from a maintaining the integrity of the frame point of view.
Frame is a Miyata built 1981 Univega Viva Sport. CroMo, lugged, no butting stickers.
I also have a lugged 1982 Miyata that has bottle holes on the downtube only-- am wondering if this is structurally better, or just more aero or due to general rider preference.
I have a bent Takara frame to practice on.
Thoughts on seat tube vs downtube appreciated.
Andrew R Stewart
06-20-12, 09:50 PM
It probably doesn't matter which tube you drill, providing yoy do a clean job. The choice of which tube production frames have bottle bosses in has only spec issues and not stress issues. Not doing a boss set decreases the cost, not the "strength". Andy.
Thanks. Unless dissenting views are to follow I'll probably go with seat tube. Works better for hot coffee.
Still trying to source rivuts, and framesaver/amsoil mphd stuff locally, but will try to remember to return with pics once it's built back up.
06-20-12, 10:04 PM
I'll offer a dissenting opinion -- use clamps like the makers of that bike figured you would do.
You're overlooking the hideousness of clamps. (I should add that the photo is of the bike on day of purchase-- $20. I already trashed the p-clamped rack. Am even adding a seat too!).
Too bad we can't hash it out further over a few pints at ****'s! I miss HV!
06-21-12, 12:43 AM
According to Bicycle Quarterly's wind tunnel study, seat tube is more aero than downtube. Harder to reach, maybe, but more aero.
Stainless steel hose clamps are ugly. "Real" bottle cage clamps, not so.
06-21-12, 09:47 AM
Yep, I agree- the proper clamps are a bit less draconian and look appropriate on a C+V bike. I got mine at Velo Orange for $3 a pair, expensive but much better looking than hose clamps.
06-21-12, 11:36 AM
You can find bottle cages for a 2L storebought bottle of water,
to increase carry volume, with still 1 bottle.
Andrew R Stewart
06-21-12, 08:47 PM
I always take claims that such and such "looks better" with a larger grain of salt. Hose clamps are so much more practical. Don't rust, can be tightened without bottoming out, adapt to any tube and clamp volume. But then I'm a mechanic and rider, not a looker. Andy.
If you are going to take a torch to the frame, do both the seat tube and down tube. You don't have to use both at any given time, but if you plan a long, potentially hot ride, having both can be very nice.
06-22-12, 05:42 PM
You can also do what they do on circumnavigating sail boats, and whip it. There are a bunch of options there that are pretty low visibility, and they are easier on the tubes.
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