Framebuilders - How to notch DS chainstay to better clear small chainring?
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04-02-12, 01:10 PM
Title says it all. What's a good method for doing this on a steel frame?
04-02-12, 06:06 PM
dimple it with a piece of wood and a c-clamp. Is this on a road bike?
04-02-12, 06:44 PM
Pictures can be found here from Alex Wetmore's blog: http://alexandchristine.smugmug.com/Bicycles/Framebuilding/Ivy-T/P1080110/1062387252_6iwL8-M.jpg
04-02-12, 08:10 PM
Thanks, I was thinking that Alex Wetmore had posted some pictures of dimpling. That setup should work, the block with the groove in it for the chainstay might have to be thinner so it will fit
04-03-12, 05:20 PM
Thanks, guys. Randomgear, that photos helps a ton more than the descriptions I've read. Yes, it's for a road bike, but I'm spreading the frame to 130mm in the rear, so I'm concerned about clearance, which is already pretty minimal. I'll cold set it first, see how it goes, and then dimple it if it's still necessary.
04-04-12, 01:54 AM
I've used a piece of threaded rod with two washers and nuts on the inside to spread a frame, it worked rather well. I spread it to 140mm then backed the nuts off then checked after 5mm increases until I got to 135mm (old mountain bike turned commuter).
A few years ago I tried the Sheldon Brown 2x4 method, it worked, but mostly opened up on one side -funny that despite being out of alignment, the bike still rides just fine no handed.
04-04-12, 03:46 AM
Keep in mind that the chain stay will be a bit shorter after it is crimped.
04-04-12, 01:25 PM
^ I was wondering about that and alignment after. Can/should this be done before cutting and brazing? Or is the change pretty minimal? I was also wondering about cutting and brazing in a scallop like the tops of seat stays. I think this would make for a clean/unique stay, but would it weaken it at all?
04-04-12, 02:43 PM
my thought is that you don't want to braze in a scallop unless you have a lot of surface area overlap. You could look around at what mtb builders have gotten away with. On a road bike, dimpling is a no-brainer. Brazing in a scallop will cause all sorts of heat related movement, might have to cold-set afterwards
It's best dimple before attaching the stays, but I have successfully done it afterwards. I used to run a round rod down the stays and hammer it into place for the tire clearance dimples. I really like the way it looks, it's probably horrible way to do it from a longevity point of view though.
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