Originally Posted by
robobike316
I did this with a large pipe a number of years ago on an old steel racing frame. Simply hammered the pipe in from the rear toward the bb and then made sure the rear end was still aligned to the desired spacing. I got enough space to run cyclocross type knobbies on a fairly tight road frame with no problems.Canti studs were also brazed on. I used this bike off road for a few years- it was the fastest mountain bike on the trails!
Obviously this could compromise the chain stay brace joints (or whatever that is called down there) or even the bb to stay joint (if there is no brace), I didn't have any problems, and was more than happy with my off-road rocket.
Hmm, that raises an interesting question... most dimpling of stays I've seen look like whatever made the dimple was small (like
nlerner 's drive bit) oriented parallel to the stays. But there have been a few that looked like whatever did it was larger and oriented perpendicular to the stays (more or less like I understand the pipe to have been as
robobike316 describes doing it). I wonder if the former is better as far as structural integrity... or if it doesn't significantly matter....?