Cold setting 120 dropout spacing to 130. Any concerns about buckling?
I have my eye on a vintage Paramount with 5sp spacing. My vision is to build it with modern components including 130mm spaced hubs. Should I be concerned that cold setting the spacing from 120 to 130mm might buckle the stays? In the past I have used 130 spaced hubs in 126mm frames by simply flexing it open each time I put the wheel on. Somehow I imagine this will not be as feasible with a 120 frame. Any advice appreciated.
Thanks in advance,
Stay material? Hardened steel hard to move , non hardened, easier. Stay length, the longer the easier. I moved a Raleigh Gran Sport out to 130 from 120 and it was really easy, but it has non hardened long stays. Moving stays is always a risk , how good is the braze job where the stays attach?
It won't hurt to stick a padded clamp on at the rear brake bridge. Just in case. I can't imagine that 5mm each side would cause buckling. Look at how much fork blades are bent although they are usually bent over a form that gives some support to the sides. I've done a few curved seatstays using the fork blade form with no problems.
Based on the Paramounts I've worked on of that vintage, the respacing would be easy to do. The quality of the frame construction however, is a total crapshoot with those bikes....they are "paramount" in name only.
I'd closely inspect everything before putting any miles on it.
Cold setting isn't a problem, pretty much every build involves cold setting. However, from a framebuilding perspective just randomly torturing the rear end for some unspecified reason isn't what I stand for. If you asked frame builders whether they just randomly designed that way, or randomly set the rear end accuracy that way you would get a hefty argument about what techniques are best and what accuracy standards are reasonable. Of course I am all for helping people and their politely asked questions, but I wouldn't want to imply it's all good, just because it is pretty common.
Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Raleigh Pro, Trek Cycle Cross, Mongoose tomac ATB, GT Bravado ATB, JCP Folder
Having done dozens of such rear end respacings over the years i have little concerns. But each time i qualify the process to my customer with the "we can't be responsible for joint failure" clause. I have never had a bridge or other brazing let go, but i have refused to spread a few frames that I didn't feel good about.
The most extreme was the French Gitane tandem that started at 120 and ended up at 140. It also got canti bosses and a Shimano SE disk brake (this being back in 1980 not many options were around, but the Atom drum had to go). Andy.