Flexing 731
 

I suppose I could attempt to do this but I am sure some of you have run a modern 130mm rear wheel in a 731 frame with 126mm spacing, any issues to speak of ? Lp

731??

531 can be spaced with no problem. 753 - I don't think I'd touch. No idea whether it's ok to tweak 853 or 953.

IIRC 731 was a heat treated tube set marketed briefly by Reynolds in the early nineties.

I can't find any description of the alloy (whether manganese molybdenum or chromoly) or indication whether or not it may be cold set. As Zorro says, 753 (which is a heat treated manganese molybdenum alloy) should not be cold set.

EDIT - I found scans of an article in the Nov/Dec 1993 Bicycle Guide that discusses 731 OS compared to Columbus Genius.

LINK

Based on the article, 731 OS is the same composition as 531 (manganese-molybdenum) and the stays are heat treated and extremely hard. Because of this, I would be reluctant to cold set the stays.

Dang I must have had a senior moment ---- The frame set is 753r. Lp

Don't do it.

I have a frame coming that I'm reasonably certain is 753. It's spaced at 126, and I'm going to run it as a fixed gear (not a Drew'd one). I had to limit my search for a suitable rear hub to one spaced at 126, since anything else would mean respacing. Of special concern on 753 frames is separation at the chainstay bridge - and this even without adding the stress of changing the spacing.

I would not cold set the stays. I thought there might be enough flex in the stays to easily drop in a 130mm rear wheel. Lp

There might be, but my concern is that you might be stressing what's the known weak spot of many 753 frames. You might want to ask this of our new guy - John Thompson - to see what he says. He's built 753 frames before.

Separation at the chainstay bridge due to: failed joint, metal fatigue or overwight rider? I was aware of a few issues with early 753. But my understanding was that by the mid to late eighties those issues had been worked out and the weight recomendation had been lifted. Lp

If you're just talking about spreading the rear triangle enough to put a 130mm O.L.D. hub between the dropouts, I don't think there's any danger of breaking or stressing anything to the point where there's any damage. You'll only be spreading the dropouts 2mm per side.

ok - I didn't recall seeing you'd mentioned what age the frame was. I'm not certain if it was metal fatigue or poor brazing.

I'd still run this by a frame builder with experience using 753 for an opinion first if it were mine. Would be an awful shame if spreading it caused the bike's demise.

"I'd still run this by a frame builder with experience using 753 for an opinion first if it were mine." Good idea ----- The bike in question is my Raleigh USA Team Pro. I have been considering STI's as I really enjoy riding this bike. Lp

Reynolds 753
 

Do you perhaps mean Reynolds 753? If so, DO NOT TRY IT!

As one of 3 brazers at Trek qualified to braze Reynolds 753 frames back in the 1980s, I have direct, personal experience with this material. Reynolds states that 753 cannot be cold-set. When a team frame was damaged in a crash, we had an opportunity to check this claim (the frame had to be replaced anyway). We put the frame on our alignment table and used the Levers of Persuasion to try to change the alignment. Exerting force that would ordinarily cold set an ordinary steel frame had no effect; the frame would always spring back into its previous alignment. We increased the force to the point where we had 2 people hanging off the levers. Nothing happened for a while but bouncing up and down on the lever eventually caused the down tube to buckle at the shift lever bosses.

I suspect that spreading the rear spacing would proceed in a similar manner.

Sorry for maybe changing the topic slightly, but as a new 753 owner (a 92 Gazelle) may I ask John what his opinion generally is of this tubeset?

John is there enough flex in the stays to drop in a modern rear wheel? As Stan said previously each stay is only moving 2mm. No, I would never dream of attempting a cold set on this frame. Lp

753
 

It's good tubing for its intended purpose: high-end racing. I wouldn't use it for a touring bike :) but for club riding and racing it's great.

753 flex
 

I think it would work ok.