duncan.c

Hello all,

I'm looking for some assistance in identifying this lightweight frame so as to restore it.
I've attempted to match certain details of the frame with other 531c frames around, but can't seem to get it right.

Link to album

Details not shown in the pictures:
Campag front dropouts and BB
BB ID number at 6 o'clock: 24638 (3.5mm standard print)
Found fitted with Shimano 600 Arabesque chainset, brake callipers and headset

Thanks in advance, i look forward to hearing your thoughts.

Duncan

753proguy

Difficult to tell much from those pics., sorry. The 531C transfer is probably newer than the frame, and was likely added at the time of a repaint (or even later). Does the ghost of the headbage image indicate anything? Looks like it was just stuck on, though, not screwed.

That looks approximately mid-1970s British, but can't really say much more at this point, and there are about 1.7 million other framesets like that, that were built back then, I'd wager. Seatpin is 27.2? Dropout spacing?

zukahn1 

I would agree that the detailing on the frame lugg work and cable rueting look to be mid 70's. The paint job stickers and 600 stuff don't appear to be original to the bike. Unfortanetly nearly every major maker of mid to higher end frames had one or two models with similar detailing about this time.

wrk101

I would place it a little newer, early 1980s due to single set of bottle braze ons, DT shifter braze ons (not clamp on) and rear brake cable braze ons (rather than clamps). If it had two sets of bottle braze ons, I would have moved it forward a few more years.

1970s tended to see more clamp on cable guides at the bb, and no other braze ons.

Of course, some of those braze ons could have been added later.


Look for a date code on the steering tube, I find them about 50% of the time, and they are usually pretty easy to translate.

+1 That tubing sticker could be bogus and not mean a thing. Seat post OD?

If drop outs do not match, then the fork could be a replacement. Branding on rear drop outs??

zukahn1 

I missed the downtube and bottle braze ons in the pics. Considering this nearly everything seems to match an early 80's Lotus but I don't believe those had 531c tubing.

T-Mar

Definitely not a Lotus. I'm wondering if the bottle and shifter bosses were additions at the time of the repaint, as the dropouts have eyelets and appear to be the long style, which is typical of early 1970s and earlier. The frame itself appears to be mass production, as opposed to limited production or custom.

wrk101

Weigh just the frame and fork (no headset or bottom bracket). That would give additional clues as to whether it is 531C. And again, look for markings on the steering tube. I often find both a date code and a brand of tubing marked there.

duncan.c

Thanks for the help so far, it's much appreciated.

I dont currently have a shimano headset wrench, so will have to wait till tuesday for the local shop to open to look for a date stamp. The headbadge ghost was just to give an idea of potential branding

For now, the only further information i can offer is -
Seatpost Diameter: 27.2mm
Rear dropouts have no branding and the spacing is:125mm

I've also updated the album with close ups of the drop outs, BB braze ons and stamp


I'll get back to you once i've had the opportunity to weigh the frame and check for a date stamp in the steering tube.

Considering the potential that this is a rebuild, is it fair to say that the frame isn't expected to be of any high quality?

T-Mar

While a Shimano headset wrench is the prefered tool, the headset is also designed to work with a standard 32mm wrench. Regardless, given that the rear dropouts are generic and the front are Campagnolo, it would suggest the fork is a replacement. In most cases the front and rear dropouts match, especially on high end frames. Sometimes a pre-built fork is used with a different brand and/or lower level dropouts. However, it is extremely rare to find a premium front dropout matched with a no-name rear dropout, with the exception of replacement forks. So, even if the fork column does yield further information, I have low confidence in it being applicable to the frame.

Still, a 27.2mm post indicates a an upper end tubeset, though the frame characterisitcs are indicative if a mass produced frame.