Band-on Nuovo Record front mech with clamp size < 28.6

[anagrama]

Has anyone heard of such a beast? I recently bought a (supposedly) NOS 4-hole NR front mech, but the clamp is too small to fit any of the 3 frames I've tried it on, all with standard 28.6 seat-tubes.
The bike I bought it for has previously sported Huret Duopar and Nuovo Valentino front mechs without a problem.

I've googled the shit out of it, and while some older French mechs were for 28.0 seat-tubes, I can find no mention of Campag ever using such a size, and would imagine that by the early 80's, 28.6 was as close to universal as they came.

I took a pic to demonstrate the problem, but apparently don't have enough posts to upload pics yet..


It's certainly left me scratching my head. I guess the most straightforward solution would be to find a longer clamp-bolt, but am not sure how easy that would be, given that the Campag one is already longer than two others I plucked out of the parts box...

 

[anagrama]

ah, and with that 5th post, pics are enabled. Thusly:

 

[roadking]

From the position photo taken does not look like an NR mech.

Roadking.

 

[fiks]

The pic's not very clear, maybe the band is not original.

 

[anagrama]

From the position photo taken does not look like an NR mech.

Roadking.

No?

 

[fiks]

My guess it was made for a 28mm seat tube.

 

[Lazarus]

Hi there anagram You say a 4hole, but thats a 3 buddy ? No matter, I've had a damned good look at your problem and what catches my eye is that the clamp is overstretching to fit the seattube. Check your 1st pic and you'll see that the clamp ends wont line up straight or meet.

If you force that on with a longer clamp bolt you'll either squash your tube or bust your mech or both.

Simple answer, post me your mech, and I'll send you the correct 1 back. Job done Without holding it my hand I can't tell you why yours won't fit, but I've just spent half an hour cross checking your mech against 1 on Velobase, and they seem to match.

Its a 3 hole standard Nuovo Record 28.6mm clamp size, made between 1982-1985. This is so because there are no small dotted thingies inside the clamp area that says Campagnolo, yours is smooth just like velobases. Yes buddy its silly how they differ, but thats the way Campy do things, small dotty thingies on older models, smooth on yours.

I have plenty of front mechs, so a swap won't be an issue. Yes I can post pics too if you like Yours Laz.

 

[Old Ned]

I had a similar problem with a Record front mech I was fitting to my lugless Dave Russell. When I measured the tube I discovered it was slightly oversize compared to other 531 frames I have. The only way to fit it was to file the sharp edges etc. from around the inside of the clip and body, especially the 'corners' leading to the fixing bolt holes. A bit 'philistine' I know but it isn't a very good example of the mech. I wouldn't do it with yours!

As the frame is lugless and intended as a time trial frame and therefore single chainring then perhaps a larger diameter seat tube was used in the building?

 

[anagrama]

Wow, thanks very much Lazarus! I was eyeing a replacement clamp body on eBay, but your kind offer is a much preferable alternative. PM pending...

And yep, seems I confused the 3/4 hole versions - I had looked it up on Velobase previously and knew it was the later one, but didn't check again before posting and counted three 3 on the outer plate plus the one on the inner.

Pretty sure it's not the frame in this case Ned - I've tried it on 3 now, none of which I'd had problems with in the past, and all had the same issue here.

Thanks all!