T-Mar

The 600AX parts would be OEM. The stem appears to be a Specialized, which would be non-OEM, so I suspect the stem/bar/lever hood assembly was swapped out as a whole unit, which would also explain the non-aero brake levers. The Italian San Marcos saddle is almost certainly another replacement. The wheels also appear to be replacements or at least rebuilt, as they are non-aero rims. The OEM 600AX hubs are readily identifiable by their conical, light blue, plastic, cone covers.

The odds of the paint being OEM is extremely small. Fade paint schemes didn't become popular until the late 1980s. I can't recall any from this era. I've always considered the 1984 Olympic Road Race winning Pinarello to be the bicycle which started the fade paint fad.

Similarly, I place very little credence in this being a "show bicycle". Based on the serial number, the frame was built in either late February or April. Both dates are late for bicycle shows. The major USA shows typically took place very early in the new year, so I'd expect a 1982 model year "show bicycle" to have been built in late 1981.

C8___

Hi All, new here and posting to say I just got the Norta branded frameset! Serial number 2A14440 !
Already had the 600ax brakes, and have a 600ax seatpost in the postal system!

How do these frames ride? I've reynolds 531, 1024 and vitus tubed bikes, and the loose tange-frame feels different: really heavy but very stiff (this is probably also because of the tubeshape). Building it up as a fixed gear and trying to decide if it's worth my fancy parts!

​​​​​​
​​​​

T-Mar

Welcome to the forums. I'm not familiar with the Norta brand but the serial number is consistent with Matsu****a/National who were best known for their Panasonic brand and also contract manufactured bicycles for several other compnies. If so, the serial number indicates January 1982 manufacture, which aligns well with 600AX production dates.

Typically, the early 1980s aero frames are very stiff vertically but relatively flexible laterally. The vertical stiffness initially gives the impression of a very stiff frame as road roughness is felt more. However, when pushed hard, the lateral flexibility becomes known through slightly less precise steering and things like chain rub on the front derailleur cage. If you're building fixie/SS, you may not notice the increase in lateral flexibility, as there will be no chain rub.

Edit: Vertical compliance issues can be mitigated, to an extent, by installing wider tyres and running lower pressures, though the tyre width will limited by frame clearances, which are often quite tight on these early aero frames.

T-Mar

Sorry for the late rely but it didn't show up in my notifications, since you didn't "reply with quote" or attach the @ symbol to my user ID.

The bicycle has almost certainly been repainted. Multi-colour faded paint schemes didn't become popular until the late 1980s. The catalyst was Alexi Grewal's gold medal winning Pinarello from the 1984 Los Angles Olympics. Alexi's manager and sponsors couldn't agree on a colour, so they used all of them on the frame. I don't recall any multi-colout faded paint schemes prior to this.

A disproportionately high number of aero frames are represented as "show" bicycles. I can't make a definitive statement one way or the other. However, if it was my bicycle and a known "show" bicycle, I definitely would not have repainted it, as it severely reduces the value by making it harder to prove the provenance. While not quite as drastic, it would be similar to repainting a bicycle that had been ridden in competition by Eddy Merckx.