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O.M.A.S. bottom bracket? On a what?
So I dragged home an Allitalia bike a few months ago:
https://cimg1.ibsrv.net/gimg/bikefor...b45db19936.jpg It has an interesting bike boom era mix of parts. Suntour Cyclone derailleurs, Sugino Super Mighty cranks, KKT pedals, Weinmann brakes, Jim Blackburn rear rack. The hubs and rims are so dirty I have no idea what they are, Front rim is steel and rear is alloy. It's surprisingly light. I want to use the cranks on another build so I pulled them. Since the bottom bracket was in much better shape than other parts I have, I pulled that too. And scratched my head a good while. https://cimg6.ibsrv.net/gimg/bikefor...e8b853a460.jpg The cup says "O.M.A.S Italy" and "36 x 24F" Neither side is a fixed cup, they both have lock rings. Sealed bearings that are still smooth: https://cimg9.ibsrv.net/gimg/bikefor...e34560421c.jpg https://cimg2.ibsrv.net/gimg/bikefor...5f6d290557.jpg The spindle is a very high quality piece of machining. Why on earth would a bottom bracket this nice be in a brand of bike I've never heard of? EDIT: If any of the hive mind here know anything about Allitalia bikes, I'd appreciate it if you shared your knowledge. |
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...using adjustable cups with lock rings on bikes with RH threading on both sides was a commonly used trick to create a BB with an adjustment for chain line. This is doubtless what someone has done on yours. It works well, so unless you are swapping the entire unit out for something else, I would just use it as is. OMAS is not seen all that often, but it was commonly available back then. It's relatively high quality stuff....probably on a par or better with Campagnolo in terms of durability. |
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...I know nothing about your bike frame itself. There were a lot of contract built Italian frames sold here under various names. Check the frame tubing for butting. Either the steel rim is a replacement and a downgrade, or the alloy one is a replacement and an upgrade. Or they are both replacements, for an original high quality set of tubular wheels. |
Originally Posted by 3alarmer
(Post 22566221)
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...unless you are swapping the entire unit out for something else, I would just use it as is. OMAS is not seen all that often, but it was commonly available back then. It's relatively high quality stuff....probably on a par or better with Campagnolo in terms of durability.
Originally Posted by 3alarmer
(Post 22566225)
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...I know nothing about your bike frame itself. There were a lot of contract built Italian frames sold here under various names. Check the frame tubing for butting. Either the steel rim is a replacement and a downgrade, or the alloy one is a replacement and an upgrade. Or they are both replacements, for an original high quality set of tubular wheels. There are clamp on Campy shift levers. I'm thinking someone in a bike shop in the 70s had a few too many beers and leftover parts. |
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...that spindle is probably sized for Italian BB shell width anyway, so using it in a 68mm shell is problematic anyway. |
Originally Posted by 3alarmer
(Post 22566358)
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...that spindle is probably sized for Italian BB shell width anyway, so using it in a 68mm shell is problematic anyway. |
Originally Posted by LittleGinseng
(Post 22566394)
Oh, and while you're at it get a magnet and see if it is attracted to the spindle. Titanium?
I was not expecting to find anything remotely like this on the bike. |
Originally Posted by 3alarmer
(Post 22566221)
...using adjustable cups with lock rings on bikes with RH threading on both sides was a commonly used trick to create a BB with an adjustment for chain line. This is doubtless what someone has done on yours.
https://velobase.com/CompImages/Bott...FC8FA657D.jpeg |
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https://cimg5.ibsrv.net/gimg/bikefor...e28a1832b7.jpg [catalogue page of 1978] --- frame - are either of the bridges plate style? lug pattern: Agrati "AMERICA" upper head lug: Agrati N. 007.8505 lower head lug: Agrati N. 086.8053 seat lug: Agrati N. 086.8569 fork crown: Agrati "AM" N. 005.8048 dropouts: Agrati N. 000.8002 fork ends: Agrati N. 000.8010 bottom bracket shell: difficult to see clearly; looks like it may be Agrati "AM" pattern --- remaining original fittings - Balilla brake levers 3TTT Tourist stem & bar set Agrati headset front wheel: Gnutti hub with NISI rim seat binder --- original gear ensemble would have been Campag Valentino original brakes would have been Balilla centrepull original chainset would have been cottered steel by either Agrati or OMG original pedals would have been Sheffield all steel original saddle pillar plain steel --- possible that identity of manufacturer could be advanced with information on placement and format of serial marking, if present one possible maker might be Chiorda - mentioned only as a possible ----- |
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