Atom (5 speed, silver cogs)
Main Photo
Category:  Freewheels
Name:  Atom (5 speed, silver cogs)
Brand:  Atom
Years:  1960's - 1980's
Country:  France
Weight:  295 grams (Actual), 5 speed
Added By: JFischer on 03/31/08
Updated By: Tom70s on 02/18/16
Additional Photos - click for full size
Atom (5 speed, silver cogs)Atom (5 speed, silver cogs)Atom (5 speed, silver cogs)Atom (5 speed, silver cogs)Atom (5 speed, silver cogs)
Cog Count 5Available ThreadingEnglish/ISO: 1.370" x 24;
French: 34.7mm x 1mm
ColorBlack; SilverIndex Compatibility Non-indexed, standard spacing
Cog MaterialsSteelIdentifying MarkingsAtom Bte SGDG Made in France - Punch mark in backside for BSC threads
Removal Tool Style SplinedRemoval Tool Atom (splined);
Bicycle Research CT-1;
Park FR-4; Var 407, 401
Original Available Ranges14-16-18-20-22;
Numerous cog arrangements
General Information
These Atom freewheels were manufactured  for almost 3 decades. Most of them had black sprockets (maybe a different model number). The used freewheel pictured above has a nickel plated adjustment lock ring that I've never seen on any Atom  freewheel before. It's a 15-24T that came on a 1965 Swiss bike. It still runs smooth as new.

All the sprockets screw onto the body and for the most part interchanged with early Regina screw on sprockets. The 3 outer sprockets have RH threads and ranged from 14-24T. The 2 inner sprockets have LH threads and were made in 17-32T (maybe even 34T in the mid 70s)..

There were some special bodies that were made for 13-17T "corn cob" or "straight block" 5 speed freewheels. Regina called these Scalare bodies.  Atom like Regina also made 6 speed freewheels that used a 13T or 14T outer sprocket that screwed into a 15T or 16T inner sprocket. The 6 speed "corn cobs" freewheels were available with 13-18T.

Atom splined freewheels came with French (metric) or British (BSC) inch pitch threads. The BSC bodies had a punch mark on the back side, see photo above.

In my opinion, Atom freewheels were far better made than those from Regina including most top of the line Regina Oro freewheels with gold colored sprockets.

Phil Wood made a special thin walled freewheel removing tool that slipped over the lock nuts on Campy and other better quality hubs without having to remove  the nuts and spacers. They were a must have with Phil Wood and other sealed bearing hubs. These were pretty fragile tools because of the thin walls. At our shop we went through 3-4 a month. Park tool makes a similar tool but the walls look a little thicker.

Came in four speed version as well.

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