The Schwinn GT510 was supposedly an improvement on the insane Schwinn GT500.

The Allen key hanger bolt has been replaced by a riveted on hanger, with a dodgy hidden plastic insert playing a key structural role between the hanger and the body of the derailleur - probably not good. You get a funky black drop out bolt and adjustable cable outer stop. Weirdest of all you seem to get one of Huret’s toothless ball bearing mounted tension pulleys - very hip in 1960.

What anyone in France or Chicago can have been thinking about speccing this gear in 1978 is beyond comprehension.

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1. •Brand: Schwinn, manufactured by Huret
   

2. •Country: USA, manufactured in France
   

3. •Date of introduction: 1977?
   

4. •Date of this example: 1978 (stamped 3778, week 37 1978)
   

5. •Model no: unknown
   

6. •Weight: 345g including hanger plate
   

7. •Maximum cog: 28 teeth (Sutherland’s 4th edition)
   

8. •Total capacity: 30 teeth (Sutherland’s 4th edition)
   

9. •Pulley centre to centre: 50mm
   

10. •Index compatibility: friction
    

11. •Chain width: 3/32”
    

12. •Logic: top normal
    

13. •Pivots: two pivots, front sprung and rear unsprung
    

14. •Material: largely steel with one bronze parallelogram arm
    

0107/D