There’s something about French touring derailleurs after about 1960. Just one look at this Simplex SJ810 GT is enough to fill me with a crushing sense of despair. I can almost hear the chain hysterically clattering on the inaccurately cut teeth of the wide ratio Maillard freewheel as the SJ810 GT pathetically attempts to find bottom gear. I can almost see the bemused expression on the face of the owner of a Peugeot tandem as I attempt to invent a reason why a seemingly rational company like Peugeot had chosen to fit his relatively demanding machine with a poorly constructed derailleur with plastic parallelogram plates.

At heart the SJ810 GT was a Simplex Prestige with a long pulley cage - not a very promising foundation. And all that lack of promise was fully borne out - the SJ810 GT was heavy, unreliable and changed gear particularly poorly.

Even Edith Piaf would have regretted producing this dog.

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1. •Brand: Simplex
   

2. •My category: Simplex - touring terrors
   

3. •Country: France
   

4. •Date of introduction: 1975?
   

5. •Date of this example: unknown (rear knuckle stamped ‘D51’)
   

6. •Model no: SJ810 GT
   

7. •Weight: 327g including hanger plate
   

8. •Maximum cog: 36 teeth (Sutherland’s 6th edition)
   

9. •Total capacity: 39 teeth (Sutherland’s 6th edition)
   

10. •Pulley centre to centre: 75mm
    

11. •Index compatibility: friction
    

12. •Chain width: 3/32”
    

13. •Logic: top normal
    

14. •Pivots: two sprung pivots
    

15. •Material: plastic parallelogram plates and front knuckle, steel pulley cage plates and parallelogram stiffening plates, aluminium rear knuckle
    

0115/D