DISRAELI GEARS

Simplex SJ810 GT/P

Simplex SJ810 GT derailleur main image

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.


  • Derailleur brands: Simplex
  • Categories: Simplex - touring terrors
  • Country: France
  • Date of introduction: 1975?
  • Date of this example: unknown (rear knuckle stamped ‘D51’)
  • Model no.: SJ810 GT
  • Weight: 327g including hanger plate
  • Maximum cog: 36 teeth (Sutherland’s 6th edition)
  • Total capacity: 39 teeth (Sutherland’s 6th edition)
  • Pulley centre to centre: 75mm
  • Index compatibility: friction
  • Chain width: 3/32”
  • Logic: top normal
  • B pivot: two sprung pivots
  • Materials: plastic parallelogram plates and front knuckle, steel pulley cage plates and parallelogram stiffening plates, aluminium rear knuckle
Simplex SJ810 GT derailleur additional image 01

Browse associated documents.




Simplex - Derailleurs 1978 scan 3 of 6

Simplex - Derailleurs 1978 scan 3 of 6

Simplex - Derailleurs 1978 scan 3 thumbnail




Simplex - Derailleurs 01/1981 scan 3 of 16

Simplex - Derailleurs 01/1981 scan 3 of 16

  • Publisher: Simplex
  • Date: 1981
  • Derailleur brands: Simplex
  • Derailleurs: Simplex SX410 T/P, Simplex SX410 T/SP, Simplex SX410 GT/P, Simplex SX410 GT/SP, Simplex SX810 T/P, Simplex SX810 T/SP, Simplex SJ810 GT/P, Simplex SJ810 GT/SP
Simplex - Derailleurs January 1981 scan 3 thumbnail




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