Simplex SJ810 GT

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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