The French wheelbuilder, JPRACINGBIKE1, extends its DUKE products range by releasing the CRAZY JACK, a carbon rim dedicated to Enduro and All mountain in 27,5” (650b) and 29”.


  • carbon rim with a high resistance impact material
  • tubeless
  • width of 25mm internal and 32mm external for a much better tire volume
  • 28mm height to reduce spoke length
  • hookless design with low sides (only 4mm high for 3,6mm wide) to improve the rim resistance and keep a safe tubeless mounting, even in the hardest conditions
  • asymetrical rim (2,6 mm) for a quite similar bracing angle on each side
  • rims made in Europe
  • handbuilt in France

Duke Crazy Jack weights

  • 650b front rim: 370g
  • 650b rear rim: 410g
  • 650b wheelset: 1475g

  • 29″ front rim: 390g
  • 29″ rear rim: 430g
  • 29″ wheelset: 1515g

Words & Photos: JPracingbike1 PR

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About the author

Aaron Steinke

Aaron was our first employee and actively helped make our company what it is today, significantly shaping the look and direction of our various magazines. Aaron has been pursuing his own projects since mid-2020 but he continues to advise and support us on issues of marketing and technology. For many years, you would usually have found Aaron at casual enduro races, but increasingly you'll find him riding his road bike – long live freedom on two wheels!