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Old 07-15-18, 05:22 PM
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Join Date: Nov 2011
Location: Boulder, CO
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Bikes: Paketa V2r di2, C-Dale MT 3000, Teesdale, 1963 Huffy Daisey

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Bikepacking Gravel Tandem Project

Fresh off an inaugural two week back country ride across gravel and forest service roads thru Colorado on our new tandem, I wanted to share our latest tandem build in case the details help others with similar goals/build in mind. Our racing gravel tandem is "Coyote" So we dubbed the packing bike "El Burro" and went with a Mexican falsa blanket color scheme.

Our criteria were:
  • 35 pounds,
  • approx $10,000 budget
  • Increased tire width from our current gravel racing from for packing tandem for 29x2.3 and for sand/rocky riding we do in AZ also fit 27.5x3.0
  • Reconfigure how frame bags and bottles fit
  • Non-suspension, non mountain bike geometry. IE: 50mm Bottom Bracket drop, straight not bent top tube, 427AC non suspension fork.
  • Something bomb proof and drive train that works for long stretches in the back country..
I started by looking at stock tandems but none suited the criteria we set. I believe Co-Mo is coming out with a gravel specific tandem for their anniversary that might be close to these criteria. We went with a "direst to buyer" outfit Granite Tandem Designs where David Lafferty did a great job engineering, applying novel and thoughtful design ideas, and helping with the most tricky parts of the spec and build. I prefer direct to buyer relationship because I've had so many tandems and have a good idea of what I want it's nice to work with someone able to address those needs. The spec sheet in the google doc link below includes all the build and component data, along with my basis of decision making for nearly all components. Feel free to comment on any of those ideas.

Hereís the link to the build spec:
The highlights in my mind, or special custom applications are:
  • Tight Q-factor road cranks. 156mm Q-Factor while still clearing large tires. Worked wonders on knee comfort
  • Eagle 12 with right side timing chain, tight timing chain line: Increase reliability, no need to recharge electric shifting for long stretches in back country, right side drive has better efficiency tranfering captains power than left side timing
  • BB 386 EVO 86.5mm bottom bracket shell gives good base for chain stays.
  • Granite tandem custom proprietary eccentric
  • 65mm offset ti fork from Blacksheep works well on washboard
  • custom Dean Bikes 240mm stoker stem
  • JPak custom bolt on bags
  • Iíll refine the numbers, but in round figures 35# ready to ride bare bike, 45# with all the empty bags, bottles, and electronic navigation and lighting, 55# loaded with gear, rain gear, safety shelter, tools, first aid, etc. add 10 pounds for food and a big water day (we usually harvest water along the way and try not to over carry) comes to 65# fully laden.

With lavender bushes showing 27.5x3.0 setup

with aspen trees how we ride back country in Colorado with 29x2.3 tires
  • Inspiration image for the bag design:

Last edited by Turbotandem; 07-16-18 at 01:00 PM. Reason: added more photos
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