Finally done -- Yoji 16 with suspension fork- Mtbr.com
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  1. #1
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    Finally done -- Yoji 16 with suspension fork

    Finally have everything together for our new Yoji:

    Finally done -- Yoji 16 with suspension fork-img_20190127_101618196.jpg

    End result is pretty close to what I was hoping:
    • Handlebar height stays about the same, since the extra fork length is offset by switching from the stock riser bar to flat bars
    • Longer wheelbase (686mm -> 740mm)
    • Slacker head angle (72 -> 66)
    • 16.45lbs


    Parts for the build:
    • XCM HLO AIR SL 20 fork
      • 1883g after cutting vs 767g stock
    • Homebuilt 16" disc front wheel
      • 417g (wheel only) vs 517g stock (including axle & nuts)
      • Kinlin 16" rim (180g) -- despite my initial concerns about how narrow the rim was, it seemed to go together OK. I did enlarge the valve hole for Schrader, since it came drilled for Presta -- it was a very, very tight fit between the valve for the tube and the two beads.
      • Circus Monkey HDW2 24H hub (119g)
      • Mission Stainless spokes
    • Performance bike 16x1.75-2.1 tube
      • 105g vs 120g stock (16x1.9-2.1)
    • Titanium hex head QR skewer
      • 16g
      • Might wind up replacing this -- the aluminum in the hex socket was pretty soft and seemed like it was starting to strip when I tightened it.
    • TRP Spyke mechanical disc brake
      • 179g for the calipers vs. ~188g stock v-brakes & bolts, not including the noodle or brake cable
      • Paried it with Alligator Super Fortress compressionless cable -- these are great cables, but super cheap for the kits in different colors on eBay. Debated swapping out the rear cable as well, but decided to leave it as-is for now.
    • Ultra light 160mm rotor
      • 70g
      • Cheaper clone of the Ashima Ai2
    • Rev grips suspension grips
      • Not sure if these will make much difference, but they were on clearance at Jenson and I figured they'd be worth a try.
      • Diameter of the small (31mm) is pretty close to the stock Spawn grips
    • ControlTech Sup MT 28A flat bar
      • 155g vs 241g stock
      • Not much heavier than carbon, but 7075 triple-butted aluminum should be a little sturdier. For only $12 when I ordered on Amazon it was hard to pass up. Had I waited a little longer, I could have gotten the 138g Scandium version when it went down to $16, though...
      • Left this at 600mm to allow for similar hand positioning to the original 540mm bars (old grips were about 30mm shorter on each side)
    • Wren 50mm stem
      • 74g vs 210g stock
    • 18T Shimano DXR rear cassette cog
    • 89mm Spawn Cranks
      • Slightly lighter than the stock 102mm cranks
      • We'll be taking it slow on upping crank length -- I'm on 152mm cranks on everything but my BMX bike now and am a convert to the shorter = better camp
    • 22T Narrow-wide chainring
      • 16g, pretty much the same as the stock chainring
      • Not particularly needed since it's single-speed, but I had it lying around from trying out gearing on another bike and I figured I might as well toss it on.
    • KMC X8.99 chain
      • Needed because the stock chain isn't long enough for 22x18
      • Forgot to weight the original chain, but this was a little lighter
      • Has the added benefit of a master link
    • Kactus 16T pedals (~210g)
      • Stock pins had almost no traction, so I wound up with:
      • DMR Moto X pins on the outside holes
      • Original8 Rascal pins on the inside holes
      • The Origin8 pins are taller, which mostly counteracts the concave shape of the pedal. While concave works well for a heavier rider and a forefoot pedal position, I'm not convinced that it works as well for a lighter rider with midfoot pedal positioning
    • Black Label 25.4x150mm Nylon Pivotal Seatpost
      • 95g vs 110g stock 125mm post
      • Also used this on our Yoji 14 -- more details in this thread


    Lessons learned along the way:
    • Measure twice, buy once!
      • Had originally thought I could get away with using some clamp-on v-brake bosses, but they wound up too small to work. Had I measured the fork before ordering, I could have saved myself a little time / money.
      • Initial spoke calculations were a little off and I had some of the specs transposed when I checked against a spoke calculator. Remeasured everything and it came out just right (originally had 133/133, wound up with 130/137). Our local BMX shop (Albe's) was super helpful throughout the process and I'd definitely recommend them if anyone is looking for some cheap spokes cut to length.
    • The calibration was a bit off on my truing stand (a TS 2.2) -- which means that the stock wheels might not have been off in their dishing by quite as much as I originally thought
    • Legos actually work pretty well as a dishing gauge. 2 stacks of 2x4 bricks to support the rim over a flat surface, then a tiered stack of thinner plates to gauge the distance to the hub.
    • I ordered a clone of the DT Swiss spoke tension meter off aliexpress, but quickly found that it's pretty much impossible to use on a 16" wheel.
    • Made a cheap nipple driver from an old screwdriver using a grinding wheel, but found that the angles were steep enough that it didn't work well in the double-walled rim. Maybe it would be better if I rounded the sides a little more on the griding wheel, but it worked out OK to just use it to get the spokes started and then tighten via the spoke wrench while eyeballing the spoke engagement.
    • Something I'd found over the summer and made use of on this build -- PTFE paste works great as an anti-sieze coating for threads and is much cheaper than most of the bike-specific products.

  2. #2
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    Maybe it's just the camera angle, but the stem looks like it's at forehead height.

    Sent from my Pixel 3 XL using Tapatalk

  3. #3
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    Quote Originally Posted by majorjake View Post
    Maybe it's just the camera angle, but the stem looks like it's at forehead height.
    I think it's the camera angle -- happy kid for reference:
    Finally done -- Yoji 16 with suspension fork-img_20190127_101709966.jpg

  4. #4
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    Had a big thaw here and got a chance to ride this morning... no gnar, but we made it over some icy patches on the sidewalk and down the block to church and then through a bunch of puddles to Big Boy for lunch with grandma & grandpa.

    About 1.5 miles of riding for him, 2.5 for me since he was looking a bit sleepy after the lunch buffet and I figured it would be easier for me to bike home to get the car and just give him a ride. His balance and bike handling always seems to get a little sketchier when he's tired.

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