Starting a Skyhawk

Discussion in 'Photos & Bicycle Builds' started by scalingdown, Sep 16, 2015.

  1. scalingdown

    scalingdown New Member

    So it begins. Acquired a Skyhawk GT frame with the intent of building a semi-legal street bike. Step A is to build a working peddle bike. I've ridden motorcycles and bicycles for a long time and have built bikes from loose parts. That said, I've never even been on one of these small motorized bikes. So, I'm largely working from theory.

    In my experience, there are two paths to going faster: Gain power and/or lose weight. So, I'll try to keep the bike part as light as I can without breaking the bank. I did come up with a pair of inexpensive suspension forks. These are takeoffs from a Kona dirt jump bike. The stanchions seem to be a bit bigger than other suspension shocks, which looks good with the big frame tubes. These forks came with a disc brake setup in the bargain. The steering tube on this thing is pretty short, I guess in keeping with the big-boy BMX style of the dirt jumper (never been on one of those, either). But, it works with the supplied open bearing headset if I throw out the decorative bits.

    Next up is wheels. I slipped a pair of 700C wheels on just to see what they looked like. They are, of course, too big for the frame. But, it seems to me that one of these things might make a nifty little café racer with a set of 27.5 hoops. Anyway, the rear dropouts were too small for the wheel's axle. Was able to spread the dropout with a tire iron, which was not too reassuring in terms of frame strength.

    I'll be back when I have some wheels laced up.
     

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    Last edited by a moderator: Dec 18, 2015

  2. butterbean

    butterbean Well-Known Member

    If you are going for a racer look, I might suggest a few things. One, smaller wheels. 27.5 is way too big for a racer. I'm building a cafe style bike in the cruiser category, and I'm running 24" wheels. Two, lower seat height and a longer seat. Ditch the rack, get a long seat and some throw-over bags if you need to carry stuff. Three, straight bars that far forward might be comfortable for you, but if not, I'm running club bars mounted upright. With smaller wheels, you may want a smaller rear sprocket because the smaller wheels will make you go slower. A smaller sprocket will compensate.
     
  3. jaguar

    jaguar Well-Known Member

    26" wheels are the right size for his frame. He can always put a larger rear sprocket on.
     
  4. butterbean

    butterbean Well-Known Member

    26" wheels look stupid on motorbikes.
     
  5. nishikidrift

    nishikidrift Member

    ...and what size do you use?
     
  6. butterbean

    butterbean Well-Known Member

    Read the second post.
     
  7. nishikidrift

    nishikidrift Member

    sorry missed that while skimming posts.i have been thinking about 24's better torque with not much speed lost.
     
  8. butre

    butre Well-Known Member

    I use a 24 in the rear but it's really hard to find 24 inch disc brake wheels so I have a 26 up front
     
  9. jaguar

    jaguar Well-Known Member

    A grown man riding on 24" wheels looks strange to me, but whatever, each to his own.
     
  10. butterbean

    butterbean Well-Known Member

    Good time to learn how to lace and true. I built my wheels myself. Motorcycle drum up front, moped drum in rear, 23" bicycle rims with 11g spokes.
     
  11. butterbean

    butterbean Well-Known Member

    You can use different size sprockets to get whatever top speed you want, within usable ratios of course. Ivuse a computer program to calculate ratios, and its dead on. I have my bike geared to cruise at 30mph at 5700 rpm.
     
  12. butterbean

    butterbean Well-Known Member

    24" wheels are not that much smaller than 26", they just look better to me. Most motorcycles don't need big wheels to go fast because they have gearboxes. An 18" motorcycle rim with a tire is about the same as a 24" bicycle wheel with tire. Even a single speed bike does not need big wheels, all you need to do is use a smaller sprocket if you want a little more speed. I have 24" wheels, but I also have 24" x2.4" tires, and I think it looks pretty nice. I calculated my gear ratio for the speed I wanted to go. I'm using a 79cc predator engine, de-governed and it will spin at least 6k. I'm geared to cruise at 30mph at 5700 rpm. My final ratio is 13.58:1. My pedal gearing is 1:1. Some motorcycles do have bigger wheels, and I also think they look stupid. It's not necessary, and smaller wheels also save weight, although usually not very much but some. I guess I just think big wheels look dumb. Even mopeds have smaller wheels.
     
  13. Timbone

    Timbone Active Member

    I like big wheels! My dream would be to build up a 29" motorbike. 26" is a good size, and the look is reminiscent of the first motorcycles. I really enjoy riding in a tuck and seeing the big front wheel rolling along, eating up the road!

    In practical terms, the bigger wheels are more stable and safer. Especially if you ride at night, things can sneak up on you! I've ridden over curbs, big parking blocks and various other debris that, for the most part, surprised me. Big wheels increase your margin for error.
     
  14. butre

    butre Well-Known Member

    I've done it before, and that's why I avoid it at all costs. such a huge pain in the ass
     
  15. butterbean

    butterbean Well-Known Member

    That might be true, but if you take the same size hub and compare a larger rim to a smaller one, the smaller rim is going to use shorter spokes for the same size wheel. Shorter spokes make a stronger wheel. So in effect, stability is probably not compromised much with a smaller wheel.
     
  16. butre

    butre Well-Known Member

    smaller wheels ride way better in my opinion
     
  17. 2old2learn

    2old2learn Member

    Men are so obsessed with size! I went with a 29er due to riding on rough fire roads that cut through our Ozark forests and that I often have to ride on. The larger the tire the smoother the ride is on gravel roads. Kinda like when you roll a heavy tool chest with small wheels and it gets stuck trying to roll over any imperfection in the surface of the floor.
     
  18. jaguar

    jaguar Well-Known Member

    that's right, larger wheels means a smoother ride, something bicycles are not known for, so any little bit helps
     
  19. scalingdown

    scalingdown New Member

    Didn't expect those pictures to generate all of that. Anyway, this will roll on 26" wheels. I have the hubs and will build my own (done that many times on bikes). I haven't checked to see if 12g spokes will fit my rear hub (Surly 36h). Hoping not to be stuck with 14g. So here's a question, does anyone ever tie and solder their spokes for a bit of extra strength? And, by the way, that "handlebar" is actually just a broomstick that I stuck in there for the hell of it.
     
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