Starting to look like something

Discussion in 'Board Trackers and Vintage Motorized Bicycles' started by wret, Feb 28, 2014.

  1. wret

    wret New Member

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    Crunch!

    I never really liked the sheet metal anchor arm of the AV88 rear hub I've been using, particularly since I had to extend it to reach a stud on the frame. It worked though and I've ignored it. Saturday it came loose, wrapped about 360° around and dragged the chain guard into spokes. It sheared off several spokes, and actually ripped a couple out of the hub flange before the inertia ceased and I skidded to an abrupt stop from about 25 mph.

    Lesson learned: don't ignore these nagging little things. Now I'm faced with a dilemma, or maybe a challenge depending on how you look at it. I don't really want to use another AV88 hub but the think I liked about it was that the spoke mounting diameter was similar to 21" dirt bike drum hubs so that it can be transplanted into a wheel using the existing spokes. I have a complete drum hub (1970's Suzuki I think) that I took out when I put the wheel together. I've been thinking of a way to bolt a sprocket to it and use it as a rear hub. I've seen disc conversions but I don't think I've seen anyone mount a sprocket to one. I know longer need the sprockets on both sides as the crank pedals are long gone and I don't think they will be returning. I'm not really out anything but my time if it doesn't work. The next thing would be to get a rear wheel drum hub, already designed to attach a sprocket, though I don't know if there are any obstacles to making one fit such as width and sprocket spacing.

    Here's what I noticed about breaking down on a motorcycle: in less than a minute a motorcycle rider stopped and offered help with tools. I was only a block or so from my house and had to walk back to get some tools to cut the chain guard out of the spokes so it would roll. When I got back to the bike, another motorcycle/rider was waiting to see if he could help, and one or two others in cars stopped to offer help. A couple of weeks ago, while several miles from the house, I threw thew the chain. Within seconds, before I even had time to think about repair options, a guy with a pickup, ramp, and straps stopped, loaded the bike, and had me home in a few minutes. I am amazed how motorcycle riders look out for each other.
     
  2. Harold_B

    Harold_B Member

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    Glad you kept it upright! I had the brake arm shear and wrap around the hub on a Shimano coaster and decided I'd be building with drum brakes going forward. I'm using the Sturmey-Archer with the thread-on sprocket though I'm not using a chain (belt drive). The spacing is wider and I'm not sure they'd have the stopping power you'd need for your heavier bike.
     
  3. indian22

    indian22 Active Member

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    Wret I'm also glad you stayed on the bike 'cause often all goes atumble when these things come apart. It sounds the wheels a mess, but know you have it sorted out with your outlined plan.

    Harold did I understand you correctly, that the coaster lever sheared and would you mind describing where it gave way? Generally the flimsy band holding the lever arm breaks or the lever strap fastener bolt falls out. If it was the lever itself breaking I'll need to give this some design consideration as I use coasters on all my rear hubs. Actually the coaster works pretty good in my bikes under 100 lbs. but I always run a front brake as well on all bikes, pedal chain failure isn't uncommon and then no brakes from the rear!

    Get her up and running Wret as she is really looking good and needs lots of riding this Spring. Rick C.
     
  4. wret

    wret New Member

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    Thank Harold. Yes it occurred to me we could all use some skid practice.

    I do like a good solid drum hub. I considered putting my original Puch hub back on. It has a great solid, antiquey look, but it's not worth the effort (or expense of custom spokes). That hub didn't have enough stopping power.

    This is what I had in mind. Plenty of meat in the flanges of this hub to support sprocket bolts. Sometimes an idea seems great until you put it together. Actually I had questions about this one, but going together, it seems solid.

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  5. Harold_B

    Harold_B Member

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    Now that's a beefy looking hub! Nice.

    Rick - the arm itself let go or more specifically the anchor bolt hole tore through. It was an after market arm made by Ridley for the Shimano 110 spline hub for use with sprockets. To be honest I'm not aware of anyone else having had this issue but I'm not interested in a repeat! Here's a link to the old thread showing a couple of pics: http://motorbicycling.com/showthread.php?t=43392&page=18
     
  6. indian22

    indian22 Active Member

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    Thanks Harold and glad you survived the incident without bodily injury. I'd think not common, but like you said...Often the "strap" breaks or the bolt works loose, but I've not heard of the lever itself failing on a coaster, it happened so they do.

    Wret that hub looks the deal and the standoffs stand out as a simple, yet robust and attractive solution to spacing. Back on the road with lacing soon no doubt.
    Rick C.
     
  7. wret

    wret New Member

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    Yes Harold, there are some similarities there to my incident.

    After taking everything apart, I think it would be unfair to blame the issue on the AV88 hub. The stamped sheet metal brake plate/arm are actually pretty stout, though I'm not a fan of the tin-can thin sheet metal that form the rest of the cover. I'm sure it was my modification of the arm and being insecurely fixed to the frame that caused the failure.
     
  8. wret

    wret New Member

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    Thanks Rick.

    I should disclose another "doh" moment when preparing for lacing the new hub to the rim. I've laced a few wheels now and it gets easier and less intimidating each time. But, most of my reference material came from the bicycle world, in particular Sheldon Brown's excellent tutorials. After reviewing some lacing tips related to motorcycle wheels I learned (and this may be embarrassingly well-known to most) that typically all the spokes in a wheel are not the same. I looked closely when I took my wheel apart and sure enough I had "mild acute" and "mild obtuse" spokes installed randomly.
     
  9. indian22

    indian22 Active Member

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    So Wret I'll just confess to being somewhat similar in mental acuity to motorcycle spokes: ranging somewhere between mildly obtuse & acutely obtuse at my best :-||...can't see acute used in a positive manner that would apply to meself except as result of mental or physical examination.

    As to spokes: I know you are in the process or have corrected the errant positioning. It all comes back to having a nice, safe Spring ride. Rick C.
     
  10. wret

    wret New Member

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    Well it's a lovely rainy Saturday so I can get some wheel work done and don't have to feel bad about shirking yard work :)

    I tried out a lacing tip I read about: inserting all the spokes in the hub first and tieing them in pairs. It actually worked quite well. This keeps the spokes close to their correct orientation and as a bonus, holds them in away from the wheel so it doesn't get all scratched up.

    [​IMG]

    This wheel went together easily
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    And ballanced nicely
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  11. wret

    wret New Member

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    Avon Speedmaster Tires

    Since I had one wheel taken apart, I decided it would be a good time to swap tires. The previous tires were selected for their narrow width (2.50) and their relatively tame tread pattern. They always looked a little to dirt-bikey to me though and I've have been keeping an eye open for alternatives. I've found only one fairly narrow, old-timey looking option: Avon Speedmaster in 3.00-21.

    Half an inch wider doesn't sound like much but I was unprepared for the massiveness of these things. I had planned for the width but was caught off guard by the diameter. They're a full inch larger than my old tires! I had to make some tweaks to make them fit but the worst part was the mounting. The dirt bike tires I was able to mount by hand and with basic prying tools kneeling on the floor, but with the thick sidewalls on these it's nearly impossible. I actually got one of the Avons mounted this way before realizing there was no way to slide the tube in after.

    To make things easier I invested in the Harbor Freight motorcycle tire changing rig. 39 bucks! That's like a dollar a pound. The tool made mounting and de-mounting easier but still a lot of work. After about the fourth time mounting, pinching the inner tube, demounting and patching, I learned its absolutely necessary to slide your fingers inside to make sure the irons aren't puncturing the tube.

    Good news is I got lots of tire-changing experience. Also got both tires on the rim, though lot's of paint chip touchup is needed.
     

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  12. indian22

    indian22 Active Member

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    Wret glad you found the tires to complement the fork and bike, tire diameter when going to wider tires is a seemingly exponential factor, I'd suggest making absolutely certain that there is plenty of tire to fork clearance on complete spring compression and fabricating a suspension stop if there isn't enough room. Very dangerous when tire meets fork, the ultimate bad stop! Rick C.
     
  13. wret

    wret New Member

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    Rolling again

    The rear hub and tire replacement needed significantly more work than anticipated, mostly due to the width of the new 3.0x21" Avon Speedmaster tires. The tires were not only wider, which was expected but more than an inch taller. The specs say 27.2" height so those of us trying to get close the the 28" board track tires of yore, these are the deal.

    -I ended up with two broken spokes that had to be replaced. There must be a spoke sellers guild preventing the sale of single spokes! I actually ended up welding two spokes.
    -Not messing around with sketchy drum arms again.
    -Increased tire height meant not enough front suspension so the front forks had to be extended. This had the bonus benefit of rendering my extension limit stops unnecessary.
    -Wider tires meant more sprocket offset and some frame widening. I may have mentioned it before but cheap Harbor Freight spring compressors make great frame expanders!
    -Then the totally unexpected: with the taller rear tire there wasn't enough clearance to put the stand in the up/riding position. I had to cut and lengthen the stand.

    I finished up in time to take her for a cruise downtown. Everything seems to be in working order. The new larger rear drum brake seems to be a great improvement. Got lots of gawkers and comments including the question: "They still make tires for that?"

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  14. indian22

    indian22 Active Member

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    Wret I really like the classic pattern Avon's and the "heavy duty" brake lever should solve that problem from ever reoccurring. I'd think safe highway cruising is now a reality, discounting having to contend with what now passes as competent average drivers allowed on our roadways. Be very aware. Admire your bike! Rick C.
     
  15. butchl

    butchl New Member

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    I like the look of that tire over the look of the repop Simplex tires.
     

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