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Extreme Hill Climber Fat Tire MTB Project.

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  • commuter ebikes
    replied
    Originally posted by Sneakers915 View Post
    If you're spinning out at 7.5 mph, you don't need a suspension fork unless you're descending at 20...
    The bike will be able to travel up to 45 mph because of the motor. Any pedaling above 7.5 mph is just for show. If anybody ever comes out with a front suspension fork that will fit a 5.05" X 31.5" tire, I would slap one on there.

    I have been working on this project a lot. My friend and I pressed in a 170mm dropout axle, but when we tried to thread new spokes, we failed.

    Using 13 gauge (2.3mm) straight gauge steel spokes purchased from Taiwan, the Cyclo spoke threading machine did not produce spokes with sturdy enough threads so I ended up purchasing Sapim spokes threaded on a Phil Wood machine from Yojimbo's Garage in Chicago. Marcus Moore is great to do business with.

    I assumed that the $160 Cyclo spoke threading machine and $80 head would be fine, but the $4,000 Phil Wood is more stout and almost certainly has higher quality heads. Then again, perhaps the Taiwanese spokes were the problem. Another day I will try using the Belgian spokes in the Cyclo.

    I laced the wheels using Spoke Prep. It was straightforward because I have identical wheels around here that I can copy. With the custom wide axles that I have, it was impossible to perfectly center the Cromotor in a Rolling Darryl rim. Maintaining reasonable spoke tensions on both sides (15 units minimum and 30 units maximum on the Park TM-1), the best I could get the dishing is 10mm off center. All six of my Cromotor/Rolling Darryl wheels have this exact same phenomenon.

    I decided to disregard this dishing issue because consistent spoke tension is important to me. Maintaining spoke tension more or less equal on both sides of the wheel resulted in a very well behaved wheel for lateral and radial truing and shockingly equal tension in all of the spokes. Curiously, when I mounted the wheel in the bike it was perfectly centered (even though the dish is 15mm off center). I can't explain that, but I'll take the result.

    Setting up the chain line was surprisingly easy. I put it all together with no spacers anywhere, and it was perfectly straight like that. I was so happy with that after taking four hours to modify my White Industries freewheel removal tool. I had fully expected to need some spacers somewhere.

    Even with no freewheel spacers and a 170mm dropout axle, the White Industries freewheel fit with only 0.8mm to spare. White Industries freewheels are noisy, with a ratcheting sound. Click image for larger version  Name:	IMG_1496.JPG Views:	1 Size:	2.67 MB ID:	34675
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    Last edited by commuter ebikes; 05-05-2017, 09:32 PM.

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  • Sneakers915
    commented on 's reply
    Another thing you might try if you want to make your bb ultra water resistant is to add a zirc fitting to the shell, line the interior with a beer can shim and fill the whole thing with bearing grease. We used to do that in the good old days of cup and cone BB's since they were worthless. Then you can just top it off from time to time. I normally coat the inside liberally with grease and it's fine, but I live in a dry place now.

  • commuter ebikes
    replied
    One of these frames had the tire rubbing a little on one side. While I was rebuilding the wheel, I realized that I could just dish that wheel build a little in order to move the tire over 2mm. And I was ready to file down the frame where it rubbed.

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  • commuter ebikes
    replied
    The old battery boxes will be used as storage boxes:
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  • commuter ebikes
    replied
    The pannier battery boxes on these bikes are made of ABS reinforced with aluminum. While the frames are at the powder coater, I will make stronger battery boxes out of aluminum bar. I have some of these made for my other bikes, so I can just duplicate these.
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  • commuter ebikes
    replied
    Finally, I was not happy with the wiring harnesses because I had used precrimped JST connectors. Using these, many of the wire colors in the crimp terminal housing don't match the colors of the wires coming from the components.

    I am going to redo all of my harnesses, still using the reliable precrimped connectors, but using colored heat shrink tubing so that, say, a blue wire is blue all the way from end to end. That is, cover the erroneous color on the precrimped connector with heat shrink tubing in a color that matches the wire in my component.

    That will be frustrating if I install my new color coordinated harness and the bike doesn't function 100%. I imagine that I can test the new vs. old harnesses using a multimeter.
    Last edited by commuter ebikes; 04-25-2017, 03:02 AM.

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  • commuter ebikes
    replied
    Another problem that I had was that I had powder coated the small 2.5mm derailleur hanger screws and put some touch up paint on at some point. The dropouts compress the area where the head of the screws are, so when I went to take these off I had to use a thumbtack to remove the paint as well as remove some powder where I needed to put the hex key. I was lucky that I didn't strip the bolts. I will use new derailleur hanger bolts and never powder coat them or paint the heads so as to leave the small female hex cavity intact.

    The derailleur hangers come in aluminum or steel. Mine were aluminum, so they will be replaced with steel derailleur hangers http://www.paragonmachineworks.com/d...el-hanger.html . Fitting a new derailleur hanger necessitates more work because it needs to be filed out to fit the 16mm Cromotor axle, but I can use the aluminum one as a template.
    Last edited by commuter ebikes; 04-25-2017, 03:01 AM.

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  • commuter ebikes
    replied
    Regarding the rust in the bottom bracket, the powder coater will do a full chemical stripping which will remove all of the corrosion. I use Frame Saver and completely rebuild my bikes every two years, but I think I am going to paint the bottom of the bottom bracket.

    I bought these replacement BB bearing cups and shell which may keep some water out of my steel BB: http://www.bikeman.com/CR8629.html

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  • commuter ebikes
    replied
    Another problem was a small amount of rust in the bottom of the frame.
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    It is not surprising because I had ridden that bike in the surf. The bike that had never ridden in salt water was rust free.

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  • commuter ebikes
    replied
    I had some difficulties removing the parts. My buddy was removing the spindle while I was making a drink run and he pulled out the spindle before removing the bearing cup, leaving me with a cartridge bearing that I will need to pull off with a bearing puller. It turns out that, after 2 years of riding, 3 of the 4 bearings needed replacement anyway. They felt like they had sand in them.

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  • commuter ebikes
    replied
    I removed all of the old parts (including the 46T chainring) from the commuter ebikes that failed to allow meaningful pedaling beyond 20 mph. I am waiting on my headset removal tool so that I can send the frames to the powder coater: Click image for larger version  Name:	IMG_1340.JPG Views:	1 Size:	2.35 MB ID:	33673

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  • commuter ebikes
    replied
    Originally posted by Sneakers915 View Post
    If you're spinning out at 7.5 mph, you don't need a suspension fork unless you're descending at 20.

    Maxxis Minions are the best mtb tires out there and are widely copied for a reason.
    The meaningful pedaling ends at 7 mph, but the bike will be able to go 48 mph. I will be doing a lot of fake pedaling ("Nothing to see here, Officer").

    The Cromotor in a 170mm dropout frame only allows room for a 3-speed freewheel and I gave up on those for the reasons listed above (hard to remove, disposable, 16-19-22T is neither tall nor short gearing).

    I usually use a 58T chainring. Look how small the new Hillclimber 20T chainring looks next to the road chainring:
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  • Sneakers915
    replied
    If you're spinning out at 7.5 mph, you don't need a suspension fork unless you're descending at 20.

    Maxxis Minions are the best mtb tires out there and are widely copied for a reason.

    Leave a comment:


  • commuter ebikes
    replied
    I anticipate having to use brake rotor spacers to get the rotor spacing right, as well as using freewheel spacers (the same thing as a bottom bracket spacer) to get the chainline right.

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  • commuter ebikes
    replied
    My buddy Alan B. wanted to use a White Industries freewheel on his 150mm dropout Cromotor, but this metal lip prevented the freewheel from screwing down far enough, necessitating the the height of the freewheel threads to be reduced.

    My 170mm dropouts give me an extra 10mm to play with, so hopefully the metal lip (which is an obstacle at this point) is less than 10mm high.

    A neat bike tip is that AR-15 flash suppressor shims (http://www.brownells.com/rifle-parts...prod42002.aspx) are the perfect size for use as bicycle axle spacers. The outer diameter of a .223 AR-15 barrel is about the same diameter as a standard 1/2" hub motor axle and the outer diameter of a .308 AR-15 barrel is about the same diameter as a 16mm Cromotor axle. These flash suppressor spacers are the only washers that I have found that are small enough to fit inside a freewheel. Using these spacers allows one to push out the dropouts to fit a taller freewheel.

    A brass thrust washer (plumbing part from the hardware store) tops it off and you're in business as long as you still have enough threads remaining to fully engage your axle nut. Click image for larger version  Name:	IMG_1307.JPG Views:	1 Size:	346.2 KB ID:	33291
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    Last edited by commuter ebikes; 04-19-2017, 12:50 PM.

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