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Extreme Hill Climber Fat Tire MTB Project.

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    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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      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


        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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          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.


            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:


            • Sneakers915
              Sneakers915 commented
              Editing a comment
              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.

            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 . 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.


              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.


                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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                  The old battery boxes will be used as storage boxes:
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                    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.


                      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.


                        These pictures show what a tight fit the White Industries freewheel is. The bolts for my torque plate require some space. 170mm dropouts and I can only fit a single speed!

                        Actually, there is no extra room anywhere because the axle nuts come up flush against the ends of the axle. Crowded house.

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                          Fat Tire Hill Climber looks very nice but how it works?


                            Originally posted by ri9rashed View Post
                            Fat Tire Hill Climber looks very nice but how it works?
                            The project in this thread is this prototype bike getting a frame off rebuild: With the 46 X 16 gearing, I found the gears way too short for use as a commuter bike. Also, it had this freewheel which can be almost impossible to remove, usually requiring a destructive freewheel removal. Gosh, I hated that freewheel. I always build bikes in pairs and I stock spare parts; when I saw the spare 3-speed freewheels hanging on the pegboard, I always felt disdain.

                            One time I was mountain biking using the bike in the video, going up steep single track on a hot day. I had it in the lowest gear and I was pedaling as much as I could. It was going uphill fine, but the temp sensor said 105.6 degrees Celsius. I stopped, said goodbye to the group, and headed down the hill. The high motor temperature reading on that climb was the impetus for this project. That was a mid drive riding group, by the way, and they had no problems climbing steep hills without overheating.

                            The catalyst for this project is when I was unable to sell the bare frame when I had the idea to switch to a 190mm dropout frame. Not that I tried very hard to sell the bare 170mm dropout frame--I only made a post on this forum and left it up for a week. I had filed out the dropouts for a larger 16mm axle, so the frame would only be of use to someone using a 16mm axle or willing to weld in new dropouts. I do love these frames so I didn't mind keeping them, but there was definitely a moment when I was "stuck with the frames" that only allowed up to a 46T chainring.

                            This bike ought to be able to pedal up anything. I will use the motor for everything else, which I realize is most of the time. I wonder if the fake pedaling will be convincing. Riding around town at 35 mph and fake pedaling with a 20T chainring is going to look hilarious to somebody who understands chainrings; maybe they will think I have some extreme IGH.

                            Honestly, I hate getting my bikes dirty so I much prefer riding on the street. There are countless very steep roads in my area. In practice, I will usually use these hillclimbers on those steep paved roads. I like to go riding with friends so we will take out the identical short geared bikes on a route with very steep hills.

                            I haven't even sent the frames to the powder coater yet, and they take 4-10 weeks to powder coat frames. While the frames are at the powder coater, I am going to redo the wiring harnesses, modify the CA from this to this (this modification is just a single solder joint) and build bomb proof aluminum battery boxes. When I redo the wiring harnesses, they will be able to be used on any of my four bikes, and I will have a few spare wiring harnesses at the ready.

                            I also used the rebuild as an opportunity to upgrade the headset from Cane Creek to Chris King, upgrade the derailleur hanger from aluminum to steel, and switch in black nipples and new spokes. Some of my wheels had silver nipples and for some reason shiny parts bother me.

                            I like to completely rebuild a bike every two years. Upon taking these two bikes apart, I found a lot of grime, three worn out BB bearings, rust in the bottom of one BB, overly thin wires in the ignition wiring in one harness and red paint from a previous build showing through my matte black powder coating on one frame. I also had an issue with a rear tire rubbing on the frame which I will rectify by filing on the frame a little, dishing the wheel as much as I can, and running a slightly more narrow rear tire if needed. Currently, the rear tires are 4.80" wide. I see that there are many choices for 4.70" and 4.60" wide tires.
                            Last edited by commuter ebikes; 05-06-2017, 11:19 AM.


                              Project update:

                              (1) The two frames are at the powder coater and will be ready anyday. My wife bought me this for my birthday so I will clean up any powder overspray in the BB threads.

                              (2) I delegated the task of building the four battery boxes (two on each bike) to my buddy who comes over every Saturday night and works in the garage with me. I pay him $13/hour. He is doing a great job so far. He is just duplicating a battery box that I have on my other bike.

                              (3) I am currently working my way through building 6 wheels with Cromotors and Surly Rolling Darryl (82mm) rims. This job was made tougher by trying to cut and thread the spokes myself with a Cyclo spoke threading machine using 13ga spokes from Taiwan. The spokes were not top quality (softer steel than Sapim spokes) and the Cyclo spoke threading machine produced threads that were not as deep as threads rolled on by a Phil Wood machine. I ended up not even using the Taiwanese spokes and purchasing threaded Sapim spokes that were rolled on a Phil Wood machine. Those spokes had harder steel and deeper threads. At one point, after I had a wheel laced, I had to unlace it, completely rebuild the motor (it was cogging because I had not completely seated one bearing) and relace the wheel. These wheels must be the most difficult to true. The spoke length is correct, but the combination of the Cromotor and wide rim results in about a six hour job to true the wheel. Also, the manufacturer of the custom wide axle has the motor set off to the brake side by 14mm so the dishing is nearly impossible. If I were to set the dishing correctly, the spoke tension on the brake side would be about 5 units (on the Park tensiometer) and about 30 units on the freewheel side. I split the difference and leave the dishing 7mm off center (tire biased toward the drive side) so that the spokes can have more consistent tension.

                              (4) As part of this project, I am completely redoing all of the harnesses on all 4 of my bikes (they all use the same harness), as well as making at least one spare harness. I delegated the job of making one prototype master harness to a professional electronics technician, and I am also making a separate prototype master wiring harness myself. I scored some 22ga 6 conductor cable for this job. It was fun deconstructing the wiring from an existing bike; I got to figure out every little wiring detail. The 5V harness that I deconstructed had some shoddy work on it; the technician had used a lot of 28-30ga wire on it, all 6 wires (ignition, e-brake (regen) and temp sensor) being white. I need my wires a little thicker and color coded. The bikes have a multifunction switch which handles power, regen and 3-speeds. It is not easy to set the 3 speeds so that it goes Low, Medium and High as you toggle from left, center to right respectively.

                              (5) I am converting my CA V3 DP-S to DP because I hate the spoke magnet, sensor and wire. That is all unnecessary clutter because a DP senses the rotations of the motor. I delegated one conversion to the electronics tech and I will do one conversion myself (it is only one solder joint, see diagram below).

                              (6) The electronics tech is fixing one 36V battery which has some bad cells. I damaged those cells by drawing too much current while I was testing an experimental Kevlar tire liner at 0psi (riding to work) with no limit on the current. The Kevlar tire liner didn't work out because it had no acrylic; Kevlar needs acrylic in order to function properly, and the acrylic makes it rigid.

                              (7) Everything else is ready, and I will assemble these bikes in August. I have two paid helpers coming: my regular helper/buddy Lloyd and a guy at work who is always telling me what a great bike mechanic he is, so I thought I would illuminate his claims. All three of us work at UPS together, so that should be a fun group activity. Click image for larger version  Name:	unnamed.png Views:	1 Size:	167.5 KB ID:	36969

                              Last edited by commuter ebikes; 06-04-2017, 09:10 AM.