These are the item you need to propery fit a motor wheel onto a set of forks with deep quick release cups, especially alloy forks.
I am really impressed with the quality of these little jewels. Made from some fairly hard steel, and very nicely cut. Not stamped out of a sheet of mild steel like ordinaly washers. The following picture is pretty poor, but sort of shows the way the c washers fit into the cup beautifully, filling the space. Taking a Tourqe washer and grinding it down can work, but then the tourqe washer gets too weak, and on alloy forks, it would break the forks anyway. So get a couple of these, and some tourqe arms if you plan to mount a motor on a set of suspension forks.
Editing in some new pictures at this point, in 2012. This one shows the axle, in an alloy dropout that has a deep cup for a QR hub. The dropouts were filed deeper to get the axle center in the center of the dropout.
Now the C washer installed into the cup. It really works great for filling in the cup. Now a washer or nut will bear on the dropout cup, which will not press on the forks unevenly. Uneven pressure on the forks will crack them, or let the axle spit out of the dropout.
See the upcoming Tourqe arms from Ebikes-ca review for more on the hub fiting process.
Edit. Pics got lost for this thread. Here is what the c washer looks like. It's the one on the upper left. It fills the space on a fork that has a cup for QR hubs. The typical stock bicycle axle nut is on the lower right. The larger nut and washer are for a hubmotor with a 14 mm axle. Stock axle is 10 mm.
This is a 10mm nut in the recessed cup on the suspension fork dropout.
The problem is, the recessed cup in most aluminum alloy suspension forks, or even some steel forks is too small. Using the big nut and washer for the hubmotor means that there will be a gap left under the nut and washer. This gap can cause the nut to loosen, or it will tend to pry the dropout open, cracking the alloy. Then the wheel falls off at 25 mph. Ouch!
This pic, though hard to see, shows a small air gap under the nut. (pic missing)
And here, the c washer fills the void so the nut is fully supported by the shoulder of the dropout. If the cup was much deeper, it would have to be filed down. If there is still a gap after the c washer is in place, the cup is too deep. Often on alloy forks, the shoulder around the cup is not flat, so you can't have the washer or nut bearing on that. You want to have all the pressure on the c washer only.
Sorry about the lost pics. My copies were also lost in a hard drive that died. Here at least, is a pic of the C washer.
Last edited by dogman
on Wed Jun 27, 2012 4:15 pm, edited 5 times in total.
THE LIPO RULES. NEVER ABOVE 4.3V NEVER BELOW 2.7V DON'T PUNCTURE
Ideal charging /discharging range for Lipo, 3.65v minimum 4.1v maximum
See battery technology section, FAQ thread at the top of the page for lipo noob info.