File dropouts and widen stays for Leah’s eBike conversion

November 10, 2010 · 0 comments

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Now that the freewheel is installed and the minimum space between the dropouts is verified to be 135mm, the next steps are to

  • Test fit the wheel
  • Check for freewheel clearance
  • Check the wheel centering
  • File and fit the axle to fit in the dropout.

Check freewheel clearance

Without the inner washer, there isn’t enough space between the freewheel and frame. The inner washer should provide enough space for it but will require the distance between dropouts to be 140mm. This will require spreading the stays.

Check wheel centering

I like to check wheel centering often because it can be an indicator that there is something else wrong that needs fixed before proceeding. It’s a confirmation that everything is in order.

If the original rear wheel was properly dished and centered in the stays, the hub motor wheel should be centered too. The E-BikeKit wheel is properly dished so there were no centering problems to solve.

File to fit axle into dropout

Most dropouts are made for 10mm axles. The rear hub motor axle is 14mm with a 10mm keyway machined onto it. This means that the axle will slide into the 10mm dropout but won’t go all the way to the top as shown in the video.

The axle needs to have a tight fit in the dropout. See the video for tips on how to do this. It’s going to require filing a little and inserting the hub motor wheel to test fit repeatedly until it fits. This can be tedious and frustrating. Be patient, take your time. Plan for it taking a while to get a smooth tight fit. All of the stresses from the wheel are focused on the dropout. It can break and hurt you if it’s not strong. So take your time and make it right.

Note about filing: Take it easy and take your time. It’s a lot easier to remove metal than it is to replace it. You can ruin your bike and make it unsafe to ride by removing too much metal or leaving jagged edges. Make sure to file a little, test fit, and then file a little more only as needed. Make it smooth, clean looking, and precise. Large gaps will make the fit loose. Jagged edges are opportunities for cracks to form.

Spread stays for correct space between dropouts

As mentioned previously, Leah’s bike is going to need the inner washers to create enough clearance for the freewheel. This is gong to require spreading the stays to 140mm between the dropouts. I made it 142mm to make it a little easier to install the wheel.

Watch the video to see how I spread the stays. It’s not too hard but will require repeating the process of spreading and measuring. Start with lighter pressure and work up to higher pressure to avoid over widening. Do it in stages.

I don’t recommend spreading the stays on an aluminum frame bike. It might be possible but aluminum tends to break before bending. Leah’s bike frame is made of steel. Steel is much more forgiving when bending. See more about selecting the right bike for conversion here.

Next Step

The next video will finish the hub motor wheel install by showing how I install the torque arm.

Click here to see all posts about Leah’s Electric Bike Conversion.

Stay tuned for more details as this project proceeds.

P.S. Want to know more? Click here to get my free Motor Selection Guide and newsletters that contain information not included on the blog.

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