*Taken from golden eagles*...
Golden Eagle Bike Engines, Geared Belt Drive Bicycle Engines / Motors for Mountain Bikes & More
Rack or rear mount belt drive
How to measure to see if our kit will work on your bike
Minimum Clearance between Inside of forks/seat stays:
3 & 3/8" is the Minimum Total clearance between Inside of forks/seat stays. Measure 8 & 1/2" up forks from Top of the axle, at that point (it's where the ring sits on the wheel) you need 3 3/8" between the Inside of the forks. 3 3/8" is exactly the length of the long edge of a credit card. At 8 1/2" up fork from axle, slip a credit card between the forks - if the card fits, so will the drive ring.
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**Not quite enough clearance for drive ring? A customer shared steps taken when found need for additional 1/8" between rear forks/seat stays and spokes for clearance for the drive ring: Remove rear wheel, insert long bolt thru axle holes on frame, secure w/nut - this holds forks/stays in correct position, measure along frame 8 1/2" to where drive ring will be positioned, spread frame using scissor jack from a small car (another cust. used 2x4's). DO NOT spread frame any more than needed. NOT recommend for the tight, 'squeezed in' frames. **This is ONLY recommended for those who need additional 1/8" clearance. ** Readjust brakes as nessacery.
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24" Wheel - Specific
Bicycles with 24" Wheels -
If your bike has Caliper, Disk or Coaster brakes, And you have measured fork width for drive ring clearance - installation of the GEBE Mount Kit - With or Without Engine should go smoothly.
BUT if your bike has a V-brake, you should take one final measurement - for Ring/Brake clearance.
Measure up the fork to the edge of the brake post - if you have 8 1/2" Clearance from the Top of the axle to the brake post, there is Adequate Clearance.
If you measure Less than 8 1/2", from top of axle to brake post - File axle drop-outs back 3/16". This will allow the wheel to be moved back 3/16", providing clearance. Re-adjust brakes!!
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** IMPORTANT! We DO NOT recommend you motorize a 27" touring bike or a coaster brake bike. The rims and spokes of these bikes may not hold up well to the pounding they will take at Eagle speed.
** IMPORTANT! This kit is NOT designed to mount on a Quick Release axle. The Quick Release should be replaced with a standard solid axle (available at most bicycle shops), comes with cones and bearings. - OR - You can purchase a Replacement axle from GEBE that fits the cones and bearings of the 10mm Fine or Sealed Bearing quick release axle.