Suggested Requirements for Electrical Conversion

Front Wheel Conversions

Front Hub

We suggest you have a minimum clearance of 4”, or 100 mm, between the dropouts of your fork, as well as an area of clearance 4” upwards and 3” width-wise between the forks.  This will ensure that there is enough room for the entire hub to fit in between the forks with enough room to freely rotate.

The axles for the hubs consist of a standard size.  A 10 mm clearance within the dropouts should suffice for the majority of our kits.  There may be a need to file away some of the paint, but this is only due to variations in bike models.  Some dropouts are just shy of 10 mm so filing away the paint will allow enough clearance.

 These are the standard clearance requirements for most of the front hubs we carry:

The one exception is the Wilderness BD-36 motor.  It has a slightly wider Horizontal clearance requirement:

Steel Forks

Front wheel conversions should only be installed into bikes with steel, or chromoly, front forks.  Aluminum forks have less tensile strength and malleability than steel.  This means under high stress situations they have more of a tendency to snap rather than bend.  The torque from the motor may cause aluminum forks to break, so it is not suggested that front wheel conversions are installed into aluminum forks.  A quick way of testing the metal is to use a magnet.  If it attaches firmly onto the forks it is likely steel.

Front Shocks

Having shock absorbers in the front fork will absorb some of the kinetic energy created by the motor itself, and this potentially problems.  Shock absorbers are designed only to handle upward and downward motion.  The additional torque caused by the motor may create too much stress and possibly break the suspension unit.  It is suggested that a front wheel conversion is not installed onto bikes with front shocks.  A rear wheel conversion is suggested for bicycles with front shocks.

Quick Release Axle

Generally forks with a quick release have a different type of dropouts since they are held in through tension.  When a front hub motor is mounted it may become loosened easily due to the indented spacing in the drop out.  This creates a gap between the surface and the washer.

This can be easily fixed by placing split lock washers (available on request) through the axle while installing.  This fills the gap to make the area flush allowing the completed installation to be held tightly in place.

Disc Brakes

Front disc brakes are incompatible with any front wheel conversion kit.  Brakes will need to be changed to V-brakes in order for front wheel conversions to work.  Otherwise a rear wheel conversion should be considered.

Rear Wheel Conversions

Rear Hub

Conversions with a rear wheel installation require less attention regarding the fit since there are no issues associated with the front forks.  The kits offered by It’s Electric will fit into any bicycle provided the correct size rims are ordered.   Rear motors require 5 2/5”, or 135mm, clearance between the dropouts, and the standard 10mm within the dropouts.

Though the fitting is simple, some of understanding in bike mechanics is required for rear wheel conversions due to the increased number of parts that have to be dealt with.  Typical skills required include: 

(a) adjusting the derailleur;

(b) configuring the shifters;

(c) removing and installing a freewheel.

Dealing With Gears

The kits carried by It’s Electric are only compatible with the freewheel.  When ordering a rear conversion kit a freewheel of the necessary speed will be provided .  The kits available can only support a certain number of speeds depending on the thickness of the hub.  The Crystalyte kits are only compatible with 6, 7, and 8 speed freewheels.  Bionx kits are able to support speeds 5 – 9.

The number of gears on your rear wheel can be determined by simply by counting the number of rings attached to your wheel.  The total speed can also be divided by 3 since there are usually 3 gears in the front (eg: 21 speed = 7 gears, 24 speed = 8, etc.)

If you choose a kit with a different number of supported speeds than your original set-up you will need to change your rear shifter as well.  The number of speeds of the shifter would need to match the number of gears.

Disc Brakes

Most electric bike conversion kits are incompatible with disc brakes due to the width of the hub.  Crystalyte provides kits with rear disc brakes, but there are too many complications so they are not available from It’s Electric.  It is suggested that Crystalyte rear wheel conversions not be installed onto bikes with disc brakes unless it is replaced with a V-brake.  However, Bionx kits are completely compatible with disc brakes because of their slimmer hub motor.

Other Requirements

Determining Wheel Size

One final thing to take into consideration is the size of the bicycle wheel.  This is not the same as the rim size, so DO NOT measure the size of the rim.  This is the diameter of the tire itself meaning the rubber exterior.  If you look closely on the tire there should be dimensions printed on that mark the diameter against the width of the tire (eg. 26” x 1.75”, which means a 26” diameter with a 1.75” width across).

he same issue on disc brakes presented on front wheel conversions apply to the rear wheel as well.