Strida KS3 Gearbox Replacement
This post is intended to provide the information needed to remove and replace the Strida KS3 gearbox. Please read the post completely before starting a gearbox removal and if you have any questions or need help please contact me.
The first step
The first step is to remove the kickstand from the bottom of the KS3 by removing the 6 mm hex bolt. Under the kickstand is a curved metal part that fits against the bike frame, it is the kickstand bracket. The kickstand bracket holds the small curved metal locating block in place against the KS3. The locating block is removed by lifting it out of it’s slot.
The next step
The next step is to remove the KS3 Internal lock ring. This lock ring should be loosened before removing the kickstand bolt so that the KS3 gearbox does not turn in the bike frame. The KS3 Internal lock ring is removed using a 95 mm hook wrench. The one displayed in the photo is the Strida 95 mm hook wrench. I also stock a custom designed 95 mm hook wrench for this operation.
After the KS3 Internal Lock ring is loose or removed then the belt can be loosened by sliding and rotating the Strida KS3 gearbox in side the bike frame.
Before the KS3 gearbox can be removed from the bike frame the left crank needs to be removed. Removal of the crank requires removing the crank bolt. The crank bolt can be very tight so care is required that the 8 mm hex key is placed firmly in the hex bolt while turning. Using a long 8 mm hex key for removing the crank bolt is a good idea for the extra leverage.
After the crank bolt is removed a crank puller is needed to pull the crank off the gearbox shaft. Much care is required when using the crank puller. The crank puller is made of two parts, the first part is threaded into the internal threads of the crank. These are very fine alloy threads that can cross thread easily so please be very careful when starting these threads. To make this easier I separate the crank puller into the two parts and thread just the one part first. This makes it easier to line up the threads. Then I thread the crank puller arm into the first part and tighten to pull the crank from the shaft. This can be done without removing the pedal but the pedal will need to be moved as you are tightening the crank pullers arm. If you decide to remove the pedal it requires a 15 mm wrench. Please note this is the left pedal so the threads are opposite from the normal counter clockwise removal.
Gear Box Removal
Once the left crank is removed the Strida KS3 gearbox can be removed from the bike frame with the beltwheel attached. If I am helping a customer with a Strida KS3 gearbox problem I will send the replacement gearbox with the beltwheel attached. By doing this the Driver Lock Ring that holds the beltwheel to the KS3 gearbox does not need to be removed. The removal of the Driver Lock Ring requires this tool, and a torque wrench.
Install the Strida KS3 gearbox in the reverse order. The belt needs to be tightened so that when depressed from the top with moderate pressure it has slack enough to just touch the bottom tube. It is better for the belt to be too loose than for it to be to tight.
Here is a link to the Strida KS3 gearbox manual in the Strida website.