Spur Gear Head motor 12V 50:1 152 RPM - encoder possibility?

Hello,
Our research group recently purchased several gear head motors which have functioned superbly, however we realized soon after that we needed a higher torque rating for one of the motors and purchased the 12v 50:1 with 16.7 kg-cm stall torque.

Here is my question/problem.
We plan to incorporate feedback into the system at some point, is there anyway to add the encoder shaft and assembly to this specific motor or would we be able to exchange the motor for an alternative? I have already looked at the 7.2v 50:1 rated at 7.1 kg-cm stall torque and am not quite sure it will be sufficient, the motor we used previously was the 30:1, with stall torque of 4 kg-cm and it was not capable to lift the desired load although it tried. Unfortunately, we can not measure the load mass either as it is already permanently fixed to the framework.

Thank you for your help,
Doug

Since the motor is already used, it cannot be returned. Unfortunately it does not have a rear shaft so you cannot mount a rear encoder (if you can find one large enough to mount to the output shaft without impeding the mounting it may be an option. If you need higher torque, we would suggest a P60 system, though the compatible motors do not have rear shafts either:
Ex: robotshop.com/en/banebots-64 … r-kit.html

We have a section for gear motors with rear shaft here:
robotshop.com/en/gear-motors … shaft.html
We’re working to expand the product selection, though at this time we don’t offer any higher torque motors.