Thoughts on Dolphin drive gear slippage

Hey folks,

I've been chasing a slipping drive gear issue with my s300i for awhile now. I replaced the drive gear twice and re-shimmed the belt wheel that is driven by the drive gear and eventually replaced the entire wheel and bushing

Here's my thoughts:
I think the failing drive gear is not always the problem but can be a symptom.

The motor unit is only located by the bottom chassis and two screws. The screw posts are super wimpy loosy goosy so the only thing holding the drive unit in pace is the tab at the front of the drive unit and a U shaped area on the right of the unit where the drive unit exits the chassis. What I think is happening is the chassis is wearing out causing the drive gear to be deflected inward towards the center of the belt drive wheel causing it to skip and eventually wear down. If you have a gear wear down and your wheel hub isn't totally worn out, odds are your chassis is worn out.



Its hard to see in the picture but at the bottom of the U on the left hand side you can see some texture where the wear is. If you see it in real life you can see the chassis has been worn away in that area creating a recession where the drive unit can slide forward in.

In the following videos you can see how unconstrained the drive unit is and how that causes the gear not to mesh correctly:


In the second video keep in mind the belt wheel, the drive gear and the belt wheel bushing are all brand new and yet aren't enough to allow the gear to mesh without skipping.

This could probably be solved by wedging the motor backwards but maybe figuring out a better tension system to pull the drive side of the motor back and create a more positive mesh would be a better solution. Anyways I ordered a new chassis because there was one in stock so I'm not looking for a solution, just putting this out there for all ya'll.

If you need a new drive gear I do have a model up for that on Thingiverse

Now you can buy them again it probably won't be super necessary though!