Janae you should have the WHOLE triangle part on the outside of the cage and the bar down the back on the outside and then the bar that the wheel attaches to poking through the bar. Zip tie everything the way you currently do and the wheel will be steady. The triangle part going through the cage the way you have it creates a bigger hole area that your babies may get stuck in.
Does what I said make sense? I'm not sure I worded it so you understand.