I just bought an 88' model, with plastic looking wheel spacers on each rear tire. I've never used them before and they seem like they are very weak the more I look at them. What's the odd of it breaking on a small jump? Like five feet or less vertical height?

I have to take the plastic spacers off of a quad any time I am doing dyno work.  The wheels wobble and hop on the rollers because they do not run true.