It appears the search engine does not like mathematical operands. For example, if I enter 235/40/17 to search for a certain tire size, the search engine does not recognize the slashes. It returns 2354017 as the search criterion, which comes back negative. Same issue with plus and minus signs, say for offsets. Is there a fix for this?

 

I noticed the same thing....although, if you are searching for tire size, 235/40/17 probably isn't the best search criteria since people key their tire sizes in multiple ways. One workaround that some people have utilized is a search engine and tag back to s2ki. See if that works.
here is an example here