Hi, I'd like to help you with your question.
Does your son exhibit any other concerning behavior, such as lack of flexibility, trouble with social interactions, or have one sided conversations with a focus on his own interests or even trouble with being socially involved at all?
It sounds like your son might have some symptoms of Aspberger's or Autism or he may have a sensory issue. If he does have Aspberger's, he is definitely on the fringe of the diagnosis and may not fit all the criteria. Although that may feel overwhelming to consider, many kids have these symptoms without actually fitting the diagnosis itself. And they do just fine in life.
The fact that he has friends is a good indication he is doing well. His high intelligence is a good sign as well. The sensitivity to noise in class and the tactile focus (feeling the tires) indicates either something like Aspberger's or a sensory issue. Either way, he may benefit from an evaluation by a psychologist. One who specializes in Aspbergers and/or sensory issues would be helpful. Talk with your son's pediatrician about a referral. Ruling out these diagnosis will help. If it is found that he does not have enough symptoms for a diagnosis, then your son's desire to touch tires will not hurt him and does not indicate he has any serious emotional issues, as long as it does not interfere with his life in any way.
I hope this has helped you,Kate