So beginning of the riding season I noticed my rear tire was completely shot. Being new to motorcycles, and completely broke I did some research and ordered a Shinko 230 Tour Master. Now I have put quite a few miles on the bike, and my front is going bad. I was going to throw another Shinko on it but turns out they don't make the correct size for the front. I also realized that the guy down at the motorcycle shop convinced me to put on a 120/90V 18 on the rear when stock is a 100/90 18. Now I am wondering if that is a bad thing? I still do not really have enough to buy two tires, and I am kinda stuck as to what to do about this. I can go with a Shinko 100/80 on the front, but stock is 100/90. Will I feel a major difference? I am worried about screwing up the handling more than I already have.