I took my front tire and rim off to get balanced. Had a very slight vibration between 50 and 60 mph. The bike shop said the tire i had was junk because of side wall cracks. So new tire same as old one and the bike bounced so bad between 50 and 60 it was scary. Found that the tire had like a flat spot about 5 inchs long. I put a dial indicator on rim and all was fine. This is a Dunlop harley tire. Whats up with that ? Anyone experience a tire problem like this or is this common .