I soon realized that the bikes tire tread was so aggressive it was creating a low-frequency sound against the contact points which also cause great vibrations in the room and floor. " That being said, I replace mine every Christmas. Ive had these on my service truck for about 2mos now and use them while on a call. My vipaspectra 600watt is much louder than this fan with filter and standard ducting at #5. All in all, you cannot be the value and quality for the price. This product is ingenious. A vast difference from my initial pair, which were immediately comfortable the first time on. 5)Faults due to wear and tear and force majeure. More and more everyday They are adorable and comfortable though. Slightly tight fitting across the foot so if you?re feet are wide fitting these might not be for you.