just a different profile of the tire. 190 is not as "sharp" and gets a little better wear since ther is more tread. 180 is sharper and alows the bike too tip over easier in to a turn, and right itself out of one. but because of there being a smaller contact patch when cruising up right they wear quicker then the flatter 190's. so if you using the bike to get from A-B everyday then consider the 190's as a tire that will last longer, but if its a weekend warrior corner carver then get the 180's and you will be happier with your turn-in.
hopes that helped
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Originaly posted by: ?
And despite common misconception, performing a wheelie to be more visible while passing a vehicle isn't the best practice in the DMV's mind.