If you want to sell a square slick then you need to make it a square slick. A square-shoulder won't handle as well as a rounded edge at extreme turning use, but then again,,, any center ridge big enough to make a difference in the handling is going to make it "not a slick". And people won't be buying it for its extreme handling abilities anyway.
Also: I grew up riding a Stingray with a slik on the back, and I don't remember it ever endangering my life. At least, I can't see that the tire had much to do with that.... :lol:
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As for the lettering, I would leave it blank. There is already latex rubber paint sold that is used for making blackwall tires into whitewalls. Painting stripes or stenciling letters on isn't that difficult.
(and besides, whatever you put, somebody won't like it. A lot of people already say they like the Schwalbe cream Fat Franks, but they HATE the company logo and reflective sidewalls..... and sanding them off is very risky, as it's easy to damage the sidewall casing.... it's far easier to put your own lettering on a blank tire than it is to get factory lettering off)
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