Thanks for all the great responses. Just today I came across a pumpless rider needing help. I couldn't get my pump to convert to presta to help him. That's great since I've been riding the last few years with presta. I haven't had flats with the knobies. Since I've gone to semi-slicks and riding in the city I've had two...lucky for me the tires went down in the garage following the rides....thanks to all....
pkgman