Note: Kenda (pre-punctured) tubes have an odd stem diameter in their presta - at least. I tried installing an anodized valve-stem collar to one recently. The stem was too large around. Bizarre. Kenda tubes are often offered as a no-name brand by web bike-parts dealers. they'll be the cheapest ones, and they won't say 'Kenda' on the ad or the box. Not a good sign.