A neighbor bought one and had problems when replacing a tube. The rims are drilled for Shrader valves and being deep "V" aero rims the Shrader stems available here are too short. I ended up using electrical tape on the Presta type tube stem so as to take up the extra space around the now too large diameter valve hole in the rim. You really can't see the tape so it looks ok. I managed to talk him into replacing the other tube as well as the original tubes on the bike are POS.