Another observation, do road bikes lose pressure in the tyres faster than mtb? Both my bikes have presta valves, the mtb gets a top up every couple of weeks (and is used regularly during the week for communting), the road bike seems to lose about 20-30 psi in a week, even when not used. They are the stock tubes it came with and it did this before I even went on my first ride, so definitely no punctures...