Conti Contact question
My new bike came with Continental Contact tires. I love them, but they don't seem to keep air for very long. I'm for ever 'topping up' the tires and if I forget they will lose most of the pressure in about three weeks?
Is this normal for these tires? I'm going on a European tour; should I change the inner tubes?
What has loosing air from the innertubes got to do with the tyres? If the valves on the innertubes leak then you can't really blame the tyres. Change the tubes.
This is most likely unrelated to your tires unless they have a piece of wire or glass in them casuing a very small leak in your tube. Most tubes are butyl rubber which is not 100% impervious to air. This means that over time some air will leak out of any tube. Some tubes may leak faster than others. In any event no tube is perfect and you will always have to add air - sometimes after a few days and sometimes after a week or so. Changing the tubes might help - but maybe not. Much better to insure you have a pump and top off your tires frequently. Latex tubes leak more and if you use a CO2 to fill your tube it will leak faster as well since the CO2 molecules are smaller than air molecules.
Good inner tubes can hold air for a surprisingly long time. I pumped my tires in early-July, rode 500 km during a week-long tour (including an entire mroning on a gravel road), did errands around town, did a 50 km trip, and finally, did more errands.
During the last week in August, I noticed the tires were just starting to need a topping up.