What pressure should I run my Road Bike tyres at?
There's a question for mountain bike tyres but I can't seem to find anything on here for road bikes. At the moment I'm running at around 90psi. Is that too much? too little? Also, am I more likely to get punctures running at higher pressure? I seem to be getting a lot lately.
Also, one thing nobody's said: go with the manufacturer recommendation listed on the sidewall.
The mountain bike tire pressure question referred to here is: http://bicycles.stackexchange.com/questions/471/what-pressure-should-i-run-my-mountain-bike-tires-at
All other things being equal, run them as high as the tyre manufacturer recommends (there will be an advisory notice on the tyre wall). For most tyres of even medium quality, this should be at least 100psi, if not 110; higher end tyres might go up to 130+. (I generally inflate both tyres to similar pressures, but I think that there are some theories that if either were to be higher, that should be the rear, because it carries the majority of the weight.)
Indeed, the higher the pressure and the harder the tyre, the fewer punctures you should expect as the surface should be better at repelling objects.
You should keep tyres topped up, natural leakage occurs and at the higher pressures you might expect 10-20 psi drift within a week.
When re-inflating, you should also take the opportunity to inspect the tyres. Any deformity or wear will be sure to be far more obvious and damaging when the tyre is inflated to the limits of its recommended pressure.
The only caveat is in poor weather, where a reduction in pressure increases the contact area and introduces give, which should make for enhanced traction.
+1 -- I'll add that the maximum not only varies with tire quality, but also width. 28mm tires are not likely to go up to 130psi.
+1 -- I'd add the second caveat that reducing pressure can make the ride more comfortable over slightly rough asphalt.
+1 -- I'll add that for most purposes, 100psi is a decent pressure to ride at. The increased performance of any higher pressures is likely negligible, and will have a noticeable decline on ride quality.
It is important to keep the pressure right, if it gets low you will get pinch flats from hitting a hard bump or hole in the road. As long as I keep my tires well inflated I rarely get flats and those that I do are the real type from something actually puncturing the tire and tube.
I'll counter the advice to reduce pressure in wet weather. On a bike tire, pressure is what displaces surface water instead of it lifting the tire off the surface (hydroplaning). With more pressure, the tire will roll at a higher speed before hydroplaning. This may not matter at normal riding speeds and pressures, but at low pressure it could make a difference.
Interesting fact - hydroplaning on a bike is effectively impossible. See Sheldon Brown's page for details: http://sheldonbrown.com/tires.html#hydroplaning
It's a good idea to have lower pressure in the front tire. In general, there is less weight over that tire. This means the contact patch (part of the tire that touches the road) will end up being smaller on the front if you use the same pressure. Using about 10 less psi on the front will give you more consistent contact patches and more stability.