Correct tyre pressure for road and mountain bike cycling is essential. If you have the incorrect tyre pressure in your bike you have to expect problems.

For a road bike with 700c high-pressure wheels, the correct pressure will be around 100 to 120 psi. For a mountain bike being ridden in the bush the tyre pressure will be anywhere from 35 to 60 psi.

On a road bike, read the sidewall of your tyre. There you will find the manufacturer's tyre pressure recommendation. It will say something like "max pressure 110psi." My recommendation is to run your bike at this max pressure.

If everything is in good condition, that is tyres, tubes and rim tapes, then running the maximum pressure will not cause blowouts but it will improve your rolling resistance and greatly decrease your chance of getting a pinch flat.

On your mountain bike things are not so clear cut. The ideal pressure will depend on a lot of variables, for example, tyre brand, type of tube used, terrain that you will be riding over and your weight. So as you can see, it is hard to make hard and fast rules.
The most important point here is to experiment a bit to find out what tyre pressure works best for you and stick to that. If you run too low a pressure you will be forever getting pinch flats and if they are too high your tyres will slide around too much. You will be very surprised at the difference 2 or 3 pounds will make.

All this information is irrelevant if you don't own an accurate tyre pressure gauge. There is no other way you will know whether you have 95 psi in your road bike tyres or 110, or if 40 or 45 works best in your Mtb. And remember, check your tyre pressures at least every second day, as you will find that over 24 to 48 hours your tyres will deflate 5 to 20 psi.

Happy Cycling!
Howard Duhs