Re: tire air pressure - Cycling Mob: Road Cycling, Mountain Biking and More

06-16-2004, 12:02 PM

Antti Salonen <[Only registered and activated users can see links. ].cc.helsinki.fi.invalid> wrote:

> Together with the bike and other gear I
> weigh about 155 lbs, and I've run my 23 mm tyres at pressures between
> 105 and 120 psi with no real discomfort. According to the graph, the
> "ideal" inflation for me would be 80 psi, which seems ridiculous.

Many 200 lb riders (~222 lb rider plus bike) ride 23 mm tires at 120 psi.
Don't you think that you (being much lighter) should run significantly
less pressure? I know it may "seem" ridiculous since most of us tend to
air up the max pressure printed on the tire. But it really should be
related to the load.

> I guess I could get away with just 80 psi without getting too many pinch
> flats (I get none now), so perhaps the graph can be helpful in determining
> the lowest safe pressure. But especially for lighter riders, there's
> usually no reason not to go higher than that.

Less pressure will give better traction and a more comfortable ride. That
could be especially important in rain or on dirt roads

The chart appears to be from Bicycling Magazine, but the website that
hosts it is tandem related. It works out about right for me: 225 lbs
(rider+bike+gear) and 700x25 tires. According to the chart, I should
run 100 psi. I usually run about 105 psi. I get good tire life and no
pinch flats.

But my wife weighs 110lbs and has a 25 lb bike with 1-1/4" tires. She
would be off the chart (less than 50 psi). We actually run about 75 psi in
her tires.

Art Harris