Tire PSI

[ezrollin]

The tires on my Trek 7000 allow 60-80 psi, what do you guys suggest or is it personal preference?

[xerxes]

You should follow the guideline pressures marked on the tyres. Too low and you can damage the side walls of the tyre, too high and you run the risk of blowing the tyres off the rim. But within the minimum and maximum you can have them how they feel best for you.

[trevgbb]

and harder tyres are more resistant to punctures.

[Bill]

Well said above, only thing I can contribute is find a comfortable pressure that suits you on the terrain you ride on. The Trek 7000 I looked up is a touring bike?

[Jordan300]

I always go just a few lbs shy of maximum in order to roll faster. That's my preference.

[cyclerUK]

Offroad I used as low a pressure that would withstand pinch punctures. (hardtail cross-country MTB)
On road - as high as the tire rating plus a bit.
My sports bikes (on road) about 100 to 110 psi.

[sidmarx]

All that being said, various sellers on ebay are telling me they have no hi pressure tires in my size. I'd like to run 100-110 psi on 20" x 1.75's, but the consensus seems to be that the high pressure tires are all fatter than my size, which is ISO 47-406.

Upshot: Does anyone know a tire source or brand of 47-406's that take 100-110 psi?

[xerxes]

A really hard tyre on a 20" wheel would probably give a vary harsh ride; smaller wheels are stiffer and have less give than larger ones. In addition wider tyres have less rolling resistance than narrow ones, so a very high pressure may be disadvantageous, providing less less comfort and grip. Small wheels also have more rolling resistance than larger ones, so it's probably impossible to get a 20" wheel to roll as well as a 29" with similar tyres.

Take a look at these:
http://www.schwalbetires.com/tech_info/rolling_resistance

http://www.sheldonbrown.com/tyres.html

[Bill]

(10-18-2010, 03:44 PM)xerxes Wrote:  A really hard tyre on a 20" wheel would probably give a vary harsh ride; smaller wheels are stiffer and have less give than larger ones. In addition wider tyres have less rolling resistance than narrow ones, so a very high pressure may be disadvantageous, providing less less comfort and grip. Small wheels also have more rolling resistance than larger ones, so it's probably impossible to get a 20" wheel to roll as well as a 29" with similar tyres.

Take a look at these:
http://www.schwalbetires.com/tech_info/rolling_resistance

http://www.sheldonbrown.com/tyres.html

This is very true. To think about it BMX was originally intended as an off road bicycle if memory serves me. The only way to get less rolling resistance is to go with with thinner tires. You can also make sure your wheels are maintained properly with undamaged parts i.e. bad bearings, bent axle etc. As far as anything else I can thinking of is make sure your wheel are true!

Hope this helps,
Bill