The 15% Rule Of Tire Inflation.

A good customer and newsletter reader, Charlie Zwick, sent me a copy of a great article from Bicycle Quarterly about tire inflation. It says, for most riding, tires should compress about 15% when you get on your bike. 

The front and rear tires, typically take remarkably different pressures. To determine yours, put your bike on a bathroom scale (with one wheel on a block of the same height) and get into your riding position. Record both front and rear wheel scale readings.

Bike and rider for me is about 210 pounds with 40% on the front wheel and 60% on the back. The chart indicates that I should be running 88/132 psi for 23C tires and about 75/100 for 25C. If we factor in an additional 11% pressure reduction that the wider rims offer (according to Steve Hed), that would equate to 67/98 for 25C and 78/117 for 23C. Note how low the pressure is in the "controlling" front tire - that, my friend, can change your world.

My significant other who with bike, hits the scales at about 140, would have these numbers. Normal width wheels 25C 55/75, 23C 62/88 and with wide rims 49/67 on 25C and 55/78 on 23C.

Tire pressure will affect your ride much more than any other factor – both in terms of comfort and performance. My guess is that less than 1% of bike riders are riding on the right tire pressures. You can experiment with tire pressures for free. Have fun.

Thanks for reading – John Neugent