We Don’t Live In A Vacuum.

If we did, aerodynamics wouldn’t matter.  At speeds of 11-12 mph air resistance is equal to all of the other factors of riding resistance combined.  At 19 mph it’s 75% and increases as the speed does.

The slower you are the more it affects your overall time because you are out there longer (or so they say).  

But people buy bicycles primarily based on weight and appearance with little regard for their aerodynamics.  The biggest factors for bicycle aerodynamics are the wheels because they lead the bike, take up a lot of frontal area, and rotate like egg beaters.

Generally speaking, the fewer the spokes and the deeper the rim the more aerodynamic it is.  Wider and bullet shaped (as opposed to V shaped) profiles are also more aerodynamic.  Getting more aero is going to get you a lot more speed than reducing weight.

Thanks for reading – John Neugent
http://www.neuvationcycling.com/

The spokes are Sapim CX Ray spokes – the best out there.

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
http://www.neuvationcycling.com/


Optimum tire pressure for 22mm wide rim
front ->  96 psi
rear  -> 106psi

or 

Optimum tire pressure for 22mm wide rim
front -> 94 psi - 96 psi
rear  -> 102 psi - 106psi

Weight lbs Rim Width Tire Size Front Tire Pressure psi Rear Tire Pressure psi 210 22mm 23c           78        117 150 22mm 23c                 75 (86)          92 (100) 140 22mm 23c             55          78 140 19mm 23c           62                                              88 150 19mm 23c           90          106 210 19mm 23c           88         132