Keeping Rubber on the Road

After my spill a few weekends ago I started to wonder why I had fallen so easily. Certainly the combination of rain, fresh asphalt, and right-angled corner were the major contributing factors. But I wondered, at 5 mph or so, could I have avoided the accident all together? An investigation of my Trek Equinox's tires uncovered I had zero tread left. I bought the bike used a year and a half ago and haven't paid much attention to the wearable items since.

This week I decided it was a wise investment to purchase a new set of tires instead of ending up with a broken wrist/arm/thumb somewhere along the way. After some online research I decided to roll with Vttoria's Diamante Pro Techs for roughly $55 a piece at the local bike shop. The manufacture boasts they're good in wet weather and puncture resistant. Works for me. I strapped them on, pumped them to 100 psi like normal, and rode to work the next day. What a completely different feeling from before.

The new tires seemed to zap power and felt squishy, like I had a flat. Now worried about dropping $110 on junk, I did further research about road tires, specifically about pressure, weight, tread, rolling resistance, and Threads Per Inch (TPI). Prior to the purchase I had read plenty of consumer reviews on tires, much geared towards the ability to resist flats and wear. A new search turned up studies on the rolling resistance of certain tires and the watts required to overcome them. In some cases, a pair of tires might require an extra 5 watts to move at the same speed as another. The resistance factor is largely based on the width, tread, material, weight, and inflation. I didn't see my Diamante Pro Techs on the list but I knew it was harder to hit 22 mph on the new tires then on the old and bald Rubino Slicks. I wasn't happy with my new purchase since I was trading speed (estimated 1.0 mph) for safety. I then noticed I purchased 220 TPI tires, which means higher internal pressures allowed, which means I can achieve less resistance with more pressure. I went back to my bike and pumped them up to the recommended minimum of 115 psi instead of the 100 psi I was using. The next test ride I felt strong and more in control with less squish, but still some of that flat tire feel remained. I'll have to keep playing with the pressure to see if it makes a difference.

If you want to learn more about tires I recommend checking out this guy's site: http://www.sheldonbrown.com/tires.html