Wet roads can be tricky. Even the best tires can lose adhesion in a painful instant.

Let's use a checklist to get a grip on this challenge.

When did it start raining? Pavement is usually slickest just after becoming wet. Traction improves as soon as it has rained enough to wash away the oily and dusty topcoat.

What's the pavement type? Well-aged blacktop or concrete generally means reliable traction. Chip and seal should be no problem because tires can grip the rough surface. Smooth, new pavement poses a risk because it releases oil when wet.
On any surface, beware of sandy corners, spilled oil, sealing tar, metal plates, leaves and painted lines. When wet, these can be like ice patches.

What's your tire pressure? Generally, reducing inflation by 10-15 psi adds traction by increasing the size of each tire's contact patch. The rule for rain: Run the lowest pressure you can without causing squirmy handling or pinch flats.

Is there slipping when you stand? Climbing or accelerating out of the saddle is a relatively safe way to test traction. If your rear wheel slips, ride gingerly.
Finally, consider the LeMond parking lot test.

Years ago, Fred rode with Greg on a rainy California day. Before they rolled out, Greg cruised around the parking lot, doing "hockey stops" with one foot out of the pedal, downhiller style. Then he knew how much traction to expect.


Source: RBR