Trainright Now: Cycling Fast and Safely in the Rain

Originally published in Road Bike Action Magazine, July 2014

By Chris Carmichael

On a recent Saturday morning I got a call from Jerry, an athlete I’ve only been working with for a short time. His criterium started in an hour and he was sitting in his car listening to the rain pound on the roof. “Should I race?” he asked. I paused, and then realized he had recently moved from Arizona and probably had little to no experience racing in the rain. So rather than just tell him to man up and get out there, I gave him a quick course on racing in the rain. 

Jerry didn’t pull off some heroic first-timer victory, but he did overcome his fear and finish the race. If you’re racing or participating in mid-summer events, chances are pretty good you’ll cross paths with a storm. Rather than pack up and go home, learn to embrace the rain. The more comfortable you are racing in the rain, the more you can use it as a competitive advantage!

Since this is Road Bike Action, I’m going to skip over some of the very basic facts about riding in the rain. I think you all know to brake earlier when it’s wet, avoid road paint and manhole covers, and keep an eye on your core temperature. So let’s more on to some more in-depth information.

Wheels, Tires, and Pressures

Some of the recent changes in tires and wheels are helpful – although not intentionally – for riding in the rain. Researchers at Wheel Energy in Finland have shown that wider tires have lower rolling resistance, partly because there’s less deformation of the sidewalls. Rims have been getting wider, too, and the benefit there is a reduction in the “lightbulb” profile of the tire/rim interface (when the tire is significantly wider than the rim). This has aerodynamic implications, but also changes the way the tire flexes as you lean into a corner. The combination of the two may be part of the reason riders report better handling and greater cornering confidence with wider rims and tires. Tubeless road tires have only added to that handling and confidence advantage, because they allow for lower tire pressures without the risk of pinch flats.

What does any of this have to do with riding in the rain? Mounting wider 25c tubeless tires on wider rims gives you the opportunity to take advantage of low rolling resistance for speed while improving cornering traction due to the shape of the tire’s contact patch on the road and the improved ability for the tire to flex/adapt as you lean into a turn.

Don’t have wide tubeless tires to mount on wide rims? You’re still better off with a relatively wide tire (25c) and lower tire pressure of about 85-90psi compared to 110-120psi. And if you’re planning on riding wheels with a carbon braking surface, be sure to get the brake pads recommended by the wheel manufacturer. Standard brake pads on carbon rims are bad in dry conditions; they’re a scary combination of useless and unpredictable in wet conditions.

Staying Safe and Riding Fast in the Rain

Here are some tips for staying upright and going fast:

• Read the rain: The most dangerous scenario is a light sprinkle on high-traffic roads that haven’t been rained on for a long time. The built-up oil on the road floats on the water, but there’s not enough water to wash the oil into the gutter. Racing after a good downpour can be the best-case scenario because a lot of the oil and grit may be washed away.
• Think smooth and sweeping: Carving tight turns always pushes the limit of traction, and when traction is already compromised because of water you have to ride more gracefully. Sudden movements that place a large horizontal force on your tires, like flicking the bike side to side or diving to the inside of a turn, can cause your tire to lose traction completely.
• If there’s a crash in a corner riders slide toward the outside and slide a lot farther than in dry conditions. Stay to the inside – even just the inside of the wheel ahead of you – to minimize the chance of getting taken down. Allow a little more space than you would in dry conditions to give yourself a better chance of avoiding a rider who falls in front of you.
• Keep your center of gravity over your tires. Lean the bike into the turn but keep your body more upright than you would in dry conditions. This keeps more downward pressure on your tires by keeping your center of gravity closer to your contact points with the road, increasing traction. You can get away with leaning your body into the turn more in dry conditions because there’s more friction keeping your tire from sliding sideways.

Practice, practice, practice

You have to ride in the rain if you’re going to gain the skills and fortitude to do it well. The goal is to get to the point where the rain doesn’t faze you and you can focus on your event goals while everyone else is worried about the water. To do this you’ll need to be willing to roll out of a dry garage into a steady downpour. This is the time when you’ll figure out how far you can push it in the corners, how early you need to brake, what tire pressure works best for you. You’ll also sort out your clothing choices.

Maintain perspective

It’s wise to be proficient and confident riding in the rain, but unless your mortgage payment is dependent on your cycling performance, it’s also important to know when to say when. Cars barely notice cyclists in good conditions; in the rain we’re invisible. If you’re going to train in the rain, use reflective clothing and front/rear blinking lights. If you can’t give yourself a fighting chance, it’s not worth the risk. And when it comes to competition, I encourage racers to face their fears and race in the rain, but when fear or apprehension is more consuming than your ability to focus on the race, then you’re a danger to yourself and the riders around you and it’s time to call it a day.