- Water: Water is your friend. If you're like me and you start off your day with coffee and need a coffee boost sometimes in the afternoon just to make it, then it's very easy to find yourself in a bad situation hydration-wise. The morning ride is usually fine since it's cooler then and hopefully you've just had breakfast. The fun starts when it's time to mount up for the ride home in the heat. I've had some bad rides where I didn't have water along, and I was dried out, and the weather was hot. Don't do that. The best thing is to start tanking up an hour or so before you have to leave and then drink early, often, and in small doses. Embrace the sweat! It's good for you, and you can shower when you get home.
- Shade: Shade is also your friend. The ride in in the morning is usually pleasant because it's cooler and the sun is lower in the sky, meaning (at least in Austin where there are trees) that your ride is shadier. In the afternoon or evening, when the heat is up and the sun is high, seek routes that have shade, even if you have to go out of your way. This can mean the difference between a pleasant ride and discomfort. Direct sunshine makes a big difference (see next point).
- Shirts: Bring an extra shirt for riding. If I wear a lycra jersey (I have a couple from some charity rides, but I don't usually like to show them off) then it's easy enough to change out for the day and put it back on for the ride home. T-shirts usually don't recover during the day and need to be stashed out of sight in a bag so bring a second one for the ride home. Short-sleeve button-downs actually have an advantage: if you practice a little bit and don't use a backpack, you can find a posture that will inflate your shirt through your sleeves or collar, and this is awesome air-conditioning. It's possible to do this with T-shirts, but I've had little success with polos, and I think we don't need to mention long sleeves for hot weather riding...
- Shorts/pants: Shorts are best, and with pants, the lighter the fabric the better, but that said, I usually have to wear jeans because I work in an engines lab, and if I can wear them year round, so can you. I recommend against spandex shorts, for several reasons. Black ones are sun-magnets and unbearable in the sun. White ones show way too much, and any other color is bound to be plastered with that ultimate poseur-sin: the team logo. Actually, in my humble opinion, spandex shorts are almost always poseur-fashion and don't really offer enough advantage to justify wearing them on a commute. They belong in bike races, not on the commuters.
- Load: Lose the backpack/shoulder bag. They leave sweat stripes. I used to be a backpack only rider, but I have made converted to a bike rack, and will not go back, especially for summer riding. I use a bike rack, two S-hooks, and two bungee cords. My backpack (L.L. Bean) has a sturdy handle which I attach to the top of the rack with the S-hooks. The pack then hangs over the side of the rack, and I hold it in place with the bungee cords. I used to worry about my laptop getting shaken, but I keep it in a padded case in my backpack and have had no trouble. The result of all this is that I can get to work without a sweaty back and sweat-stripes on my shoulders. By all means lose the back pack and let air flow in and through your shirt.
- Effort: Don't sweat it! Last of all, and probably most importantly, remember to enjoy the ride and not try to beat your personal speed record when the heat is up. Relax, take it easy, leave plenty of time, and enjoy the ride. There's no shame in going slow, and it can make the heat a lot less oppressive. Consider the payback as you pass long lines of cars waiting at traffic lights.
1 week ago