Riding in extreme heat

Discussion in 'The Perfect Line and Other Riding Myths' started by eatpasta, Jun 20, 2008.

  1. eatpasta

    eatpasta Lawnmower Target

    Jul 5, 2006
    Santa Barbara, Ca
    I posted this elsewhere - and Madbrit told me to post it here. I do what Im told.


    lifted from Sport touring.net


    This article was taken from the LDRiders list, and was written by Tom Austin.
    I spent a lot of time riding in REALLY hot weather a couple of weeks ago. On one leg of my trip, I rode for over six hours straight with temperatures in the vicinity of 115°F. Living in the Sacramento area, I frequently ride in ambient temperatures of approximately 100°F and I've ridden in temperatures as high as 113°F for shorter periods of time (e.g., crossing Death Valley). This week I learned that additional preparation is required for running at temperatures above 110°F for several hours. Several things that I experienced during the trip prompted to me to write this. Hopefully it will be useful to others.
    Why Mesh Riding Suits Don't Work in Extreme Conditions

    Human bodies exchange heat with their surroundings in four primary ways: convection, conduction, radiation, and evaporative cooling (from perspiration). When ambient temperatures are below the body's normal temperature of 98.6°F, all of these pathways can provide cooling. The higher the windspeed, the more cooling there is from convection. But when ambient temperatures rise above 98.6°F, only evaporative cooling can work. More importantly, too much wind becomes a bad thing. There is a limit to our body's perspiration rate and when the wind speed uses up all of the available perspiration, more wind increases convective HEATING. This is the opposite of "Wind Chill". I found an interesting article on this effect at:
    What this means is that you do NOT want to maximize the wind against your skin when the temperature gets extreme. Mesh suits, or wearing just a lightweight shirt, are NOT the right approach. You will actually stay cooler with a conventional suit with the vents adjusted so there is a more moderate air flow across your skin.
    You Have to Carry Much More Water to Ride in 110°F+ Temperatures

    When temperatures are below 98.6°F, you may perspire less than 1 quart per day. But when the need for evaporative cooling kicks in, you perspiration rate can increase to 1.5 quarts PER HOUR. If you aren't drinking 1.5 quarts per hour under extreme conditions, you will start becoming dehydrated. Your perspiration rate will decrease, you will feel hotter, your heart rate will increase, and your judgement will start to become clouded. If you are a competitive endurance rider, you can probably go at least 300 miles without stopping. If you are averaging 75 mph, that's four hours. You may need to consume 6 quarts of water in that period of time when the temperature exceeds 110°F.
    I carry an insulated 1-gallon cooler with a drinking tube attached when I know I will be riding long distances in hot weather. It was barely adequate for this trip because I deviated from my normal routine and purchased an extra bottle of water to drink during my fuel stops. On one leg, I made the mistake of starting with less than a full gallon and started experiencing the early signs of heat exhaustion. I felt much better after sitting in the shade for 10 minutes while consuming a full litre of bottled water.
    Based on my personal experience and research, there is a world of difference between 100-105°F and 115°F in terms of how much water you need. A half quart per hour is more typical of what's required near 100°F. You might even be able to to run without water for several hours at about 100°F and make up the deficit by drinking at lot at your next fuel stop. But at 115°F, the level of dehydration you will be experiencing between fuel stops is excessive; you will definitely experience heat exhaustion and possibly heat stroke.
    Why You Might Not Want to Be Wearing Shorts Under Your Riding Suit

    Some popular bikes have "issues" with high levels of engine heat. My K1200GT makes the lower half of my legs warmer than on my K1200LT, but it's never been a problem for me, until this trip. Air passing through the radiator on both the LT and GT exits at the side of the fairing just in front of the rider's legs. On the LT, the hot air is blown far enough away from the bike that it does not impinge on the rider's legs. On the GT, the fairing is not quite as wide and you can feel heat from the radiator on your lower legs. The heat I feel on the GT is clearly less that the heat I've felt riding other bikes, such as the FJR1300. But on this trip, the heat became a problem. I rode for a long stretch with a slight crosswind which increased the amount of radiator discharge that impinged on my right leg. It got very uncomfortable. When I stopped for the night, I discovered that I had second degree burns on the back of my right calf:
    This wouldn't have happened if I had been wearing long pants under my Aerostich. Under identical conditions, I did not get burned wearing blue jeans under the riding suit.
    This problem showed up for the first time because the radiator discharge temperature is directly related to the ambient temperature. Although engines run hotter in hot weather, they actually discharge about the same amount of heat energy into the radiator. That heat energy raises the temperature of the radiator discharge the same amount that it does at lower ambient temperatures. At 100°F, the radiator discharge might be 140°F and it might get knocked down to 110°F before it impinges your leg. It feels very warm, but it won't burn you. If the ambient is 15°F higher, you leg might be exposed to 125°F and you can eventually get burned if your leg isn't insultated from the radiator discharge.
    According to data from the National Burn Center, the time at temperature to cause a second degree burn is as follows:
    113°F 1.7 hours
    122°F 2 minutes
    131°F 11 seconds
    140°F 2 seconds
    The only thing protecting you from being burned when your bare skin is exposed to ambient temperature of 113°F or higher is evaporative cooling and the cooling of the skin surface by blood flow. To be protected from radiator discharge temperatures in excess of 113°F, you need INSULATION between your skin and the hot air stream. What I painfully discovered is that the insulation provided by an Aerostich suit is not enough.
  2. MaddBrit

    MaddBrit Now officially a Yank.

    Jul 14, 2004
    Allen, Tejas. Blissful state...
    Lots of good advice in this post.

  3. Rad

    Rad Done riding

    Sep 24, 2001
    Another important thing about hot weather riding; knowing when to change sports.
    These folks have the right idea for when it is over 100 degrees :thumb
    devo2002 likes this.
  4. ragtoplvr

    ragtoplvr Long timer

    Oct 18, 2007
    central USA
    I puut ice in pockets in my jeans and shirt, it will really help for 50 mile or so.
  5. Norhasken

    Norhasken Tryin' to find my way

    Aug 20, 2007
    On the couch
    If I chose not to ride when it is above 100, I would miss about 30 days per year. I appreciate the content of the article.
  6. Skippii

    Skippii Milkshakes, my lad.

    May 11, 2008
    Richmond, Va
    As the wind passes over your body going fast, doesn't that make it lower pressure than normal, and therefor actually be a few degrees cooler than a stationary thermometer?

    DELTATANGO Motorcyclist and Dog Walk

    Nov 27, 2005
    Good article.

    It does not take into account humidity. The relative humidity is directly related to the effects of evaporative cooling. If you are out west and it's hot (and dry) get wet. Soak yourself with water at stops. Get in the river or the creek and get wet. The cooling effect is very effective.

    If you are in the south where it's hot and humid you are screwded.
  8. justacommuternow

    justacommuternow Been here awhile

    Jan 11, 2005
    in the event you're on diuretics for some reason, you probably should not even be out there in that kind of heat

    friend of a friend died in a solo glider accident on a long cross country flight, accident investigation concluded aircraft went down intact, coroner ruled she became dehydrated (and probably simply passed out) despite the jugs of water she always carried on her flights. Later, it was found she was taking diuretics for weight loss.

    the common thread here being the sun, when you're in a glider, you're sitting in direct sunlight all the time, just like on a motorcycle in extreme heat

    gratuitous glider photo follows, just 'cause they're so darn pretty
  9. GWHayduke

    GWHayduke SW Neanderthal

    Aug 11, 2007
    El Paso, Tejas
    Great article...I remember our heat during the summer of 1993. Over 60 days at 100+ and I was driving a Toyota pickup without air conditioning. I rode with the windows up because it was cooler. The blast from the open windows would cook you.

    I just got a TourMaster Intake Air jacket and loved it on a ride this morning. I'll probably have to wear a long sleeve shirt under it on the afternoon & evening commute to limit the air flow. Thanks for the insightful read.
  10. hankgs

    hankgs Long timer

    Dec 2, 2005
    Solvang, CA
    Just returned; Left June Lake this morning, drove through YNP and took 41 across that gawd-forsaken Central California Valley:puke1 Hot and shitty, but it's the only way to get to the Eastern Sierras. I wore a BMW Airflow Jacket over a long sleeve goretex tee, Joe Rocket Phoenix pants with "HH Under Armour" underware to keep the boys cool.
    All of that with a camelback suckin down a couple quarts of Gatorade & water.
    When it's over a 100, there is nothing you can do except take your A/C vehicle if you truly want comfort; If you choose to ride, be prepared and psyched to be HOT!
  11. fourstroke650

    fourstroke650 You got red on you

    Aug 18, 2006
    San Diego
    I have been riding with an evap vest under my mesh jacket, in 115 degs here in Phoenix area. It has been great, I do however notice a difference between a underarmor (wicking) shirt versus a cotton tee under the vest. Cotton feels cooler. Underarmor keeps you dryer. But it is the best 35 buck I spent since moving here. They are available from Motoboss, at Cycle gear etc. You soak it for two minutes and you are ready to go. It lasts 1-2 hrs. I also use when I mow the lawn. Keep in mind if you are geared up in regular gear and sitting in traffic, you are gonna overheat. It's better being wet with a mesh jacket. No matter what you where, stay hydrated.
  12. Grinnin

    Grinnin Forever N00b

    Dec 10, 2005
    No mention of electrolytes?

    I rode past Philly as people were dying there of the heat two weeks ago. I drink plenty of water, but after a few hours, water just goes through without as much being absorbed. I stop and have a cold Gatorade to re-balance the salts and I can go back to water for a while.

    This ride I used a thermos plus a Platypus Big Zip hydration bag. The thermos kept cold water that was far more refreshing. Exercise physiologists in the '70s showed that a body absorbs water faster if it's body temperature. No more cold water on bicycle rides. Then more research in the '80s showed that cold water helped cool a body (even if only a little) and increase performance. I'll take that little bit of cooling.

    Aerostitch/RiderWearhouse sells a pair of compact stainless thermoses.
  13. Skippii

    Skippii Milkshakes, my lad.

    May 11, 2008
    Richmond, Va
    When stranded on a desert island, mix 3 parts freshwater to 1 part saltwater for the electrolytes.
    Plus, then you get 33% more water free!
  14. VegasRider

    VegasRider Ya, I'm a n00b.

    Nov 6, 2007
    NV, Henderson
    Thanks for the great info! We've already had 110F days here. 108 today on my ride home. I think I may have to pick up an evap-vest. My commute is only 30 -45 minutes and always hydrated but even with a light t-shirt and vest that wind is terribly hot.
  15. beemer boy

    beemer boy Oh no, he's gone Asian

    Jul 18, 2003
    Chiang Mai , Thailand
    One small tip. I know this will cause some mental anguish for the coffee drinking riders, but I must get it off my chest. On long hot rides I avoid coffee in the morning. Coffee is in fact a diuretic,
    causing you to lose water when you need it the most. As was said earlier, you almost need to force yourself to drink water at rest stops. By the time you feel thirsty, you are already into the early stages of dehydration.
  16. Klay

    Klay dreaming adventurer

    Nov 19, 2005
    right here on my thermarest
    Great advice on riding in heat.
  17. cyrilgrey

    cyrilgrey Been here awhile

    Jul 10, 2007
    Queens, NY
  18. Big Jim

    Big Jim Adventurer

    Jan 9, 2008
    back in Ca.
    I am, unfortunetly in Bahrain for all of this summer. it is realy starting to heat up. the radio said it was 44 c today. i don't know what that works out to be but they also said the high last summer was 58, I think that works out to about 130 F. I was thinking my tiger would be my olny means of transport but as it turns they have fucked around for 70 days shipping it here and i am riding a mountian bike. it realy sucks giong 6 miles into the wind when it is 110 plus. I drink at least 2 gallons af water a day and sometimes it is not enough. thanks for the tips and for reading my rant
  19. bubbabob

    bubbabob Adventurer

    Jul 22, 2007
    I tried out my new Evap Vest a couple days ago, and it's great for a couple hours, then you need to re-soak, or at least I did. Maybe the Silver Eagle brand (about $90 bucks) would be more efficient, but my cheapo $40 model needs re-watering pretty often.
  20. Yuma

    Yuma Adventurer

    Feb 28, 2007
    Southwest Arizona
    Only 30 days????

    Here that would be five months..... There are days the low temp is only 90 :lol3
    I agree with the first post on almost all of the information. :clap
    But one other thing is to start to hydrate the day before if you can, store some extra water weight...:eek1
    I ride behind a full fairing so Mesh works great but if one does not have a fairing wear light long sleeves and pants under the mesh gear....