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Grey Manrod
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Discussion Starter · #1 ·
Depending on humidity, I'd have to say 95 degrees.

Right now, 88 degrees, 55% humidity at 9 am. I've ridden in worse, but it takes a lot of the enjoyment out of it. Particularly mountain biking. Last weekend I was sweating so much I couldn't keep my grip on the bars.

Right now it's not so bad, but it's only going to get hotter as the day wears on. Yesterday I went out when it was 95 for a quick 20 miler.......it was ok, a slight breeze, but at times felt like I was riding in my tiny bathroom after someone just took a really hot shower. It's just killing my motivation. I always judge how hot the summer is by how soon I'm wishing for fall. This summer may be a new record for me.......

What is this "real feel" stuff, anyways? How do they figure that out? Sounds might subjective to me.
 

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Grey Manrod
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Discussion Starter · #2 ·
Forgot to add that wife and kids just left town. As a result, I usually do some epic mtb ride that I otherwise wouldn't be able to do. But the weather has got me waffling.

\\First person to post "HTFU" gets a pm box full of Celine Dion.
 

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Adorable Furry Hombre
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Brick Tamland said:
What is this "real feel" stuff, anyways? How do they figure that out? Sounds might subjective to me.
It really is a bunch of voodoo and made up numbers. This is the actual equation from Wiki:



where
HI= Heat index (in degrees Fahrenheit)
T= ambient dry-bulb temperature (in degrees Fahrenheit)
R= relative humidity (in percent)
c1= -42.379
c2= 2.04901523
c3= 10.14333127
c4= -0.22475541
c5= -6.83783 × 10−3
c6= -5.481717 × 10−2
c7= 1.22874 × 10−3
c8= 8.5282 × 10−4
c9= -1.99 × 10−6.


Note all those weird constants thrown in with nice even integers? :)

Alternatively a "more accurate" formula is:

 

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Mountain Biking Defector
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45 Posts
65' F.

Anything more than that, and it's too hot.

But limits are somewhere between 90 and 95, with humidity above 80% being given extra consideration.

This has got to be one of the hotest, wettest summers I've ever seen in Michigan.
 

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I hate humidity, but will deal with 1-3 hours of intense heat....yesterdays ride averaged 106* for the 3 hours I was out riding. Typically I try to limit it to 2 hours, but will push the extra hour when everything feels ok. YMMV.
 

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Call me a Fred
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16,999 Posts
Marc said:
It really is a bunch of voodoo and made up numbers. This is the actual equation from Wiki:



where
HI= Heat index (in degrees Fahrenheit)
T= ambient dry-bulb temperature (in degrees Fahrenheit)
R= relative humidity (in percent)
c1= -42.379
c2= 2.04901523
c3= 10.14333127
c4= -0.22475541
c5= -6.83783 × 10−3
c6= -5.481717 × 10−2
c7= 1.22874 × 10−3
c8= 8.5282 × 10−4
c9= -1.99 × 10−6.


Note all those weird constants thrown in with nice even integers? :)

Alternatively a "more accurate" formula is:

That's what you get when the project is outsourced to India.
 

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Master debator.
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8,777 Posts
I stop riding when it's consistently under 38 degrees or so, it just isn't fun. The upper end doesn't matter, of course I've never rode when it's 115 degrees out so I'd say my practical upper limit is around 100.
 

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Banned
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Here if you want to ride in the summer, you have no choice but to get out in temps close to 100. Sucks, but you really can't tell until you stop riding.
 

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I don't have an upper limit. I will go ride in the heat, what ever it is.

In the winter, my low is about 25ish, with less than 20mph winds, and some sun. Any more wind, less temp, or no sun and I ride inside.

The coldest ever was 12 with almost no wind, and sun. With the right gear, its not that bad.

But extremes on both sides make it work instead of enjoyment.
 

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gazing from the shadows
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27,288 Posts
I have no upper limit for a road ride, none I've ever actually hit. Cut down the time/miles/effort? Sure. But not ride? No. But I am more likely to ride very early, I can get on the road by 6am without problem, and even with a later start I have a totally flexible schedule in the hottest months. That means if I go out later and get cooked it's no big deal.

MTB is a different story, since under the trees it will be worse when the humidity is high, and probably no breeze at all. I am not likely to ride MTB in temps of 80+ with mid to upper 60s dew points, and once it hits 70 for a dew point forget it. I've done it. Just like I've commuted at -20 F. It's just not worth it.
 

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My limits are at the low end, heat and humidity don't stop me. I got the bright idea to take my mtb out for a road cruise once when it was -20c... that won't be happening again.

dr hoo: -20f? You're insane. I hate going out the door when it gets into that range. We usually get a few months that hover in the -20f - -40f range and my bikes are inside keeping warm during that time.
 

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pedalpedalpedal
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I've ridden at 115° for 3 hours and wasn't too bothered by it, other than sweat in my eyes. I'd like to go higher just to say I did.
 

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Misfit Toy
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I was nuked by heat exhaustion one year. My limit is now 75 - 80, providing there is lots of shade. I pretty much avoid the sun like a vampire.
 

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Whatever it is I'll probably never find the limit here in New England.

It gets really hot and humid sometimes, but between the shade on the road sides and the wind in your fact it's never 'that' bad even when just walking around is bad.
 

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I have none. This morning ride at 7 am was only 82 degrees with 85% humidity.
Buy 10:30am when I got home, it was 88 with 97% humidity.

I run all the time around Noon. Avg 92 degrees 89% humidity.

Now I won't ride when its below 4o degrees, but will run!
 

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f3rg said:
I've ridden at 115° for 3 hours and wasn't too bothered by it, other than sweat in my eyes. I'd like to go higher just to say I did.
This time of year around here, my only options are 100 degrees or ride on a trainer. I'll take the heat over the trainer every chance I get.

An old trick I picked up racing dirtbikes is to take a feminine product and stick it to the part of your goggles (helmet in this case) that contacts your forehead. Not foreskin, forehead.
 

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6 degrees of Kevin Bacon

Oh hell, for a minute I thought RBR was the smartest website on earth, then I realised, nope I am just an idiot. I saw the degrees symbol in the quote and was thinking RBR replaced "degrees" with the symbol, so I thought I would test it. Then I figured out it wasn't even my post.
 

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waterproof*
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I don't have an upper limit. You just have to adapt in the heat, ride slower, plan for more water stops etc.

My limit for a cold road ride is about 40F depending, so in winter all you hardmen can laugh at me.
 

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jaded bitter joy crusher
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Brick Tamland said:
Depending on humidity, I'd have to say 95 degrees. ...
What is this "real feel" stuff, anyways? How do they figure that out? Sounds might subjective to me.
I did 56 miles yesterday where the official "in the shade" temperature was 97 degrees and the thermometer in my computer read up to 120 on the road when I was out in the direct sun, but I spent a lot of time on shady country roads where the temperature was in the 97-102 degree range.

It was nasty. I drank about a liter per hour and still came back four pounds lighter than when I rolled out.

Last summer I did a century where the on-the-road temperature was around 105 for most of the ride. At one point I stopped because I thought I had a flat; in fact, my tire was fine but it was sinking into the road where the tar in the chip and seal had softened in the heat.

For low temperatures, zero F is about as low as I'll generally go in dry conditions and 40 is as low as I'll go when it's raining.

Real feel is a proprietary variation on "wind-chill" and "heat-stress" indices. It's based on the rate that your body can cool off. The lower the humidity and the higher the wind, the faster you can cool off by sweating. Basically, your body's core temperature will be higher if there's more humidity, and it will be lower if there's more wind. The real-feel is an estimate of what temperature with low humidity and no wind would make your core temperature just as hot as the actual temperature, humidity, and wind conditions.

To determine the real-feel they use measurements that were taken of research subjects' core temperature under different conditions (the military did a lot of this because they need to know how to keep soldiers from getting hyper- or hypo-thermia in all weather conditions).

Real Feel is a very reasonable rough estimate of the effect of wind and humidity, but it still has problems: the actual core temperature also depends on other variables, such as how you're dressed and whether you're standing in direct sun or in the shade.

Here's an interesting site that discusses the role of temperature in fatigue for athletes: the key, according to this discussion, is that every animal has an internal thermostat and when its core temperature rises above a well-defined threshold, it's like a switch flips in the brain and the individual cannot will itself to perform physical exertion. For people, that threshold is about 40 Celsius (104 Fahrenheit):
it seemed that humans have this "off-switch" at 40 degrees Celsius, irrespective of the external intervention. The only thing that changed was the time it took to get there---for example, a person who is well adapted to the heat is able to sweat more, lose more heat and therefore takes much longer to reach this limit than someone who goes straight into a hot environment. But they still stop at around the same temperature, according to this lab research.
 

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gazing from the shadows
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LWP said:
dr hoo: -20f? You're insane. I hate going out the door when it gets into that range. We usually get a few months that hover in the -20f - -40f range and my bikes are inside keeping warm during that time.
At least there was no wind!

It was a commute, and only about 5 miles. But yes, insane. That is painful cold. I did it one year because I committed to riding all year. Never again.

I can tell you that mine were not the only track in the snow. And it made the 0F days seem a lot easier, that's for sure!
 
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