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Why does it seem so much harder to ride in the cold.(18 posts)

Why does it seem so much harder to ride in the cold.MB1
Dec 2, 2002 10:40 AM
On Sunday we did our usual in town Century.

What is normally an easy recovery sort of ride was pretty difficult for the both of us even though we hadn't gone hard or long on Saturday.

The only change from the last few months was the weather. We started out in the mid 20's and it probably never got much above freezing-there was ice along the side of the road all day.

We both agreed that it was a pretty hard ride and that riding in the cold is much harder than in the 60's and 70's. We were both dressed fine for the weather and perfectly comfortable except on the downhills that got a bit nippy. It sure seemed like a pretty tough day though.

Any thoughts?
For me, its never as hard as I imagine it will be ...Humma Hah
Dec 2, 2002 10:58 AM
... I have to watch myself. I'll try to talk myself out of riding because I'm imagining how cold and awful it will be. But once I'm riding, I'm usually surprised as to how nice it is.

But I always feel the extra drag. Cold air is significantly denser than warm air, and its enough to feel. Cold also stiffens tires and grease, adding a pinch of extra drag that way, as well.

Comparing 0C (273K) and 27C (300K), aero drag is higher at any given speed by 300/273, or about 10%. That's a pretty big increase in a world where most roadies are concerned about shaving grams.
For me, its never as hard as I imagine it will be ...pbraun
Dec 2, 2002 1:21 PM
Is that a linear 10% across the board or does it increase exponentially with speed? My ego needs to know!!
Temperature affects density, ro ...Humma Hah
Dec 2, 2002 2:05 PM
... dynamic pressure (the principal source of aero drag) increases as ro v^2. The pressure increases with the square of air velocity, and work increases by the cube of air velocity. But the ro component is a constant increase across the board.

That 10% is not trivial. I'd guess its more drag increase than riding my cruiser with the tires nearly flat.
For me, its never as hard as I imagine it will be rider
Dec 3, 2002 6:57 AM
Hey Humma. Do you think the pavement surface being harder, from tempatures being under 32, a cause to your bike also going slower?

I always felt my tires are harder in winter were because the pavement changes as well as the grip your tires have with it because of the tempatures. This may explain why my butt hurts more in colder weather with the same psi I put in all year.

Just a question, not a debate.

Harder pavement should be beneficial ...Humma Hah
Dec 3, 2002 9:55 AM
... just like more air in your tires. But, unless your tires are rock-hard with too much air, they have some sidewall flex. As the tire compound starts getting a little stiff, it will rob energy more than it does when warm. The effect is much worse on cruiser and MTB tires than roadbike tires.
Thanks. I'm still running 125 psi. going to lower it (nm)pa rider
Dec 4, 2002 3:30 AM
re: Why does it seem so much harder to ride in the cold.netso
Dec 2, 2002 11:02 AM
Below freezing it takes 10% of your metabolism just to keep your body warm. This fact alone would reduce your efficiency.
Headwinds .Dave Hickey
Dec 2, 2002 11:04 AM
I find headwinds in the winter to be brutal. Like you, I'm dressed for the weather. It just seems so much harder.
Maybe the 15-30 mph wind?pmf1
Dec 2, 2002 11:16 AM
After getting soaked on Saturday, I bailed on Sunday. Too windy and cold. Went Christmas shopping instead. Try it sometime.
We took it easy all week long.MB1
Dec 2, 2002 11:31 AM
When it started raining on Saturday we packed it in and caught a couple of movies (bummers since I only needed 9 more miles to reach 1500 for November). Sunday wasn't too bad wind wise and we were riding in fairly protected areas.

Still, it seemed harder to roll the bikes along.
Wind -- where were you on Sundayms
Dec 2, 2002 12:21 PM
"Sunday wasn't too bad wind wise" I encountered a lot of wind yesterday in Baltimore County and according to weather reports the same winds blew across Northern Virginia the the DC area as well. Yesterday's winds were significant enough that low tides on the Potomac and western shore of the Chesapeake Bay were 1-2 feet below normal. Even if you were in protected areas, I think that you underestimate yesterday's winds.
Dec 2, 2002 12:32 PM
Sunday was one seriously raw day. I rode for 90 minutes in the wind and rain Saturday (like always, it started right when I was furthest from home) and that was enough for me.
re: Why does it seem so much harder to ride in the cold.trekkie1
Dec 2, 2002 11:25 AM
1. denser air
2. more bulk from clothes, meaning more air drag, more "internal friction" drag, more weight, especially if sweat soaked
3. you are not in as good of shape as in summer
4. stiffer from cold, even if not obvious
5. btu's used to heat body and inhaled air
6. less motivated
re: Why does it seem so much harder to ride in the cold.commuterguy
Dec 2, 2002 11:52 AM
I have noticed this effect as well, and didn't realize how temperature-dependent aerodynamic drag was. I can add my subjective impression that, in the DC area, cold weather and higher winds tend to be correlated. Perhaps this is at least partially due to the absence of leaves on trees, which create wind blocks along much of the CCT.

On a related note, I have observed separate, independent effects from cold weather and riding at night. Each costs me about 1 - 1.5 mph for any given level of effort. My only guess why darkness slows me down is that I have to devote a lot of mental effort to looking where I am going, and my uncertainty about what lies ahead makes me slow down.

Bottom line is, my ride home in the winter is quite a bit slower than the same ride in summer, even though my route is a lot less crowded, and even though I feel just as tired at the end.
Darkness and speed ...Humma Hah
Dec 2, 2002 2:10 PM
... I've got a good headlight, and can maintain a pretty good clip safely in the dark. What the headlight does NOT illuminate is the cyclocomputer, and that removes one of my motivations to keep my speed up. I have a tendency to ride faster during daylight, in an effort to maintain the average speed calculation.
re: Why does it seem so much harder to ride in the cold.dickruthlynn
Dec 2, 2002 5:04 PM
It is my experience that a lot of energy is wasted just to keeping warm, even though you are dressed for it. During the entire year, I ride 30-50 miles per day 5 to 6 days a year. But when it gets very cold, I only do 30 per day. The trick is to always committ to 30 miles and do it regardless of the temps.
We rode our planned distance...MB1
Dec 2, 2002 5:21 PM
We just didn't plan on it being so hard. Looks like it is going to be a cold winter so I guess we will get used to it. Don't plan to cut back on our riding any.