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  1. #1
    pedalphile
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    Temp effects on speed.

    This morning was the first warm weather commute for me this year. I pretty much took the winter off, but have been getting back into it over the last few months.

    So far every ride in has been under 40 degrees. My usually kit in such weather consists of a pair of cotton sweats over cycling shorts, long sleeve lycra shirt, fleece jacket and if it's below freezing, a nylon windbreaker.

    Outfitted in such a way, I take the better part of 50 minutes to make the 12+ mile commute.

    Last summer I was able to do it consistently in 37-40 minutes. I attributed my cold weather times mostly to being an out of shape fatty.

    This morning, I was back in just my cycling shorts and long sleeve lycra and I was back down under 40 minutes.

    Does temp really matter that much? The extra weight isn't much.

    I suspect the big difference is aerodynamics. Smooth lycra cuts through light warm air quite a bit better than loose fitting fleece through heavy cold air.

    Makes me think that spending a few bucks on some cold weather cycling gear might get me out therer more often next winter.

  2. #2
    uke
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    it's easy if you let it. uke's Avatar
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    Don't forget...warm air is less dense than cold air. Also, most engines are more efficient at room temperature than they are at freezing. Both of these reasons are applicable to cars and cyclists. :O)

    JesseDuncan:I just love how "cars will be forced to cross the double yellow lines on dangerous limited visibility roads".

    I don't want to have a head on but oh god, I HAVE to fling myself into oncoming traffic to pass, theres no alternative!!!

  3. #3
    Senior Member
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    I am noticeably slower in cold weather, but I always assumed it was from the increased drag of wearing a bunch of clothes.
    Surly Pacer

  4. #4
    Seņior Member ItsJustMe's Avatar
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    I wouldn't have thought it myself without my own experience, but it's been posted that air at 80*F is about 10% less dense than air at 32*F and it does seem to make a difference.
    For me the biggest issue is headwinds. I often have 15 MPH headwinds, if they calm down or turn around, it can turn my commute from 47 to 35 minutes.
    Work: the 8 hours that separates bike rides.

  5. #5
    pedalphile
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    Quote Originally Posted by uke View Post
    Don't forget...warm air is less dense than cold air. Also, most engines are more efficient at room temperature than they are at freezing. Both of these reasons are applicable to cars and cyclists. :O)

    Nope, I didn't forget. That's why I said this...

    "Smooth lycra cuts through light warm air quite a bit better than loose fitting fleece through heavy cold air."

    I am sure that air density, clothing air drag and clothing leg drag all play into it. The cold muscle not being as efficient may also play into it, although, I think that is pretty much solved by proper clothing.

    In my case, I think another factor is that cold seems to be accompanied by wind 'round these parts. And yes, it's always a head wind ). Warm weather, not so much. This morning was especially still. I know this because the thermal layers I passed through were amazing. I left my house in what I would guess was around 60 degrees, maybe a bit more. My ride starts with a good down hill stretch into a valley. It was like riding into a refrigerator. Even though I was warmed up from peddling 5 minutes, I was a bit chilly riding through that low spot. I am certain that the temp drop in less than a miles was over 10 degrees. As I climbed back out the other side, I was back to 60 plus degrees.

    This sort of thing does not happen when there is any kind of wind at all.

  6. #6
    on your left.
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    Plus all components on a bike that require lubricant of any type perform better at higher temperatures. Like my cassette, which dosen't operate below about 30 degrees F. My fixed gear, on the other hand, keeps going strong well into temperatures i wouldn't think about riding in.
    Quote Originally Posted by caloso View Post
    I learned this the hard way. They say that experience is the best teacher, but I would have been preferred to just read about it on the internet.

  7. #7
    Senior Member degnaw's Avatar
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    I attribute slower wintertime riding to generic internal clock issues (i.e. getting up before sunrise, generic sluggishness), and slower summertime riding to the heat.

    I typically average 3-5mph faster in the spring and fall than in the winter, 1-2mph faster than in the summer.

  8. #8
    Seņior Member ItsJustMe's Avatar
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    Quote Originally Posted by nahh View Post
    Plus all components on a bike that require lubricant of any type perform better at higher temperatures. Like my cassette, which dosen't operate below about 30 degrees F. My fixed gear, on the other hand, keeps going strong well into temperatures i wouldn't think about riding in.
    That's odd. I ride every day regardless of temp, down to -25*F and have never had a single problem with a freewheel or freehub not working, over 5 years and 17000 miles. I don't even bother cleaning things, my bike is a muddy mess all winter.
    Work: the 8 hours that separates bike rides.

  9. #9
    Female Member KitN's Avatar
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    I'm noticeably slower in HOT/HUMID weather because the heat and humidity sap the strength from me and makes it hard for my body to cool itself down.

    I'd rather ride in 42 degree weather than 92 degree humid weather any day!
    Ride what you like. Ride in what you like.

  10. #10
    Senior Member rumrunn6's Avatar
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    In the past 12 days the temps have really risen. I'm looking forward to my first warm weather commute in. I plan on wearing very little and I'm hoping for a quicker easier ride but I'm not getting my hopes up. I'm torn between my "livestrong" bright yellow shortsleeve bike shirt and my bright hi-vis lime green windebreaker with zip off sleeves. I guess I'll be buying a bright hi-vis lime green bike shirt at some point too. I'm leaning toward bike shorts and t-shirt only for the morning ride in. I'm gonna feel naked compared to bike shorts tights and wind pants below and base layer up top with fleece, windbreaker and head band, 2 layers of socks - yeesh - sure won't miss all that! yuk
    cycling is like baseball ~ it doesn't take much to make it interesting

  11. #11
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    hmm never thought about air density. maybe thats why i love to take a deep breathe of cold air in the winter. i prfer cold weather anyways even if i do go a bit slower. 100 degrees makes me feel like falling over on the side of the road and laying there to die with my bike.

  12. #12
    Have bike, will travel Barrettscv's Avatar
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    I've also noticed a 3 to 5 mph difference from sub 45F weather to warmer temps. I'm now using tights under bike shorts from 35F to 45F, these are faster than wind pants and work well when kept dry.

    I'm also slower at dusk and dawn, I'm less willing to rocket around when vision is reduced.

    50 to 65F is my ideal zone for riding. Warm enough for shorts and vests, cool enough to keep the "motor" from overheating.

    Michael
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  13. #13
    Senior Member no motor?'s Avatar
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    I'm slower when it's noticeably cold and noticeably hot out. The heat and humidity saps the energy out of me and makes me want to sit on the front porch and read Faulkner, while the cold slows me down in some other way. The thinner tires I use in the warmer weather help make me faster, but that's a relative term in my case.

  14. #14
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    It's been a topic of discussion here before - for reasons we don't completely understand, once it gets down below 50 degrees (Fahrenheit) everyone bikes slower. Reasonable theories so far include increased wind resistance or that the grease/oil gets thicker as it gets colder...

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