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#21
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Anyone wear a helmet or elbow pads 4 black ice conditions?
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Anyone wear a helmet or elbow pads 4 black ice conditions?
On Sun, 07 Jan 2018 20:30:21 -0500, Radey Shouman
wrote: Frank Krygowski writes: On 1/7/2018 1:28 AM, Sir Ridesalot wrote: Just wondering if when it's known that there can be black ice on the roads if anyone here wears a helmet or other protection (such as elbow pads) that they'd not normally wear when the roads are clear. Do you? Well, "it's known that there can be black ice" sounds to me like "It's near or below freezing." Surely you need two things for black ice: freezing temperatures and liquid water. Hoarfrost isn't black, neither is snow. To get transparent ice on a reasonably crowned road you need quite a bit of liquid water, so I expect black ice when snow melting temperatures are quickly followed by temperatures well below freezing. That's not black ice, that's regular ice. Black ice is visually transparent, usually formed by condensed moisture in vehicle exhaust freezing to the roadways. The road can be otherwise dry without a visual clue. It's more prevalent on bridges because those road surfaces are colder than roads on top of the ground. Usually this is a phenomenon that happens below 0F or about -20C, at which temperatures crystal salts or brines tend to have little benefit. Here in Minnesota and over by Madison where Andrew is, we get those conditions multiple times most winters. Since there is no visual cue to its presence, the first hint is often that vehicle up ahead slewing out of control... if you're lucky and it's not the vehicle next to you- or your vehicle. Drivers around here just know to beware when the temps are down to 0F- it's one of the ways to spot the newbies, too. I remember driving from Chicago back to Minnesota many years ago as a young driver. I was on I-90 in the middle of Wisconsin on a bitterly cold late afternoon; between Madison and the Dells. No snow cover yet, just danged cold and not a sign of ice on the road. I drove onto a short three lane bridge with a curve; started out in the inside lane and a second later was exiting the bridge in the outside lane- white as a sheet and with eyes like saucers, I'm sure. It was sheer luck I didn't park it in the guard rail and that there weren't any other cars anywhere near me. |
#23
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Anyone wear a helmet or elbow pads 4 black ice conditions?
On 1/9/2018 1:21 AM, Tim McNamara wrote:
I remember driving from Chicago back to Minnesota many years ago as a young driver. I was on I-90 in the middle of Wisconsin on a bitterly cold late afternoon; between Madison and the Dells. No snow cover yet, just danged cold and not a sign of ice on the road. I drove onto a short three lane bridge with a curve; started out in the inside lane and a second later was exiting the bridge in the outside lane- white as a sheet and with eyes like saucers, I'm sure. It was sheer luck I didn't park it in the guard rail and that there weren't any other cars anywhere near me. As long as we're telling stories: My most exciting winter driving moment happened when I was in my early 20s. I was motoring along on a two-lane road on a slippery day. Approaching me up ahead was a large box truck. Its driver put on his left turn signal and commenced a turn into a grocery store parking lot. He didn't make the turn. Instead, his truck began a complete rotation within the roadway. After 90 degrees it was coming at me perfectly sideways, taking both lanes. Fortunately, the rotation continued. There was no way I could stop, of course. I had enough traction to move to the left (oncoming) lane, and fortunately, there was no other oncoming traffic. I used that lane to drive past the truck as it slid backwards along in the right lane I had been using. I'm not sure, but I think the truck came to a stop on the shoulder still facing backward. I went on my way, perhaps a little more carefully. BTW, that was in my '66 Corvair Corsa. -- - Frank Krygowski |
#24
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Anyone wear a helmet or elbow pads 4 black ice conditions?
Tim McNamara writes:
On Sun, 07 Jan 2018 20:30:21 -0500, Radey Shouman wrote: Frank Krygowski writes: On 1/7/2018 1:28 AM, Sir Ridesalot wrote: Just wondering if when it's known that there can be black ice on the roads if anyone here wears a helmet or other protection (such as elbow pads) that they'd not normally wear when the roads are clear. Do you? Well, "it's known that there can be black ice" sounds to me like "It's near or below freezing." Surely you need two things for black ice: freezing temperatures and liquid water. Hoarfrost isn't black, neither is snow. To get transparent ice on a reasonably crowned road you need quite a bit of liquid water, so I expect black ice when snow melting temperatures are quickly followed by temperatures well below freezing. That's not black ice, that's regular ice. Black ice is visually transparent, usually formed by condensed moisture in vehicle exhaust freezing to the roadways. The road can be otherwise dry without a visual clue. It's more prevalent on bridges because those road surfaces are colder than roads on top of the ground. Usually this is a phenomenon that happens below 0F or about -20C, at which temperatures crystal salts or brines tend to have little benefit. Here in Minnesota and over by Madison where Andrew is, we get those conditions multiple times most winters. Since there is no visual cue to its presence, the first hint is often that vehicle up ahead slewing out of control... if you're lucky and it's not the vehicle next to you- or your vehicle. Drivers around here just know to beware when the temps are down to 0F- it's one of the ways to spot the newbies, too. I won't hold myself out as an expert on ice, nor have I lived anywhere that 0F temperatures are really commonplace. But I have watched this bit by Key and Peele repeatedly: https://www.youtube.com/watch?v=efiW2K8gASM and find it as illuminating as anything else. Having heard a number of black ice stories, my working definition of black ice is a thin, transparent layer of ice on the roadway, that *took me by surprise*. You are correct in that 0F is around the limit of efficacy of road salt, so brine that has melted during the day, and adsorbed water, either from ambient humidity or vehicle exhaust, tends to freeze. This may be surprising to drivers. I don't believe it's true that bridges tend to be colder than other roadways. I think bridge decks tend to change temperature, either up or down, faster than other roadways, which may freeze more brine before it gets a chance to run off. I remember driving from Chicago back to Minnesota many years ago as a young driver. I was on I-90 in the middle of Wisconsin on a bitterly cold late afternoon; between Madison and the Dells. No snow cover yet, just danged cold and not a sign of ice on the road. I drove onto a short three lane bridge with a curve; started out in the inside lane and a second later was exiting the bridge in the outside lane- white as a sheet and with eyes like saucers, I'm sure. It was sheer luck I didn't park it in the guard rail and that there weren't any other cars anywhere near me. I remember driving from Austin (TX, not MN) to Dallas in December. It had rained, and the temperature fell rapidly to below freezing, solidifying lots of dew. It was humid enough that the carburetor in my car actually froze up (I could see ice in the throat after removing the air cleaner). Fortunately exposure to small planes had made me aware of carburetor icing, and I scavenged a piece of cardboard from the side of the road to put in front of the radiator in order to continue. When I got to Dallas there was ice everywhere -- on the fences, on the bushes, and all over the road. Large vehicles were doing their impression of the hippos in Fantasia. It was hard to walk on any paved surfaces. Naturally, Dallas doesn't have *any* road salting or sanding equipment, nor is salt or sand stockpiled, so the ice there is as black at 25F as it is in Minnesota at -5F. To get back to bicycling, it seems to me that cyclists actually have a few advantages when it comes to detecting ice: a better view of the roadway, slower speed, a sensitivity to that "oh ****" feeling caused by even a very momentary loss of traction, and, if you're as timid as I have become, a ready resignation to slowing down for poor conditions. Of course, it is still possible to fall on the ice, as I have proven to myself several times. That could hurt, especially in traffic. Tonight, riding home from work, it was warm, right around freezing. I detoured around a number of patches of roadway snow, but didn't see much ice. I did see a number of patches of water, which may have frozen by now. -- |
#25
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Anyone wear a helmet or elbow pads 4 black ice conditions?
Sir Ridesalot wrote:
Just wondering if when it's known that there can be black ice on the roads if anyone here wears a helmet or other protection (such as elbow pads) that they'd not normally wear when the roads are clear. Do you? I have 56 width tires (2.20 or 2 inches) even tho it isn't a MTB, and the tires have drive/direction and an aggressive tread. When I put them on, I thought, "great, now I don't need studded tires anymore in the winter", but this has proved incorrect. But I only slipped once (this winter), and that was when jumping on the bike and turning at the same time. The back wagon loosed touch and slided for half a meter or so. An unpleasant moment of mini-panic, for sure, until I regain control. However when riding down the small slopes and valleys we do (don't) have here, I feel the grip isn't 100 as it is with studded tires, and I feel a little less bold. I think about it then, but the only time it could actually loose touch is when turning, for example in roundabouts, and that was exactly the case with 44-622s as well. -- underground experts united http://user.it.uu.se/~embe8573 |
#26
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Anyone wear a helmet or elbow pads 4 black ice conditions?
On Saturday, January 6, 2018 at 11:28:40 PM UTC-7, Sir Ridesalot wrote:
Just wondering if when it's known that there can be black ice on the roads if anyone here wears a helmet or other protection (such as elbow pads) that they'd not normally wear when the roads are clear. Do you? Cheers as a snow country biker, does SR use studded tires / |
#27
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Anyone wear a helmet or elbow pads 4 black ice conditions?
On Wednesday, January 10, 2018 at 1:25:58 PM UTC-5, wrote:
On Saturday, January 6, 2018 at 11:28:40 PM UTC-7, Sir Ridesalot wrote: Just wondering if when it's known that there can be black ice on the roads if anyone here wears a helmet or other protection (such as elbow pads) that they'd not normally wear when the roads are clear. Do you? Cheers as a snow country biker, does SR use studded tires / No, no studs for me. I drop; the air pressure a fair bit if I think I'll be on black ice. Early in the season I take the bike to an outdoor ice rimnks after dark when the rink is closed (It's a temporary one they build forthe winter in a park) and practice riding the bike on that ice. Btw, contrary to many who believe that black ice is always thin, that's not always true and also, black ice can form very quickly even if the air temperature is above freezing but the moisture is in shade and thus quite a bit cooler. Cheers |
#28
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Anyone wear a helmet or elbow pads 4 black ice conditions?
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#29
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Anyone wear a helmet or elbow pads 4 black ice conditions?
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