black ice

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MGrant74
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Joined: 20 Jan 2019, 12:51pm

black ice

Postby MGrant74 » 20 Jan 2019, 4:16pm

I really don't like cycling when there is a possibility of black ice. Is there a temperature below which I shouldn't go out?

whoof
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Joined: 29 Apr 2014, 2:13pm

Re: black ice

Postby whoof » 20 Jan 2019, 8:57pm

Obviously there if it's warm enough there's no chance of ice however it's difficult to quote an actual temperature for ice to form on the road as the are a number of other considerations. There needs to be some moisture, temperatures quoted on weather forecasts are air temperatures (ground is different),cold air can collect into dips and form small areas far colder than surrounding areas, if it's windy or not makes a difference.

If the weather forecast says its going to be below zero over night then for my commute to work I use a bike with studded tyres designed for use in icy conditions. But I probably would have been ok on normal tyres 19 out of 20 times.

https://www.chainreactioncycles.com/sch ... -prod80796

If you do go down the above route you have to consider will other roads users be able to drive safely in icy conditions and not slide into you. My commute is mostly on traffic free paths.

tim-b
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Joined: 10 Oct 2009, 8:20am

Re: black ice

Postby tim-b » 20 Jan 2019, 9:08pm

Hi
I'll happily cycle in minus temperatures provided that the road is dry. Any combination of low temperature with glittery surfaces, damp surfaces or fog and I don't bother. Simples
The problem is that temperatures are usually taken above the road surface and don't reflect the surface temp, hence my requirement that the road is dry. A bridge over water is often colder than the rest of the road surface
Regards
tim-b
~~~~¯\(ツ)/¯~~~~

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mjr
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Re: black ice

Postby mjr » 20 Jan 2019, 9:50pm

MGrant74 wrote:I really don't like cycling when there is a possibility of black ice. Is there a temperature below which I shouldn't go out?

No. But if it gets below zero and you want to go out before it gets to 4°c, use studded tyres such as Schwalbe Winters.
MJR, mostly pedalling 3-speed roadsters. KL+West Norfolk BUG incl social easy rides http://www.klwnbug.co.uk
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gaz
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Re: black ice

Postby gaz » 20 Jan 2019, 10:42pm

It has been an especially mild winter so far. I encountered a small patch of black ice on Friday morning. Studded tyres now fitted on the commuter.

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foxyrider
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Location: Sheffield, South Yorkshire

Re: black ice

Postby foxyrider » 20 Jan 2019, 10:54pm

MGrant74 wrote:I really don't like cycling when there is a possibility of black ice. Is there a temperature below which I shouldn't go out?


20c :lol:

Oh you mean because of ice? The basic physics is that ice can form when 0c is reached, however that doesn't mean there will be ice, that can depend on other factors like location, wind strength etc. And once formed it doesn't just disappear above 0c either.

If at all concerned stay indoors.
Convention? what's that then?
Airnimal Chameleon touring, Orbit Pro hack, Orbit Photon audax, Focus Mares AX tour, Peugeot Carbon sportive, Owen Blower vintage race - all running Tulio's finest!

awavey
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Joined: 25 Jul 2016, 12:04am

Re: black ice

Postby awavey » 20 Jan 2019, 11:18pm

well black ice can form at air temps below 3C, though as others have said its the road surface temp thats more significant and you will absolutely find that temperature can vary alot on a ride.

Id also agree it can be much colder around 0 or -1 but if the roads are dry then it will generally be fine, if the roads look damp then its almost certainly icy, especially under overhanging trees, and in the bits of the roads most cars would prefer we stick to, my own extra test measure if you like is if the windscreen of my car needs scraping at the time I want to go out, its too icy.

but also appreciate conditions change and can vary, Ive certainly been out on rides I felt reasonably quite comfortable the road wasnt icy even though it was very cold and looked damp in spots,but then ended dropping down a hill into a lower area of countryside and it was completely different, the temperature must have dropped a good 2 degrees just in a few metres descent, and there was frost and ice everywhere, Ive also had it a bit like that new Game of Thrones trailer where Ive been out and seen a cold weather front move in and suddenly you felt you could almost see the frost and ice forming in front of you, then you feel a bit kind of nervous because you went out because the conditions were ok, now you are stuck out there in conditions you wouldnt have chosen to ride in, but youve got to get back somehow.

ultimately its better to be safe than sorry, so if theres ever any doubt in your own mind,then dont risk it

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The utility cyclist
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Re: black ice

Postby The utility cyclist » 20 Jan 2019, 11:43pm

As others have pointed out, if it's actually dry then you can ride in sub zero temperatures no problem. I came off xmas morning, local authority didn't bother gritting despite it being damp the night before and predicted lows to zero/sub zero. mini roundabout 150yds from home so I've been round it several thousand times and what I thought was just damp like much else of the road (it was 9:30am) turned out to be ice, 5mph trying to be careful, slight turn and down I went.
Not impressed, have had a moment on a mini rbt about 10/11 years ago but recovered it as it was just a top frosting, this was just a skating rink :evil:
Was out this morning and don't think it got much above 2C even by 11am but roads were ok.

roubaixtuesday
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Re: black ice

Postby roubaixtuesday » 21 Jan 2019, 8:53am

I acquired some ice spiker tyres for the MTB this winter, which has been very mild to date. I've used them all of three or four times so far.

This has, however, resulted in me trying to predict the iciness of the surfaces and I can report the results. Temperatures are from BBC weather app.

I suggest that any forecast temperature below about 3C with clear skies will produce potentially very icy surfaces. If it rained the day before, much worse again. For my money, temperature per se is a poor predictor of iciness of roads once you're below about 3.

Coldest cycle -4C: No ice whatsoever. On ice tyres. Cloudy.
Iciest cycle: 2C: very dicey. On road tyres. Clear skies.

fastpedaller
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Location: Norfolk

Re: black ice

Postby fastpedaller » 21 Jan 2019, 9:19am

There are other hazards to these cold conditions (let alone the other road users)..... Many years ago I was out in sub-zero for a few hours, and a few miles from home I cold feel a heartbeat in a tooth. I thought nothing of it until several days later when an abscess developed! A trip to the dentist, where he said "Wow, I haven't seem this since the days before full-face motorcycle helmets" - The nerve in my tooth was killed by the cold!

Marcus Aurelius
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Joined: 1 Feb 2018, 10:20am

Re: black ice

Postby Marcus Aurelius » 21 Jan 2019, 10:18am

Image

Job jobbed. There’s no such thing as the ‘wrong weather’, just the wrong kit.

Marcus Aurelius
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Joined: 1 Feb 2018, 10:20am

Re: black ice

Postby Marcus Aurelius » 21 Jan 2019, 10:20am

fastpedaller wrote:There are other hazards to these cold conditions (let alone the other road users)..... Many years ago I was out in sub-zero for a few hours, and a few miles from home I cold feel a heartbeat in a tooth. I thought nothing of it until several days later when an abscess developed! A trip to the dentist, where he said "Wow, I haven't seem this since the days before full-face motorcycle helmets" - The nerve in my tooth was killed by the cold!


I’ve recently lost a tooth to exactly this. I’ve now got a balaclava which covers my mouth, with a vented mask bit.

whoof
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Re: black ice

Postby whoof » 21 Jan 2019, 10:37am

Marcus Aurelius wrote:< Trike photo >

Unfortunately unless you change out the standard tyres a trike just stops you falling over sideways and not sliding onto the wrong side of the road on a bend or sliding straight through a junction.

Marcus Aurelius
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Re: black ice

Postby Marcus Aurelius » 21 Jan 2019, 10:54am

whoof wrote:Unfortunately unless you change out the standard tyres a trike just stops you falling over sideways and not sliding onto the wrong side of the road on a bend or sliding straight through a junction.

Prior planning prevents p poor performance though. If you know there’s a strong likelihood of ice, stick to main routes where possible, as they are more likely to have been treated, brake a bit earlier than you normally would, ride a bit slower than you normally would, stay off cycle paths and trails wherever possible, and put some ice tyres on if you must. Winter riding isn’t for everyone, and staying safe is the most important thing. If you don’t enjoy the ride, there’s not much point. If you absolutely have to ride, see above.

whoof
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Joined: 29 Apr 2014, 2:13pm

Re: black ice

Postby whoof » 21 Jan 2019, 1:36pm

Marcus Aurelius wrote:Prior planning prevents p poor performance though. If you know there’s a strong likelihood of ice, stick to main routes where possible, as they are more likely to have been treated, brake a bit earlier than you normally would, ride a bit slower than you normally would, stay off cycle paths and trails wherever possible, and put some ice tyres on if you must. Winter riding isn’t for everyone, and staying safe is the most important thing. If you don’t enjoy the ride, there’s not much point. If you absolutely have to ride, see above.

For some a bike isn't just a plaything, the point of the riding it is to get to work. When doing so I choose a route to stay on cycle paths as much as possible which in my case eliminates being hit by a skidding car.