Black ice

General cycling advice ( NOT technical ! )
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pedalsheep
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Re: Black ice

Postby pedalsheep » 24 Jan 2017, 12:08pm

Set off today 10.00am, sun beating down, thermometer reading 4 degrees, seemed like a perfect cycling day. A fog bank sitting on the sea looked spectacular. 3 miles down the road there was a thin, cold mist and the temperature plummeted. Rounded a bend and the bike just slid from under me on black ice. Somehow I landed on my feet and continued to slide down the road until I hit the verge, still upright!! Returned home to where it still looks like a perfect cycling day! You just can't tell.
'Why cycling for joy is not the most popular pastime on earth is still a mystery to me.'
Frank J Urry, Salute to Cycling, 1956.

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horizon
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Re: Black ice

Postby horizon » 24 Jan 2017, 1:05pm

Last night the predicted temperature was about 4 deg (in fact it was too high by about 2 deg but nevertheless both values were above freezing). The roads were dry and the day had been sunny. But I had to scrape ice from the car at 6.00 pm. My studded tyres weren't ready to go and I knew I needed them for the stretch where the streams run across the road (in the dark). So I was glad to use the car (not often I say that).

I think the probem with dry, cold weather is that the roads are generally ice free. This gives a false sense of security - where there is water, it will be frozen. So you have to use studs on a just-in-case basis even though you might not even need them for 95% of the journey.
I have two doctors, my left leg and my right leg. (G. M. Trevelyan)
PS I always wondered why the YHA HQ was called Trevelyan House. :)

Psamathe
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Re: Black ice

Postby Psamathe » 24 Jan 2017, 1:32pm

My concern where I ride is that narrow country lanes with hedges (and pools/potholes for water) mean that some parts of the road receive little or no Sun through the day so have been getting just colder and colder through the last few weeks. And there are a lot of such areas, cool down a lot through the cold nights and hardly warm atall in the marginally above freezing air temperatures in the shade.

And little traffic which I always assume must add some warmth to the road (e.g. a main road with streams of cars, those warm tyres, warm exhaust gases directed downwards, that hot engine just above the road surface, all having a cumulative impact as car after car passes).

Ian

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horizon
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Re: Black ice

Postby horizon » 24 Jan 2017, 1:42pm

Psamathe wrote:My concern ...
Ian


You're right to be concerned. So, translate that concern into action and get some studded tyres. :shock:
I have two doctors, my left leg and my right leg. (G. M. Trevelyan)
PS I always wondered why the YHA HQ was called Trevelyan House. :)

Psamathe
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Re: Black ice

Postby Psamathe » 24 Jan 2017, 1:47pm

horizon wrote:
Psamathe wrote:My concern ...
Ian


You're right to be concerned. So, translate that concern into action and get some studded tyres. :shock:

As I cycle for leisure and despite having never used studded tyres I do wonder about how the studs could penetrate into tough black ice to get a decent grip and still be ok for use on dry warmer roads (and I don't want to keep changing tyres and don't want to get a 2nd set of wheels when I could just wait for a couple of days for warmer weather).

Ian

Threevok
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Re: Black ice

Postby Threevok » 24 Jan 2017, 3:14pm

Psamathe wrote:As I cycle for leisure and despite having never used studded tyres I do wonder about how the studs could penetrate into tough black ice to get a decent grip and still be ok for use on dry warmer roads (and I don't want to keep changing tyres and don't want to get a 2nd set of wheels when I could just wait for a couple of days for warmer weather).



As a matter of interest, I have ridden mine on an Ice rink (or a Supermarket car-park setup as one at Xmas) I would dare anyone with normal "winter" tyres to do the same, without falling off.

There is an argument that, should the ice be thicker than the studs but the ice itself is not fixed to the surface below it, that the studs would slip along with the ice. This is true and happens to me quite regularly off road (less regular on road) but is easy to recover, as such ice breaks as you hit it and the studs dig into whats underneath, as the tyre rolls. If this happens to you at a standstill, there is little you can do anyway - hence studs on the feet too. Another thing to consider is not to wear clipless pedals in such conditions.

They are fine on dry or wet roads too, although a bit noisey - like riding on Rice Crispies

A bit sketchy on the warehouse floor though :wink:

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[XAP]Bob
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Re: Black ice

Postby [XAP]Bob » 24 Jan 2017, 4:04pm

As I cycle for leisure and despite having never used studded tyres I do wonder about how the studs could penetrate into tough black ice to get a decent grip and still be ok for use on dry warmer roads (and I don't want to keep changing tyres and don't want to get a 2nd set of wheels when I could just wait for a couple of days for warmer weather).


The trick that studded tyres have is the studs 'retract' if the surface is solid (tarmac) so that you still get the grip of the rubber.

i.e. they either push through the ice (good, lots of grip) or push into the rubber (leaving rubber on the tarmac for lots of grip...
I mean they'll not provide the same grip as a summer tyre in the summer - but it's not a bad solution.

I'm yet to fit mine this year, despite about 10 miles of my commute being rural. I've not come across any ice *on* the road - plenty of frozen puddles to the side though.
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.

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Mick F
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Re: Black ice

Postby Mick F » 24 Jan 2017, 4:17pm

Woke up to -5degC and I was out riding yesterday in -1degC and frost .................. lots of it.
The thing is, half a mile up the hill, it was +5degC, and later +8degC
When I got home, it was -1degC and still frosty.

Frost didn't go until this afternoon.
Mick F. Cornwall

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mjr
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Re: Black ice

Postby mjr » 24 Jan 2017, 5:59pm

Psamathe wrote:As I cycle for leisure and despite having never used studded tyres I do wonder about how the studs could penetrate into tough black ice to get a decent grip and still be ok for use on dry warmer roads (and I don't want to keep changing tyres and don't want to get a 2nd set of wheels when I could just wait for a couple of days for warmer weather).

I don't think the studs do penetrate - I think they just scratch the surface until they give enough grip. They really are remarkable but I've probably waxed lyrical in this discussion already.

But yeah, if you don't cycle for transport in winter at all, I guess it's not a burning need, but they're often less than £50 a pair and sometimes discounted to less than £20, which isn't many bus fares (as if it's frozen here, the car will probably end up in a bank or fencepost before it gets to the deiced road, so I can't use that).
MJR, mostly pedalling 3-speed roadsters. KL+West Norfolk BUG incl social easy rides http://www.klwnbug.co.uk
All the above is CC-By-SA and no other implied copyright license to Cycle magazine.

Threevok
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Re: Black ice

Postby Threevok » 24 Jan 2017, 8:16pm

Agreed about the price being steep. Mine cost close to £160 for the pair, but when you consider how many days I didn't miss work thanks to them, they've more than paid for themselves. Plus they last and last because you only use them for about 1-2 months a year - unless you off-road them too - like me :twisted: