Speed and the fear of falling off

Commuting, Day rides, Audax, Incidents, etc.
Peter F
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Joined: 25 May 2020, 8:16am

Re: Speed and the fear of falling off

Postby Peter F » 1 Jun 2020, 3:25pm

mikeymo wrote:I don't cycle faster than about 25 mph. Even then only if I know the road, and it is clean and dry, with a good surface, little or no traffic, and few or no junctions.
.

There are quite a lot of hills where I live. If I was to keep my speed below 25mph then I'd be on my brakes constantly. That hill, Birk Brow is one of two routes I regularly use to access the North Yorkshire Moors. I agree, junctions are a problem, but I can ride for miles and only see a dozen cars and there are long stretches with no side roads. The roads are up and down constantly and 25mph is passed very quickly.
In fact Birk Brow is on the main road to Whitby. There are a few sections along there where the road is well sighted, the surface is very good and the few turnings are easy to spot. 15 minutes before I had the incident I was doing 35mph in entirely different circumstances.
You can't tell from the picture, but that is down Hill. We all have a different tolerance for risk, but I've never applied a number to speed in that way. Where there are pedestrians and side roads I try to exercise caution, but on the road below 35mph feels entirely safe.
Screenshot_20200601-151553_Maps.jpg

mikeymo
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Re: Speed and the fear of falling off

Postby mikeymo » 1 Jun 2020, 3:32pm

Peter F wrote:
mikeymo wrote:I don't cycle faster than about 25 mph. Even then only if I know the road, and it is clean and dry, with a good surface, little or no traffic, and few or no junctions.
.

There are quite a lot of hills where I live. If I was to keep my speed below 25mph then I'd be on my brakes constantly. That hill, Birk Brow is one of two routes I regularly use to access the North Yorkshire Moors. I agree, junctions are a problem, but I can ride for miles and only see a dozen cars and there are long stretches with no side roads. The roads are up and down constantly and 25mph is passed very quickly.
In fact Birk Brow is on the main road to Whitby. There are a few sections along there where the road is well sighted, the surface is very good and the few turnings are easy to spot. 15 minutes before I had the incident I was doing 35mph in entirely different circumstances.
You can't tell from the picture, but that is down Hill. We all have a different tolerance for risk, but I've never applied a number to speed in that way. Where there are pedestrians and side roads I try to exercise caution, but on the road below 35mph feels entirely safe.
Screenshot_20200601-151553_Maps.jpg


Sure, different circumstances mean different risks. And as I think we agree, we've all got a different feel for what is comfortable. I'm a relatively new cyclist, and my bike is a heavy tourer. But if it weren't for Covid-19 I'd be on my usual remote island holiday, where the roads are narrow single track (usually) but also very good surfaces, hardly any traffic and really long sight lines. Sometimes I can see the road, literally, for miles and so can the drivers. As a lot of the roads are single track with passing places, I think the drivers are a little more aware, as it happens. So if there were any hills steep enough I might try to get up to 30 or 35 mph. Can't imagine getting much past that, to be honest. Depending on the wind.
Last edited by mikeymo on 1 Jun 2020, 3:36pm, edited 1 time in total.
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Marcus Aurelius
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Re: Speed and the fear of falling off

Postby Marcus Aurelius » 1 Jun 2020, 3:35pm

There are a few descents on some of my regular routes, where 100Km/h ( 60mph ) is do-able. However, having come off the bike at 50mph, after getting a speed wobble, several years ago, and knowing what that entails, I don’t push my luck on descents anymore. There are mire things than you can easily imagine, that can cause an ‘off’ descending at speed. In a race, you need to accept those risks, or you’ll end up getting nowhere. When riding normally, on open roads, I don’t find it’s worth the risk, so anything over about 35 mph, on a descent and I ease off.

Peter F
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Joined: 25 May 2020, 8:16am

Re: Speed and the fear of falling off

Postby Peter F » 1 Jun 2020, 3:36pm

Nigel wrote:
There is a sign, its a warning sign of a bend, with a suggestion (advice) about speed. The suggested speed doesn't apply legally to motor vehicles either.
Speed limit signs have an arrangement of a white circle, red ring on outside, black writing in middle. There's a clear visual difference between advice and limit signs. From the pictures posted, I'd say its a national speed limit, 70mph for cars on dual carriageway, reducing to 60mph when one reaches the single carriageway indicated by the sign on the right.

I agree that any road user ought to pay heed to those signs and adjust their speed on the hill into the bend .


Nigel


The limit is 50mph on the stretch. Despite the bank being a dual carriageway It's only ever been 60, but the limit was reduced on the bank and for a couple of miles once you get to the top, due to fatalities. The 2 mile section leading to the bottom of the bank is 40 mph due to a number of poorly sighted turnings.
Last edited by Peter F on 1 Jun 2020, 3:45pm, edited 2 times in total.

Peter F
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Re: Speed and the fear of falling off

Postby Peter F » 1 Jun 2020, 3:43pm

Marcus Aurelius wrote:There are a few descents on some of my regular routes, where 100Km/h ( 60mph ) is do-able. However, having come off the bike at 50mph, after getting a speed wobble, several years ago, and knowing what that entails, I don’t push my luck on descents anymore. There are mire things than you can easily imagine, that can cause an ‘off’ descending at speed. In a race, you need to accept those risks, or you’ll end up getting nowhere. When riding normally, on open roads, I don’t find it’s worth the risk, so anything over about 35 mph, on a descent and I ease off.

60 mph? :shock:
That's mental. Any hill I can think of where that speed is possible, due to gravity, isn't well sighted enough or the surface good enough. 45mph is about the most I have ever done. On main roads, with decent tarmac, they tend to flatten out the big hills or go round them :D

pwa
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Re: Speed and the fear of falling off

Postby pwa » 1 Jun 2020, 3:50pm

Peter F wrote:
Marcus Aurelius wrote:There are a few descents on some of my regular routes, where 100Km/h ( 60mph ) is do-able. However, having come off the bike at 50mph, after getting a speed wobble, several years ago, and knowing what that entails, I don’t push my luck on descents anymore. There are mire things than you can easily imagine, that can cause an ‘off’ descending at speed. In a race, you need to accept those risks, or you’ll end up getting nowhere. When riding normally, on open roads, I don’t find it’s worth the risk, so anything over about 35 mph, on a descent and I ease off.

60 mph? :shock:
That's mental. Any hill I can think of where that speed is possible, due to gravity, isn't well sighted enough or the surface good enough. 45mph is about the most I have ever done. On main roads, with decent tarmac, they tend to flatten out the big hills or go round them :D

Here in Wales there are a few descents with long straights that are steep enough, and long enough, to get 45 - 50mph with low risk, but they are few and far between. At 50mph you are encountering a lot of resistance from the air to stop you going faster. I don't know of any descents around here where you can get 60 and not finish up in a wooden box.
Last edited by pwa on 1 Jun 2020, 3:51pm, edited 1 time in total.

Marcus Aurelius
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Re: Speed and the fear of falling off

Postby Marcus Aurelius » 1 Jun 2020, 3:50pm

Peter F wrote:
Marcus Aurelius wrote:There are a few descents on some of my regular routes, where 100Km/h ( 60mph ) is do-able. However, having come off the bike at 50mph, after getting a speed wobble, several years ago, and knowing what that entails, I don’t push my luck on descents anymore. There are mire things than you can easily imagine, that can cause an ‘off’ descending at speed. In a race, you need to accept those risks, or you’ll end up getting nowhere. When riding normally, on open roads, I don’t find it’s worth the risk, so anything over about 35 mph, on a descent and I ease off.

60 mph? :shock:
That's mental. Any hill I can think of where that speed is possible, due to gravity, isn't well sighted enough or the surface good enough. 45mph is about the most I have ever done. On main roads, with decent tarmac, they tend to flatten out the big hills or go round them :D

The candidates for a 60 mph descent are basically profiled like a ski jump, I avoid them where possible, because if you’re not concentrating, you’ll be moving at a rate that’s very difficult to control, very quickly. There are a couple of prime examples just outside Basingstoke. Green Lane in Ellisfield , and Farleigh Wallop are two that spring to mind. You’d have to be a pickled pepper short of a peck to go flat out down either of them.

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RickH
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Location: Horwich, Lancs.

Re: Speed and the fear of falling off

Postby RickH » 1 Jun 2020, 4:13pm

mikeymo wrote:I don't cycle faster than about 25 mph. Even then only if I know the road, and it is clean and dry, with a good surface, little or no traffic, and few or no junctions.

I don't often go much above 25mph off road. I'll happily do 40+ on the road where the sight lines & the gradient permit it. Still haven't managed to get past 50, to my knowledge, in the UK but have recorded 48s & 49s. I did enjoy coming down numerous mountains in the USA at a sustained 55 mph back in '96. None of us could keep up with the couple on the tandem who were with us as they could easily get to 60+! :D

whoof
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Re: Speed and the fear of falling off

Postby whoof » 1 Jun 2020, 5:15pm

Sometimes what seems to be a reasonable speed to go into a corner can go wrong very quickly.

https://m.youtube.com/watch?v=hRM3bFXly ... =emb_title

Postboxer
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Re: Speed and the fear of falling off

Postby Postboxer » 1 Jun 2020, 5:57pm

Kinetic energy is 1/2 x mass x velocity squared, so doubling velocity will approximately increase stopping distance by a factor of 4. Is that right? Triple the speed and stopping distance increases by a factor of 9.

roubaixtuesday
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Re: Speed and the fear of falling off

Postby roubaixtuesday » 1 Jun 2020, 6:03pm

Postboxer wrote:Kinetic energy is 1/2 x mass x velocity squared, so doubling velocity will approximately increase stopping distance by a factor of 4. Is that right? Triple the speed and stopping distance increases by a factor of 9.


Yes, that's correct, for a given braking force the distance taken to reduce speed to zero is proportional to the square of the original speed.

Plus the effect of reaction time.

pwa
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Re: Speed and the fear of falling off

Postby pwa » 1 Jun 2020, 6:07pm

whoof wrote:Sometimes what seems to be a reasonable speed to go into a corner can go wrong very quickly.

https://m.youtube.com/watch?v=hRM3bFXly ... =emb_title


Whatever went wrong there started somewhere further up the road, out of sight. The cyclist was going too fast, certainly, but also well off line.

Peter F
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Joined: 25 May 2020, 8:16am

Re: Speed and the fear of falling off

Postby Peter F » 1 Jun 2020, 6:13pm

whoof wrote:Sometimes what seems to be a reasonable speed to go into a corner can go wrong very quickly.

https://m.youtube.com/watch?v=hRM3bFXly ... =emb_title


That was just stupid. Far too fast. The rider clearly didn't know the road.

Peter F
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Joined: 25 May 2020, 8:16am

Re: Speed and the fear of falling off

Postby Peter F » 1 Jun 2020, 6:15pm

Just driven the road where said incident happened and I didn't hit a cats eye. I hit the pot hole left where a cats eye, including the metal mounting has been ripped out if the road.

Not that it really matters...

whoof
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Re: Speed and the fear of falling off

Postby whoof » 1 Jun 2020, 6:46pm

pwa wrote:
whoof wrote:Sometimes what seems to be a reasonable speed to go into a corner can go wrong very quickly.

https://m.youtube.com/watch?v=hRM3bFXly ... =emb_title


Whatever went wrong there started somewhere further up the road, out of sight. The cyclist was going too fast, certainly, but also well off line.

He was probably passing team cars hence the position on the road approaching the corner which i assume he didn't see.