Steep descents

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NATURAL ANKLING
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Re: Steep descents

Postby NATURAL ANKLING » 1 Jul 2013, 11:51pm

Hi,
MattyDeez wrote:Fastest i've done is 52.6mph, i cant seem to find any longer hills and with a decent tailwind!
I got that coming off dartmoor to moretonhampstead.

Saw 53.5 mph down pork hill dartmoor twenty years ago (speedo might not be acurate), Mick F's done close to that same hill and he's got his bus pass :lol:
Probably been faster on some hills before LCD speedos, You could go faster but the short steep ones are normally kamakazee terrain :(
Most of the time if there is no tail wind I think that the hills are not steep or not long enough to overcome the frontal wind pressure.
No brakes off haytor to bovey no wind asistance use'to give me 45 coasting, but last week I hit that on the 18 kg tourer with a panier.(51.5 wind assisted Dartmoor Devil on MTB)
There is a long hill into Ashburton from cold east cross on the dartmoor classic (49.7 on the course somewhere) sportif which would render some speed but another kamakazee hill.(51.7 MTB 2010)
There are a lot of hills that give 50 on a knobbly MTB on dartmoor but over 50 is rare.
Telegraph Hill now I did that once a week in the 80's no speedo, worth a try next time I am over there.
After driving through Gunnislake last month, some evil hills but simply too dangerous for a try.
Dartmoor to Mortenhampstead the big dipper yeh fast hill :wink:
Helps if your all up weight is 96 KGs, but that Lidl's pannier is always there :(
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NATURAL ANKLING
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Re: Steep descents

Postby NATURAL ANKLING » 1 Jul 2013, 11:56pm

Hi,
consett k wrote:I hit 50.7 would be interesting to see the speeds that have been set by others and where. One thing I'd like to see in the tdf is the speeds they are reachng being shown on the screen as the race is progressing . Blows me away the speeds they generate.

Yeh I would LIKE to see some more tech info on actual steepness of climbs and gears they use, this would be of interest rather than the innacurate dribble from the british speaking commentaters, and when they do give some info I swear they are on another race :?
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rfryer
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Re: Steep descents

Postby rfryer » 2 Jul 2013, 8:43am

Mark1978 wrote:Any advice?

I'd start by checking your equipment. If your bike is not that stable when descending, you'll never build up much confidence. It's hard to tell someone what to look for here; there's no alternative to just experiencing how different bikes behave. Though, I suppose, you can always ask the forum :lol:

Second thing is to check your brakes. If they're not effective, or if they grab or judder rather than modulating smoothly, you'd be a fool to trust your life to them on a steep descent.

Finally, there's technique. For building confidence, I'd recommend repeatedly going as fast as comfortable, then practicing fast, controlled braking in a straight line. As you gain experience, you'll probably find that you can give the bike its head on safe sections of the descent, and have the confidence to be able to brake for corners, hazards, etc.

Then there's cornering technique, but that's a whole different poost...

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Re: Steep descents

Postby Mark1978 » 2 Jul 2013, 9:04am

A lot is down to the brakes. By no means all of course.

I'm braking down to walking pace because I think if I go too fast I won't be able to slow down enough for the corner.

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Mick F
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Re: Steep descents

Postby Mick F » 2 Jul 2013, 9:28am

Try 42mph down into Gunnislake on a Raleigh Chopper.
http://www.youtube.com/watch?v=JP_3OfVQjF0
Mick F. Cornwall

thirdcrank
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Re: Steep descents

Postby thirdcrank » 2 Jul 2013, 10:32am

I'd say that dead slow is the best approach to an unfamiliar hill because it's very easy for a cyclist to lose control of their speed eg if the descent is a bit steeper than it looks.

Then, even on a familiar hill, don't assume there's nothing around the corner or in a dip out of sight, just because it's never been there before.

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NATURAL ANKLING
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Re: Steep descents

Postby NATURAL ANKLING » 2 Jul 2013, 10:58am

Hi,
Yes that was the gunnislake hill I was thinking of, I always said that they should means test bus pass holders, electrically powered invalid carridges and and human powered vehicles are definately a mandatory "PASS IS VOID" :!: ......:lol:
I see that on other side of river the road snakes up the hill with an old v-narrow road going straight down,l you've not tried this one MM (MercianMick) When climbing in the car I saw white man transits whipping up the old hill so I guess its too risky ( dont try it)
Yes unfamiliar hills should allways be taken with caution, I guess that mark1978 has other mechanical issues :?:
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Mick F
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Re: Steep descents

Postby Mick F » 2 Jul 2013, 11:20am

Gunnislake.
The main road down into the village from the west is the hill on my YouTube video. The real name is Sand Hill, but most folk call it Gunny Hill. The road down from the village to the river at Newbridge is Newbridge Hill. 47mph is possible, but you have to be VERY careful and know the road very well too.

On the other side - Devon - the road does indeed snake up and the old packhorse road is still used. The bottom section is one way - upwards - but the other section is two way. The snaking main road is turnpike road built in the 18thC.

The trouble with the old packhorse straight section further up, is if you do try to hurtle down, the road surface will slow you down, plus white vans going up will put the mockers on a decent speed. It's straight and clear, but not best suited to high speeds.

Coming down the snaking turnpike is ok, but you have to pedal hard to get to 40mph. Freewheel speed is maxed out at about 35mph even tucked in.

One of the steepest roads round here is Stony Lane. It's basically parallel to Gunny Hill, so if you're ever round here, have a go at it!
https://maps.google.co.uk/maps?q=stony+ ... m&t=m&z=16
Many folk wouldn't even consider walking it, let alone trying on a bike. It's mainly 25% but in places it could be 33%. Climbing is bad to say the least. The road is straight and there's nowhere to rest like if it was a zig zag.

I climbed Larrick Hill yesterday.
https://maps.google.co.uk/maps?q=Higher ... 7&t=m&z=15
This one zig zags up and up and is as steep as Stony Lane, but because it zig zags, you can go over to the outside of the bends to lessen the gradient.

Neither Stony Lane nor Larrick Hill are any good whatsoever to get a good speed going down despite their steepness.

Main ingredients for a high speed descent are:
12% or steeper gradient
Long gradient
Smooth surface
Wide and straight
Following wind

Pork Hill off Dartmoor down to Tavistock fits the bill very well, but you need an easterly wind off the moor to get above 50mph. The other side down to Moretonhampstead is ok too but you need a westerly wind of course.
Mick F. Cornwall

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Re: Steep descents

Postby Vorpal » 2 Jul 2013, 12:00pm

Mark1978 wrote:A lot is down to the brakes. By no means all of course.

I'm braking down to walking pace because I think if I go too fast I won't be able to slow down enough for the corner.


It's best not to hold the brakes on, but to let the bike freewheel for a bit, then brake, then let it freewheel again, then brake, etc. Holding the brakes constantly a little on is more likely to result in brake fade. It shouldn't be a problem at walking pace, but if you go a bit faster, don't try to hold an even speed.
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mig
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Re: Steep descents

Postby mig » 2 Jul 2013, 7:49pm

although impressive cancellara's descent does have the assistance of being able to confidently use the whole road though. not a luxury we mortals often/ever have!

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Re: Steep descents

Postby MattyDeez » 2 Jul 2013, 7:59pm

Mick F wrote:Try 42mph down into Gunnislake on a Raleigh Chopper.
http://www.youtube.com/watch?v=JP_3OfVQjF0


Just watched this and thought why did you have to brake at them points on the road? Its not even a corner.

Obviously i dont know how a chopper handles at speed, so im not sure if it wobbles at them speeds!

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Re: Steep descents

Postby Mick F » 2 Jul 2013, 8:10pm

The first braking point is the lefthander at Drakewalls on the top corner by the petrol station.
The camber isn't too good, and taking that curve at 35mph puts you way out onto the white line. The curve is tighter than it looks and 30mph is much better.

The second braking point is on the righthander by the escape lane. It's at that point - or just before - that you hit max velocity. 45mph is about it, though I have done 47mph on my Mercian, and you have to get right out to the white line to do it. Practice makes perfect, and I know that hill very well indeed.

Visibility is good most of the way down. The main problem is cars sticking to the 30mph speed limit and getting in the way! :wink:
Mick F. Cornwall

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Re: Steep descents

Postby byegad » 2 Jul 2013, 8:32pm

consett k wrote:
byegad wrote:Mmmmm! Dropping into Wolsingham is one of my favourites. I tend to clock 40 mph+(Record is 50mph! :-) ) on the last stretch into the 30mph limit and let the trike slow before the junction with the main road.


Is that the approach from tow law? Great run down .


It is and, as you say, great fun. Dropping from the South and over the bridge means you need to be sure of your brakes, I suspect riding a 3 wheel recumbent makes for such confidence.
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PaulCumbria
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Re: Steep descents

Postby PaulCumbria » 2 Jul 2013, 10:09pm

rfryer wrote: For building confidence, I'd recommend repeatedly going as fast as comfortable, then practicing fast, controlled braking in a straight line.

I think this is critically good advice. The problem is that most of us simply don't know how hard we can brake in a controlled manner, because we never experiment with braking.
It is potentially disastrous if the only time you try to apply maximum safe braking power is when you need it in an emergency. So you need to find a wide, straight, smooth and quiet stretch of downhill (not easy I know!), and then repeatedly descend at a comfortable speed, applying your brakes with progressively increasing power and bringing your bike to complete, controlled stop. You will be surprised by just how rapidly you can lose speed safely (and you may well find you need to readjust your brakes because the levers are coming right back to the bars!)
It is no surprise that motorcyclists like Sean Yates are such good descenders - they are used to high speeds and very hard braking.

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Re: Steep descents

Postby rfryer » 3 Jul 2013, 7:47am

One other thought about braking. I find that if I'm on a road bike, the limiting factor for braking (in good conditions) is when my rear wheel starts to lift, which happens all to easily on very steep terrain. To avoid this, I've made a habit of getting myself very low on the bike, with hands in the drops, and my rear end (a substantial contributor to my centre of gravity :wink: ) well behind the saddle in order to keep as much weight on the rear wheel as possible.

Of course, if you're carrying panniers, etc, it's much less of an issue.