Decending

open topic, for anything cycling related.

Re: Decending

Postby you cannot be sirrus » Sun Jan 15, 2012 3:46 pm

liamb wrote:Hi All

Good test on the Ride Like Cray ride today a few decent hills to run down, and I went faster and safer than I have ever. The main things I tried were
Looking as far as I could ahead through the corner and thats where I went and had heaps of time to correct if there were things to miss
Rear brake trailing, I had very light pressure on the handle only enough to have the pads just touching and just applied a tiny bit more if needed to pull me in a bit tighter and wash some speed off.
Bum as far as back on the seat as possible but not touching and legs in tight.
More weight on the outside pedal than I used to apply.
Every bend I took was much more stable and as such faster than ever before

Cheers

Bill


Me too Bill, I put a few of the tips in this thread into practice today on RLC and can vouch that they make a big difference.
Scott CR1
you cannot be sirrus
 
Posts: 725
Joined: Sun Apr 25, 2010 4:33 pm

by BNA » Sun Jan 15, 2012 4:14 pm

BNA
 

Re: Decending

Postby jules21 » Sun Jan 15, 2012 4:14 pm

descending can be dangerous, but not always for the reasons people think.

1. golden rule - ****descend within your limits**** it's common for newbies and risk takers to seek a rush from doing stuff they shouldn't. the result can be fairly permanent and painful.
2. leaning over is not necessarily what makes descending dangerous, which is:
a. entering blind corners too hot without knowing whether they will tighten up (there is a beauty coming down the Kinglake climb that has left me and others on the wrong side of the road)
b. not accounting for run-off - if there is a huge drop where you would slide off, or traffic you would slide into, that's a signal to slow it down slightly.
c. entering blind corners too close to the centreline - car drivers often don't care about crossing over the centreline and committing yourself to where they might be driving is asking for a full frontal collision (and your death probably).

a general tip that i've found improved my descending (there are probably dozens) is to enter wide - i.e. like a motorbike racer. not so much as it increases the turning radius and straightens out the corner a bit, but as you get an earlier and clearer view of what's ahead. as above, that is of critical importance in safe descending.

if you abide by those rules (and others i've neglected i'm sure) and develop your skills progressively, you can learn to descend very quickly and safely.

quick != dangerous and slow != safe

like riding in traffic, you should learn to hard-code into your head some rules that you use to assess how to approach each corner/circumstance.
Image
User avatar
jules21
 
Posts: 8376
Joined: Thu Apr 02, 2009 10:14 pm
Location: somewhere out in the melbourne rain

Re: Decending

Postby rustychisel » Mon Jan 16, 2012 9:08 am

jules21 wrote:c. entering blind corners too close to the centreline - car drivers often don't care about crossing over the centreline and committing yourself to where they might be driving is asking for a full frontal collision (and your death probably).

a general tip that i've found improved my descending (there are probably dozens) is to enter wide - i.e. like a motorbike racer. not so much as it increases the turning radius and straightens out the corner a bit, but as you get an earlier and clearer view of what's ahead. as above, that is of critical importance in safe descending.


Under many circumstances, such as tight left turns point [c] directly contradicts 'a general tip', sorry. Keep a margin of error, always. We're not paid to be pro riders, putting it all on the line. Nothing can prepare you for how badly it can go wrong so quickly.


jules21 wrote:quick != dangerous and slow != safe


and this is why internet opinions are merely opinions. It's bad advice in some situations. Here in the Adelaide Hills there are many descents where using your brakes to slow down will put you in greater danger through cooking off the tyres when your rims become dangerously overheated.
rustychisel
 
Posts: 3330
Joined: Thu Jan 10, 2008 12:39 pm

Re: Decending

Postby igstar » Mon Jan 16, 2012 9:43 am

Cardy George wrote:Alternatively, find a riding buddy who's a bit fearless. I learnt to corner fast by trying to stay with my mate, who at 90kg definitely had gravity on his side.


Not to be pedantic, but the gravitiy acts on everyone with the same force...
igstar
 
Posts: 348
Joined: Mon Jan 12, 2009 9:54 pm
Location: Melbourne

Re: Decending

Postby jules21 » Mon Jan 16, 2012 9:53 am

rustychisel wrote:Under many circumstances, such as tight left turns point [c] directly contradicts 'a general tip', sorry. Keep a margin of error, always. We're not paid to be pro riders, putting it all on the line. Nothing can prepare you for how badly it can go wrong so quickly.

you're dead right, rusty. i did realise that after i wrote it. you should only swing wide if you've got a clear view of what's coming ahead, such as on RHers or LHers where you can see through the corner. but at the end of the day i agree, it's about common sense and leaving a margin of error. one simple question to ask yourself: "what would happen if...?"
Image
User avatar
jules21
 
Posts: 8376
Joined: Thu Apr 02, 2009 10:14 pm
Location: somewhere out in the melbourne rain

Re: Decending

Postby rustychisel » Mon Jan 16, 2012 10:36 am

jules21 wrote:... at the end of the day i agree, it's about common sense and leaving a margin of error. one simple question to ask yourself: "what would happen if...?"


Agree totally. And funnily enough, the reverse is also true, because descending well is about fluidity and being smooth... picking the right line, using your brakes sparingly and smoothly, setting up for the next corner.

When common sense kicks in (What am I doing at 70kmh wearing only lycra??!?!??) you start to use common sense to second guess. What if...? What's around that corner? Are my tyres feeling right?
And when that happens you lose your mojo, start reacting to potholes that aren't there, hit the brakes 'just because', start your turn too early...
rustychisel
 
Posts: 3330
Joined: Thu Jan 10, 2008 12:39 pm

Re: Decending

Postby trailgumby » Mon Jan 16, 2012 10:42 am

igstar wrote:
Cardy George wrote:Alternatively, find a riding buddy who's a bit fearless. I learnt to corner fast by trying to stay with my mate, who at 90kg definitely had gravity on his side.


Not to be pedantic, but the gravitiy acts on everyone with the same force...

Given that drag relates primarily to frontal area, the force pulling them downhill in excess of the drag slowing them down is going to advantage heavier riders.

Braking for corners is another matter, though :wink:
"People have a right to their own opinions, but not their own facts. Evidence must be located, not created, and opinions not backed by evidence cannot be given much weight." -- James W Loewen

http://www.facebook.com/Drive2WorkDay
User avatar
trailgumby
 
Posts: 9911
Joined: Sat Jan 03, 2009 4:30 pm
Location: Northern Beaches, Sydney

Re: Decending

Postby jules21 » Mon Jan 16, 2012 10:48 am

everyone's different. i have a habit of becoming more confident and lax in my riding habits, until something bad happens, when i go back to being very timid, but then slowly return to taking more risks. i tend to go through a cycle where i'll crash every few months as a result of taking just one too many risks. for me, the trick is to ask myself every now and then "is that really good practice?" in my commutes, i have become gradually more careful around pedestrians on shared paths, as i've concluded that certain riding practices combined with the high no. of km i ride on shared paths = too high a risk, even if the risk is very low on a case-by-case basis.
Image
User avatar
jules21
 
Posts: 8376
Joined: Thu Apr 02, 2009 10:14 pm
Location: somewhere out in the melbourne rain

Re: Decending

Postby rustychisel » Mon Jan 16, 2012 11:50 am

ah yes, shared paths are a whole different ball game innit?

joggers, dog-walkers, iPod numpties, piles of leaves, crumbling edges, bollards and other constrictions...
rustychisel
 
Posts: 3330
Joined: Thu Jan 10, 2008 12:39 pm

Decending

Postby RonK » Mon Jan 16, 2012 12:57 pm

jules21 wrote:i tend to go through a cycle where i'll crash every few months as a result of taking just one too many risks.

so you are what most would consider a slow learner...
Cycle touring blog and tour journals: whispering wheels...
User avatar
RonK
 
Posts: 4927
Joined: Mon Aug 24, 2009 2:08 pm
Location: Brisbane, Queensland

Re: Decending

Postby twizzle » Mon Jan 16, 2012 12:59 pm

The other weekend I melted the front shoes (KoolStop "Road") when pulling up after a fast descent ("What's that burning rubber smell?"). The following day, someone on the same descent popped a tyre (a badly worn one), luckily they didn't crash.

Having total confidence in your bike is important - tyre pressures & condition, brake pad condition - they should be checked before the ride.
I ride, therefore I am.
...real cyclists don't have squeaky chains...
User avatar
twizzle
 
Posts: 6382
Joined: Wed Aug 13, 2008 11:45 am
Location: Taking a break.

Re: Decending

Postby jules21 » Mon Jan 16, 2012 1:05 pm

RonK wrote:so you are what most would consider a slow learner...

so they tell me..
Image
User avatar
jules21
 
Posts: 8376
Joined: Thu Apr 02, 2009 10:14 pm
Location: somewhere out in the melbourne rain

Re: Decending

Postby eeksll » Mon Jan 16, 2012 2:39 pm

So do people keep a finger on the brake lever when descending?

I did a ride on the weekend and I usually have a finger on the brake lever (whether it be while on the hoods or the drops). However, this time it was a new road and bumpy so the one/two finger on the brake lever was no good, just kept felt like my hands where going to be thrown off.

I also don't like having no fingers on the brakes as opening my hand to do the braking is even worse. I get this MTB'ing as well, if I forget to leave a finger on the lever, but leaving a finger on the lever on the MTB I still have a adequate enough grip on the bars over rougher terrain.

I ended up resting a finger or two on the rear brake lever and no fingers on the brake lever on my right hand. this seemed to go OK for me. Ill try this again next time.

Any tips for this ?
eeksll
 
Posts: 1230
Joined: Tue Oct 20, 2009 9:36 pm

Re: Decending

Postby rustychisel » Mon Jan 16, 2012 3:00 pm

road bike?

Be in the drops. Wrap the thumb loosely around the bars so that you can employ 1 or 2 fingers at any time... I'll usually have the index finger resting on the lever. More than that you don't need, really, under most circumstances. If you cannot reach the the bars are wrongly shaped/the levers are incorrectly positioned/ or they're too far away for small hands. Most commonly people seem (with modern STIs in particular) to have them angled up far too much, but that's partly to taste. Even so, if you can't use the drops then you'll have problems; when descending it gives much better stability to the front of the bike, lowers the centre of gravity (lowered torso) and shifts the weight distribution slightly to the front wheel. (which is why when elongated on the bike - as in the drops - it's also important to shift the weight back on the saddle.

Also, be loose as a goose on the saddle. Seated but not planted; on bumpy roads using your legs as the primary shock absorbers by raising your rump slightly off the saddle will still allow you to use your inner thighs to steer the line. Be loose and relaxed, let the bike pivot fore and aft on bumps, let your shoulders do the work rather than your hands, which should never have a 'death grip'.

Use the brakes firmly but smoothly; the front brake will do 90% of the work. Never use the rear as a 'drag' brake for more than a second or two. Pulse them on and off rather than have them dragging and heating the rims. etc
rustychisel
 
Posts: 3330
Joined: Thu Jan 10, 2008 12:39 pm

Re: Decending

Postby Eleri » Mon Jan 16, 2012 7:53 pm

Here's a thing to try that's completely safe and helps to understand what the bike does when cornering.

Get off your bike on a flat bit of road or the footpath or something. Give yourself plenty of room. Now put your hand on the seat or the bike and push it along with just that one hand on the seat. If you want your bike to go straight, you'll find you need to lean the bike left or right in order to counteract what the front wheel wants to do when it hits a bump or something. Your bike basically wants to go straight. But it doesn't always do what you think it will do. Practise making the bike zig zag down the street, all the while just holding the seat.

That's why the advice to push down hard with your outside leg. It helps counteract what the bike wants to do naturally.
Image
Eleri
 
Posts: 301
Joined: Sun Jan 17, 2010 11:16 am
Location: Inner West, Sydney

Re: Decending

Postby Cardy George » Mon Jan 16, 2012 8:38 pm

trailgumby wrote:
igstar wrote:
Cardy George wrote:Alternatively, find a riding buddy who's a bit fearless. I learnt to corner fast by trying to stay with my mate, who at 90kg definitely had gravity on his side.


Not to be pedantic, but the gravitiy acts on everyone with the same force...

Given that drag relates primarily to frontal area, the force pulling them downhill in excess of the drag slowing them down is going to advantage heavier riders.


Feather and Bowling Ball, with me being the feather. We were commonly know as Captain Downhill and Boy Drafter

trailgumby wrote:Braking for corners is another matter, though :wink:


Really sucky part: On our favourite descent, he never touched his brakes, hairpins et al.
Image
Fondreist R10, Dura-Ace, Cosmic SL's
Specialized Hardrock, Spinergy Xyclones
And the occasional trailer full of kids......
Image
User avatar
Cardy George
 
Posts: 287
Joined: Sun Aug 23, 2009 11:10 pm
Location: Cardross, Vic

Re: Decending

Postby uncle arthur » Mon Jan 16, 2012 9:01 pm

This is the Cancellara descent so many of us have seen.....
[youtube]http://www.youtube.com/watch?v=RxXqQqAc2pA&feature=endscreen&NR=1[/youtube]

While it is amazing to watch his descent, (and try to forget the drama of Mozart in the background) it is also important to remember he doesn't have to contend with ANY oncoming traffic - although he does have to deal with the support cars also travelling in his direction.

The thing to watch is his position over the bike - how he holds his legs, loading the outside, pushing the bike into the ground.

Watch how he positions his head - looking through each corner. He also uses the shape of the road - starting wide, to set himself up to clip the apexes - smooth in, smooth out, brake BEFORE the corner, power out (otherwise known in car/motorbike racing as slow in fast out).

You can tell he is looking at where he wants to go, not at distractions along the side of the road - if you look where you want to go, your bike will go that way.....

Basically this is a masterclass in descending at speed. Yes - he's a professional bike rider, but you can be sure at this stage he still wanted to maintain the yellow, and not be a blood stain on the side of the road.
What is it with cycling? 30+ kmh and lycra???!!!
User avatar
uncle arthur
 
Posts: 1387
Joined: Tue Oct 02, 2007 9:45 pm
Location: Brisvegas

Re: Decending

Postby Downhill » Mon Jan 16, 2012 11:04 pm

After watching the Canellara video I have a totally newbie question:

Where should the rider's centre of gravity be while cornering? Should it be over the centre line of the bike? Or should it be to towards the inside (or outside?) of the corner?
Today's effort = Tomorrows reward.
2010 Oppy C6
Downhill
 
Posts: 353
Joined: Thu Sep 30, 2010 1:11 am
Location: WA

Re: Decending

Postby PawPaw » Tue Jan 17, 2012 1:39 am

Don't think about abstractions like your centre of gravity when descending. Just get your eyes and head to look at where you want to go, keep your outer foot down with as much weight on it as you can, keep you butt right back on the seat and slightly or fully unloaded, your neck,hands,arms,shoulders, and trunk loose, your hands on the drops with at least two fingers on each brake lever. Then as your eyes track the line you want to take around a left hand corner, your head, neck, and trunk will lean left, while weight through your outer right leg will help counterbalance.

Something I didn't mention earlier is counter steering. It is a difficult concept to explain, but basically when you are leaning left into a left hand corner, you get a little more control by pushing forwards slightly with the left hand against the left bar. It seems counter intuitive, but it helps to assist and stabilize cornering partly by allowing you to lean a little more to the left and partly by stabilizing the front wheel in its leftward trajectory. Best thing is to experiment with it, conservatively at first.

I dont' agree with rustychisel's view not to use the rear brake as a drag to avoid overheating. The rear wheel has a lot less weight on it during steep descents so you can leave it on permanently when you want to stop speed from building, and alternate the front on/off to avoid it overheating. I've never known a rear wheel to heat anywhere near the temp of a front wheel. Once again don't take my word for it, go and experiment.

The other thing I'd reinforce is to ensure before big descents that your wheel rim is centred between your brake pads, or vv. Before a ride, I often see so many guys whack their wheel on quickly after removing it from a car or rack, that the brake pads push the rim off centre when applied.
User avatar
PawPaw
 
Posts: 1244
Joined: Sat Dec 10, 2011 6:53 am
Location: Brisbane

Re: Decending

Postby Ken Ho » Tue Jan 17, 2012 5:55 am

Another good reason to load the outside pedal, is that it ensures that the crank is in the correct position to avoid pedal strike on the inside.
Seems the topic is still "cornering at speed".
You have officially become your parents.
Ken Ho
 
Posts: 1256
Joined: Mon Mar 21, 2011 6:28 pm
Location: Pikey, based on Southern Gold Coast

Re: Decending

Postby jules21 » Tue Jan 17, 2012 10:41 am

Downhill wrote:Where should the rider's centre of gravity be while cornering? Should it be over the centre line of the bike? Or should it be to towards the inside (or outside?) of the corner?

Image
Image
User avatar
jules21
 
Posts: 8376
Joined: Thu Apr 02, 2009 10:14 pm
Location: somewhere out in the melbourne rain

Re: Decending

Postby notwal » Tue Jan 17, 2012 7:23 pm

PawPaw wrote:...

I dont' agree with rustychisel's view not to use the rear brake as a drag to avoid overheating. The rear wheel has a lot less weight on it during steep descents so you can leave it on permanently when you want to stop speed from building, and alternate the front on/off to avoid it overheating. I've never known a rear wheel to heat anywhere near the temp of a front wheel. Once again don't take my word for it, go and experiment.

....

This is true, sort of. Both the front and back brakes feel the same resistance when when doing the same job. It's wheel traction that changes. Under breaking there is an effective transfer of weight to the front wheel. When the back wheel loses traction it can't stop you but up until that point the breaking front and back is much the same. Whether the back rim can overheat or not is moot. For me it wouldn't. For a heavy bloke it might. Use both to share the load and heating I reckon.
judged, insulted, gone
User avatar
notwal
 
Posts: 1097
Joined: Fri Nov 20, 2009 9:57 pm

Re: Decending

Postby uncle arthur » Tue Jan 17, 2012 8:36 pm

As far as I know the idea of braking the front into the corner is to shif weight over the front wheel to achieve a better turn in.

I use the rear brake on descending to even out any speed wobbles - because training the rear very gently affects the balance of the back end of the bike.

In the Cancellar vid, you can also see him getting over the rear on braking entries to corners - obviously using the front braking for turn in and shifting weight back towards the rear to maintain even balance and wheel connection with the road surface. You probably find you do the same thing instrinctively, but won't realise it until you actively think about it while you're doing it.....
What is it with cycling? 30+ kmh and lycra???!!!
User avatar
uncle arthur
 
Posts: 1387
Joined: Tue Oct 02, 2007 9:45 pm
Location: Brisvegas

Re: Decending

Postby jules21 » Tue Jan 17, 2012 8:39 pm

uncle arthur wrote:As far as I know the idea of braking the front into the corner is to shif weight over the front wheel to achieve a better turn in.

the rear brake will have the same effect (of rotating the bike onto the front wheel)
Image
User avatar
jules21
 
Posts: 8376
Joined: Thu Apr 02, 2009 10:14 pm
Location: somewhere out in the melbourne rain

Re: Decending

Postby Downhill » Tue Jan 17, 2012 11:05 pm

Thanks Jules, that sketch matches my current understanding.

Next question: If the C of G is normally supposed to be over centre line, why does the rider extend his knee to the inside of the corners? Is it to counteract the centrifugal force in order to keep the bike just a little more upright through the corners?

(Admittedly when you're on the bike you have to "do", not "think". But when off on the bike, it's worth trying to develop a better understanding of the forces and techniques involved).
Today's effort = Tomorrows reward.
2010 Oppy C6
Downhill
 
Posts: 353
Joined: Thu Sep 30, 2010 1:11 am
Location: WA

PreviousNext

Return to General discussion

Who is online

Users browsing this forum: Google Adsense [Bot], MSNbot Media, NhiTrac



Support BNA
Click for online shops
Torpedo 7 Torpedo7 AU
Ground Effect Ground Effect NZ
Chain Reaction Cycles CRC UK
Wiggle Wiggle UK
Cycling Express Cycling Express
Ebay Ebay AU
ProBikeKit ProBikeKit UK
Evans Cycles Evans Cycles UK
JensonUSA Jenson USA
JensonUSA Competitive Cyclist