Advice on downhill curves?

[Wizard]

We were visiting one day and telling scary corner stories (they got more better with more beer),,.. we figured out the worst possible corner;
A downhill, left turn, banked wrong way, on a cliff, at night, in the rain, with a logging truck coming the other way - 1/2 in your lane.
Some physics here, if your brain doesn't already hurt;
Your bike always wants to go straight. If you fall off, it'll straighten up and go without you.
Your Front Tire Contact Patch is smaller than your rear tire (Rear Tire is bigger).
Your Front Contact Patch is already under great duress, trying to turn all 700+ lbs of Bike + Rider in a different direction. Adding a lot of Front Brake is asking for trouble, a little is OK.
Then come the Suspension Torquing.
Adding throttle pulls the chain across the top of the sprockets, squating the rear suspension.
Chopping the throttle tensions the chain along the bottom of the sprockets, raising the Rear Suspension.
Grabbing the Front Brake stands the bike Up. Releasing the Front Brake drops the bike.
Depending on how aggressive the actions are, the bike can really bounce around.
Standing still I can use the brakes and 1st gear to make the suspension bounce up and down.
Shaft Drive bikes have different dynamics,,,.. WOT makes the back end Stand Up like a Funny Car off the line.
BMW uses their ParaLever system to reduce this.
Honda once experimented with a Shaft that went thru the rear wheel and geared from the Right Side (don't know how well that worked).
The fastest/skilled riders always look the smoothest.
Dragging your Rear Brake while leaning into a turn (stay on throttle) will reduce your speed, help the bike fall into the turn, and NOT Upset your Suspension.
There, the secrets out.
Modulating your Rear Brake will modulate your speed. When you're comfortable with the turn set up, you can release Rear Brake and Roll On more gas and power around, smooth and under control.
Always Stay inside your limits.
Here's Sandy's Tail Light, real bright, during this surprise corner;

[mrbill5491]

Depends on the grade, really steep grades, less front brake. Steep grade or any grade with loose sand, gravel, I barely touch the front brake. Last thing you want to do is push/slide that front tire out and play street sweeper. Body position, throttle, gear selection, using the engine for some braking in some situations. Look through the corner, see what is coming up. Experience is the best teacher, though make sure you learn the basic skills by taking a MSF course.

I was going up the ski run road (which has some hair pin switch backs). Was about to come to one of these switch backs when I looked up over to the left checking out the curve, and low and behold here come two bikes down and almost out of control. I was already committed to the corner and saw the two bikes all over my side of the hiway. First response was sh*t, then I acted by jumping on the rear brake and leaning hard to the left which put me in the left lane. The two bike wizzed by me in the lane where I was when I spotted them, now get this, the look of fear on the faces of those two had and they where dragging their feet to STOP!! No joke. they both ended up in the bar bitch hitting the side of the hill on the corner. I stopped and look to see if they were okay, they were. Just messy pants for the both of them. Walked over and said thanks for making my day. Walked away roaring with laughter, you had to see their faces. Moral of the story, if I hadn't been checking out the corner I would have missed them and well, I think you can guess what would have happened.

[tkent02]

Depends on the grade, really steep grades, less front brake. Steep grade or any grade with loose sand, gravel, I barely touch the front brake. Last thing you want to do is push/slide that front tire out and play street sweeper. Body position, throttle, gear selection, using the engine for some braking in some situations. Look through the corner, see what is coming up. Experience is the best teacher, though make sure you learn the basic skills by taking a MSF course.

A really steep grade and all the rear brake in the world only you will be speeding up, not slowing down, it is just not enough. I was there yesterday, first gear and the rear brake on hard enough to slow the engine, the bike is building speed and front brake must be used. Too much weight is shifted forward already even without using the brake. Especially with gravel or sand thrown in... Not slowing down can mean a long painful fall down a hillside is in your immediate future.

People have a different concept of steep in places like Florida than they do in places like Colorado.

[7981GS]

People have a different concept of steep in places like Florida than they do in places like Colorado.

Thus why I posted a video of only dropping 3,000 feet in 6 miles.
In most of the Eastern states, a few HUNDRED feet is all that they drop in several miles. Nothing at all IMHO/E.

Eric

[mrbill5491]

Oh I agree, just where I was, just less, more like a real slow squeeze just enough to keep the speed down. As for the gears, rarely will I go below 2nd gear, I'm usually shifting between 2nd and 3rd with application of the rear and just a little with the front. One time I was on this road they just graveled and sealed it. It was like riding on marbles. One of the few times I never touched the front brake (that day it was 1st gear and rear brake at 10mph!). A couple of guys in front of me did and just about bit it. This road climbs 6,000 ft in 12 miles, so you can imagine the grades it has. One corner is so tight and it climbs, 90% of the bikes have to use 1st gear just to get around it. The big dressers are really a handful on this road.

A really steep grade and all the rear brake in the world only you will be speeding up, not slowing down, it is just not enough. I was there yesterday, first gear and the rear brake on hard enough to slow the engine, the bike is building speed and front brake must be used. Too much weight is shifted forward already even without using the brake. Especially with gravel or sand thrown in... Not slowing down can mean a long painful fall down a hillside is in your immediate future.

People have a different concept of steep in places like Florida than they do in places like Colorado.

[pmong]

Adding throttle pulls the chain across the top of the sprockets, squating the rear suspension. Chopping the throttle tensions the chain along the bottom of the sprockets, raising the Rear Suspension.

Grabbing the Front Brake stands the bike Up. Releasing the Front Brake drops the bike.

Depending on how aggressive the actions are, the bike can really bounce around.

Shaft Drive bikes have different dynamics,,,.. WOT makes the back end Stand Up like a Funny Car off the line.

Dragging your Rear Brake while leaning into a turn (stay on throttle) will reduce your speed, help the bike fall into the turn, and NOT Upset your Suspension.

Ok, I think I understand about what happens with a chain driven bike, although I have not thought about it. Appropriate for my son's bike, which is a starter Suzuki GZ250, so I will pass this information along to him.

When you say grabbing the front brake cause the bike to stand up, do you mean that the rear wheel wants to lift up? Or do you mean that it forces the bike to become more vertical on a curve.

My Suzuki is a GS450GA, the automatic with a shaft drive. So, any more details on how to best handle it into, through and out of a curve? I just use the normal slow before entering, counter steer to start the lean while adding just a little gas, and then add more throttle on the exit.

[snark]

Just my two cents...

The first thing I did was find a good place to practice the techniques at low speeds without traffic. In my area we have a few good parks with a lot of great twisties that I could practice on. I started a lower speeds and then increased as my confidence grew. The hair pin took the most practice but was the most fun. When I have friends who want to go for a ride right after they get their license or a new bike we always hit the park first thing.

As for the technique...

Experienced riders have constantly pointed out that every bike / set up is different and so your technique has to be adjusted a little to match each bike. I learned this when I switched from touring tires to sport tires.

What I do on a downhill curve is slow down using the engine and both brakes going in and the I start to accelerate out after about the mid point. I keep my knees against the tank, feet on the foot pegs instead of the highway bars, and look through the curve.

[pmong]

mrbill5491, tkent02, and 7981GS

Been following you discussion. Interesting, but not sure when I will have an opportunity to practice on similar roads. Motivated to go and learn some basic dirt biking to learn a different set of skills, some of which are transferable while others are not. On my growing list of things to do.

7981GS, can you provide a link to your videos? Always interested in seeing how others do. Am in the market to get a action video camera so I can review my rides.

Was able to get out early this morning for some riding and practicing. Counter steering is become more second nature, and some nice curves. Also practice some quick lane changes. Only one difficult event, when I had to stop on a steep downhill slop. A little unbalanced because of bike's downward angle and my forward footing. Not bad, and good to get the experience.

[pmong]

Just my two cents...

The first thing I did was find a good place to practice the techniques at low speeds without traffic. In my area we have a few good parks with a lot of great twisties that I could practice on. I started a lower speeds and then increased as my confidence grew. The hair pin took the most practice but was the most fun. When I have friends who want to go for a ride right after they get their license or a new bike we always hit the park first thing.

As for the technique...

Experienced riders have constantly pointed out that every bike / set up is different and so your technique has to be adjusted a little to match each bike. I learned this when I switched from touring tires to sport tires.

What I do on a downhill curve is slow down using the engine and both brakes going in and the I start to accelerate out after about the mid point. I keep my knees against the tank, feet on the foot pegs instead of the highway bars, and look through the curve.

Yeah, I hear you about practicing in a nice safe place. I try to get to work before everyone else so the parking lot is empty. This allows me to practice my slow-speed maneuvers, tight turns, weaving, u-turns and figure 8s. Still need more practice.

On weekends, try to get out on the road before 7 am, when there is very little traffic. In fact just got back from a ride. There are roads through the Santa Monica Mountains with fairly easy curves, a few tight ones, and a couple of nice switches. Always easier going up than coming down, but good for practice. Getting to the point of being light on the handlebars.

I know what you mean about riding different bikes. Along with the old Suzuki, I have a more recent Aprilia. Two very different bikes, very different feel and handling. I am able to take curves much more quickly on the Aprilia, but the Suzuki is my everyday ride.

I am off for another ride. Ride safely everyone.

[haztoys]

Pmong ...Hi ...

I'll start here ...

So Pmong ..What is it that 'you' did not feel was right in the down hill (dr)turn ...? Front tire wash ..? ..back tire loose ...the car ....bike head shake...????..

I'm The Devil of the down hill my friend .....

[Wizard]

A Shaft Drive Automatic?! Cool, that's a keeper, unless you sell it to me.
Chopping the throttle while in a corner will drop the suspension (Shaft Drive) and you might Ground Out, seen it happen.
Typically on a descending 270 degree hiway ramp, right where it ends and the turn can actually tighten up.
You get comfortable with the lean/speed, then it surprises you with a last second tightening curve, so you chop throttle and bottom out.
Most pronounced when carrying a passenger.

The "Standing Up" effect of Front Braking occurs when in corners, when the Handle Bars are Not straight.
In a straight line the weight of Bike + Rider will end up on the Front End, nosediving.
But in a turn, all the Triangles/Geometry gets complicated.
Your Front Forks are not Vertical, they are out at an Angle (Rake Angle).
Are your Front Axels on the Leading Side of Forks?, Trailing Side, or direct under the Bottom of Fork?
When turning, your Front Tire Contact patch is no longer in a direct line with the bike, its now off to the side. Offset Triangles now.
It gets Complicated. End result is, the Front End rises And tries to straighten up the bike (Hard Braking in a Turn).
Rember, your Front Contact Patch is already under duress, hard braking Front can be asking too much.
If I'm getting in too hot, I'll pull in Clutch and use both brakes to save my sorry hide
(yes, its been burned before, though I have yet to win the "Off Road Reconnaissance Award").
These effects occur at the Fringes of the Handling Dynamics.
Normal riding should be peaceful, shouldn't scare you.
I'm glad you're asking, thinking (When in Doubt,,.. Think!).
Don't over-think it (well not yet) and don't think too much when riding, it should be natural.

[Hovmod]

Some very good points in this thread (and some bad...).
Just yesterday I rode my new GS1000 700 km, across two mountain ranges. Ups and downs, lots of curves and twisties, but also highways.
I had one incident where a downhill right hand curve was tighter than I had anticipated, and it really is among my least favourite kinds of trouble to be in.
My instinct was to downshift quickly and lift my head to look where I wanted to go, and then to keep a fair amount of throttle going for control. It worked, but I was almost fully across the center line (if there had been one) of the road, and meeting traffic would have been way scary.

There is no better way to avoid this than to follow the advice from tkent above: Haul ass uphill, go slow downhill.

[Griffin]

The "Standing Up" effect of Front Braking occurs when in corners, when the Handle Bars are Not straight.
In a straight line the weight of Bike + Rider will end up on the Front End, nosediving.
But in a turn, all the Triangles/Geometry gets complicated.
Your Front Forks are not Vertical, they are out at an Angle (Rake Angle).
Are your Front Axels on the Leading Side of Forks?, Trailing Side, or direct under the Bottom of Fork?
When turning, your Front Tire Contact patch is no longer in a direct line with the bike, its now off to the side. Offset Triangles now.
It gets Complicated. End result is, the Front End rises And tries to straighten up the bike (Hard Braking in a Turn).
Rember, your Front Contact Patch is already under duress, hard braking Front can be asking too much.

Yes, it gets very complicated when heeled over in a curve with two rotating wheels, a rotating crankshaft, pistons going up and down, and 700 lbs of man and machine moving down the road. Lots of forces to deal with, particularly when you throw in teh effects of gravity while heading down a hill.

As I stated earlier, and as reiterated above, applying hard front braking while heeled over in a curve will induce forces trying to make the bike both stand up, and head through the outside of the curve in a straight line in the direction the bike was pointed the moment you hit the brakes. This effect is exacerbated when going downhill, because now gravity is forcing the bike in this direction (straight ahead, not throught he curve) already.

Many, many people have used too much front brake near the apex of a curve, resulting in them either heading across the centerline (sometimes into an oncoming vehicle), or into the ditch.

Too much rear brake going hot into a curve can cause the rear end to start wobbling, which can result in the worst case wreck, high siding over the bike into the oncoming traffic (or outside side road ditch with a big dropoff).

Several times I've been riding behind someone in curves, and see their brakelight flash while in the curve. They instantly lose their line, the bike is destabilized, and they start to go wide. How much the bike is affected is determined by how hard they're braking and how fast they were going. The skill of the rider (i.e. experience and coolness under pressure) inevitably determines if the outcome is happy or not.

[pmong]

Pmong ...Hi ...
I'll start here ...
So Pmong ..What is it that 'you' did not feel was right in the down hill (dr)turn ...? Front tire wash ..? ..back tire loose ...the car ....bike head shake...????..
I'm The Devil of the down hill my friend .....

Main concern was being beyond my skill envelope and prior experiences. Entering too hot relative to intention is a problem on a flat or uphill curve because normally aim to go slower than I can handle, unless purposefully practicing to increase ability. But it was a problem on the downhill, where I entered too fast relative to anything I have done. Very little experience or practice on tight and steep downhill curves. (Yes, I know, prevention is best, but misjudged because it was a new route for me.)

Not only knew that the bike had less traction on the rear but also felt it, and I felt I was over the front of the bike, not extreme, but the downhill did pitched my body forward. I did not look at the car, just noticed it on my peripheral vision, so had to stay in my lane. Fortunately did not panic, but was very disconcerting, very uncomfortable trying to figure what to do in a split second. In the end I tentatively added a little gas and counter steered enough to keep me safe. My reaction was clearly not second nature, and the outcome was more of a testimony to the bike's ability than mine. Now I have a little more confidence in the bike.

The purpose of the post is to see if I could have made a better decision. And then, go out and practice some of the recommendations to be better prepared for the future.

Thanks.

[Griffin]

One thing I haven't seen mentioned here is the "accelrating through the curve" philosophy, and how it applies to steep downhill curves.

Normally, we are taught that you want to reduce speed before entering the curve, maintain it through the front part, then smoothly accelerate out of it by rolling on some throttle. When you are going downhill, gravity is already accelerating you through the curve, so rolling on the throttle the same amount as on a flat curve will accelerate you much more quickly.

Descending radius curves going downhill are where people really get into trouble. They are maintaining throttle position, gravity is accelerating them, the curve gets tighter, and they've already lost their engine braking revs.