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hughwauton

Cornering In The Mountains

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Despite having done 6 school days the last involving 1:1 with Gary in April nothing has quite prepared me for riding in the Austrian Alps. There are numerous twisty high alpine passes which are great for bikes but doing so smoothly is a problem. On steep 1:4 type roads riding uphill I am finding that throttling off ahead of the apex doesn't work, because if the revs drop too much into the uphill part of the corner momentum is lost and there is not enough torque to pull you round smoothly. It seems counterintuitive and against everything learnt at CSS but solution seems to be that ahead of the apex you drop one or two gears and then as you start to hang off the bike and push on the bars you accelerate at the same time in order to keep momentum and grip - remember though the corner itself is on a sharp uphill. Any thoughts on how to perfect this much appreciated.

The sharp downhill poses different problems. With a steep downhill gradient the bike has got plenty of momentum of its own and early braking required. But once hanging off the bike and getting the bike over finding it difficult to work out how much throttle to apply if any given that the centre of gravity of the bike is so far forward. Any thoughts on what I should be doing?

I am riding an HP4 and seem to be going a lot faster than my Continental cousins. The good news is that I am not going wide or drifting in these demanding corners but my technique doesn't feel right due to lack of experience in these conditions. One road had 38 bends over 6,000ft of climb so not like Stowe!

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I'm no expert, but I can certainly sympathize with you, having done a lot of my sportbike riding in the north Georgia mountains and a little bit also in the hills around Rimini, Italy and down towards Misano.

 

I am a bit surprised by your problems on the uphills. I always felt like a hero on uphill corners because if I overcooked it I could just roll off and let gravity do the braking. To me the only difference there was that I could stay on the throttle longer and harder, which was an easy adjustment. The downhills were murder - too much weight on the front tire, too much extra braking taking away from the traction available for cornering. Even difficulty keeping loose on the bars with gravity trying to push all of my weight forward onto my hands.

 

That said, all of that mountain riding experience predated my initiation to track riding and racing. At my current skill level, no doubt I would have a different set of problems, maybe more similar to yours. Sorry, no help to you I know. Just sympathizing!

 

To be honest, the concept of trying to explore the sport riding performance envelope on public roads is not one I can really get my head around anymore. In my mind, no speed that could be considered prudent, with oncoming traffic and close proximity to guardrails, requires much in the way of advanced track riding skills. For me they are two different worlds.

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The center of gravity of the bike does not change while going uphill or downhill.

The vector weight tilts aft and forward, loading one tire and unloading another.

The whole purpose of throttle control while cornering is to distribute the loads on each tire according to bike design.

That is a 40% of the total weight on the front contact patch and 60% on the rear contact patch.

An acceleration of 0.1 to 0.2 G makes that vector weight tilt aft enough (6 to 11 degrees) to achieve that ideal load distribution.

A hill with 1:4 gradient has 14 degrees and exactly that is what the vector weight tilts.

As you can see that is a little more than the ideal distribution of weight when going uphill with zero acceleration (maintenance throttle only).

The rear contact patch is the weakest link in that case and too much acceleration could overwhelm it while cornering fast.

Going downhill that steep is much more critical, because your front contact patch is loaded with around 70% of the total weight; with more if you are breaking to keep speed.

For both cases, the solution is slowing down your entry speed according to these scenarios (way more for downhill cornering) and not applying throttle control (smooth acceleration) as for horizontal track riding.

While going uphill or downhill, the tires have less available traction as well due to a reduced normal force respect to the pavement.

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You would be wise to consult with the local mountain carvers to see what type of bikes rock on the uphills and downhills... It could be 2 very differnt bikes.

I had the opportunity to go mountain carving with a R1 and a GSX-R on my local mountain roads ;

barring rider skill, the veteran who was on the GSX-0R 1000 in our group says he goes the fastest on a certain UPHILL stretch with a CB400 spec2 on 2 bike virtues:

1) shorter wheelbase as there are ALOT of low to medium speed corners , less body positioning and countersteering needed . Less of the 10$ of attention needed.

2) Higher torque range/plateau = much less gear shifts esp coming out of uphill corners; he can floor it coming out of corners and get ready for the next corner without a gear shift

again , Less of the 10$ of attention needed.

The S1000RR is built for racetracks with medium/high speed hence the low end torque would be relatively "weak" for a hill climbing task without some small hardware mods.

The longer wheelbase and swingarm that is designed for high speed will also "get in the way" at places with alot of low to medium speed corners too in the form of much more effort in terms of body position and massively more lean angle on public roads ...

You could drop a teeth on the front sproket or go up 2 teeth in the rear or so I've heard to squeeze more torque out .

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The CB400 has no torque worth mentioning. It does carry a low gearing, though. And it is easy to ride. On a Gixxer or S1000RR, you will just sit in first gear as that will cover the same speed range as the first 5 gears for the Honda 400. The tall gearing can be an issue, though, as on a 1:4 hill coming out of a 20-30 mph corner a litre bike race rep will likely has less acceleration available than something like an SV650. Even worse is the riding position, which on race reps are targeted towards high speeds, not hairpins. MOTORRAD many years ago tested many types of bikes in the Alps, and the Ninja 636 could not keep up with the V-Rod going up because the corners are so short that cornering clearance isn't vital. But the V-Rod was much easier to stop and would stomp out of every corner, giving it advantages that could not be made up through the corners. Downhill, in the rain, no bike could keep up with the simplistic Kawa ER-5, a 50hp twin, because it was so easy to ride and power was of less importance than going up.

 

Personally, I have enjoyed hard street cornering for decades, but recently have - finally, after too many accidents in injuries - found pleasure riding with much greater safety margins. You can ride as hard as you want on the street as long as you always make sure you can stop in the distance you can see to be clear. However, when the juices start to flow and you enjoy the brisk riding, it is oh so easy to ignore that and start cornering much faster than that, meaning a blocked road around a blind corner can be the last thing you will ever see. Lately, I have had tons of such and similar situations appear, situations that would have ended horribly had I been flying at the sort of pace I have practiced for most of my time on the road.

 

As to your questions about technique - I think it is important to ride in a manner where you feel in control, otherwise I cannot comment since I am not skilled enough. It boils down to whether you want to achieve the ultimate satisfaction or the ultimate speed as they are not always related.

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Personally, I have enjoyed hard street cornering for decades, but recently have - finally, after too many accidents in injuries - found pleasure riding with much greater safety margins.

 

I am hoping to get to this point in the near future. I would love to take up street riding again, but I found it so hard not to push the limits of safety and the law. If I do get back on the street it will be on something with very low hp, maybe a V7 or even a Royal Enfield. Putt, putt, putt, putt.....

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My very low hp bike is a 1968 Triumph Bonneville that I restore(d) [a process that never ends if you ride it] - all 38 horses. Despite it's limitations, it is a blast to ride.

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Try a 1971 Kawasaki 175 street legal dirt bike. It was my dads bike that i first learned to ride on. Pain in the butt getting it to start nowadays (good old kick start). Everyone turns to see what that noise is.

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Thanks for everyone's input. It looks as though it's a case of less is more. An HP4 may have a lot of bhp but in some situations it is not necessarily an advantage. I agree the mountains are not a race track and therefore riding well within limits makes plenty of sense. What I want to be able to do is to be as smooth and in control as I am on the track when riding in the mountains where some of the drills learnt in CSS don't necessarily work. One that does is wide vision and also having the confidence to properly countersteer. It's goingto be a case of continuing to practice!

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I have found that staying off the brakes as much as possible and not charge into corners have done wonders for my smoothness without slowing my progress from what I can tell. Using only the throttle for the majority of my deceleration is a far more relaxed way of riding than braking late and hard and keeps the momentum up and the suspension happy.

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