hypothetical situation - high speed turning.

[ajb]

Presuming there was an expanse of tarmac large enough.

If a bike was doing say, 150mph and the rider initiated a turn, and continued to turn giving as much countersteer and lean angle as possible, would the bike reach a point where the tyres lost grip?

Thanks.
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CBR125R '05 > CB500 '00 > CBR600F '99

[Bendy]

Well they're gonna go 'off' aren't they? Otherwise, barring punctures, we'd all still be using our first set of tyres.

[ajb]

[brooky]

Wouldn't it just get to a point and then lowside?

Edit* Ok now I'm not even sure what you're trying to ask
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Suzuki GSX-R 750 K6.

[owdamer]

Thats going to have to be a very large stretch of tarmac to do a 150mph circle.....My guess is that your tyres would overheat you would either lowside or have a very big highside.

[Bendy]

[iooi]

If you kept the same speed and increased the amount of countersteer, then you would end up on the deck.... It would be the tyre's that gave out on the grip. Either from the bike grounding down and lifting the tyre, or from them simply running out of grip.
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Just because my bike was A DIVVY, does not mean i am......

[Paulington]

Uh huh, think about it, the more your countersteer the more the bike leans over to try and corner tighter.

If you corner tighter, and tigher, and tighter while still maintaining the same speed, a tyre only has a finite amount of grip so odds on it will not be able to maintain 150mph of movement tangential to the way you are leaning, and will lose grip.

And lowside if the front goes, probably highside if the back goes.
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"Four wheels move the body, two wheels move the soul."
Current Vehicles: '89 Kawasaki KDX200, '99 Yamaha XV535, '00 Honda ST1100 Pan-European, '08 Suzuki GSX-R1000, '08 Mitsubishi Lancer GS4 2.0 TDCi, '15 BMW 1 Series 116d Sport Turbo.
CBT: 27/08/08. Theory: 04/09/09. Module 1: 16/09/09. Module 2: 01/10/09.

[Vin]

Just promise me you won't go out and try it

[craigs23]

Do you mean a completely flat, spotless, warm road surface?

I'd have thought grip would only be lost once the bike's gone over its maximum lean angle.

There are a couple of 'turns' in Motogp when the riders corner at over 150mph (1st corner at Laguna Seca for example). Both tyres are approaching or have gone over their level of grip (and thus spinning), more down to the rate of turn in and amount of power applied, rather than the tyres just giving up the ghost in the hypothetical situation described.

[G]

Depends on many situations. Some tyres can probably handle the limit of a bike's lean at maximum speed.

Given ok but not amazing tyres that can still lean to the edge of the tyre / other limit of lean (ie bits of bike touching down at low speed), it will probably start to slide at higher speed.

Presuming the tyres run out of grip at low speed too (say on a roundabout) you will initially notice the bike suddenly turn in slightly, not really an obvious slide.
If you continue to go faster, you will then notice the rear stepping out a bit generally. Go much faster and you'll notice that the bike is spinning down the road from you (voice of experience, there ).

Highside is unlikely to be a big issue at large lean angles unless you're really cack-handed with the throttle. Low side is more likely, but if you're progressive, this sort of situation is usually easily savable.

[ajb]

I was just trying to visualise the relationship between lean angle, speed and grip. The main point I was thinking about is does the amount of turn reduce for a given lean angle at higher speed (I dont truely understand how bikes turn).

It''s funny but most of the computer games i've played with bikes in, and you could just apply full steering at any speed and it turned (I know games are not a true representation of real life!).

I'd try to draw a graph if I could be bothered.
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CBR125R '05 > CB500 '00 > CBR600F '99

[Paulington]

The further you lean a bike over, the tighter it trys to corner.
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"Four wheels move the body, two wheels move the soul."
Current Vehicles: '89 Kawasaki KDX200, '99 Yamaha XV535, '00 Honda ST1100 Pan-European, '08 Suzuki GSX-R1000, '08 Mitsubishi Lancer GS4 2.0 TDCi, '15 BMW 1 Series 116d Sport Turbo.
CBT: 27/08/08. Theory: 04/09/09. Module 1: 16/09/09. Module 2: 01/10/09.

[Kwaks]

[Kwaks]

[Bofh5]

So in a turning situation where the front starts to let go would it be better to add power to try and push the bike more upright or would this result in just pushing the front tyre across the road surface leading to a lowside ?
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Bikes: Honda 50 / CB125-TDC / 93 CBR600 F2 (Stolen & Trashed) / 2001 SP-1 (Sold) / 95 CBR600 F3

[mattjs895]

are you not supposed to accelerate through a corner to reduce the grip on the front making it easier to turn, rather than decelerating and putting the front under to much pressure causing it to loose grip?

[Kwaks]

[Bofh5]

i brake before entering the corner then start to power on through the corner to help settle the back.

My question is that during this lean over power phase if the front starts to slip then does adding more power help or hinder.
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(L)users...Disk space is to good for them.

Bikes: Honda 50 / CB125-TDC / 93 CBR600 F2 (Stolen & Trashed) / 2001 SP-1 (Sold) / 95 CBR600 F3

[Kwaks]

[Bofh5]

a few times i've as i've been cornering the front has slipped and so i've caught it by standing the bike up a bit but this can lead to a highside which is probably gonna be worse than a lowside.

I've been told i need to lean off more as i'm scraping the centre stand so maybe just too much lean angle is my problem.
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(L)users...Disk space is to good for them.

Bikes: Honda 50 / CB125-TDC / 93 CBR600 F2 (Stolen & Trashed) / 2001 SP-1 (Sold) / 95 CBR600 F3

[Kwaks]

Best technique would be to carry your speed through the corner and accelerate as you straighten on the exit.

If you are accelerating as you enter the corner then you have slowed too much for the corner, if it is to simply "settle" the back then try to come off the front brake a little sooner to allow the bike to settle before turning in. Back brake can settle the bike during the turn if used lightly without dropping off too much speed.
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[G]

While mid-corner at a stable lean-angle, you should generally be accelerating slightly, to account for the larger rear tyre having more grip.

There should be no point you're on a neutral throttle - braking, then accelerating to stablalise the bike at worst. In some shorter corners you may actually get on the brake quite hard as soon as you finish braking, as you're braking pretty much right up to the apex, then squirting it out again.

Generally if you can accelerate straight away, you could have kept the speed up and braked much deeper into the corner. However, there are some cases where this may lead to being faster - for instance if you're turning in late to pass another rider, you may slow down more, so you can get on the power earlier to get better drive out of the corner.

[Mil17b]

[Shay HTFC]

Will actively counter-steering and leaning decrease your turning circle and sharpen up the turn?

I low sided after my pegs / centrestand / something was scraping the floor, so I was over as much as possible. However, I don't exactly think I was pushing the bike to limits and turning as much as it could.

I can only think that if you simply lean a bike over, you could push it in a straight line whilst it is still leant right over, so it isn't so much how far you are leant over, but rather the positioning and amount that the wheel is turned that causes the bike to turn more/less.

Does anyone get what I am trying to say and is it true?


i.e. on the same bike, someone could steer the bike sharper when it is more upright, than someone else who is counter-steering less could when they have it leant over further
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