Using gears to slow

[Octy_Ross]

So a handful of bends tighten to a degree that people feel they couldn't get round them at their entry speed is the curve obscured by trees or a wall why can't you anticipate the exit by the position of the lamp posts, hedgeline or the lights of opposing traffic.

Probably more than a handful. Come for a weekend to Scotland - I'm sure I could acquaint you with a couple not far from my virtual back yard A939 has a specifically good example which lulls you into a false sense of security before tightening and giving you minor palpitations. Also there's 'that' corner which the stressed one enjoys.

They may be few and far between, but they do exist. As such we should allow ourselves to brake when we need to into and round bends.

[kfae8959]

Why is anyone slowing down going round a bend ?

Could it be because they are using limit point analysis?

David

[TripleS]

In any case, should not a differential share the torque between the driven wheels, whether it is driving torque or braking torque that is being applied?

Not a fully open diff - if you have one wheel has grip one wheel doesn't - the gripless will spin, hence the introduction of 'limited slip'.

Yes, sorry: what I said was wrong. It depends on what type of differential is on the vehicle.

[Octy_Ross]

what I said was wrong.

Careful old boy

[Octy_Ross]

Why is anyone slowing down going round a bend ?

Could it be because they are using limit point analysis?

David

If they're doing it right, right?

[Ancient]

Why is anyone slowing down going round a bend ?

Could it be because they are using limit point analysis?

David

For some yes . Limit Point Analysis simply doesn't work when the LP remains constant on approach (nice), starts to run away (Wheee!) then suddenly shuts down hard towards you as the bend tightens again.

So a handful of bends tighten to a degree that people feel they couldn't get round them at their entry speed is the curve obscured by trees or a wall why can't you anticipate the exit by the position of the lamp posts, hedgeline or the lights of opposing traffic.

More than a handful around here (Ceredigion / Carmarthenshire), which can't be predicted by lamp-posts (not that civilised) hedgeline (there's a bl@@dy great hill in the way!) or oncoming lights (usually not enough traffic). Bends are not simple curves, but irregular shapes following the contours of the hills. Real fun once you get used to them of course!

Modern roads or those that are reprofiled wouldn't include such a bend.

What are "Modern roads" ? Most tightening bends here include an adverse camber (maybe that's a 'design feature' to ensure the water flooding out of the hills falls away ).

I was refering to people who regulaly brake in corners for most people it probably doesn't matter that much as they are so far from the limit of the vehicle that an unbalanced vehicle is of little importance it's when you actually drive quickly for a purpose that advanced techniques matter and you appreciate why they are done the way they are.

Again I'm failing to see the advantages of engine braking by sticking the lever down rather than using the foot brake and also wondering why such a technique isn't used by racing or response drivers ?

If the bend does suddenly tighten too much for the current speed, the best solution is obviously to straighten as much as possible, then brake, then get back on the throttle and steer back into the bend. For a brief moment (unless heel-and-toeing) this does mean that engine braking will be present before the foot-brake is reached; but this is better than continuing at too high a speed.

[Octy_Ross]

Limit Point Analysis simply doesn't work when the LP remains constant on approach (nice), starts to run away (Wheee!) then suddenly shuts down hard towards you as the bend tightens again.

Yes it does - you've just explained how it works - it opens then closes... you must drive to that.

If the bend does suddenly tighten too much for the current speed, the best solution is obviously to straighten as much as possible, then brake, then get back on the throttle and steer back into the bend. For a brief moment (unless heel-and-toeing) this does mean that engine braking will be present before the foot-brake is reached; but this is better than continuing at too high a speed.

Why bother with straightening the wheel? just get the brakes on (if necessary). Sometimes just easing off is enough. If you really must avoid having feet off the pedals, one could use the left foot to brake

[GJD]

Are we overcomplicating this a bit? Regardless of what exciting things the radius might or might not do, at any point around any bend there could be some obstacle in the road just beyond where you can see. If you're driving in a manner that you can't, if necessary, adjust speed for a tightening radius with the brakes, then you're going to come horribly unstuck when a stationary queue of traffic or some such pops into view around the bend.

[TripleS]

what I said was wrong.

Careful old boy

Aye, I know: but you don't see much of this around 'ere.

At least I accept that I'm wrong part of the time.

[TripleS]

Are we overcomplicating this a bit? Regardless of what exciting things the radius might or might not do, at any point around any bend there could be some obstacle in the road just beyond where you can see. If you're driving in a manner that you can't, if necessary, adjust speed for a tightening radius with the brakes, then you're going to come horribly unstuck when a stationary queue of traffic or some such pops into view around the bend.

Overcomplicating? Yes, it happens too often in my view.

A bit more flexibility of attitude from the experts might make this forum a bit more appealing to a wider readership, and that could yield more benefit to the driving scene generally. I have considerable respect for experts, but I think they over-reach themselves at times.

[Ralge]

Over-complicating it goes hand-in-hand, in my view, with an insistence on occasions from AD purists on extracting every last ounce of progress out of the road.

And, in truth, I have to remind myself of the dozy sheep about to step into the road around the next corner when driving over the Snake Pass.

[TripleS]

Over-complicating it goes hand-in-hand, in my view, with an insistence on occasions from AD purists on extracting every last ounce of progress out of the road.

And, in truth, I have to remind myself of the dozy sheep about to step into the road around the next corner when driving over the Snake Pass.

Pah, you should have been driving the A171 between Whitby and Teesside in the 1960s; then you'd have known what the sheep 'problem' was all about. In those days I used to get very frustrated by the hazards they presented, and in fact I hit one at about 70 mph in the dark in 1969.

In more recent years I've become inclined to share the roads with them on a more tolerant basis, though the fencing is now better, and they don't appear on the main roads so much.

[Ancient]

Limit Point Analysis simply doesn't work when the LP remains constant on approach (nice), starts to run away (Wheee!) then suddenly shuts down hard towards you as the bend tightens again.

Yes it does - you've just explained how it works - it opens then closes... you must drive to that.

If the bend does suddenly tighten too much for the current speed, the best solution is obviously to straighten as much as possible, then brake, then get back on the throttle and steer back into the bend. For a brief moment (unless heel-and-toeing) this does mean that engine braking will be present before the foot-brake is reached; but this is better than continuing at too high a speed.

Why bother with straightening the wheel? just get the brakes on (if necessary). Sometimes just easing off is enough. If you really must avoid having feet off the pedals, one could use the left foot to brake

'Just how it works' in practice but the over-simplistic bends shown in HTBABD or RC do not show that. Driving to the LP will sometimes force you include slowing in the bend (this was all in answer to someone who asked "Why is anyone slowing down going round a bend ?").
It depends how easy the earlier LP was relative to how fast it is shutting now. Back when I drove a '59 MGA straightening was more needful than with all the modern gadgets that prevent the wheels from losing grip, but it was an education in how to give the vehicle the 'best chance' of remaining on course. Reducing cornering forces is A Good Idea (TM) when increasing braking force.

[7db]

Reducing cornering forces is A Good Idea (TM) when increasing braking force.

Ah yes.

It's always good to remember that if you have £10 of grip and spend £5 on cornering, then there's only £8.66 left for braking.

[Ancient]

Ahh, well, of course I'm teaching granny to make painted eggshells with that sort of remark, but there's me, old enough to have driven a variety of machines, sometimes at silly speeds; yet I've often wondered how 'Follow the LP like a piece of string' and 'Don't brake on a bend' fit together, when the LP can rapidly shorten within the bend, instead of simply running away.