Weight transfer mid-S bend

[jcochrane]

Surely the speed through the series of bends is only going to increase for one of two reasons:

(a) We are descending a significant gradient, or
(b) We are applying sufficient power to accelerate through the bends.

If it is (a) then we simply have to brake to keep the speed down to a suitable level, in which case we do it; and we don't give ourselves a hard time worrying (unnecessarily) about 'unbalancing' the car.

If it is (b) we have the option of restraining our use of power.

Either way, I don't see that it need give rise to uncomfortable situations.

Best wishes all,
Dave - glossing over 'problems' as usual.

You have it Dave. It requires a rethink to avoid discomfort.

[TripleS]

Surely the speed through the series of bends is only going to increase for one of two reasons:

(a) We are descending a significant gradient, or
(b) We are applying sufficient power to accelerate through the bends.

If it is (a) then we simply have to brake to keep the speed down to a suitable level, in which case we do it; and we don't give ourselves a hard time worrying (unnecessarily) about 'unbalancing' the car.

If it is (b) we have the option of restraining our use of power.

Either way, I don't see that it need give rise to uncomfortable situations.

Best wishes all,
Dave - glossing over 'problems' as usual.

You have it Dave. It requires a rethink to avoid discomfort.

Ah, now I am in trouble. I just don't do proper grown-up thinking, let alone rethinks.

You know reference is sometimes made to a second childhood: well I ain't finished with my first one!

Best wishes all,
Dave.

[Astraist]

Interesting. If the RoadCraft line is the "Last Apex", as I have been told, than how can you compromise it through a series of bends? Would it not be the desired line to reach the second bend from the high-side?

For those who do not want to brake mid-corner, you can choose a line that enables you to retract the steering when you brake for the second bend.

[7db]

This is a narrow road with a DWL system. I don't think line is our big lever. Whilst there is a little to play with in terms of lengthening the S, we mainly have entry speed, throttle and brake to balance the weight with.

More space under the bridge.

[TripleS]

This is a narrow road with a DWL system. I don't think line is our big lever. Whilst there is a little to play with in terms of lengthening the S, we mainly have entry speed, throttle and brake to balance the weight with.

More space under the bridge.

I've been under the impression that it was strongly advised that we apply some power in order to balance the car, after settling on a suitable entry speed for the bend.

The 'experts' have often given the impression that braking in a bend is a bad thing to do because it unbalances the car, but from what you say it now sounds as if the use of brakes can also be accepted as a means of balancing the car.

Once again I'm confused regarding some of the advice we are given. Fortunately I'm not confused on the road, at least on this aspect of driving. I'm quite happy to brake - sometimes quite firmly - in a bend, and it invariably feels OK to me, i.e. no risk of running off course or losing grip etc.

Best wishes all,
Dave.

[Gareth]

I'm quite happy to brake - sometimes quite firmly - in a bend, and it invariably feels OK to me, i.e. no risk of running off course or losing grip etc.

Too firmly and/or too abruptly in slippery conditions runs the risk of a spin. The trick is to know what's possible and when.

I wouldn't be too comfortable with an inexperienced driver braking in a bend, as I wouldn't have the confidence they could apply the control inputs smoothly enough nor the judgement to know how much they could get away with in the prevailing conditions.

I remember you writing that you didn't want to be told hard and fast rules, so here is a situation where some blurring of the rules is possible, depending on experience. However, as I wrote previously and I mean to go and check sometime, I suspect this is a problem of failing to apply the limit point correctly.

[7db]

Dave -- I wasn't saying that you'd necessarily want to be braking in the bend, just that given a constrained line, your major inputs to this system are entry speed, throttle and brake. For my money you'd be trail braking through the first and powering through the second, but I don't know how the hazard near entry affects entry speed: I haven't driven that road. You might just be in a neutral space through the first.

Typically the issue with braking through a corner is the modulation of the braking force (particularly the sharp transition between braking, not braking and accelerating), as well its tendency to soak up some grip from the tyres overall and unbalance the f/r weight: in particular unload the rears.

Passenger comfort is a secondary concern - passengers tend to feel better being pushed back into their seats, although this additional comfort is lost if they are screaming with terror: it is typically better to brake mid-corner than pile blind through it if you are going faster than you can see. Neither option is better than entering at a sensible speed.

[Gareth]

I went back this evening, mid-dusk. Since it is too easy to see through the trees to know where the road is going, the idea was to ignore that and concentrate on what I could see of the complete road surface in a continual sweep from the front of the car as far as the limit point.

Doing this resulted in me reducing speed on approach, down to an upper limit of about 30 mph. As I entered the bend it was easy to see how the limit point going through the left quickly ran away but at the same time it was immediately obvious that the limit point for the right bend was initially static. Bearing this in mind there was no real encouragement to accelerate significantly, so I kept the speed constant, still at about 30 mph.

As the limit point though the right bend began to move then that was the time to accelerate. Going back to the question asked by the original poster - at 30 mph the transition between the left and right bends is easy to control and not noticeably unpleasant.

As I surmised previously, being able to see where the road goes distracts from using the limit point to control entry speed to the left bend.

[faboka]

Interesting conclusion Gareth. It's similar to a road I travel down everyday. I've never been able to execute it right (well gimme anyway). However very recently I've realised I've been looking past the corner instead of reading the limit point.

[Horse]

How quickly can a gear-change sensibly be completed?

Much quicker than three seconds!

Really?

Off throttle, clutch in (no, thanks, I'll not be clutchless changing), hand from wheel to stick, move, rev, engage clutch, hand back to wheel [not nec. in that complete order] - all in significantly under (you've said 'much quicker') three seconds?

[Horse]

. . . with this thread in mind, paid attention to what we each did with compact S bends. Without exception, we treated the first bend as preparation for the second, compromising our line through that first bend from the Roadcraft "ideal" as needed to remain safe.

. . . it's usually the following bend or last bend in a series that takes priority. Certainly is the case with regard to throttle use. Otherwise you can end up with entry speeds of the following bends becoming ever increasingly quicker leading to those uncomfortable moments that can spell disaster.

In my defence here, 'line' is not relevant to this left-right sequence as there's relatively little option for moving about in the lane width, and for 'throttle' I'd been negotiating the first bend with an appropriate speed for the entry to the second bend.

However, what I now do (allowing for the varying responses required by other traffic, particularly that attempting to enter or leave the side turning immediately prior to the first bend, is to set a reasonable entry speed, then ease off the throttle enough to bring body roll back in-line as I reach the turn point for bend two, and reapply throttle and turn.

It struck me this morning that I would advise riders to 'check' the throttle slightly and reapply between bends rather than continue through . . .

It stuck me just now that I'd not thought of ^ this earlier as I was thinking of it as a 'handling' (for want of a more apt term) problem rather than a 'throttle' problem - neatly ignoring the link between the two

[TripleS]

How quickly can a gear-change sensibly be completed?

Much quicker than three seconds!

Really?

Off throttle, clutch in (no, thanks, I'll not be clutchless changing), hand from wheel to stick, move, rev, engage clutch, hand back to wheel [not nec. in that complete order] - all in significantly under (you've said 'much quicker') three seconds?

Hm, I'd have thought it could be done in under three seconds without rushing unduly, but I think my hand would go to the gear lever before declutching.

Best wishes all,
David.

[Gareth]

but I think my hand would go to the gear lever before declutching.

Me too, if I'm doing it right!

[Astraist]

However, what I now do (allowing for the varying responses required by other traffic, particularly that attempting to enter or leave the side turning immediately prior to the first bend, is to set a reasonable entry speed, then ease off the throttle enough to bring body roll back in-line as I reach the turn point for bend two, and reapply throttle and turn.

It struck me this morning that I would advise riders to 'check' the throttle slightly and reapply between bends rather than continue through . . .

It stuck me just now that I'd not thought of ^ this earlier as I was thinking of it as a 'handling' (for want of a more apt term) problem rather than a 'throttle' problem - neatly ignoring the link between the two

You describe something common in slalom courses, which is to apply the throttle between changes of direction (stabilizing the car), and letting go of the throttle (smoothly, I should add) just as the throttle is eased off.

[7db]

Music tends to have phrasing with beats, pauses and lifts. So it is with corners. I sometimes conduct whilst I drive (which is pleasing for any francophones).