Hinting the steering

[Kawasicki]

bigothunter said:

I like to use circuit driving as an extreme condition which is useful to illustrate the point.

A very common driving error is clipping the apex of a bend too early, which slows exit speed and can mean you run off the tarmac on the bend exit. Almost all drivers learning on circuit exhibit this early apex error and it creeps in even when experienced.

I combat this temptation by intentionally driving straight ahead holding the wheel firmly whilst braking heavily, and then turn precisely but smoothly to align with the late apex. Rate of steering input is fairly fast. Trail braking can be adopted during this turn-in phase.

On certain lower speed bends such as Lodge at Oulton, intuitively I 'counter-steer' on entry: small left steer input before turning right into the bend. This excites the car in yaw which reduces understeer and improves turn-in.

Both of these techniques apparently conflict with 'steering hinting'. Also if 'steering hinting' results in actual steering deflection, the car will move towards centre of track spoiling a decent corner entry line.

This whole subject of 'steering hinting' remains a mystery to me, unless it's simply to alleviate nasty on-centre steering friction?

If you are driving a car at the limit, and you are trying to get the quickest time out of that vehicle... then you end up fighting the weakest link of that car. In some cars the weakest link might be yaw damping, where it is tricky to keep the rear of the car in a stable condition.

Other vehicles might have a lot of inertia, which makes the car too stable in fast direction changes... here you can get a benefit from really forcing/muscling the car in the turn in phase... or, and I do this a lot too (probably a bit too much...but hey, it's fun), using the natural yaw frequency to get the car to turn(which is what you obviously do too)... personally, I don't think I get much benefit from doing this on a normal turn-in on a high mu surface...but maybe I just haven't driven the car that needs it. I do get a big benefit from this on loose surfaces though, as do many others. Where I have found a bit benefit for this "natural yaw frequency" turn in, is in high speed S bends, where it is possible to get the car gripping hard in one direction to gripping hard in the other direction as quickly as possible. I have had an instructor sit beside me and tell me that this can't work, that it is not smooth enough, that it is too brutal. Then I lapped faster than him, he was very confused. After about 3 months he came back and told me that he finally beat my lap time, and that he admitted it was a simply faster method... for that car, on that track. It friggin' ate the tyres up, though.

One other point, is that on turn in (in a normally balanced car) you have a short lived initial peak of grip from the dynamic weight transfer to the outer front tyre...then it decreases momentarily as the suspension rebounds...then it climbs again as the vehicle starts to achieve steady cornering. If you preload the steering a little, then this fluctation of vertical loading is reduced. So maybe you can win a little time there.

[bigothunter]

Kawasicki said:

One other point, is that on turn in (in a normally balanced car) you have a short lived initial peak of grip from the dynamic weight transfer to the outer front tyre...then it decreases momentarily as the suspension rebounds...then it climbs again as the vehicle starts to achieve steady cornering. If you preload the steering a little, then this fluctation of vertical loading is reduced. So maybe you can win a little time there.

Interesting

Is that preload without steering deflection, just overcoming steering system friction? Which reduces steered angle overshoot and hence outer front tyre load fluctuation?

Sounds like an endorsement for low friction steering systems. That's my aim, so the car can be balanced with subtle low effort steering inputs. I hate 'sticky' steering especially if on-centre feel is absent.

[Kawasicki]

bigothunter said:

Kawasicki said:

One other point, is that on turn in (in a normally balanced car) you have a short lived initial peak of grip from the dynamic weight transfer to the outer front tyre...then it decreases momentarily as the suspension rebounds...then it climbs again as the vehicle starts to achieve steady cornering. If you preload the steering a little, then this fluctation of vertical loading is reduced. So maybe you can win a little time there.

Interesting

Is that preload without steering deflection, just overcoming steering system friction? Which reduces steered angle overshoot and hence outer front tyre load fluctuation?

Sounds like an endorsement for low friction steering systems. That's my aim, so the car can be balanced with subtle low effort steering inputs. I hate 'sticky' steering especially if on-centre feel is absent.

No the preload also means steering deflection, the car is already steering slightly when preloaded...though your points about steering friction are very good... but for controllability in normal driving, rather than limit driving. For the friction to have a negative on limit driving it would have to be so high as to be almost undrivable normally.

Sticky steering is the work of the devil. There is nothing more fatiguing than a lot drive on a dark, wet autobahn with excessive friction in the steering.

It happens that car companies make mistakes and then plaster over them, for example with steering parts that mesh together with high force, to stop steering rack rattle, causing high steering friction. There are a few other common faults, too. For a while BMWs were very sensitive to any sort of excitation that could cause steering wheel vibrations. Guess what the solution was!?