This was my answer :When cornering would you say that braking in a straight line before turning in is quicker than braking into the apex?
The above is a combined post in that it explains what a technique is (how to do it) and why you'd do it. It also introduces the concept which is perhaps THE principle key to understanding how to drive quickly and safely, CONSIDERING THE WEIGHT OF THE CAR, or more specifically, understanding weight transfer, how it effects the car and how you can exploit it.To answer the question you have to understand that whatever you do with the brake & gas they do more than just make you stop & make you go. At rest or at constand speed with a balanced throttle (neither accel or decell) the weight of the car (for example) 50/50. With weight goes grip, so grip is 50/50 [F/R]. When you come off the gas weight goes forward, depending on how much revs you have etc. this could be quite considerable (60/40?). If you apply gas weight goes rearward, this could be (40/60?).
If you apply the brakes this moves even nore weight forward (70/30?) and if you really press them it could be as much as (90/10?).
So, when you turn in on a balanced throttle (i.e. you get all your braking done first before turning) you are turning in with say 50/50 grip balance. You don't need as much grip on the back of the car as the front so it is often better to have more weight (grip) on the front than the rear, so you turn in with some degree of braking still happening (trail-braking). Maybe this is 70/30
Once you are in the corner, the relatively low amount of rear grip vs. front grip would tend to cause the back to lose traction (oversteer) so, to counteract that you'd need to move some grip back to the rear. To do that you'd EASE off the brakes and gradually apply power eventually to get back to a balance throttle by mid-corner (you rarely need to brake all the way to the apex, but some corners benefit from this).
Of course, we all know that exit speed is THE most important aspect of MOST corners so, at the apex we would want to start applying power. Now, the grip we have has to be shared between the cornering grip we still require (mid-corner) and the power we wish to apply. If we add power it takes grip away from cornering, so we need to UNWIND (less grip required for steering, more available for power). As it also moves grip more rearward we need to ensure we account for this also.
As I said initially, it does vary from corner to corner and car to car but that's the science behind it. Most corners where braking is required benefit from some slight degree of trail-braking but often this is just enough to give that initial "bite" but it takes skill to move beetween brake and gas smoothly to gain the benefit from this.
A common trait of trackday drivers, in their quest for quicker laptimes is to leave the braking as late as possible and brake as hard as possible. Often this ends up with them coming off the brakes just at (or just before) the point of turn-in. What happens is there is huge "energy" (weight) over the front tyres which "whiplashes" backwards when you come off the brakes, turing what was perhaps 80/20 to more like 40/60 or worse.
This means they cannot take anything like the speed into the corner as even the 50/50 driver, never mind the 70/30 driver. Outcome is they end up slower over the lap.
Given that all the front 12 drivers in this years SEAT or CLIO championship have the abililty to control the car, drive the optimum line etc and have honed the 1000s of other skills required to drive quickly on track, the guy on pole is dealing with/using the weight better than those behind him ... in general of course, the only things thats black and white in racing is the chequered flag!
So, now you know about trail-braking you can all go back out on track, brake even later and keep the brakes on as you turn and go quicker yes? well no, of course not, before you can trail-BRAKE you need to be able to BRAKE and most trackday drivers and even most club racers can't/don't brake properly. I think it was Jackie Stewart that said it took him years to learn how to brake properly and he put it down as one of his most valuable skills in making him the driver he was.
Well, I shouldn't really dangle the carrot without giving you a chance to read it. I recently emailed a "student" about proper braking technique etc. Ideally it needs to verbal follow up, trial-error, feedback etc. etc. but it does explain what I mean, will post it as a reply to this thread...
Maxx
