There's been some excellent detail in this thread... If not a bit above my head at times. Thank you for those contributions.
If the suspension is stiff there is less travel, therefore a car will lift its wheel slightly more when there is a bit of a camber in the road. If this is in a breaking area, that wheel lift means it can lock up easier than if it were in full contact with the ground. It may look like a huge lock-up but in fact it doesn't cause much damage to the tyre as the tyre is not under load when this happens. The benefit of stiff suspension is flatter cornering but that may make the car less compliant over bumps and camber. But then again, what do we know that you can't see on teh tv. I mean, all the cars look the same don't they so they all drive and handle the same..........
My apologies to Sea-Man. I've just noticed his interesting post. Busy now but will reply properly when I have more time, later today if possible. P.S. It is also very relevant to Saint's last post.
sorry i dont believe that saint -- the driver is the one who presses the brake peddle , his foot on the brake peddle decides whether or not the car locks up or not -
For anyone who does not want 'technical', simply skip the next two posts. They are divided due to the 10000 character limit per post. Trail-Braking (part 1) Earlier in the thread, I referred to "brake induced oversteer" which is very much associated with trail-braking. Sea-Man's mentioning of it warrants an explanation. (My apologies to those not wishing to bother with technicalities, who might do well to skip this and the next post)⦠- - - 'Trail-braking' is the term describing braking which continues after the point of steering into a corner It is a subtle technique which seeks to exploit tyre grip to the maximum in order to get through a corner in the shortest possible time. It requires great skill to be done accurately; especially with the very low cM (centre of mass); light weight; and grip levels associated with an F1 car and it is important to remember that all race drivers do it to some extent. However, like anything else, perfection is what is sought; and even amongst the very best F1 drivers, there are inevitable differences and preferences. For trail braking, itâs implications and possible side-effects to be properly understood, it is important to lay out some basic principles. Maximum ******ation is achieved when braking in a straight line. For the principles of driving on a public road (which are entirely focussed upon maximising safety), one is encouraged to complete all braking in a straight line, then select the most appropriate gear and only then to steer into a corner, thus separating each of the various elements of car control, in order that they each be given exclusive attention by the driver. A side-effect of this process is that it tends to force a driver to approach and negotiate a corner more slowly than might otherwise be achieved. (This helps make allowance for the countless unforeseen dangers one should anticipate on public roads). The following discussion goes against the principles set out in the point above. It is therefore essential that the reader understands that it is applicable to race driving only, and in principle should not be practiced on the road - although most people tend to do this to some extent if they have not undergone advanced driver training! The purpose of trail-braking ⦠is to allow later braking and to make use of 'weight-transfer', in order to fully exploit all available grip, often all the way to the apex of a corner. Limited grip: the âtrade-offâ At all times, there is a limit to the amount of grip any tyre can give (which quickly evolves during a race) but the driver is at liberty to use whatever is available in different ways. For instance, when braking in a straight line, 100% of the available grip can be used for braking; and when cornering, 100% can be used for cornering - but only if one does not involve the other! Thus, it is a trade-off which must be calculated accurately. Weight transfer ⦠is a consequence of any change in speed or direction on a level surface. Disregarding losses such as fuel consumption and braking materials, a carâs weight is constant and is shared between all tyres which are in contact with the track surface. However, inputs from a driver (in particular braking or steering) will alter the distribution of this weight. Under braking, weight is transferred towards the front wheels with a corresponding reduction at the rear. When cornering, centrifugal force (which is trying to resist going round the corner) forces weight towards the outer wheels, with a corresponding reduction in weight acting upon the inside wheels. If braking and steering occurs together, the âoutsideâ front wheel will support most weight, and the âinsideâ rear the least. For instance, with a left turn, the front right will be under greatest load and therefore least likely to lock; whilst the left rear will be âunloadedâ and the most likely to lock. N.B. Weight transfer is greater - and therefore more noticeable - when a vehicle has a higher cM (centre of mass). It is therefore far easier to control in a vehicle with a higher cM. ⦠continued below.
Trail-Braking (part 2) Fastest possible cornering Trail-braking seeks to exploit 100% of available grip at all times up to the point of maximum steering input (usually the âapex), in order to get through the corner as quickly as possible. On approach to a corner, all of this grip can be used for braking until the point of steering input, whereupon braking must be feathered (trailed off) to allow the grip required for cornering. Greater steering input requires a corresponding reduction in braking input, thus sharing it out so that the combination never exceeds 100%, which would otherwise always cause at least one tyre to âgive upâ. N.B. It should be clear that the longer a driver uses 100% of available grip, the quicker the tyres wear out! Effects Bearing in mind that braking shifts the distribution of weight towards the front and away from the rear, and that a tyre grips best when it has more weight acting downwards upon it, braking will increase the effect of steering inputs, so long as 100% is not exceeded. This has the effect of turning the car into an unnatural attitude (relative to no trail-braking), which allows a tighter turn in at precisely the moment that the rear goes light. Remember that the objective is to exploit but not go beyond everything which is available, and that as steering increases, so braking must be reduced. N.B. A driver knows that exploiting the tyres reduces their life. Consequences of errors If a driver does not calculate the trade-off correctly, at least one wheel will lose traction and stop rotating (because it is still being braked). A driver now has three wheels on his wagon and unless an immediate adjustment is made, his race is over. Too much steering (relative to braking) will cause sudden understeer, (nearly always locking the âinsideâ front wheel - that which is in the direction of the turn) and an appointment with the scenery is almost inevitable because braking was left later in the first place and without enough steering available, he is travelling too fast. On the other hand, too much braking (relative to steering) will cause sudden oversteer (often with a locked âinsideâ rear wheel) and - unless immediately feathered â a spin because the rear is too light to grip whilst the fronts are gripping and still going around the corner! N.B Any error will further increase the rate of tyre wear. The four-wheel-drift This is where things get really tricky. A four wheel drift is a combination of both âerrorsâ described above occurring at the same time! It is a very fine âbalancing actâ in the most literal sense and has virtually no room for error at all. It is initiated with brake-induced oversteer through trail-braking, whilst at the same time steering slightly âtoo muchâ (causing slight understeer) but not as much understeer (exceeding 100% at the front) relative to the amount of oversteer (exceeding 100% at the back)! This has the net effect of twisting the carâs attitude relative to its direction, whilst at the same time deliberately exceeding the limit of grip at both ends! Now the problem is not so much causing the four-wheel-drift but returning to âgripâ so that there is no sudden âbiteâ from any tyre which would result in a loss of control because there is no time to fix it. This requires great skill and all racing drivers can do it to some extent, especially in cars with a higher cM, such as Rally Cars and Touring Cars. Sports Cars are closer to F1, but still a long way above them. N.B. Employing the above technique makes huge demands upon the tyres, wearing them very quickly indeed; even if a driver executes it perfectly every time. Special considerations for F1 F1 cars have the highest power to weight ratio of any racing cars. There is very little weight. F1 cars have the lowest cM of any racing cars, which minimises weight transfer (remember there is also very little weight to âplay withâ in the first place) making the control of it very very difficult indeed, especially at the unbelievable speeds and G-forces involved. F1 cars have the most efficient, most powerful braking systems of any vehicle. They are typically made of carbon-fibre which gives very little feedback (âfeelâ) to the driver and require to be stood on in order to work properly, typically requiring 100kg of pressure at the pedal, which is considerably more than a driver weighs. (So imagine trying to âfeatherâ the brake when youâve given it slightly too much). F1 cars have the grippiest tyres in motor racing and give almost no warning that they are about to âgive upâ. One millisecond you have 100% grip; one millisecond later you have no grip whatsover. Adjustments to the car can be - and are - made to accommodate driver preference. In particular, this will involve spring rates and camber angles, anti-roll bars and damping, as well as differential settings and brake bias (both of which have a dramatic effect upon cornering. N.B. A âstifferâ set-up increases the chances of a loss of traction with corresponding increased tyre wear but allows a more instantaneous response from driver inputs. A softer set-up increases traction and reduces wear rates but reacts more gently to driver input. Footnote It should by now be apparent why it is so difficult to control a four-wheel-drift in a modern day F1 car, and why some drivers will explore it more than others (Hamilton); whilst some will choose to limit tyre wear by cornering ânaturallyâ, with minimum slip-angles for all tyres (Button; and, to a lesser gegree: Vettel): the exact opposite of the four-wheel-drift â even though, like any racing driver at this level, these guys is quite capable of it. Still others wll prefer considerably more understeer (Alonso) which gives early warning about approaching the limits of adhesion. ©
what can i say -- i have proved you wrong twice in recent days cc , once when you said senna had poor technical feedback and then you backtracked when i showed you the mika hakk link , and secondly when you said button thrived on a neutral set up , when in fact the link from button himself said the he thrived on understeer , when you have got things like this wrong in recent days you cannot blame people if they dont believe your four wheel drift theory and how it benefits hamilton and how only hamilton can do it - what can i say -- it is everybodys nature on here to disagree with people if they dont agree with some of the things people say on here - --------- on certain matters i dont agree with you and in recent days i have proved you were wrong -
maybe i am wrong then -- maybe the driver does not press the brake peddle that causes the car to lock up - ---- maybe the brake peddle operates of its own free will - --------- what was i thinking --
ok cc -- so you have consulted wikipedia or whatever for a gettysburg address of mumbo jumbo -- buts whats your point , if indeed you are trying to make a point with me -
Cosicave you have excelled yourself!! That was well explained and easy to follow, made for an interesting read as well. Must have taken you a fair amount of time to write all that out so thanks for that lol. Made my little explanation look a little feeble haha That must put enourmous pressure on the tyres, I recall Brundles saying if normal road car tyres were fitted to an F1 car they would last 3 corners and then blow up
end of the day it might be sarcasm --- but i am right - -what else can cause the car to lock up violently but the drivers foot on the brake peddle --
I note that you asked a question earlier Martial - Cosi gave a very extended and thorough explanation on Trail Braking and the general use of tyres. You then reply with - The point was that you asked a question and were given an answer. Further to this, you chose to reply not with a thank you or some note of appreciation to the effort that Cosi went to, but instead were rather rude. Banter, opinion, debate. Call it what you want, but there's always room for respect and being polite. You're an enthusiastic poster on this forum which is a good thing. However, sometimes you give the impression of not willing to concede a good point when one is made which makes participation in a thread such as this tiring instead of informative and enjoyable.
