Gutmann pug

I always thought you needed your best tyres on the front, most tread etc, but remember watching top gear prove that the best tyres should be on the back instead.

Car is for track day use and the rears are better than the fronts at the moment.

what say you guys??

Paulo P

iTrader: (42)

Buy some new ones you Pikey bugger

Personally I'd have the best tyres on the front because they stop, steer and pull the car along. The rears just follow the front and don't do as much work

craigdmcd

iTrader: (2)

On the front! What's it better to do: control the front when it gets away from you or control the back wheels that have no steering or power put through them

Gutmann pug

lol at Paul .... they still have plenny of tread on them to be fair and no time to buy new ones ... up to 4am to go the 'ring' again.

I was thinking of changing front to back but remember the top gear bit with them doing stopping / slalom (spelling) etc etc and best on the back was the order of the day.

Might do a day the way they are then swap them over there and see if it feels any different

ScoobySport (SdB)

Gutmann

Remember, that more tread doesn't automatically mean better grip. On a dry track, you MIGHT find that a worn tyre will give you more traction / grip than a newer one.

In addition, if they are different types, there is pretty much no way of telling which way round to fit them.

Having said all that...

if you are talking theoretically, then the front tryes should be the better ones as they have far more demand on them.

This of course doesn't always work in practice as it all depends on how the car is set-up and how the characteristics of the tyre match what it is trying to do at the time.

As a rule of thumb though.. I would personally look to do everthing you can to increase the available grip from the fronts, even if that is at the expense of grip at the rear.

All the best

Simon

Brit_in_Japan

Requirements for road and track use are different.

Consider the following situations.

Road in the wet:
You have 2 new tyres and 2 tyres approaching the legal limit. It's wet and and there's running water across the road, on a corner. The worn tyres will aquaplane, the new ones will displace the water and maintain contact with the road. Do you want the good tyres on the front or rear?

Dry on the track:
A worn tyre will have tread blocks of smaller height. The tread blocks will move less under cornering loads and they will generate less heat.

Consider extremes, tread blocks with say 2cm depth (don't exist) and tread blocks with 0.1 cm depth (almost slicks). If pressures and condition of the rubber is the same, which do you think will provide better traction when cornering?

So where do you want the tyres with greatest grip in the dry on a track? If you have a FWD car then undoubtedly on the front. RWD/AWD I guess eveyone will have their own preference.

Steve Whitehorn

iTrader: (13)

On my FWD car on the road.
I have the softer tyres on the back running a slightly lower pressure for more grip
And I have harder tyres on the front with slightly higher pressure for slightl;y less grip
(I wouldn't mix tyres on a performance car, but this is a low powered car)
My reason for this is
When I induce the car to the limit of its grip I know that the fronts are definately going to break away before the rears. I like the predictability of this especialy on a wet road. I want the car to Understeer in the limited confines of the road as this is safer/simpler to sort out. Understeer would probably happen anyway given that it is FWD and as has been mentioned how the car is set up counts for alot. However I can see why for the track people may want more grip at the front.
Steve

ScoobySport (SdB)

Steve

You've thought all that through carefully, so it's probably right for you.

Important to remember though, that oversteer is safer in the right hands that understeer.

Underteer leaves you very little options, but oversteer tends to give you more options to deal with it. Obviously this is dependant on the driver.

Plus.. having harder tyres on the front is sometimes a good thing anyway as the fronts will get hotter due to the greater demand on them, but remember that this might mean you end up with more grip on the front than the rear as, if they were the same soft compound, you might heat the fronts beyond their optimum making them produce less grip than the rears.

Another thing to be careful of.. increasing pressures does not necessarily mean less grip. What it does mean is a smaller contact patch area which means you will be putting more heat into the tyre, which usually, ultimately means less grip, but as your compound is harder it may mean the oposite again.

in addition, in wet conditions, an overinflated tyre CAN create more grip due to the reduced contact patch area and a slight V profile cutting into the deep water.

But.. all in all, tyres a chaotic and strange things that nobody fully understands, so you just can't tell for sure unless you test.

Cheers

Simon

Turbohot

I like this thread ! Thats all I can say

Steve Whitehorn

iTrader: (13)

Interesting comments Simon - Thanks
It does seem to be a dark art this tyre thing.
On performance cars it seems to take me quite a while playing around with different tyres and pressures untill I get a set up that I am happy with and feels predictable near the limit. Never really thought about a reduced contact patch giving you perhaps better grip in the wet.
Cheers
steve

ScoobySport (SdB)

A black art indeed.

It is a genuine fact that there is not a human being or computer alive that fully understands tyres.

We know enough about them to have a pretty good idea what the general principles are, so we can make a pretty good stab at it if we know what we want to achieve.

But at the end of the day, it all comes down to testing. As you have discovered and indicated, it takes quite a while to fine tune things, as (sometimes) even the slightest change in a setting can have that pivotal effect on the handling that you were looking for.

So if that is true, and the fact that we don't understand the entire package completely, it means that the reverse is also true and the chances of getting it right through "science" alone is next to zero.



Cheers

Simon

Steve Whitehorn

iTrader: (13)

Simon
What do you think of the understeer v oversteer thing.
I have been trained in fast road driving, defensive, offensive and tac driving.
This is where I am comfortable, I have very limited track experince. So am not a good track driver
So for the road
My feelings are that for the road the key is how progressive is the grip is lost.
All this is broad generalisations I know
Many cars having large amounts of grip but letting go in an unprogressive way
Many cars having low levels of grip letting go in a progessive way.
Which is why I enjoy scoobs as they have huge amounts of grip but if driven correctly let go very progessively all be it at fairly high speeds in an understeery kind of way

So given that the progresive loss of grip is the key

Oversteer v Understeeer for the road
As you point out Oversteer does give you more more options and is certainly more involving therefore can see the appeal for the track. ('I drive a powerful RWD car, I can handle it, Ive got hairs on my chest etc - fair enough actually)

Back to real world of a wet drab A road Tuesday at 10.00 hours in Berkshire.

However on the road making swift but safe progess from A to B I don't want to play about I want to get there f**king quicky but safely. I have always felt that predictable understeer is better. You kind of need less space to sort it out. What do you think?

People knock understeer but can you see where I am coming from.
Subaru
Huge amount of grip - normally associated with RWD
Progressive loss of grip - normally associated with low powered stuff
When it losses grip - Understeer
PERFECT

Sorry about the ramblings - but always interested to find different points of view from experienced people. Please feel free to disagee

Cheers
Steve
(Understeer for the road fan)

N1 SPAN

The reason why Top Gear or whichever TV program said to put the better tyres on the back is because 90% of drivers who lose grip / control would back off or brake whichever end of the car lost grip first. Therefore the theory goes that if the better tyres are at the back, the car is more likely to understeer first and due to natural reaction, most people can deal with a bit of mild understeer.

I think that to some, understeer is a safer option but i now find that understeer scares me like oversteer used to! If the back lets go during cornering there is plenty that you can do to still make it round the bend. If the front lets go, you just have to hope you can scrub enough speed off before you hit something.

Being brought up on front wheel drive stuff (and before I started doing track days and learning what happens past limits) my theory was always slow in and accelerate through a bend and come out quickly. This always brought on understeer so my theory was to have the best grip (best tyres) at the front and it still understeered anyway as most FWD cars will.

I know from past posts Gutman that you do loads of track time so I am not sure why you are asking this question as it is always down to personal preference.

If the track is wet, it is a pretty obvious choice. I also think in the dry that the better tyres should be on the front. Worn ones 'go off' quicker as they can't get rid of the heat. I am sure there is a happy medium between new and bald tyres though.

If you are running different types of tyre front to back it will make no difference how good a condition any of the tyres are in. It will just be down to which is the best tyre.

If I want to drive sideways all day around a track then what I have done in the past is mix tyres and put a rubbish tyre on the back, even if it has more tread than the fronts. e.g. If I run P-zeros on the front and Avon?? (whatever was o.e in 99) at the back the car will just go straight into oversteer and stay there in wet or dry. If I want my car to be balanced then it has P-zeros all round.

Just do a couple of laps, swap em over and you will know what to do.

ScoobySport (SdB)

Great Thread..

Steve

I'm impressed with your analysis and approach to what you want, and I truly believe that you have thought it through enough that your choice of where you want the grip is exactly right for you.

Some interesting points to pick up on ...

For the road, there is no training (that I know of) that can beat this. Variations on the advanced road driving courses are something that everyone should IMHO.

An interesting side to this also highlights the main difference between driving on the roads and driving on a track / stage. These courses train you to stay WITHIN the limits, and hopefully never to reach them. Competition driving is based on staying AT the limit and occasionally venturing over it in the search of perfection.

The latter simply doesn't work for the road, and genuinely anyone who drives their car on the road attempting to be as fast as possible wants their head testing, before they break it.

100% agreed that progressive break away is of paramount importance... but linearity is of equal importance which I'll try to remember to explain later in the post.

Scooby = Understeer...

This is an interesting one - the current sideways world record holding car, might dissagree!

sorry, jokes aside..

Scoobies do not always break away in understeer. Their biggest potential challenge for an inexperienced driver is lift off oversteer.

The interesting thing is that lift off oversteer is pretty much the only thing a 4wd chassis has going for it in terms of handling. If by some strange twist of physics they no longer had this trait, they would be the least competitive formula on the planet.

But.. the average driver can get caught out badly by it and the reasons are highlighted in your post.

You can be barrelling along with your foot planted.. everything seems easy and you're king of the road. This is because the scooby chassis is INCREDIBLY forgiving and easy to drive *whilst you're on the gas*. Suddenly on that wet tuesday morning a deer pops his head out of the hedges on a nasty bend, you lift and all of a sudden they become just a prone to agressive oversteer as any other car.

The extra challenge is that you have gone from VERY easy to "just as hard" as any other car - which is a BIG difference - and of course, you tend to be going a whole lot faster that you would be going if you were in another car.

Oversteer v Understeer for the road

This is the biggest subject of them all I guess.

Speaking completely personally.. I am absolutely terrified of understeer. Going into a high speed bend, there is a almost always a moment at which you are hoping the fronts are going to turn in. This fear / consideration is the entire reason for the scandinavian flick so you can all but 100% guarantee that the car will turn in on time and accurately.

So.. for me, I will take oversteer every day. It is MUCH more controllable, and can be sorted out in a much safer and accurate way.

HOWEVER ..

This is not the case for the majority of road drivers. So.. from a general point of view, I would support your standpoint that on the whole the average driver is able to cope better with understeer than oversteer.

Again.. (BTW - NONE of this is to try to say you are wrong - as there is no wrong or right in vehicle dynamics, especially on the road - your statements are based on your preferences) ...

"predictable understeer" is an interesting concept. For me, if the car was set up to be 100% predictable in understeer, I would always be driving up to the point of understeer and not beyond. In other words, if you can always predict it, you'd always avoid it.

I guess what you're saying is that you would rather the car was predictable in that it will understeer before it oversteers, and that is again absolutely valid.

Great post Steve.

N1 SPAN

That's an interesting theory, although.. there are two main areas that generate heat in a tyre.. arguably the main cause is hysteresis (as the tyre deflects and bends generating heat within the carcass of the tyre) and arguably the most vital is the friction of the mechanical adhesion in the contact patch.

If you have more rubber on the ground, the second generates less heat per sqr cm of tyre, but the hysteresis remains potentially the same.

a bald tyre will likely have more rubber on the road generating less heat per sqr cm. Plus, with a tread block, the heat soak into the block is quicker and the relative surface area of the tread block is lower than on a bald tyre.

So, the upshot is.. it will be marginal, but I would dare bet that a bald tyre denerates slightly less heat than a treaded one for the same loads.

regarding them going off... we come back to the heat soak problem with tread blocks..

if takes very little effort to overheat a tread block, so the smaller surface area at a hotter temperature will go off quicker than a treaded tyre.

Linearity (glad I remembered )..

In general, the average driver and even the best, tend to prefer linear..

This means things like "you turn the wheel this much - it turns that much", "you turn the wheel the same again - it turns twice as much as before".

The reason for this is that it makes the car very predictable and requires less "knowing the car" to be able to make it work.

So whilst it's important to have the progressive breakaway (although in competition ther eis more importance placed on max lat acc) it is vitally important that this breakaway and the handling that leads up to it, is linear.

All the best

Simon

Steve Whitehorn

iTrader: (13)

Thanks for the reply Simon

Scooby = Understeer...

This is an interesting one - the current sideways world record holding car, might dissagree!

LOL

Sorry - Scooby with standard set up with out switchable diff basic 50/50 front back split = Understeer.

I whole heartedly agree with your lift off oversteer comments.
In scoob if you are going quickly then it does cross your mind that 'I have to get this just right'

Once in a blue moon when I have overcooked it and havent wiped off the speed quickly enough and have too high an entry speed. I have trail braked what ever I am driving through the bend and induced losts over oversteer to get the car pointing in the right direction. Okay it is good that I can cope with a situation like this. However I feel that if you have to resort to a technique like this on the road you are driving too fast. You have messed up big time, you won't get away with inducing big oversteer time and time again - by chucking weight about like that you will come a cropper.

So I feel that I have messed up badly and am very angry with myself if this ever happens ( which I can assure you is very very rare - but hey we all make mistakes).

I suppose I enjoy any car that is progressive. Perhaps I havent driven the right RWD car or AWD scoob with the diff chucking more power to the back. Most of the RWD stuff I have driven/owned (e.g BMWs/Mercs/Supercharged MX5) seems to be a bit all or nothing - all of them gripped the road like glue none of them gave me too much feed back as when they were about to go, they felt as if they weren't going to be forgiving, which is fine if you have the space. The MX5 had avery stiff set up and it seemed to hop round bends
'Lots of grip on the back - Oh no grip what so ever for a second - Oh there it is back again - Gone again - Back again and off we go down the straight'

It might be down to driver ability - perhaps I don't know how to get the most out of RWD??

Cheers
Steve

N1 SPAN

Simon, a very interesting thread, thanks.

I am not well up on the technical understanding re tyres going off etc. I speak purely from experience. In the Subaru, i seem to get far more grip from a well treaded tyre than a low treaded one especially when they are hot.

I run another car on track that uses cut slicks and when these get down to being just slick, they literally go off after approx 3 laps of a short circuit. There is still plenty of life left in them at this point. When they are new it will take up to 10 laps to notice a loss in performance.

I would say however that noe of this is due to tyre deformation or anything else mentioned above, it is purely from sliding.

I have never had a tyre 'go off' on the road and I think anyone that has must be bonkers. I would pretty much say it is impossible. You do however notice better grip with the little heat that you can get into a tyre through road use.

Just a quick one regarding slides on the road. This can be done at much lower speeds than people may think. It is possble to carry at least 30% more speed smoothly through a corner than if you are powersliding. Admitedly you need to be going reasonably quick in a Subaru to get all the tyres lit up.

ScoobySport (SdB)

Steve

The world record holding car was completely 100% standard bug eye WRX.

To be honest it is, and that's the whole crux of this particular part of the discussion. What is good for you, might not be good for someone else. The comments you made about certain cars not appearing to give much feedback. All this is, is tuning yourself into the car. Certainly the powerful BMW's give lots of feedback, but you just need to be listening to the right station!

The comments I made about my personal preference being oversteer rather than understeer is not dependent (except in extremes of dodgy set-ups) on the car, diff arrangement, etc.. I am just saying that understeer is less potentially controllable than oversteer.. so if I have to encounter one of them in a bend, I would prefer to encounter oversteer.

A good way to explain this is to think about rally driving. The latest breed of drivers drive far more like racing drivers, less oversteer and neater lines. This is partly due to the way the cars work now, but also just progress. The interesting thing is that they are definitely faster than the old style (colin mcrae, etc) but they do end up having a lot more half spins, etc.

The reason for this is that while you're punting around sideways, you have a lot more ability to adjust the car and keep it safe. Whilst it may sound strange, on a rally stage, driving around with big sideways action is the "be careful and keep it safe" option.

I completely support that driving like this on the road is bloody stupid, but like I say. If I personally have to encounter one or the other, I'll go for oversteer every time.

For you, this is obviously not the case, and that is absolutely fine.. it doesn't mean you're better, or worse, you're just different to me.. just as every other driver is different to everyone else.

N1 SPAN

when sliding, the heat is in the tyre is generated by the friction of the mechanical grip in the tyre and the hysteresis of the tyre deformation.

Hmm, interesting. Of course, nothing is impossible with tyres... but I wonder whether you are effectively generating more grip, which will then of course heat of the tyres more (assuming you use the grip - or if sliding, overuse it)??

Believe it or not, I know of a winter test where a certain rally team was testing snow tyres. Towards the end of the test they said "let's give some gravel tyres a go, just to see"...

they tried them, and of course they were desperately slow by comparrison to the fully studded snow tyres.

They then said "tell you what.. just for a laugh, let's give slicks a go".. to everyone's amazement (which continues to this day) the slicks were faster than the gravel tyres on that particular test.

This makes absolutely no sense whatsoever. Just goes to show how little we understand about these things, and why each situation is different, and testing is necessary.

All the best

Simon

N1 SPAN

Simon, You really must believe me when I say that tyres with tread on work better.

Why do you think that race teams use new or freshly scrubbed tyres and they then bin them so the likes of me can buy them cheaply to play around on.

Do you not think that if your theory worked then we would all be using sha**ed tyres to set record times on the track!

I use 3 sets of tyres for my track car depending on weather, circuit and how fast I want to go compared to how much I want to slide. And you really must believe me here, I use the best set of tyres I have if I want to go quickly.

When they get down to nearly bald the grip levels are rubbish, so no, they do not generate more grip and get more heat into them that way!!!

I genuinely appreciate what you are saying Hysterics!?! but in the real world it doesn't work like that. Certainly not on track anyway. It may do on the road where heat in the tyres is low.

Steve Whitehorn

iTrader: (13)

Simon

'For you, this is obviously not the case, and that is absolutely fine.. it doesn't mean you're better, or worse, you're just different to me.. just as every other driver is different to everyone else.'

I know my fast road approach is effective and safe (As my passengers will vouch for). However as you rightly say there is no right or wrong and many different ways to approach things which work for other people.

This has given me a bit of inspiration to go out and play around with RWD again whilst taking the cotton wool out of my ears and making sure that I do know how to work the radio this time

Given that the car was standard, briefly how did you approach the sideways thing from a driving /choice of tyre etc perspective. I would be interested in your thoughts on this
I know am hijacking the thread a bit - but you could work a bit about tyre choice/pressures in there (Or is it a trade secret )

Cheers
Steve

N1 SPAN

Hi Steve,

I would start practising in the wet first. The worst enemy of powerslides is not the risk of spinning but the risk of fishtailing and being spat off the other way. Most spins will just see you facing the other way whereas a fishtail will put you firmly into the scenery.

There is no point messing around with tyre pressures until you can consistently do what you want to do. Pressures recommended my manufacturers are usually the best compromise between grip and handling so would stick with those.

What car are you practising in? some are naturally harder than others. e.g. I found a standard MX-5 was a doddle wet or dry to drive sideways safely around just about any corner you could come across however my girlfriend has now upgraded to a sport and with its bigger tyres and slightly different set up it is a better car and quicker around corners but much trickier to drift. Nearly impossible in the dry.

Slow speed stuff is where to get the practise in and using a bit of weight shift to get the car moving will make it easier to then get the power through the back wheels doing its stuff.

An Impreza is one of the easiest cars to drift but the speeds are usually greater than for a RWD car so can end up worse.

Take care

ScoobySport (SdB)

LOL

N1 SPAN

This isn't a competition mate.. and there's no "not believing you".. i'm just trying to come up with solutions..

With regard to competition tyres being binned.. firstly, they are illegal to start a race on if they are worn.. secondly they have been HUGELY heat cycled.. if this is the case with your worn tyres, or if you have melted the tread blocks to the point they've squirmed all over the tyre, this may be the reason for the lack of grip.

I'm sorry, but if you are saying that heat in the tyres on track does not come from hysteresis and mechanical friction, you are mistaken.

Whenever a tyre deflects (as it does contrinuously when moving) the bending / flexing action of the tyre causes an effect called hysteresis... this effect generates heat.

Secondly, when you slide and scrape at the bottom of the tyre, the mechanical friction is the very thing that is caused to create the other part of the heat.

If you think this is not what causes the heat in your case.. where else does it come from?

"why are we not running round on sha**ed tyres to set record laps?"...

We're not running round on treaded tyres to set record laps either. A record lap will almost certainly be set on full slicks.

---

Hi Steve

Regarding the record. The tyre choice was indeed important.. and comes back again to your original point.. We chose toyo t1s tyres as they were the best road tyre (road tyre to ensure the "standard road car" thing) as a balance between overall grip and most importantly progressive breakaway.

With regard to the driving... this is more straight forward.

With non-active AWD, you need to have all 4 wheels spinning in order to maintain a powerslide. So effectively, give it large and throw it in to break traction, and from that point on its just a case of constant throttle modulation balanced with steering. I was not allowed to use left foot braking as the brakes would destroy themselves too quickly.. this was a little bit of a challenge to get used to, but after a few minutes was fine and you forgot about it.

The biggest challenge was keeping the engine cool due to the direction of travel compared to the angle, and very little air going through the rad and intercooler, etc. But we solved that by shifting to third and reducing the angle slightly when it got too hot.

Keeping it at a shallow angle rather than a bigger angle was much more of a challenge. For a given radius and speed, the car has a natural settling angle that is easier to maintain. Beyond that angle is usually a little easier than under it.. and unfortunatley we had to go under it.

Not something I would want to do again (unless someone finally breaks it! ) as the concentration levels required were the biggest challenge.

All the best

Simon

SomeDude

You haven't said this is a HUGELY complex topic yet

Just kidding, FWIW, I once made the mistake to use fresh SO2 PP's on track... even though my normal laptimes can be set with a calendar, I destroyed them in just a few laps in the dry. As much as I rate (rated ?) them on the road, they were next to useless on dry tarmac.

OTOH, fairly new Toyo's at Elvington kept together really well, but after a few laps the overheating was obvious (still, they didn't desintegrate like the SO2's did).

Oh, and the record car wasn't standard, as it was stickered

About the "understeer"... aren't we mainly talking about power on understeer on the UK Impreza, and probably especially on grippy surfaces ? Or is it still very much down to the driving style ? I personally had to install 3 new diffs to get my MY99 car to be any fun on (dry) airfields.

N1 SPAN

The track tyres I am talking about are treaded but the tread pattern is fully in tact and I think they use them in formula ford.

I guess the point I was trying to make earlier on was that on the road it will be tyre deformation and a little bit of friction causing heat in the tyre and on track it works differently as there is a lot more friction and the tyre flex or hysterisis as you state I don't believe has a lot to do with tyre temps. I reckon it is down to the friction mainly. I am guessing that is why on the road you can sometimes feel a tyre is warm but on track you can get them to the point where you can't keep your hand on them.

I dont actually have prolonged experience on track with the Impreza but I know it feels better on fresh tyres. I also genuinely feel that as the tyres get worn there is less grip. That is on my road car where tyres have been on from new.

When I stated about setting record laps i wasn't meaning just race cars that run on slicks. I will be doing a day with some timing gear on a tight circuit later this year and I know the car will be quicker on fresh tyres than on well worn ones with a larger contact area. I don't really know why this is but that just seems to be how it works. Or certainly how it feels to me. And I know I am not the only one. I have run this car on tyres from new all the way to the canvas and the grip levels just gradually die away until they are useless.

I don't know why this is the case but it just seems to be in contradiction to the original theory.

p.s. You posted about left foot braking in 4wd whilst going sideways. Do you mean constant left foot braking or the occasional pulse to keep things in check?

I have also been thinking recently about left foot braking whilst going sideways in RWD. I havn't tried this yet and was planning on doing at the next track day. Have you had a go at this? I am just thinking if I could use it to hold the car up around a long corner so I could hold it at a lesser angle without accelerating. ?

Do you think another thread should be started on this one? The original tyre question seems to have turned into an oversteer / understeer forum.

Gutmann pug

Just got back from the 'ring' and have been reading what went on with this thread while I was away.

I decided to leave the tyres how they were. More tread on the rear then on the front. The result seemed to be less understeer and more oversteer. Now that doesnt seem feasible I know and may be a result of me driving the car harder than before, ie later, harder braking and more agressive turn in resulting in a more nervous rear end.
Having read other comments about Yoko A539's being good for going sideways it may be time to try a different tyre. I want to get round as quick as I can, not show off if that makes sense.
So its time to try some 'R' rated tyres. They will only be for dry track use and transported on spare wheels.

Can anyone recommend anyone who does these tyres at a reasonable price??

Pirelli want £136 each for 195/50/15 which is ridiculous when my friend payed £50 yes £50 each for 225/40/17 for his 944.

TopBanana

Haven't read the whole thread, but just wanted to add an observation. I put some cheaper (Kuhmo) tyres on the back of my Passat, and it improved the balance of the car no end. Fun in the wet too

ScoobySport (SdB)

Apologies for the delay chaps...

SomeDude.. I've also made the S02 mistake They're superb tyres until they get too hot then basically destroy themselves. Luckily, this level of temperature is pretty much impossible on the road unless you drive like a muppet

N1 SPAN

Modulation. You don't need to be braking the whole time, but it's very useful for accurate adjustment of the car (something the world record attempt required). So the odd dab, the odd period of careful modulation, then nothing for a while.. just as needed.

LFB in rear wheel drive
This is an interesting one and the camps are split. Many people say that LFB is not necessary in RWD cars.. but to be honest, there really are genuine benefits, so "necessary" is not the right word. It's more a question of whether it is of enough benefit.

The complications are more apparent in rally driving rather than circuit driving.

One thing that LFB does have, is the ability to catch you out if you get your planning wrong and need to change gear whilst on the brakes due to something unexpected. But..

for circuit driving (which I think it what you're more interested in) there are definite benefits.

For instance.. If you really know what you're doing, you can run significant rear brake balance.. maybe as much as 50/50, and can use the gas to modulate the dynamic brake balance all the way through the braking zone. This can make an enormous difference to stopping distances and ultimately lap times.

In addition, because you have so much rear brake power available, you end up with many more options of control without needing to be hard on the gas.

If you don't have adjustable brake bias, the benefits are still there. The main benefit is tightening your line, etc.. but there is also a fabulous disaster recovery option available to you (As long as you don't have ABS)..

Imagine you're into the corner and give it a heap too much gas and end up at about 45 degrees to the road. In AWD cars, you can get more than 90 degress to the direction of travel and still bring it back, but RWD requires you to stay within the max angle of the steering. If you exceed this, you have keep it nailed and give the brakes a prod to lock the fronts, effectively snapping you back into line.

Modulation of this technique is very powerful and again just gives you way more control options.

All the best

Simon

N1 SPAN

Excellent Simon thanks,

I had never thought of your disaster recovery technique. I will definately try it when I visit Anglesey in July. I usually end up having a few spins trying to keep the car near the lockstops. I understand what you mean and will report back as to whether I got it figured in a months time.

I use a caterham on track so no ABS etc. I find the Subaru will go to much larger angles and looks more dramatic but with the front wheels to drag you back into line it is not a problem when you run out of lock but is in the Caterham.

i don't have an adjustable brake balance but will be trying left foot braking to see what happens.

Years ago when i was used to front wheel drive and therefore left foot braking I bought myself an old BMW and found left foot braking in that to be useless but I was much harsher back then and can now do it reasonably smoothly.

Cheers for now.

prana

edit: never mind, t'was a silly question. Will ask again some other time when i am more awake Thanks...