Leon & Oversteer

[Simsy]

Have a remapped Leaon Cupra TDI and I have had 3 intances in the last 2 weeks where the back end of my car has gone completely. It was not freezing although maybe a bit slippy and my tires are about 3mm all round.

It happened when I go into a tight corner and accelerate out of the it, the back end swings out and I have to fight to control the slide, which is a bit disconcerting in a front wheel drive car which should normally understeer if pushed.

Can anyone suggest why this might have happend, is it the 'lift of oversteer' effect and the fact I have poor tread on the tires with slippy road conditions?

Any ideas would be appreciated.

Did Ya check your tyre pressures?

I had a sketchy moment on a roundabout and the rear end got a bit wild for me, it caught me by surprise. Got home and checked the tyres and noticed that one rear tyre was way under pressure (slow puncture) and was causing the car to oversteer.

Just a suggestion, could be a combination of lack of tread & or a under inflated tyre?

 

[rdjmoose]

I learned this recently after sticking two new eagle F1's at the front and leaving the Continentals on the rear. I can now make this oversteer happen at will!!
Replacing the Continentals this week hopefully for another couple of Eagles.


This is my exact set up at present, and I thing it is a combination of crap conditions, poor tires on rear and way I was cornering, at least I have experienced it and come away unscathed.

Will be getting new tires and cornering without unbalancing the car the way I was.

 

[Ruddmeister]

I allways work opposite to this much recommended set up and allways have my best tyres on the front..
I dont recommend that I am right or that you copy me but I prefer my best tyres on the front to give me better traction under acceleration and better braking in an emergency and also less chance of aquaplaning with the steering...
I realise that I will have a grip imbalance during two periods of my tyres life..ie just before swapping my front for new ones (where the back will have more grip) and just after swapping my fronts for new ones where the front will have more grip..
But this has never caused me any problems in many years of fwd hot hatchbacking

Like you my Dad recommended best tyres to the front (I respect his opinion as he does a lot of racing and hillclimbing etc) also one of the tyre places I use recommend the best tyres at the front.......I can also see the logic with the weight and drive at the front, hence why you would want your best tyres there........there probably is no right answer just maybe whether people are more comfortable with a car that has a preference to oversteer or understeer at the limits.

 

[m0rk]

I'd agree.

If the tyres @ the back don't grip, replace them. but bestest rubber up front.

 

[jase750]

Unless there is standing water the tread depth is not an issue, if the road was reasonably dry with no water for the tread to displace having less tread will help grip as there is less tread shuffle on the tyre.

Also slick tyres have the most grip F1 put 4 grooves in them to SLOW the cars down.

How far had you been driving ? were the tyres warm ? as in a fwd car the rears take longer to warm up as there just there to stop the back end draging on the ground

most possibly it was just the weight of the car being unsettled by aggresive inputs .

Fifth gear did a test on mixing new and old tyres and the resounding conclusion was to put the new tyres on the back of a fwd car ! !

 

[mik]

Several years ago the advice was always best-to-the-front, for all the reasons Mark Sheerin mentions.

They reversed that when they realised how few people could deal with unanticpated oversteer......

Preference now is for new on the rear - which does of course mean less traction and worse braking in the wet.

I personally prefer to rotate my tyres front-to-back to avoid big tread differences, and then I change all 4 at once (on the Leon at least - not so bothered on the porker). This means I wear them a smidge faster just after they are swapped - as the tyres have to adjust to whatever camber settings front/rear they are now on. This also means 200 or so miles of slight instability. Which you are aware of.

 

[jase750]

Arn't the back on the porker wider than the fronts ? ?

 

[mik]

they are different sizes

My comment was that I prefer to change all 4 at once on the car. Any car.

Since I can't rotate those on the porker, it's a bit difficult to achieve. I just didn't make the point very well.

 

[djawol]

I remember my LeonR snapped round when exiting a roundabout once. I had put the new Eagle F1's on the front and still had 6mm worn Pirelli's on the back. I soon went and swapped them round.

As an aside the rears on my Zed are right on the little markers now and I can get it sideways at any speed, usually without wanting too.

 

[Fast_Eddie]

most of us on this forum drive cars that are blessed with an amount of power/performance that we should all be aware of. MOST of us also drive FWD cars, that usually under everyday curcumstances understeer when pushed too hard( esp in the wet!).
most people who drive cars with an un-equall amount of tread depth on their cars are usually, blissfully unaware about the problem until a serious irregular problem occurs ie-having to brake on a bend/brow of a hill or hitting black ice etc etc. Surely everyone on this forum is aware of the dangers of pushing their cars to the limit and the consequences of having to control an understeering/oversteering/fourwheeldrifting motorvehicle?????
I know many people who have driven their cars for years and years and years, without ever experiencing ANY of the previously mentioned car handling characteristics.
Surely the car crazy lot that 'we' are should be more aware of the natural traits of a motor car when its tread depths are different----otherwise, 'we' should not be driving our cars beyond their natural grip levels???
I know I sound a bit 'old' here but if you are going to drive a car quickly, then surely you should understand EVERYTHING about the car and its handling traits before you go quickly round a roundabout?
Before I get shot down, I have suffered a few times due to inexperience and luckilly it was only my credit card that took a pounding!
My best piece of advice:

take the current car that you own to a skid pan for a couple of hours and learn how it behaves when it all goes wrong in the safety of a large area, under proffesional guideance,then remember that feeling of how the car handles with that given tyre combination----if that combination changes, then so will your cars handling!
However, if you are JUST going to drive your car normally, the I would also recomend a trip to the skidpan, as it also helps you to prepare for any unplanned sheep/dog/cat/ice/diesel/ leaves/gravel etc ect that may or may not be in your way!!!!

Please dont have nightmares!!

 

[Ruddmeister]

Surely everyone on this forum is aware of the dangers of pushing their cars to the limit and the consequences of having to control an understeering/oversteering/fourwheeldrifting motorvehicle?????
I know many people who have driven their cars for years and years and years, without ever experiencing ANY of the previously mentioned car handling characteristics.
Surely the car crazy lot that 'we' are should be more aware of the natural traits of a motor car when its tread depths are different----otherwise, 'we' should not be driving our cars beyond their natural grip levels???

I think it's also the shock of discovering how the cars behaviour changes between good tyres and poor tyres, full tread and worn tyres and different combinations of these front and rear.

I think we all try and adapt to driving within the conditions as for many of us these cars are our pride and joy.....and I'm too old to be a boy racer

Having had a couple of Leon's over 4 of the last 5 years and having done well over 100,000miles in them I prefer a Leon that understeers a little rather than one that has snappy oversteer.......maybe it's just personal taste

 

[Fast_Eddie]

I think it's also the shock of discovering how the cars behaviour changes between good tyres and poor tyres, full tread and worn tyres and different combinations of these front and rear.

I think we all try and adapt to driving within the conditions as for many of us these cars are our pride and joy.....and I'm too old to be a boy racer

Having had a couple of Leon's over 4 of the last 5 years and having done well over 100,000miles in them I prefer a Leon that understeers a little rather than one that has snappy oversteer.......maybe it's just personal taste

Fully agree with you about the understeer bit. Its a lot safer than snappy oversteer, especially on the road. Its not as if all of our cars are driven on the circuit all the time where they would benefit from a different set up and a less understeer orientated front end.
Usually when I change my tyres, I take it very easy to start with, then gradually bring the conering forces up on roads I know just to see how the car is behaving. It normally takes a few hundred miles for me to feel fully confident in the car again!

 

[hungabunga]

Only last week my backend snapped round at around 20mph, ended facing the roundabout. Caught me completley offgaurd. It was not very wet so it must have been some spillage.
Interested in going to a skid pan to find out how the car behaves, are there any located close to Manchester ?

Thanks
Sully

 

[Fast_Eddie]

the last one I went to was in york and it was with the police advanced driving unit. It was quite a long time ago now, but it might be a good place to start?

 

[chris_m]

I've always had this concern ever since i bought the Leon. Great car, but always felt twitchy when compared to my last car, a MK4 Golf 1.8T. Very wierd considering its the same chassis, i can only assume its down to weight distribution or whatever SEAT tinkered with in the suspension..

I could take liberties with the Golf, even considering its shocking wallowy setup - it could be thrown into a corner without almost any worry and it would just stick, and understeer horribly. The Leon seems more poised, more agile, but ultimately more on the limit at times.

I actually had the car back to the dealers a few months after buying it, complaining it felt far too nervous. They apparantly checked and found something on the rear suspension to need 're-torqueing' - i've no idea whether they were bulls**ting me or what, but it instantly seemed to make a difference, i could even feel it over bumps in the road.

I did unfortunately nearly write the car off in June. Fortunately the roads were dead, i was on my way home from work at 6am on a Friday morning.

I admit to entering the corner a tad quicker than i previously had, but nothing dramatic. As soon as i began to turn in, i didnt have a second to think before the back end was coming around me and i was planted into a crash barrier at a 45degree angle at 45mph. I am in absolutely no way a 'great' driver, but i have previously been able to 'catch' other moments in the car, but literally had no chance - it was far from the progressive nature id previously experienced. The car scrubbed along the barrier before snapping me out, slamming the passenger side into the kerb and facing me the wrong way on a single lane slip-road, on a blind bend with £4k of damage

It took me quite a while to build my confidence back, but im still very very cautious in the wet. Probably a good thing, cos i still dont either trust myself or the car

 

[Fast_Eddie]

sorry to hear about your crash!!!
It can and does happen to anyone for all manner of reasons!!!

Just a thought, was your tcs turned on at the time? as I have nearly been caught out on an oversteer momment due to the very intrusive electronics...when the car starts to oversteer suddenly, the tcs takes over and cuts the power to the driven wheels and prevent you from applying more power to pull yourself out of the rear end slide.....
I turn the tcs off as soon as I get in the car as I feel much safer knowing that I can potentially balance a rear end drift with a modicom of power and if needed a little twist of opposite lock?
seems to work for me but I know everyone is different?

 

[mark sheerin]

I have learnt over the years never to take any handling charecteristic for granted...
in karting you can alternate between under and oversteer and back three times in a meeting depending on how much rubber is laid on the track how cold or warm ar wet or dry it is and even ten minutes of a cloud overhead will have you adjusting your tyre pressures to suit anticipated track temperature changes...

when I drive a road car I allways drive a little briskly at first to get a feel for the cars behaviour in the cnditions before ever giving it any real pasty...
fortunately most times the handling changes it is gradual over a course of months and its only when replacing new tyres that you really need to pay particular attention to the cars balance...

Ironically longer service intervals are to blame for these problems as in the days when cars needed servicing every 7500 miles it was easy for the mechanics to rotate wheels as Mik mentioned so that tyre wear would be even accross all four wheels...