Damp Roads & Understeer

[wolosp]

I know the text books say that understeer is the result of carrying too much speed into a bend, but I am experiencing understeer when driving quickly but not what I would have called fast for the bend, particularly on damp roads. Obviously this can be turned into oversteer by applying the throttle, but I am looking for a more neutral handling characteristic. Do other PH-ers consider this another case of 'they all do that Sir'?
Tyres are Toyos (though I don't want to start the great TOYO / Chimaera debate at the mo) and are set at 22lbs (front) and 24lbs (rear) as per the handbook.
Paul.

[Don]

If the car understeers when you put it into the bend then you put it in too fast and that's the cause. Another possible contributor might be that you don't have a balanced throttle (i.e. enough accelerator to keep the car's speed constant even though you are getting the braking effect of the steering as you go around the corner...)

I would add to this that unless you have excellent visibility all the way around the corner that if you are close enough to the limit of grip to be experiencing understeer or oversteer then you are probably going too fast. Remember - whatever is just around the corner out of sight could require you to brake..if you are anywhere near the limit of grip this will be disastrous.

Don't mean to be an old woman...but there are far too many single car incidents in these beasts...

Now if you *really* feel its the rubber letting you down...

[incorrigible]

Could also be the tracking, too much toe in will cause understeer

If I go in too hot I prefer the lift off oversteer followed by tastefully executed power slide

But then I have got a thread running asking for peoples tyre choice as mine are a bit tired (3000 road miles, is this a record )

[wolosp]

Thanks for your reply Don.
I hadn't felt I was barrelling into bends too fast, though it is easy to be decieved when you're enjoying yourself. I accept your justified warning about not knowing what's around a bend, and I'm too fond of my pride & joy to take risks. The roads at the moment are rather greasy making the speed for limit of grip lower than you might expect. Thanks again.
Paul.

[Don]

wolosp said: Thanks for your reply Don.
I hadn't felt I was barrelling into bends too fast, though it is easy to be decieved when you're enjoying yourself. I accept your justified warning about not knowing what's around a bend, and I'm too fond of my pride & joy to take risks. The roads at the moment are rather greasy making the speed for limit of grip lower than you might expect. Thanks again.
Paul.

Well I wouldn't have made the comment if I hadn't done it myself... The Boxster can be a bit understeery on slick roads with damp on 'em - even at 30mph (and with a good view around)...and its always my error not the car..

Keep it shiny side up and on the black stuff! Enjoy!

[heliox]

IMHO.
when fast skirmishing at this time of year, their is a very small line between getting it right and getting it very wrong no matter what tyre or driver skill.its cold...
heliox

[JohnnyS]

I have not experienced understeer in my Chimaera.

Either your car is different or your driving style is different. I usually get on the brakes very late for taking a corner at speed to ensure that there is plenty of weight over the front wheels to get a good turn-in. Then I can have some fun with the light rear end!

[Don]

I think Paul got my point, chaps - and perhaps you haven't.

Yes the limit of grip is closer at this time of year than it is on warm dry summer days.

That is precisely why you have to modify your driving style to take that into account. I'll make the point again - if the car is sliding through any part of the corner - if you do not have TOTAL visibility - then you are probably going too fast.

Of course...if you DO have total visibility..and you don't get it wrong..then sliding the car is jolly good fun. But its rare that there's someplace where this can safely be done on the road. I'm not saying that there aren't places = I know a few - just not many. On track of course.... .. its a different matter.

Careful guys...please. Like I say. I have heard of far too many single car incidents recently.

[camlifter]

Don,

Ditto.

Wait until the roads are dryer in the summer then you'll get a better indication of whether your front settings could do with some adjustment.

Cammy.

[granville]

Don, Heliox - damn right!

I'm aching to vapourise some tarmac at the moment but with black ice a constant danger and general slip-slideyness all around us, let's put into action the classic advice of the old commander from Hill Street Blues and "be careful out there."

Perils abound on that thar tarmac!

Summer's not that far off, after all (yeah, right!)

[GreenV8S]

TVRs are all set up as standard with mild understeer, and this is most obvious on tight, slippery corners with little/no throttle. So in a sense yes, "they all do that". However, the recommended driving technique, especially on roads which have limited visibility, uncertain grip or are unfamiliar to you, will mean that you should rarely encounter understeer. The technique is usually described as 'slow in, fast out'. Essentially you enter a corner well below the fastest speed you could get round it, accelerate gently through the corner and gradually increase the power as the corner opens up. This technique has a lot of advantages for all cars - most cars are most stable under gentle acceleration. In a high power car like a modern TVR it lets you put the power down earlier and gives you a higher exit speed, and when combined with 'vanishing point' and 'late apex' techniques it is generally the fastest way to get from A to B. It also gives you the greatest margin of safety if the corner turns out to be tighter or less gippy than expected, or something gets in your way - you keep the initial speed down and only accelerate when you know it's safe to do so.

So, although understeer is normal, if you encounter it routinely it may be worth reassessing your driving technique.

Incidentally, the subject of understeer, why it happens and how to drive round it was discussed at length about a year ago so a search of the archives might turn up some relevant threads.

Cheers,
Peter Humphries (and a green V8S)

[tantivy]

wolosp - how much tread on your fronts versus your rears? Higher tread and grip levels at the back can cause the front of chimaeras to 'wash' out a bit on bends if going fast. I got this with my new rear S03s when first on even tho the fronts still had 5mil tread - also depends on tyre profile of course - are you wearing 205s or 225s behind Ned's bite-marks? Have been driving the Tiv on & twice beyond its limit recently & have become quite used to the patent 'wash effect' which is now gradually disappearing as the rears wear down. cheers, (all IMHO ) Tant.

[wolosp]

tantivy said: wolosp - how much tread on your fronts versus your rears? Higher tread and grip levels at the back can cause the front of chimaeras to 'wash' out a bit on bends if going fast. I got this with my new rear S03s when first on even tho the fronts still had 5mil tread - also depends on tyre profile of course - are you wearing 205s or 225s behind Ned's bite-marks? Have been driving the Tiv on & twice beyond its limit recently & have become quite used to the patent 'wash effect' which is now gradually disappearing as the rears wear down. cheers, (all IMHO ) Tant.

Hi Tant,
Fronts are nearly new - rears have around 5mm tread depth, so they're ok. Wheel/tyre sizes are standard (205s F & 225s R). I'm quite happy with Don & Peter's summary, and recomendations. I do not consider I have been driving unduly rapid, but have just felt the front 'go' a little on occasions when the conditions are slippy.



>> Edited by wolosp on Sunday 23 February 14:42