Just Did My First Trackday...

[Cameron 16]

Remember kids: don't swap worn-in tyres front to rear if you have different camber settings.

[welshpug 1,668]

I do remember someone rolling their 205 at RAF Marham, the recipe?

 

 

Sticky tyres and standard suspension!

[Baz 421]

Yep!

 

I've seen it happen a couple of times at sprints etc too.

[Cameron 16]

Coupled with..? Come on, it's not like they cornered so fast that the car flipped over! What did they do, clip a kerb or get airborne and land sideways?

[Baz 421]

Nothing. No kerbs, no magic, nowt.

 

A mini did it last year too, although slightly differently as it got a bit sideways then gripped, so dug in and flipped over about 6 times.

[Cameron 16]

Well, I'm not calling you both liars but I find it really hard to believe that a standard 205 could generate enough cornering g to flip itself over on level ground. There has to have been something else involved.

[Baz 421]

Christ, thinking about it, i nearly rolled mine on road tyres last year after a clipping a very small kerb through the old kart track at Debden!! I was well up on 2 wheels, sh!t me up a bit!

 

You can see the kerbs in question in the pic below, although it wasn't that very one, and i literally brushed it coming out of the last corner in the complex that's actually quite an open corner!

 

[Baz 421]

Here you go, here's another example as filmed from Johno on here's 205; (Who iirc, is who rolled his 205 at Marham too!)

 

 

Although yes, that was going across the 'piano keys' so changing grip levels.

[Cameron 16]

Yeah exactly, you can see how bumpy that place is so it would be very unwise to start sliding there!

 

Surely you can see what I'm saying though.. I bet those cars would have still rolled if they were on road tyres. Sticky tyres alone won't make you start high-siding round corners on decent tarmac.

[Baz 421]

It's actually pretty flat at that point though!

 

And maybe those yes, but i disagree if they were on road tyres they still would have rolled, especially the 2 at North Weald i've seen, the 205 literally was just a low speed 'topple' over, and the Mini was coming up a straight into a long left hander with a bit of a bump in the middle, that i enter into at about 80ish, and have a massive slide at times if carrying a bit too much speed and have a lift, which is effectively what the Mini did, but then dug in and flipped because of the tyres extra grip. I've had faster/longer slides in the same place on road tyres and never rolled.

 

So it certainly made me open my eyes to it, suffice to say since then even in runs that were then not important, either because they were non counting or i've screwed them up previously, i don't pitch it sideways there like i used to anymore...

[Cameron 16]

 

Ok, well we can agree to disagree then!

[Baz 421]

Seriously, go and do it...

 

I have a standard 1.6 outside with a set of 888's on it and it seriously feels like you could get it on 2 wheels VERY/worryingly easily.

 

I won't 'agree to disagree' because i know what i've seen with my own 2 mince pies!

Edited February 17, 2010 by Baz

[Rippthrough 98]

It'd be fairly easy with sticky tyre if you take a big inside kerb on standard suspension tbh, shock loading + soft damping + lots of lean + those stiff sidewalls...

Edited February 17, 2010 by Rippthrough

[Rob Thomson 6]

One thing that might affect roll-over threshold is poor damping; if the body's bouncing about you're likely to get nearer to the roll limit than you ever would if things are better controlled.

 

My standard 1.6 on R888s is fine on track; never feels like it's going to roll even when attacking kerbs, it just slides nicely and progressively. Having said that it does ocassionally feel a bit marginal when autotesting. The airfield where I usually compete has a very coarse tarmac and ever now again it feels a bit dodgy when it bites whilst handbraking at high speed (40mph). I think it's the very sudden transitions combined with high grip levels that result in poor body control in those extreme circumstances.

 

If I ever modify mine top of the list are some proper dampers, a very slight drop in ride height and a stiffer rear ARB.

[Cameron 16]

It'd be fairly easy with sticky tyre if you take a big inside kerb on standard suspension tbh, shock loading + soft damping + lots of lean + those stiff sidewalls...

 

Exactly my point though, you aren't going to flip a car on level ground just by cornering quickly. There HAS to be another factor involved, like bumping a kerb, sliding across a pot-hole, or getting airborne and landing sideways. There's absolutely no way you'll flip a 205 by hard cornering alone on level ground. Should I say that again? LEVEL GROUND! Not hitting a pot hole, not sliding across "piano keys" and not attacking kerbs. If you're going to flip a 205 on sticky tyres doing those things then it's more than likely you'd still flip it on road tyres.

 

God I hate repeating myself.

Edited February 17, 2010 by Cameron

[Baz 421]

Ok, if you're going to split hairs, no there's no way you're going to roll a car by not doing anything in it.

 

But any car on any tyres on any suspension could roll given the right circumstances and conditions. It's not as unheard of as you're trying to make out just for argument's sake is it.

Edited February 17, 2010 by Baz

[Rippthrough 98]

LEVEL GROUND!

 

Slight problem with theory vs real world there though....

[Baz 421]

[Rob Thomson 6]

[Baz 421]

Indeed it does!

 

Excellent find Rob.

[Cameron 16]

Ok, if you're going to split hairs, no there's no way you're going to roll a car by not doing anything in it.

 

But any car on any tyres on any suspension could roll given the right circumstances and conditions. It's not as unheard of as you're trying to make out just for argument's sake is it.

 

Here we bloody go.. Did I say the car would flip over when you're parked up doing your shopping? No. Don't be stupid.

 

I'm not saying roll-overs are unheard of, what kind of idiot do you think I am? You're exaggerating what I've said because you just can't admit that you aren't right!

 

Slight problem with theory vs real world there though....

 

You know what I mean by level ground. I mean ground that hasn't got large bumps and dips and potholes, i.e. a track. I don't mean driving on a perfectly ground surface plate.

 

 

Yes, he rolled over because he was being an idiot and whipping the car around down a hill. That's totally irrelevant anyway as you don't know what tyres he was using!

 

I'm getting pretty fed up of this bulls*it to be honest. Every time I mention something slightly contrary to your opinions you make a massive bloody fuss about it and try and exaggerate and ridicule every point I make. Now I'm sorry but Baz, what do you do for a living? What other than what you've been told or read about on the internet qualifies you to such an extent that you believe you know more about vehicle dynamics than someone who is studying a course largely based on the subject?

 

This is exactly like the rear ARB argument a couple of months ago, I say something about a small area of a vehicle and suddenly I have a load of people jumping down my throat with all these arguments that are absolutely nothing to do with what I said!

 

It's like if I said fitting suspension component X would cause a tendency to oversteer, then people come back at me saying yeah but I've fitted components A, B, C, D, X , Y and Z and my car doesn't oversteer, it does backflips on command so you must be wrong. It's all bollocks, read my posts properly before you reply with some nonsense that has nothing to do with it.

Edited February 17, 2010 by Cameron

[Baz 421]

Thinking about it, in that vid i'm sure it's just us that can't see the hidden bumps, or the jack-in-the-box hidden in a little secret compartment in the rear inside tyre, or Zebedee and Tigger that were hidden under the boot floor that just wanted to bounce a bit too hard...

 

I'm not saying roll-overs are unheard of, what kind of idiot do you think I am? You're exaggerating what I've said because you just can't admit that you aren't right!

 

Ok, i admit it, i'm wrong. I often am because there's always some physics or similar to prove what i've done and seen myself wrong. Happy?

 

I don't think you're an idiot for the record, i think you're pretty damn clever in fact. You just seem to have trouble proving and showing that sometimes.

[Quarryman 1]

So.....

 

*grabs coat and heads for the door*

 

i reckon I'll stick with what i have for now and practice my driving on the track a bit more. Might look into suspension and sticky tyres after that.

 

Thanks for the help guys.

[Cameron 16]

Baz:

 

It was the down hill slope that added to the roll if it had been on the flat it wouldnt have rolled.

 

Taken from that video link.

 

And unless my vision is extremely wonky that roll happened going sideways down a hill.

 

It isn't about the physics, it's just common sense. Now just so we can be absolutely clear what I'm saying:

 

1: Your total roll angle is comprised of body roll and tyre roll, so if you reduce the tyre roll, you reduce the total roll angle. Saying that sticky tyres create more body roll simply isn't true. You may be getting more body roll but it will be because you are able to corner faster, and the reduced tyre roll may even negate those effects.

 

2: Body roll is caused by the lateral acceleration (G force) acting on the centre of gravity, which creates a moment about the vehicle's roll centre - which is the point the body will pivot around due to suspension geometry. So it follows that if you keep the same cornering force (i.e. corner at the same speed as before) then your amount of body roll HAS to be the same. The only way you will experience more body roll is if you corner faster, i.e. the cornering force is higher, creating a larger roll moment.

 

3: You may be slightly more likely to flip a 205 with sticky track tyres than with road tyres, but unless you're being a muppet (that video) or you're unlucky (the MG on the previous video) then you aren't going to be able to flip the car just by cornering quickly.

 

Please please say that you understand what I'm getting at now.

Edited February 17, 2010 by Cameron

[Baz 421]

Oh i've always understood what you're getting at mate, it just doesn't change anything. And personally in the vid above, the car was back on level ground when it started to roll rather than on the hill, it was more the fast transition between sliding one way then the other and it gripping, LEVEL GROUND or not, it happens.

 

I have seen a 205 literally topple over going round a 180d hairpin on flat ground at level ground on an airfield runway, and seemingly not even going that fast, and it certainly wasn't being driven eratically, as yes, the one above was, Darren (VisaGTi16v) may have seen it too if he was there, i'm not sure.

 

My dad stood behind me earlier as i reminded him about it and he commented 'yes that was very odd'. So by your way of thinking as presented above in your little rant, irrelevant of what he does for a living thanks, i think he knows better than you.

 

He has a bigger cock too for that matter.