Tyre Wear

[Tony V12V]

silverspeed said:

Tony V12V said:

silverspeed said:

Had the Intermediate tyres fitted before a 1500 mile trip around Scotland a few weeks ago. Had all seasons in one trip including torrential rain and temps of 5c. The tyres and car were faultless. The car always felt planted and can thoroughly recommend them.

What car are you running SS ?

V12Vantage

[Murph7355]

yeti said:

I wonder how much of this bravado is due to geometry settings, not just mechanical grip? And also one person's 'limit' is very different to another's......

I think you might be right.

I know my V8V is making broadly the right power (380bhp give or take). And my experiences are similar to Luna's - needs proper provocation to make it break traction (regardless of tread depth).

Either others cars' geometry isn't right, they have a lot more power and/or their TC isn't working the same as mine (though to be honest, even with it off it's not a tail happy car) and/or I just drive like a girl

Luna - my Griff 500 has a breathed on V8 and so is probably kicking out nearer to the quoted power (340bhp ish?) of a factory Griff. But don't forget that they weigh 600kg less than the Aston. Even a Griff pumping out just 240bhp would have the same power to weight ratio as a V8V. But the V8 in the Griff is much lazier - head to head a V8V would need to be worked harder with the full rev range used against a Griff.

Mind you, even with the wheels pointing in the right direction my Griff has still stepped out on me on slightly lumpy tarmac (and it has decent springs and dampers)

I often think that rather than have more power and all the electronics, people who like driving would be better off with less power, less in the way of tyres and a more unruly chassis to have fun. All modern cars are really too fast for today's roads and even cars with 100bhp/tonne differences will be very close to each other point to point on proper roads.

[Lunablack]

Murph, I think that sums it up nicely.....

For me personaly, if I was that interested in maximum performance and white knuckle excitement, I'd have bought a Busa powered caterham or suchlike...

As it stands, I just love the comfort and ease with which the AM passes the miles.....it puts a smile on my face

[mikey k]

Lunablack said:

Murph, I think that sums it up nicely.....

For me personaly, if I was that interested in maximum performance and white knuckle excitement, I'd have bought a Busa powered caterham or suchlike...

As it stands, I just love the comfort and ease with which the AM passes the miles.....it puts a smile on my face

I agree

Also many people don't understand there is a big difference between traction and grip

[BingoBob]

I'm one of those people. Care to enlighten us?

[George H]

BingoBob said:

I'm one of those people. Care to enlighten us?

I'm not 100% but I've always thought that traction is forward accelerating and grip is cornering. So a car could have great traction but not good grip by being able to put the power down well but not being fast through the corners.

[BingoBob]

I don't know, George. I must admit I'm struggling with the difference. Perhaps the Oxford English dictionary will help us understand this vitally important difference.

Grip: [mass noun] the ability of something, especially a wheel or shoe, to maintain a firm contact with a surface: these shoes have got no grip

Traction: the grip of a tyre on a road or a wheel on a rail: his car hit a patch of ice and lost traction

Nope, still struggling. Help us to understand, Mikey.

[mikey k]

OK

So grip is defined by numerous factors (tyre compound, surface, temperature, corner loads, vertical loads, suspension geometry etc) but is essentially linked to the slip angle of a tyre. The aim being to keep the slip angle with in the "circle of forces" (just with in if you are racing/driving hard )
Traction is an additional factor/force that affects grip by reducing the slip angle of the tyre taking yoo out side the "circle of forces" sooner/quicker (ice is the usual example)
Once you go outside it you lose grip (& traction)

Don Palmers web site has a REALLY techie explaination

http://www.creativecarcontrol.co.uk/modelgrip.htm

This is also good

http://www.mgf.ultimatemg.com/group2/suspension/ch...

Edited by mikey k on Monday 11th June 13:59

[BingoBob]

That's a very interesting guide (Don Palmer). He does seem to use the terms grip and traction interchangeably, so I'm no further forward on that. I think I'll just stick with what I have always assumed - that they are synonyms. Thanks for trying to explain though.

I couldn't help noticing that Don says this:

Don Palmer said:

Tread depth

Check the depth of tread at several points around the tyre and across its width. Legally the minimum tread depth is 1.6 millimetres across the central three-quarters of the width around the entire circumference, but such a shallow tread depth provides little resistance to aquaplaning. For safety's sake, replace tyres well before the tread is worn down to the legal minimum.

[v8woollie]

Is not traction the ability to make forward or backward progress, and grip (together with other things such as power) is one contributing element to provide traction? If one of those contributing elements is lost (e.g. grip) then traction will also be lost (e.g. wheels will spin/slip in the case of grip being lost or wheels will slow/stop in the case of power being lost).

Edited by v8woollie on Monday 11th June 14:26

Edited by v8woollie on Monday 11th June 14:27

[mikey k]

v8woollie said:

Is not traction the ability to make forward or backward progress, and grip (together with other things such as power) is one contributing element to provide traction.

In a nut shell - though traction is really only about putting the power down

[v8woollie]

mikey k said:

In a nut shell - though traction is really only about putting the power down

I thought grip was about putting the power down, and if there is grip then you get traction

[mikey k]

v8woollie said:

mikey k said:

In a nut shell - though traction is really only about putting the power down

I thought grip was about putting the power down, and if there is grip then you get traction

Nope if you floor it or are on ice there is less/no traction
If you exceed the slip angle of the tyre (cornering, too much power etc) there is no grip

[BingoBob]

Looks like there are more people that have difficulty with the difference between grip and traction than anyone suspected.

Can. Open. Worms everywhere.

[mikey k]

BingoBob said:

Looks like there are more people that have difficulty with the difference between grip and traction than anyone suspected.

Can. Open. Worms everywhere.

That will badly affect the traction

[BingoBob]

Hehe.

[yeti]

Have been trying to explain this to the OH recently... she thinks our Carrera 4 (4WD) has more grip than our old Carrera 2 (2WD). Which all things (like tyres and road surface) being equal, it doesn't.

What it does have is more traction as the load is spread between all 4 wheels. On a trailing/neutral throttle going round a corner at speed, both cars have the same mechanical grip... But when putting down some power, the C4 has more traction.

[mikey k]

yeti said:

Have been trying to explain this to the OH recently... she thinks our Carrera 4 (4WD) has more grip than our old Carrera 2 (2WD). Which all things (like tyres and road surface) being equal, it doesn't.

What it does have is more traction as the load is spread between all 4 wheels. On a trailing/neutral throttle going round a corner at speed, both cars have the same mechanical grip... But when putting down some power, the C4 has more traction.

Yep another good example!

[Lunablack]

All I know is that my Vantage won't break traction, in the dry even with TC off, and brutal throttle application...
But it grips like st to a blanket when cornering or braking hard......


Whereas my griff would break traction at the drop of a hat, even with reasonably light throttle applications, and also had crap grip when it came to cornering and braking


In other words one is very easy to drive briskly......and the other always felt like it was going to go wrong sometime soon

[CraigV12V]

Lunablack said:

......and the other always felt like it was going to go wrong sometime soon

i.e. Kill you!

Whilst I have not had a garage full of Lambo's Porkers etc for experience, I can say the adhesion, grip what ever you call it in the V12V is something else. Lets say I was recently on what appeared to be something like a race track with a long left hand curve. At 140 with my foot still pushing the car on it just kept hugging the tarmac even when been thrown around by undulations. After a few months I have the confidence to know the car has the grip and traction control to keep me from meeting the scenery. The Chimera I used to own which had quite good grip; I would only ever drive at that speed in a straight line and even then it felt like much more and you would take off.

Astons; you gotta love em.