"Snaking" like wiggle from back under strong accelleration .. tyres?

[Submariner1]

I inherited Accelera 275mm budget tyres on the rear, with 7mm tread.
My initial thoughts were "lets run them in the dry season", say till September or down to 4 or 5mm.

I have New Goodyear Eagle F1 Assy 3s on the front. Maybe not the best, but OK tyres.

For general driving these Acelleras are surprisingly good VFM.

But after a long dry warm spell we had some solid rain, ( a great recipe for sliding, due to lots of rubber granules mixed with water on the road surface ); I found if I accelerated in a hard and sustained fashion. Not balls out kick down. The rear end seemed to "snake" pretty easily. Reduction of the right peddle instantly corrects it. (and yes my diff is perfect so I assume its the tyre's inability to grip in the wet )
Stupidly I didnt look at the dash to see if traction control was blinking etc. Probably concentrating too much, to ensure it didnt get out of hand.

I assume this is the budget tyres not being able to handle 387 bhp?

I feel powerwise, that this 5.5L V8 engine coupled with the 7G Plus gearbox is a surprisingly significant upgrade over the 5.0L with a 7G combo.

I just wondered if anyone, especially anyone with a 5.5L V8 M273 7 G Plus combo who had moved from Budget to Decent tyres had noticed this effect, and seen it reduce with decent tyres?

Seems a shame to bin these perfectly adequate tyres, especially if say Pirelli PZeros or Eagle F1s wont cure this snaking.

 

[A.J.]

I have experienced this in the past. It turned out to be tyre pressures

 

[Westheath]

Tyres are how the rest of the car reacts with the road.

Budget tyres don't not exist for me, they are dangerous in wet weather.
I remove them from vehicles I have purchased and sold on.

And I advise my customers to fit proper tyres asap.

 

[Submariner1]

I have experienced this in the past. It turned out to be tyre pressures

Thanks, didnt think if that.
Just checked both of Mine are both at exactly 33 psi
Where for under 130 the flap says between 32 to 36 with 4 people and luggage
So it cant be that.

Were yours uneven pressures, or both too high / too low.

Note no problems in the dry hence I assumed its tire adhesion.
Plus whell arches are same height, and MBII shows the ride height that was set with Star when I had a front ABC strut replaced.
Also handles perfectly. So I ruled out suspension setting.
And the initial tracking job said only one front wheel camber was lightly out of alighnment.

 

[A.J.]

Were yours uneven pressures, or both too high / too low.

Mine were too low. I actually put 2psi over the lower recommendation which I thought made the car roll better and it did get rid of the snaking sensation. Although the snaking sensation was quite minimal it was a little unnerving.

 

[A.J.]

Tyres are how the rest of the car reacts with the road.

Budget tyres don't not exist for me, they are dangerous in wet weather.
I remove them from vehicles I have purchased and sold on.

And I advise my customers to fit proper tyres asap.

Budget tyres do not exist for me either. Tyres are one of the most important elements of a car, tyres and brakes !!

 

[Naraic]

It's the tyres...move on, nothing to see here.

Accelera are carp I had them on an E320cdi...could never get off the line in the wet.

 

[JBell]

So you are driving a £100k car on £100 tyres, you do the maths!!!!!!

 

[rf065]

But after a long dry warm spell we had some solid rain, ( a great recipe for sliding, due to lots of rubber granules mixed with water on the road surface )

I think you'll find after a long dry spell all the oil & grease dropped on the road floats to the surface after heavy rain, not sure about rubber granules unless your local road is a race track! Not many tyres have a chance with an oily, greasy & wet road.

Russ

 

[Submariner1]

Thanks for the replies.
Seems pretty unanimous.
Just thought I would ask, as I have never had Budget tyres before.
From my experience the difference is too great, they will have to go

So you are driving a £100k car on £100 tyres, you do the maths!!!!!!

actually the previous owner paid £75 for them
I have never bought budget tyres, except Pirelli Cinturaro P1 ( if that is classified as a Budget tyre) for the wifes shopping cart A Class. But that rarely goes over 60 mph ... probably average max speed of 50 mph.

 

[Submariner1]

I think you'll find after a long dry spell all the oil & grease dropped on the road floats to the surface after heavy rain, not sure about rubber granules unless your local road is a race track! Not many tyres have a chance with an oily, greasy & wet road.

Russ

The guy who did the Porsche High Speed course said during the dry weather the rubber that wears off the tyre's lays on the road. If it rains daily, most is rinsed off the road. But it builds up during long dry periods and then when it start to rain the first time it creates a slippery colloid like emulsion.
No idea if he was right ... but Jesus could he handle a 911!

 

[Submariner1]

Tyres are how the rest of the car reacts with the road.

Budget tyres don't not exist for me, they are dangerous in wet weather.
I remove them from vehicles I have purchased and sold on.

And I advise my customers to fit proper tyres asap.

Well this is my first experience of them, and they are not for me.

 

[JBell]

actually the previous owner paid £75 for them

I was talking a pair .

What else did the previous owner skimp on???

 

[JBell]

The guy who did the Porsche High Speed course said during the dry weather the rubber that wears off the tyre's lays on the road. If it rains daily, most is rinsed off the road. But it builds up during long dry periods and then when it start to rain the first time it creates a slippery colloid like emulsion.
No idea if he was right ... but Jesus could he handle a 911!

He is correct, they go on about it in F1 all the time as well

 

[rf065]

The guy who did the Porsche High Speed course said during the dry weather the rubber that wears off the tyre's lays on the road. If it rains daily, most is rinsed off the road. But it builds up during long dry periods and then when it start to rain the first time it creates a slippery colloid like emulsion.
No idea if he was right ... but Jesus could he handle a 911!

On a race track with soft compound racing tyres, yes. On a public road with ordinary everyday tyres, no chance!


Russ

 

[Submariner1]

I was talking a pair .

What else did the previous owner skimp on???

The last annual service was at non MB garage, non MB air filter, non MB oil filter, and Quantum fully synthetic Oil , it was top MB spec but , and non MB rear brake pads .. Ferodo?
Fortunately that was 40 miles before I bought it . So I just treated it as an oil flush, and drove it straight to the maindealer for a full B service. mobil 1 0W40, and MB oil and air filters.
He also thankfully didnt change the gearbox oil, or brake fluid. So as it had done 40,000 mikes I had Phil at Welwyn do a full gearbox overhaul, new filter, new oil , drain TC and a good clean out. And new MB brake fluid.
So luckily his last ditch skimping didnt effect the car.
Other than I have non MB rear brake pads.
Previous services were all at a main dealer so it was properly looked after, spark plugs changed etc. ( apart from the ABC fluid was not flushed until 40,000 miles ... but then MB dont do that ... it did however have a main ABC hose replaced at 25,000 miles because it was "sweating??" wtf is that ... (and I suspect they flushed some of the ABC fluid, because when I changed it, it was extremely clean ... clear light green with only a few tiny black specs)
Plus then I had a new strut, and a full ABC filter and flush and new diff oil at MBS at 40,800.

So overall it was looked after pretty well and is now up to spec.

And goes like stonk! If prodded politely

Of course she is no Echo Warrior .... and regularly one sees 26 mpg!
Persoanlly I thinks thats pretty dam good for such a massive car that really can accellerate.
But if petrol bothered me ! would not drive a big V8

 

[Wighty]

Could the snaking be caused by all the oil leaking from your rear diff and over your rear tyres . (Only joking )

 

[Submariner1]

On a race track with soft compound racing tyres, yes. On a public road with ordinary everyday tyres, no chance!


Russ

So when you look at your tyres that had an 8mm tread and now have 3 mm .... where did the 5mm go?
Seemed fairly logical to me that the road surface grinds it off and that dust gets trapped on the rough road surface

.... and he really knew his stuff. And as I said christ could that guy handle a car!
Probably the best driver I have ever sat in the passenger seat with.

His explanations of what to do when driving fast were superb ... learnt a hell of a lot from him, never had an accident, and I am quite sure had I not had his instruction I would definitely have killed myself by now. Lol
In my late 20s I wasnt exactly your "model" driver with a new 911!

 

[rf065]

So when you look at your tyres that had an 8mm tread and now have 3 mm .... where did the 5mm go?
Seemed fairly logical to me that the road surface grinds it off and that dust gets trapped on the rough road surface

On a racing track you can actually see the "marbles" or bits of rubber from soft compound tyres, show me any evidence of them on a public road? On the other hand, after it rains you can see an oily greasy film lying on the surface of the road.

Russ

 

[Submariner1]

Could the snaking be caused by all the oil leaking from your rear diff and over your rear tyres . (Only joking )

Love it
Made me laugh that!