Aquaplaning on track

[Preseh]

Hi All,

I currently drive a supercharged K20 Lotus Elise (One year to go until my Atom 4 arrives ) and had a pretty scary moment at Abingdon airfield track day the other day where I aquaplaned on the back straight and span onto the grass at near 100mph. This got me thinking, how does the Atom get on in super wet conditions? In hindsight, I probably should have slowed down or sat the session out until the worst of the rain went. What do you guys tend to do when conditions are rough? Any scary aquaplane moments?

Annoyingly it was the one session I wasn't filming on my GoPro!

[PaulF]

Only driven once in heavy rain. Had no issues with my Uniroyal Rainsport 3 tyres. To be fair, wasn't trying to get good laptimes, only drifting.

[markwetherall]

The Atom 4 is very stable in the wet. I had a set of ZZS's fitted and found them and the car excellent in the heavy rain. It was much more stable than my old 3. I would say you will still aquaplane if weather is horrendous as it is still a light car but the 4 does seem to have a lot more grip due to wider tyres but I did have traction and boost both fully on. I certainly wouldn't use the ZZR's in the wet even with the electronics

[Peter255]

I've driven the 4 in the rain but not in anger on track.

It'll come down to the tyres tbh if your worried over aqua-planing.

The wider tyres won't help you, infact the opposite is true. They will make aqua-planing worse and the more advanced suspension won't help either as its all about weight, tyres, speed and water depth. No amount of clever suspension will help if the tyre lifts off the tarmac on a layer of water.

You need the correct wet weather tyres to avoid aqua-planing at speed.

I have done a soaking wet track day at brands back in the day (in my old 2 300 on the wrong tyres) and it was hideous. On some racing wets it would have been cold and wet but do-able. Frankly on a048s it was amusing for a bit, but soon annoying. There was ZERO grip.

Some might like sliding around and wheelspin but it frustrates me as you have to potter about and cant either accelerate out of the corners, or carry any speed through the corners. You also get into trouble drifting!

[Preseh]

Yeah I'm not massively fond of driving in the wet. Drifting can be fun but understeering off the circuit and unpredictability are not! I think the takeaway for me is to respect the conditions more especially as I was offline overtaking a slower car at the point of aquaplane

Do you guys have different sets of tyres depending on the weather or is it a grin and bear it type of situation if you get caught in the rain?

Will be praying to the weather gods on the next track day!

[PaulF]

Do you guys have different sets of tyres depending on the weather or is it a grin and bear it type of situation if you get caught in the rain?

Went to a trackday with a damp cold track, not even rain, and my Avon ZZRs were pretty worthless. Understeering and sliding all over the place. Swapped them for Uniroyal Rainsport 3s and the difference was mindblowing. I only use the Uniroyals in the wet/rain now.

[Preseh]

Do you guys have different sets of tyres depending on the weather or is it a grin and bear it type of situation if you get caught in the rain?

Went to a trackday with a damp cold track, not even rain, and my Avon ZZRs were pretty worthless. Understeering and sliding all over the place. Swapped them for Uniroyal Rainsport 3s and the difference was mindblowing. I only use the Uniroyals in the wet/rain now.

Interesting! Do you have two sets of wheels for the different tyres? Something for me to consider when my A4 build slot rolls around.

[PaulF]

Yes, 2 sets of wheels. One with the Avon, one with the Uniroyal. Swapping takes about 15 minutes - half of that if you've got a friend helping.

[thomas_fr]

I use my atom with R888R on track and dry roads,
and when using it on rain or winter, i like the AD08R tires,

dry grip is 90% of a R888R, and wet grip is so much better, not as good as a road tyre like a Rainsport, but acceptable.

R888R on wet road is scary

[cvjoint]

I'd go as far as saying wet conditions are the Atom's achille's heel. I run time trials and I top the charts from time to time but I'm dead last on the day that it rains.

Cars that do well in the wet have a lot of weight, AWD, traction control, 50/50 weight distribution, downforce, and stability control. Of these my Atom had none last wet time trials. To top it off, my Dash 2 leaked and before I lost all my dash information I could tell the engine was not getting up to temp so all I could think of is I'm going to blow a headgasket.

I even came with a spare set of wet slicks that were super skinny. Totally pointless, I would aquaplane at 50 mph everywhere. The car is simply too light. My trick for next season is to add downforce and max out the wings on wet days, waterpoof the dash, and have since switched to full electric water pump to pulse in order to get it up to temp. If I can move from the back of the pack to midpack I'd say that's as good as it gets for an Atom.

[dooke2000]

For what it's worth here are my thoughts on aquaplaning reasons.

If the standing water is deeper than your tread pattern, you will aquaplane.

Tires with a groove cut all round the circumference will fair better than the tires that try and disperse the water sideways.

Racing car drivers and good motorcycle riders rules of thumb in wet conditions.

Mat track surface = you will find grip.
Shiny track surface = be careful.
Mirror track surface = forget it, good chance of aquaplaning.

[autobackup]

There is a scientific formula for calculating aquaplaning velocity :

The formula for aquaplaning speed in Knots is 9 x square root of tyre pressure in PSI. The formula for aquaplaning speed in Miles per Hour is 10.4 x square root of tyre pressure in PSI. This formula is based upon the validation of hydrodynamic lift theory by experimental evidence.

[Sir Nick]

There is a scientific formula for calculating aquaplaning velocity :

The formula for aquaplaning speed in Knots is 9 x square root of tyre pressure in PSI. The formula for aquaplaning speed in Miles per Hour is 10.4 x square root of tyre pressure in PSI. This formula is based upon the validation of hydrodynamic lift theory by experimental evidence.

Gotta love science Paul!

[autobackup]

Nick

That's why aircraft tyre pressures are so high as you probably know!

The tyre pressures on a B.747-400 were usually circa 200 psi - but most aircraft tyres are inflated with nitrogen as it doesn't expand when it heats up.

Despite this I experienced a 'heart in mouth' moment when my 270,000kg Jumbo started acquaplaning at about 160kts shortly after landing on runway 14 (slopes slightly downhill) at Mauritius airport during a heavy rainstorm!

Bit of an adrenaline moment - necessitating the imbibing of a fair few beers after arriving at the crew hotel!!

[Alec]

I've been an advocate for the Directional Toyo R888 for a very long time, as opposed to most owners preference for the Yokohama Advan A048, which I never liked, and I was pleased to see Ariel choose the Toyo's for the 500 V8.
Any way, I only ever had one problem with the Toyo R888 aquaplaning, which although not on track, could happen anywhere.
I'd been at a Track Day at Aintree Circuit when it started to rain in the afternoon, but I was virtually the last car to go out in the final session with no problems at all for grip.
It was a week later on the M57 when I was cruising along at about 70 in a queue of cars in the outside lane when it started to rain a bit.
Before I could pull off at the next junction to put waterproofs on, we rounded one of the curves to see what looked like a bead curtain of torrential rain.
I started to slow & move over lanes, but as I went through what was obviously the edge of the very heavy downpour, it was like driving into a lake so I had absolutely no grip whatsoever.
As I aquaplaned & spun, I was lucky enough to pass between the cars and numerous lorries in the inside lane without touching any, or worse still, going under one of the lorries.
I ended up going up the embankment and hitting a tree backwards.
Out of all the vehicles that must have seen what happened, just one Birmingham lorry driver stopped and helped, flagging down an Ambulance going in the opposite direction, who turned around to also help.
I then had to wait for the Fire Brigade, Police, Paramedics and a local Ambulance to get me out and take me to Hospital.
I'd snapped my Humerus as I was thrown sideways onto the Frame, and so couldn't climb out unaided.
I knew I'd broken my arm, as although I hadn't moved my arms, I recognised my glove as it went past my face.
The point of this is, no matter how confident you are in your tyres in wet conditions, as I was, too much water on the road will negate virtually any tyre on a very light car like the Atom.
Within six months of my Accident on the M57, they installed these warning signs.