Don't try this in your 993

[Mark Elder]

As a 993 does not have ESP (PSM) I think my car/me might have suffered if I'd taken out the 993 last Tuesday.

Writing this as a reminder that it can happen easily - I still can't work out what I did wrong...which makes me feel worse about the incident.

Heavy rain (but not so heavy that the wipers on my RAV4 were on speed 2), there had been the odd pool of standing water on side roads and on the motorway. I was just moving into the outside lane of the motorway and was on full throttle to move into a gap between a car (ahead) and a big van (behind). I was in 4th at about 4000 RPM but this is only my 2.0 litre RAV4 remember, it's not like I was going to lose traction through overdoing the power... and I hit some more standing water - but there was no loud noise - it was less water than I'd seen earlier, I did not see it as an issue.

Then suddenly the car's not pointing where I'm steering, the back has swung towards the central reservation, and I'm pointing 45 degrees back towards the middle lane at the car I'd moved out to pass. My immediate thought was "this has gone too far to correct I'm going to spin and get hit by that van and a few other things". My memory of the ProDrive-skills-day a few of us had a couple of years back was that you could correct slides on the skid pan if you caught them early - but 45 degrees is far too late, and in any case we were playing at low speeds on that day. By now I obviously had the wheel hard to the right to try to correct, but then an alarm went off and a light started to flash on the dash and, wow, the car's straight again. I'm shaking but very impressed by how much an inertia sensor and some software can fix.

The rest of the journey was much slower!

As I said above, this was not a big pool of water - I've certainly been through much worse floods (at higher speeds) and never had a problem before. Maybe it was the full throttle, maybe it was because the rear tyres were getting to the point where I'd started to think about changing them. They now have been changed! Maybe it was because I'd just altered direction slightly having just finished the lane change.

Anyway - take care out there.[8|]

 

[IndischRot]

Glad the tale has a happy ending - sounds like a brown trouser moment.

How much tread on the rear tyres? Assuming front and rear tyres are the same size I tend to put the tyres with more tread at the rear figuring understeer is easier to deal with than oversteer.

 

[Mark Elder]

ORIGINAL: phelix

How much tread on the rear tyres? Assuming front and rear tyres are the same size I tend to put the tyres with more tread at the rear figuring understeer is easier to deal with than oversteer.

Depends where I measured them - got a neat little measuing stick from a talk Michelin did to our region and it was showing 1.5 in some grooves but nearly 3mm in some of them - not different amounts of wear, just some grooves seem to be cut deaper than others.

I've always put the better tyres on the front on the grounds that they need the most grip in an emergency stop - but I can see what you are saying about reducing oversteer.

Anyway - have now changed the tyres!

 

[997GT3_KO]

Good to hear that you are unscathed... I am always worried about standing water on roads as I really don't like the aquaplaning experience !!

 

[Johnny C]

I've done something similar - as usual heading onto the M6 at J26 at about 40-50 but accelerating, it's a fairly straight entry to the motorway and it was dry, but the back end suddenly went far too fast for me to do anything, I span once through a gap in the slow lane (bit hairy as I went sideways between two lorries) and then did another cmoplete spin in the middle lane and ended up pointing forwards. Someone was looking down on me that day!

My tyres were okay, it wasn't wet so there must have been diesel on the road or something. Maybe the same happened to you, you just hit a bit of floating diesel.

Living 'Oop North' as I do, water on the motorway is a regular occurrance, especially between J23 and 26 on the M6. I've found that Pirelli zero Rossos outperform any other tyre I've had through surface water, you just don't notice it's there, even if it's a bit deep you don't get the sudden deceleration as you hit it. Even where they're down to the minimum tread, they don't budge.

 

[JB 3.2]

Close call Mark

My understanding is that with rear wheel drive the tyres with the most tread and hence best grip should be on the front of the car. The theory being that you stand more chance of catching the back end as it breaks away, but you need good grip on the front to be able to maintain steering control.

The diesel theory sounds possible, I've certainly experienced it on a motorcycle not good and one of the resons I retired from bikes.

Pleased it worked out Ok in the end, although I do wonder if this is one of those occasions when the C4 system would have been of use.