Funnily enough, dropping your tire pressures a little often DOES help reduce hydroplaning, because it doesn't usually make the contact patch much WIDER, it generally makes that contact patch proportionally LONGER - and in doing so allows the sipes & grooves in the tread to move a little as they flex onto the road surface,, gripping the road like little fingers, as well as effectively PUMPING the water away from the contact patch, and in doing this it also lessens the wedge of water created in front of the tire that is what lifts the contact patch & creates the hydroplaning problem in the first place!! :shocked:
But it is a fairly fine line, tire pressure that's too high makes the tire unable to flex so it can't act as a pump or reach optimum operating temps, so it's like running on a railway wheel.... fine while you are going slow enough, but they'll always give an awful rough ride, and once you get going faster, it gives you all the drawbacks of an ice skate on polished concrete & none of the benefits!! Plus it only lets the tread pattern grooves move water away from the contact patch - none or very little gets moved by the smaller sipes; the tread compound itself is too cold & hard to do any 'gripping'; the sipes don't open as the tread flexes onto the contact patch so it doesn't do any of the 'pumping action' that the tread is designed to create; and the compound itself is either too cold & hard to grab (cos the tire hasn't flexed enough to warm up) or it's too hot & runny & floppy as it approaches delamination temps!! :sour:
Then there's the little window which is the optimum pressure for the load that Mike & I spend so much time talking about, where both the tread pattern and the tread compound get to work as they were designed under the load placed upon them and btw, once you are running aftermarket tires, those optimum pressures generally have little to do with the vehicle manufacturers 'recommended pressures' for the OE Spec tires, simply because they are mainly TIRE & LOAD dependant, varied a little by riding style & ambient temps etc, but definitely not aimed at selling more vehicles or OE Spec tires. The tread grooves start moving water away from the contact patch as the tire rolls onto the road; the smaller channels & sipes open as the tread flexes down onto the road & then start to close as they pass thru the contact patch, initially collecting & grabbing water & then forcing it out to the sides of the tire as they close, acting like little pumps to move more water away from the contact patch; and at the same time they are acting as sticky fingers grabbing onto the road surface & hanging on because they are hot & sticky without being too hot to be virtually useless &/or runny/delaminating!! :2thumbs:
And then you can get pressures that are too low, generally down so low that the tire might have difficulties staying on the rim. This is where lowering the pressure starts making the contact patch wider more than it makes it longer, and it is pretty low for most aftermarket tires carrying the fairly light load imposed by our Spyders.... think about even lower than about 8psi, down in that vicinity, but if you do the 'ink test' on the contact patch (use a small puddle of water on an otherwise dry road instead of ink & paper tho, it's easier to source, do, and clean up!
) you'll see very quickly when the contact patch width stastaincreasesr ts to increase proportionally MORE than its length increases as the pressures drop & you lower the tire under its load onto a dry surface.... you really don't want to be fown there, cos the tire CAN roll off the rim, the centre of the tread/contact patch starts to bow up & in, lifting off the road surface & allowing even more water to collect in there, the outside edge of the tread becomes the only bits left touching the road surface, massively reducing the contact patch area & minimising grip & the ability of the tread to move water out of the way, and basically becoming almost as dangerous as running pressures that are too high!!
So in a nutshell, tire pressures that are too high are dangerous; tire pressures that are too low are dangerous; & the 'just right' tire pressures that Mike & I bang on so much about are as safe as you'll get, JUST SO LONG AS YOU DROP YOUR SPEED to be SLOW ENOUGH BEFORE YOU HIT THE WATER!! :thumbup:
Someone said it earlier, ! I'll paraphrase it here - the
best preventative action against hydroplaning you can take is less twist in that right wrist.... :lecturef_smilie:
