Replacing front tires

Yes, hydroplaning rear tires is very rare, simply because the fronts tend to clear a path for the rears - the water doesn't have time to cover the road surface before the rear tires get there, unless it's

*really* deep. However, locking the rears first under hard braking is seriously bad juju, you do NOT want that to happen, trust me. Also the rears braking loose under hard cornering can be scary - on the street, cornering hard enough to break traction generally tends to happen in an emergency-avoidance type maneuver, not steady-state cornering, so "plowing" (fronts break loose first) is generally easier to deal with by a surprised or unskilled driver than oversteer (i.e. a big ol' spin.)

nate

You really think understeer is better than oversteer ?

When the front wheels lose traction, you cannot control the direction of the car any more. If you're on a corner -- YGHN (you go to hospital/heaven now).

Having said that, I have a RWD car. The only time I have hydroplaned, was while driving a FWD hatchback in a passing zone on a rural road, in heavy rain. There was traffic to one side, and oncoming traffic about 2 metres away at a speed differential of about 200km/h.

I felt the fronts lose traction (thankfully, it was on a straight), and had no idea what to do. I just held the wheel straight and continued to apply light throttle as I had been before the hydroplaning started. Thankfully again, traction came back a couple of seconds later. What's the best thing to do in this situation?

For most people, yes. Most OEM's agree with that assessment, as most cars "out of the box" will be set up to "plow" a little. The reason is that the recovery procedure for understeer - getting off the gas - is reflexive even for an untrained driver. The recovery procedure for oversteer is not.

That's true. However, the car will continue in the direction it was pointed when it lost traction, which is reasonably safe, assuming that you were pointed the direction you wanted to go.

gradually lift off the gas and let the car coast down, but nothing else. Definitely do not turn the steering wheel as you don't want to unsettle the car when traction comes back.

nate

Very nice response, Nate.

FloydR

"Floyd Rogers" wrote

Late thought: rather amazing to actually be posting ON-TOPIC to RAD...

FloydR

Because if the rears had 'floated' the ass end of your truck might have come around on you sending it into a spin....

No. You do not want the ass end of the car to come around under any circumstances.

Before the sniping trolls step in with some special case where one wants the ass end of the car to come around, I clearly mean normal street driving, not some movie stunt or whatever other special case you are thinking of.

That's exactly why you SHOULD place the new tires on the front and leave the old ones on the rear. Finally, a FWD car that doesn't plow. :)

Seriously, having put new tires on the front of the wife's car last winter I can confirm this is exactly what happens, and if you don't want it, it's not a good thing. (some of us find that a little less plow and a little more loose IS a good thing.)

(and fwiw, the wife's car will get new tires probably this winter if we keep it another winter. Since we've had the car we seem to replace a set every two-three years.)

Ray

Yes, if they'd floated. They didn't.

True, but it's more likely the front tires will hydroplane than the rears. The *best* advice, then, is to replace your tires as soon as they show any signs of wear. But I seriously doubt anyone will want to do that. We play the percentages.

If you had better tires on the front than the rear, the rear would float and swing around.

Actually it's less provided your vehicle has the engine in front.

Yes, so put the new tires on the rear or risk having the assend go down the road first.

Personally, I rotate tires and replace in sets of four.

A completely unsupported assumption.

The front tires hit the water with nothing to remove the water but the tires themselves. The rear tires hit the water aftert he front tires have cleared much of it away, and what's there is disturbed, making hydroplaning much less probable.

Try basic physics and basic driving experience.

F=mu*N If you don't understand that, then there is no point in continuing. Take a gripping front end and a sliding rear end and see what happens.

You'd people would actually ask for cite for the statement the 'sky is blue'.

While there is some benefit to diving in the wipes... if the back looses traction, the ass end comes around. If the front looses traction you keep going forward.

Wipes or no, the rear can still break loose and come around. This is highly undesirable in most regular driving. It can also be tricky to control. Meanwhile, losing traction in front means letting off the throttle.

Actually, COMPLETELY supported:

FloydR

I don't think constant radius wet skidpad testing transfers directly to real world hydroplaning.

I suspect they weren't even sure the loss of the rear tires traction was due to "hydroplaning", but jumped to that conclusion. Since the rear wheels don't steer the loss of traction in hard cornering is more likely attrbutable to simply exceeding the available lateral traction of the rear tires on wet pavement, IMO.

The Tire Rack team includes not a single shred of data in their report; not the vehicle, not the tires or their tread depths, not the velocity at the point of "hydroplaning", absolutely nothing but assumption, opinion and wags, AFAICT.

I find that report completely and utterly useless. -----

- gpsman

So in exactly what way does that NOT translate to on-road safety? Again, for most drivers, understeer is safer. When you put worn tires on the rear, you get oversteer, in ALL conditions, even dry. Worn tires not only don't shed water as well as new ones, the rubber itself gets harder as the tire ages.

nate

It's unsupported because you're trying to use math to to show what can happen (IF* the rear tires float; it's been said by myself and opthers that it's more likely for the fronts to float, because the rears enter water that's already been moved and disturbed by the front tires. I understand what happens if the rears come loose; you seem to be missing the situation that's being discussed.

Which is what's being said. Glad to see you caught up.

Of course it can. But it's much more likely the fronts will float before the rears do, so the better tires should go on the front.

On a continuous curve pad. Not many street situations are such; most driving is straight, where the fronts will wipe the rear tire track.

When the fronts float, there's NO steering; not just understeer.

Hardly. Most people never get anywhere near the limits of even worn tires.

Most people don't drive in circles and accelerate looking for the point where traction is lost? And I would guess that most people would not encounter those lateral G's (whatever they were, who knows?) at hydroplane velocities

But there's more and better (duh), if not great, evidence that I might be wrong.

(Them's gotpichurs, altho they fail to mention in which position the tire ismounted when photographed). And with a video I haven'twatched yet, -----

- gpsman