What's safer during the day - DRL or headlights ?

Actually, the best tyres should always be on the rear. While the rear tyres don't turn or brake, they have a greater effect in stability than the fronts. I've got a paper by DUNLOP somewhere stating that, and there was a write-up in a Motoring Magazine in response to it where they, after testing, agreed. The most likely scenario of a car going out of control is with oversteer, with the tail sliding out. And while you can probably control an oversteer slide (a drift), it's much harder with poor tyres in the back. Many sports cars even run wider wheels on the back - Aston Martin for instance puts 255/35 on front, 305/30 on rear.

How do I know? I bought 2 new tyres, where the tyre service insisted on putting the good ones on the back. It drove really well, and, as a young guy, I got stuck into it in a few corners, and it hung on well. Of course I knew better, so I rotated them as soon as I got home, putting the brand new ones on the front. And took them for a "spin" - exactly, the back slid out the first time I "tried it out" - fortunately nobody was on that side of the road, and the road was dry. WHOOOOPs. Back home and rotate them back where they'd been put - new on the back, old on the front. The car was transformed - controllable again.

Since then, I've come across at least 3 incidents where they'd put the good ones on the front, and who were involved in accidents, one quite seriously.

 

I'd say that an oversimplified version is that (at least in the old days, before ABS and stability control), in an emergency wet braking situation, regardless of the starting position, the best tires will end up at the rear of the sliding event. The weaker tires will slide to the front. So the question becomes, can you try to steer better while facing forwards, or facing backwards.

 

My Mother would have been great - when we were little kids, we were convinced she had eyes in the back of her head.

 

I agree in general for wet or dry pavement that better tread in rear is preferable.
However, on my first front wheel drive car, a SAAB 93B, it was safer to put best tread in front in the winter snow in Wisconsin. With bald tires in front I would simply get stuck in the next snow drift. With good tread in front, the front wheels would kind of chew through the snow drifts gradually and I could at least keep moving. Bald tires in the back did make directional control and braking rather dicey , of course, but you get used to compensating for that.

 

Getting stopped safely is far more important than getting moving.

 

'Yuppy mode" being what, in a CHMSL?

 

I got a bone to pick with you cheapskate Prius drivers!

When there is heavy FOG, turn on your freakin' headlights!! Is it just the idiot California Prius drivers? Or does this happen all over the country, too? We had two mornings of fog in the past few days, and here come all the Prii drivers... with NO lights on! I couldn't believe it. Are you trying to save 5 cents!? One less run to Starbucks every week, will pay for your headlight usage.

Is there some unwritten rule that I am not aware of, or some "secret club" policy that says we have to be a cheapskate because we drive a Prius? Some guys are hesitant to turn on the heater when it's cold! Or use their AC when it's 90! I just don't understand it. It sounds really silly to me. I don't care if I only get 45 mpg… That is still excellent in my book.

I'm going to be comfortable in my car, and safe! I am not going to pinch pennies. I think that's ridiculous.

 

Completely agree about lights, but well-designed fog lights may be a better alternative as some headlights, and particularly high beams, disperse in the fog in such a manner as to blind the driver rather than illuminate the road surface in front.
But not sure about your second point. You don't HAVE to be a cheapskate to own a Prius, but it helps! You are not considering the marital entertainment value of driving without heat on a cold winter day whilst DW complains in the passenger seat! That can segue easily into the "who has the coldest feet in bed" conundrum, which will rpvide endless miles of discussion . Conversely, discussing AC usage and the avoidable "wear and tear on the compressor" when it's hot and humid outside , also provides scope for meaningful discussions with your spouse. Hypermiling techniques can also be fruitfully discussed, from the ever-popular "pulse and glide" to the eXcruciatingly slow stops required to "maximize regenerative braking". Particularly for those of us who do not use the onboard infotainment system, we must turn to our Significant Other for entertainment on those long drives. Thus it is not really miles per gallon that critically matters to some of us, but rather smiles per mile!

 

Yes, it happens here too. But it seems to be equal opportunity among many many car models. It clearly is not a Prius-only thing, nor even something that most Prius drivers do.

 

That's correct. Many other vehicles did not have any lights on. (I could only see about 30 meters in the fog.)
I would say only 40% of the drivers had their lights on. Many people in California do not know how to drive in fog or rain. It seems some even speed up!

The Prius does not have a good fog light, but they should turn their low beams on.

 

Getting back to the off-topic discussion of where to put the best pair of tires: tread wears faster on the front, agreed? Then if the best (new, full tread depth) tires are put on the rear, how are things ever going even up??

 

DUNLOP's stipulation was to put the most worn ones on the front, they wear on the front, you toss them out, put new ones on the rear, moving the partly worn ones to the front - ad infinitum. I've been doing that for 35 years.

The problem is that most tyre fitters have no idea, and work on the misguided fallacy that the best tyres should be on the front.

Doesn't work if you have a PORSCHE, FERRARI or F1 car (or my '70s VW) with wider wheels at the rear. They've already worked on putting their best tyres on the rear.