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Driving in snow

Discussion in 'Gen 4 Prius Main Forum' started by bob2004, Jan 11, 2017.

  1. Starship_Enterprius

    Starship_Enterprius Active Member

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    The old All-weathers maybe. But there are newer All-seasons (which they are trying to differentiate from the All-weathers) that are good enough to qualify for the government approved Snow-flake-and-mountain logo. Hakapaliita WRG and Hankook Optimo 4s are two that I'm aware of.

    I'm currently testing the Hankooks and so far with all the snow we've had (up to 15cm or 6 inches), my unscientific butt feel (sorry I'm too lazy and dumb to know how to do a real study) is they are just ever so slightly less grabby on acceleration, and about a foot or a foot-and-a-half longer when stopping....not difficult to compensate for by someone who didn't know what snow tires were a decade ago.

    But I did mount them on my summer rims so that if I ever lose confidence with them then I will swap in my xIce3 set and relegate them purely for summer.
     
  2. Mendel Leisk

    Mendel Leisk Senior Member

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    I'd agree, if you reverse the terms "all-seasons" and "all-weather". Nokian for example: refers to their moderately aggressive tread, softer compound tires with mountain/snowflake as the latter.

    And with any "winter" tire, they will loose more or less all advantage below 6/32" tread depth. Nokian provides two wear bars, recommends replacement at the first if they are acting as snow tires.
     
  3. CNYhybrid

    CNYhybrid Member

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    I ride on the Michelin X-Ice tires and find they are excellent in snow, quiet and comfortable. The mileage penalty is minimal.

    Posted via the PriusChat mobile app.
     
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  4. Absolu22

    Absolu22 Junior Member

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    It would be very hard to say how much is attributed only to the snow tires since the cold temperature is also a significant factor. With my previous cars, snow tires and cold temperature affected the fuel consumption with an overall average 10 MGP, which I find comparable numbers with the Prius now, on short trips. On longer trips, penalty is very minimal.
     
  5. Absolu22

    Absolu22 Junior Member

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    You would need the snowflake and mountain pictogram on tires, only if your vehicule is registered in Quebec.
    Winter Tech Information - How to Confirm a Winter Performer
     
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  6. GreenJuice

    GreenJuice Active Member

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    If he really was on stock tyres in that video, that performance was really quite reassuring.

    I say reassuring because it would apply to situations which were unplanned or unexpected. The video is less impressive if the vehicle (and driver) was completely prepared for the conditions; and indeed although the video showed many stuck vehicles, there were many others getting through too.

    I am unlikely to experience such driving conditions. The largest hazard for me would be other vehicles. For those more familiar with conditions like on that video, what would you think about applying a '2 second gap' from the vehicle in front?
     
  7. Tideland Prius

    Tideland Prius Moderator of the North
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    Depending on the surface of the road and the speed of travel, I would extend that 2 second gap. Compact wet snow doesn't offer much traction. Compact dry snow offers a bit more traction. I suspect London gets more of the wet snow than dry continental snow.
     
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  8. RCO

    RCO Senior Member

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    I have followed all his Prius uploads on Utube and he has always stipulated that the car is bog standard. However, many of the stationary vehicles in the video did not seem to be stuck to me, but just left on the road with hazard flashers going.

    Whenever driving with other traffic on snow or where ice may be present, I would strongly suggest you drive will within your own limits. You would be well advised to treat all other drivers with a healthy dollop of caution. You never know which one is going to be the crazy idiot, so just make sure it isn't you!
     
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  9. ATHiker

    ATHiker Senior Member

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    From my perspective, those conditions merited caution but would not cause me much concern regarding my stock tires.

    The roads were mostly plowed and he was driving slow. Visibility was great and the roads were not at all crowded with crazy folks in 4WD cars thinking normal speeds and gaps were appropriate.

    The people getting stuck looked to be driving over a piles of snow at the end of their driveway or in parking lots. That can be an issue if the snow comes down good while you are at your office, say. Good to have a collapsible shovel for that, or if you slide into a bank (not recommended).

    As far as slopes, near where I live ther is a short section of very steep road after a stop sign-- maybe 50 feet -- where my stock tires got me up just barely in similar conditions. I had a lot of wheel spin. Other cars in front of me were having trouble, too.

    I need to think about whether or not it's best to turn off traction control in those situations.

    I plan on going around in future storms rather than getting special tires-- I cannot think of any similar spots in my past 12 months of driving.
     
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  10. Mendel Leisk

    Mendel Leisk Senior Member

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    Have to admit Tideland woke me up on this. Anyway:

    Bad snow conditions and you are thinking "2 second rule"? What do I think? You are the hazard, lol.

    In ideal conditions, day-in-day-out, I'm applying the "4 second rule". For a couple of reasons:

    1. Safer, not only guarding against running into the guy ahead of you, but allow you to brake more gradually, for the too close follower.
    2. Good for mpg: allows you to stay off the brakes much more, just coast through the extra buffer.

    Whatever second rule aside, I find I have very little application for such rules, because I tend to abide by the speed limit, am very rarely pacing a car in front. What's going through a lot of drivers minds I think: "if I leave too big a a gap some one's going to butt into it, "cut me off". So? This is a bread line in Russia? You're in such a rush you need to be somewhere 2 seconds faster?
     
  11. GreenJuice

    GreenJuice Active Member

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    I couldn't recall when or where I first came across the 'rule', which is why I carefully carefully called it 'gap' in my post. I never mentioned rule and I certainly didn't invent it! The fact that it has changed to 'rule' in subsequent postings is probably a good sign that the concept is in existence out there and possibly well known.

    I should have been clearer why I asked about it. The video shows someone clearly testing a new vehicle in new conditions where you can see others having trouble. There is a segment where a line of vehicles appear to be equally spaced, moving well and smoothly, and I timed his gap at about 1.5 seconds. That is a gap I see frequently in motorway (highway) situations in the UK in perfect summer conditions! I wondered, therefore, whether this 'confidence' came from having a lot of familiarly in driving in snow, despite being in a new situation. I didn't specify this before because I did not want to appear critical of him. I was just curious what others with much snow experience would be doing.
     
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  12. Mendel Leisk

    Mendel Leisk Senior Member

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    Yeah, I get on a tear sometimes lol.
     
  13. MrMischief

    MrMischief Active Member

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    When I watched this video a day or two ago I remember there were a few times I thought he was going too fast for conditions. I seem to recall him hitting 40 mph in what appeared to be a residential area. That might be the limit there but it seemed too fast to me. There was also a point where he went by people trying to push a stuck car. People were out, a dog was running around and he didn't slow up for them. I think he was going 25, but again it was residential and it felt faster than what I would have been doing. Maybe he felt he needed to keep the momentum up. Maybe it's not as bad as it looked, cameras can make things look a bit different than they really are, but in general I found his video to not be helpful because all he showed me was on flat land you can get some speed up then hold that momentum where you probably shouldn't.
     
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  14. Mendel Leisk

    Mendel Leisk Senior Member

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    I recall once, driving our youngest to a doctor appointment when he was a toddler, over 30 years back, lol. It was snowing hard, and we just had all seasons, on an Accord. I see a woman waiting at a crosswalk, decide to do the right thing, stop for her.

    Didn't go so good. I started sliding, ended up almost in the crosswalk, turned about 30 degrees. The woman watched, made sure I was quite stopped, then walked across, kinda shaking her head I think.
     
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  15. RCO

    RCO Senior Member

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    I believe you're thinking of the two-chevron rule employed on some UK motorways. The large white Chevron's are spaced 40 metres apart. We are advised to keep at least two Chevron's visible between the vehicle we are following. See below....

    View topic - Motorway 'safe' distance chevrons
     
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  16. Tideland Prius

    Tideland Prius Moderator of the North
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    @GreenJuice @Mendel Leisk

    Just for reference, I had a situation once where I was travelling at 38mph/60km/h (I know.. I probably should've been going slower) on an empty A road (boulevard/main street. Speed limit is 60km/h) with compact snow (city leaves a minimum 5cm layer of snow on the road to reduce road damage) and some freezing rain to glaze the surface. The light turns yellow up ahead so I went full on ABS braking. I had Nokian Hakkapeliita R winter tires (full winters with the mountain & snowflake symbol. non-studded). It took me 90-100m (295-328 feet)* to come to a complete stop. I did stop before the line (about half a car's length), which was good as there was a semi trailer (HGV) waiting to turn left.

    I credit the car's stability and Nokian's tire design for the uneventful braking. The car tracked straight and true.


    But that's the worst road condition with one of the top rated winter tires. If I had all-seasons, I would've slid through the intersection.

    So yeah, depending on the condition of the road and the type of tire, you may want to rethink the distance needed.


    *Estimated based on Google street view from where I thought I started braking.



    Here's a video of braking on compact snow. The owner doesn't say if he has winter tires or not. The vehicle in the video was travelling faster at 76km/h and took more than 100m to brake (look at the odometer in the bottom right. Just said "firm braking".

     
    #36 Tideland Prius, Jan 13, 2017
    Last edited: Jan 13, 2017
  17. Mendel Leisk

    Mendel Leisk Senior Member

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    One more thing while you're hard braking for a red light: check the rear view. Summer, bare roads, it was a fish-tailing Harley I saw back there. I let off the brakes, rolled partially into the intersection so he could swerve by and blow through the red. Got the finger (from his girlfriend) for my troubles. I'm thinking maybe the guy at the controls understood the situation a bit better though.

    No collisions, no problems.
     
    #37 Mendel Leisk, Jan 13, 2017
    Last edited: Jan 13, 2017
  18. WilDavis

    WilDavis Senior Member

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    I do not know about the "2 second gap" - I learned to drive in the mid 1960s in the UK, and distinctly remember something about leaving a whole car's length for every 10mph you're travelling, and double that if it's wet.

    I've lived here on the top left-hand corner of this side of The Pond, since 1983 and so am quite familiar with driving in adverse conditions, and after experiencing over 30 years of New England winters I think I'd always choose good snow-tyres for winter, and something nice and quiet, and good in the wet for the rest of the year. IMNSHO, all-season tyres are "Jack of all trades, master of none", I realise it's convenient not to have to fiddle around changing tyres twice a year, but I bought a set of cheap, steel rims for the winter snows, and leave the summer tyres on the OEM alloy rims. Better for the rims, and far better for the tyres since the seals won't get damaged by the removal/refitting twice per year, and it's far easier to change wheels than tyres!
     
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  19. GreenJuice

    GreenJuice Active Member

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    Thank you. Actually I wasn't, as I've had some interesting discussions with friends over the years about the relative merits of chevrons vs seconds.

    Very interesting discussion on that link along similar lines, especially given that website of supposedly those interested or involved in the Advanced Driving qualification in the UK. Thank you.

    I will also come clean that I also had an experience that shook me up as a hot head in my 20s, several decades ago. Those of us who are here to tell a tale will know just how easy it is to misjudge speed and stopping distances, and we must be amongst a small cross section of the driving public who take in interest in these things.

    So I'm guessing that these guides, chevrons or seconds, were aimed at capturing the attention of a wider driving public. Is there a way of learning good judgement of speed and stopping distance, without having to learn the hard way?
     
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  20. WilDavis

    WilDavis Senior Member

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    One car-length for each 10mph of speed, and double that if it's raining, and even more if it's snowing. 60mph = 88ft/sec
     
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