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MartinT

Our Cars in the Snow

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I would say that our cars are 'challenging' in the snow on summer tyres.  Had a real white knuckle ride into work yesterday with the car fishtailing down a country road doing 25mph in third gear and the inevitable white van up my backside.  The slightest touch of the throttle would lose rear traction.

I've decided that I'm going to put winter tyres on my stock wheels during summer when they're cheap, then swap them in each winter.  Any tips for a good winter tyre in stock size?

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From tips .. even if you reuse stock wheels, for winter tires i suggest getting narrower size, eg. 205/50 ir 205/55(if also a bit more ground clearance is wished, and not caring much about slight gearing change and a bit more sidewall flex). With narrower tire there is more mass per (smaller) contact patch area, so tire/(relatively light) car is less susceptible to aquaplane in snow slush, easier to push through tire to something grippier or for tire thread to hook into road surface/ice uneventies. I'd use stock or wider tires only if one almost never sees snow/ice.

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Well, I'll be getting some winter tyres soon.  The drive home last night was horrible, the M3 was slushy and I needed a push through the village and then got well and truly stuck in the snow on the single track country lane leading home.  No amount of second gear rocking could get it up the gentle incline.  Ended up abandoning it at the side close to home.  Going to have to assess whether I can move it tonight.  :(

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On 01/03/2018 at 10:49 AM, MartinT said:

Thanks - pricy, though.  Anyone tried Avon WV7 or Kumho WP71?

I focused on the bit where you said you wanted good winter tyres. For the bit of extra cost you get something well recommended and used by quite a lot of people on the 86/brz. My journey home last night would have been a total nightmare without them. It was quite entertaining though seeing the puzzled looks on other drivers of why they couldn't get anywhere but my 86 wasn't having any problems! 

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A GT86/BRZ on Primacy tyres is a daunting prospect in the snow! I'm not sure I've driven anything so unsuited to the conditions and that includes and Elise!

I've held off buying winter tyres for it and in reality may not get any before the end of this winter, but I'm convinced it's the right way forward for next winter, even if it doesn't snow a flake.

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It occurs to me that a special ECUTeK 'snow' map could help.  Rather like the mode 4 'safe' mode but with even less torque and slow responses.  Combined with winter tyres this could really help keep us on the road during testing conditions.

Would that be possible, @Mike@TD.co.uk ?  I'd be happy to lose mode 2 and just keep mode 3.

Mode 1: full power
Mode 2: auto-blip & flat foot shifting
Mode 3: fuel safe
Mode 4: snow

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33 minutes ago, MartinT said:

It occurs to me that a special ECUTeK 'snow' map could help.  Rather like the mode 4 'safe' mode but with even less torque and slow responses.  Combined with winter tyres this could really help keep us on the road during testing conditions.

Would that be possible, @Mike@TD.co.uk ?  I'd be happy to lose mode 2 and just keep mode 3.

Mode 1: full power
Mode 2: auto-blip & flat foot shifting
Mode 3: fuel safe
Mode 4: snow

@Mark@Abbey M/S offered a soft throttle map so it should be possible. 

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Why not use snow mode implemented with being more careful with driver inputs? :/

One can limit/retard performance with ECU tune, but FFS why if one can simply not floor accel in winter all the time?

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It was nothing to do with big inputs or flooring the accelerator.  I had so little grip (i.e. zero friction) that I applied the clutch gently in 2nd gear at idle and the wheels span.  I simply couldn't get any further without a tow.

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You are describing precisely the set of circumstances which motivated me to have some winter wheels. Fortunately I was stuck in a parking spot, rather than on the road. It doesn't take much camber or incline to complete befuddle a RWD car on ice with hard tyres. Those country lanes are the last roads to thaw :/

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Zero friction? Not getting further without a tow? If you posted that started thinking about winter tires, then very probably you are on stock primacies or other summer tires? THAT is a reason for zero friction in cold. So THAT is what should be fixed, not special ECU tune invented with weird limits to halve or more performance or do something alike. ECU tune may change engine output for acceleration (though why not be much gentler on gas instead or start at lower rpms/in 2nd gear?) but won't do a thing to braking or cornering grip.

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Have you actually read this thread?  How exactly can I be gentler than trying to move off in 2nd gear with no throttle (i.e. idle)?  Even rocking wouldn't move it, nor would two people helping by pushing.

I'm well aware that summer tyres are no good in the snow.  I got caught out, like a lot of other people in a level of snow which was unusual for the UK.  What I'm trying to do is be better prepared for next winter by getting winter tyres and also using the ECU in a gentler mode (the ECUTeK map is superbly responsive but not the best for snow).

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If it won't move with no throttle/idle, it won't move with proposed ECUtek ''Mode 4: snow' tune "with even less torque and slow responses", that was what i poked at. If grip is sufficient to drive but with less pushing, it makes little sense to move driver inputs with car controls to ecu tune, except paying more for tuner shop for them to make something with no real use. "Safe" tune if one happens to have available only bad quality fuel may see it's real life use, but some hypothetical tune with 75% of performance artificially taken out/limited and/or some very weird throttle mapping?

As for throttle mapping, it's often stock tune, that is worse in fine-control. I guess, it might be decision/hack of toyobaru to artificially make our little NA engines feel like if bigger engines, by mapping throttle in fashion for throttle opening much more then if it had been mapped linearly in first 1/3rd of gas pedal travel, robbing a bit fine control in low/mid rpms. But so do many tuners remap throttle to more linear one (at very least if asked, if they not do so by default already), so it's often so that rather aftermarket tunes are easier to fine-control engine power, then stock map. Providing more power/torque mid & top, but also finer control at idle-low rpms.

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Just to say, no-one got "caught out" by the snow. The predicted weather conditions were well advertised and if you failed to prepare for them by taking out your RWD sports car in the snow without winter tyres or a suitable "plan B" it's not the fault of your throttle map but more the person in the driver's seat.

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2 hours ago, Paul said:

Just to say, no-one got "caught out" by the snow. The predicted weather conditions were well advertised and if you failed to prepare for them by taking out your RWD sports car in the snow without winter tyres or a suitable "plan B" it's not the fault of your throttle map but more the person in the driver's seat.

My first Triumph TR7,  rwd sports car was brilliant on 175/70-13 S-rated summer tyres, so neither rwd nor sports car make for impossible driveability in winter.  It's modern, high-speed, wide (and even 'not-very-wide GT86) tyres that are the problem.

Interestingly, my next TR7 (yes, I liked the first one so much I had a second!) was absolutely terrible on snow.  It had the same make and model of tyre as the first, but 10mm wider (185/70) and H-rated (18 mph faster-rated) tyres.

If I buy winter tyres, I'll be buying the lowest speed rating my insurance company will accept.  Even S-rated are good for 112 mph - I won't be exceeding that on the road...

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There is also weight to consider.  My BMW 335d M-Sport Coupe was a pig in snow, but not quite as bad as the BRZ.  The big difference is weight, with about half a tonne between them.  The auto in manual '2' mode helped to apply torque very gently, too.  Getting rid of the runflats also helped, but that's another story.

Life is a learning experience, which some people seem to forget.  I will be buying suitable tyres (I'm currently looking seriously at Michelin CrossClimate + due to the large amount of motorway driving on my commute) and will use the soft map to aid low speed traction.

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MartinT: if there is no snow or temps under freezing temps expected this spring in forecast, i'd leave buying winter or all season tires to autumn. Half a year less to think where to store them and possibly half a year newer manufactured tires :)

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