Winter tyres. Discuss.

[flyingscot68]

I now have winters on the mighty ST, so combined with its fairly light weight (1088kgs) it will hopefully be fairly reasonable in the poor conditions. Already noticed a big improvement in traction over the warn summer tyres that I was using until recently.

Lightweight counts against you in these conditions.
Heavier car with narrow tyres works best.


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[Dominic]

I now have winters on the mighty ST, so combined with its fairly light weight (1088kgs) it will hopefully be fairly reasonable in the poor conditions. Already noticed a big improvement in traction over the warn summer tyres that I was using until recently.

Lightweight counts against you in these conditions.
Heavier car with narrow tyres works best.


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I would dissagree; more weight is more difficult to get up hills, more weight is more difficult to slow going down hills. Momentum is everything in bad conditions - your best friend and worst enemy. Agree that narrow tyres work better though

[rossybee]

Why? Wide tyres, rear wheel drive and auto is not a good combination for snow. On winter tyres they would be decent enough. I bought a couple of snow sox this year as I'd just bought new tyres so hopefully this'll stop me from getting stuck on mild slopes like a lot do.

Ahhhhh you misinterpreted me Donald.....I meant I was amazed at the fact they still venture out....this chap in particular got approximately 20 feet out of his garage, which is on one of the canny slopes on the south side of the Law, just up from Dudhope Park.....the getting stuck bit was no surprise lol

Meh, my old panzer E wagon wore Conti winters all year and was only stopped when the ride height became a problem.

This chap weren't on winters

[rossybee]

I now have winters on the mighty ST, so combined with its fairly light weight (1088kgs) it will hopefully be fairly reasonable in the poor conditions. Already noticed a big improvement in traction over the warn summer tyres that I was using until recently.

Lightweight counts against you in these conditions.
Heavier car with narrow tyres works best.


Sent from somewhere using something

I would dissagree; more weight is more difficult to get up hills, more weight is more difficult to slow going down hills. Momentum is everything in bad conditions - your best friend and worst enemy. Agree that narrow tyres work better though

Yip, lightweight has less inertia

[flyingscot68]

The weight pushes the narrow tyres through the crap and onto the road surface giving you grip.
Grip is everything in the snow, lightweight counts for nothing If you've no grip.
Unless you're planning to visit some Icelandic glaciers, plenty of weight and narrow tyres over the driving wheels would be my preference.


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[j2 lot]

I remember when I was a nipper, my old man putting bags of sand and the like in the boot of his old MK 1 Escort when it was snowy and telling us to bounce on the back seat when we started to slow up

[robin]

From a static perspective, weight is irrelevant - the coefficient of friction means that for a given tyre size the amount of force you can develop from the tyre is proportional to the weight of the car; so you double the weight AND you double the force available from the tyres.

From a dynamic perspective the friction argument is the same (in this context dynamic means wheels locked, car moving; static means wheels turning, car moving). Whilst the available friction is less, it's still proportional to the weight of the car.

As we all know F=mA (Force = mass x acceleration). Your ability to start/stop/change direction is a function of the force you can generate (more is better) divided by the mass (aka weight in this context) - so for any given tyre, the weight is irrelevant.

Inertia = mass (in linear terms - ignore what happens when you're spinning) and so is subject to force in the same way as mass is.

Momentum is proportional to mass and change in momentum is proportional to force - so if you double the mass, you double the momentum but you also double the force available due to friction so the two cancel out and you're back where you started.

Where weight does come into play is the pressure on the tyre surface and how snow reacts to that - double the weight and you'll double the pressure; this increase in pressure will cause the snow to compact more and thus you get to use more of the side wall (and tread blocks) in guiding the car.

Alternately the more pressure on the tyre surface, the more likely you are to sink down to the ice (or even create it - when you compress snow you get ice) and be unable to generate enough friction to push the tyre forward into the wall of snow.

Thus there is no right answer, but if I had to choose I would choose the car with the better tyres regardless of weight!

Cheers,
Robin

[flyingscot68]

From a real world perspective, that's all bollocks.



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[campbell]

I have great tyres on my MINI Clubman. Seems I may be needing them in the morning.

[robin]

From a real world perspective, that's all bollocks.



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No, it's not, though I agree you can do a more complex analysis, I think 90% of the time mass will cancel out.

In case you could not be bothered to read it properly, the summary is that it is the tyres that matter more than the weight. That's just as well in my case

Cheers,
Robin

[rossybee]

That's just as well in my case

Cheers,
Robin

Just get a new pair of grippy-soled boots?

[Corranga]

From a real world perspective, that's all bollocks.



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No, it's not, though I agree you can do a more complex analysis, I think 90% of the time mass will cancel out.

In case you could not be bothered to read it properly, the summary is that it is the tyres that matter more than the weight. That's just as well in my case

Cheers,
Robin

From a real world perspective, a lightweight car is the better option as when you get stuck, there is less to push, and it's easier to add a higher proportion of weight above the driven wheels (ie by sitting on the wing, or in the boot)

[Corranga]

...also apparently a Toyota Auris isn't a good choice...

http://www.thecourier.co.uk/news/local/ ... s-1.784823

[rossybee]

Saw that in yesterdays creepy-crawlie run to drop Mrs Bee in the town centre...couldn't imagine why anyone would try the Conshie in such slippy conditions but hey, there's always one (or more, in this instance)

My theory of lightness took on some weight (pun totally intended) this morning...did a dummy run out of the garage and up the wee brae in wife's Citigo, no real issues, other than some slight flickering of the TC on the dash. Did the same ten minutes later, with wife and two kids on board (kids are now adult-sized) and it struggled far more, with wheel slippage etc...

...thus proof the extra mass which was trying to be moved had more of an effect to the same mass over the driven wheels....

[Dominic]

My theory of lightness took on some weight (pun totally intended) this morning...did a dummy run out of the garage and up the wee brae in wife's Citigo, no real issues, other than some slight flickering of the TC on the dash. Did the same ten minutes later, with wife and two kids on board (kids are now adult-sized) and it struggled far more, with wheel slippage etc...

...thus proof the extra mass which was trying to be moved had more of an effect to the same mass over the driven wheels....