>I've got to put some new winter tires on my 190E .... it uses 185/65/15
>tires .... however, been thinking of using 195/65/15 because these will also
>be good on my 300E in future.... will the slightly wider tires be OK on the
>190E? or would the slightly narrower tires be better on the 300E later?

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>>I've got to put some new winter tires on my 190E .... it uses 185/65/15
>>tires .... however, been thinking of using 195/65/15 because these will also
[quoted text clipped - 6 lines]
>The 10 mm bewteeen 185/65-15 and 195/65-15 isn't going to make much difference
>though. Go for it.
OK, I will - thanks. re narrower being better in snow.... still a bit
uncertain though. Narrower (more force/area) will 'cut' through snow better
OTOH, surely Wider tires may provide more friction on ice (I'm guessing that
the friction coefficient may be greater - ie. coeff x weight = Frict Force)
.....maybe it's just wishful thinking.
cheers, guenter
Tiger - 09 Nov 2006 21:03 GMT
If you buy the Nokian Snow tires... you don't have to go narrower... they
are that awesome. I think stock size of older MBs is narrow enough.
I prefer to go wider for other three seasons.
Richard Sexton - 09 Nov 2006 22:55 GMT
>If you buy the Nokian Snow tires... you don't have to go narrower... they
>are that awesome. I think stock size of older MBs is narrow enough.
>
>I prefer to go wider for other three seasons.
Agreed. Blizzaks are almost as good, they're just noisier on dry roads.

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1970 280SE, 72 280SE | Home pages: http://rs79.vrx.net
633CSi 250SE/C 300SD | http://aquaria.net http://killi.net
Richard Sexton - 09 Nov 2006 22:54 GMT
>>The 10 mm bewteeen 185/65-15 and 195/65-15 isn't going to make much difference
>>though. Go for it.
[quoted text clipped - 4 lines]
>the friction coefficient may be greater - ie. coeff x weight = Frict Force)
>.....maybe it's just wishful thinking.
Well, that's the theory anyway. I have 235/55-16 Blizzak on my 126
way-stupid wide and they stull cut through snow just fine - as long
as it was fresh powder. They were rock solid then but on wet slushy
stuff not as good. And in the rain not much better than stock MXV4s
(which are particularly good in the wet)

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Guenter Scholz - 10 Nov 2006 18:06 GMT
>Well, that's the theory anyway. I have 235/55-16 Blizzak on my 126
>way-stupid wide and they stull cut through snow just fine - as long
>as it was fresh powder. They were rock solid then but on wet slushy
>stuff not as good. And in the rain not much better than stock MXV4s
>(which are particularly good in the wet)
I am a bit suprised at your observations... the wider tire should
have (from theory) better traction on slushy/wet stuff I would have thought
because there are more 'sipes' (spelling?) exposed. Isn't it these sipes
that provide the friction - ie traction in slush/ice etc - and the more sipes
the larger the friction coefficient between tires and road.
cheers, guenter
Tom Plunket - 10 Nov 2006 18:29 GMT
> OK, I will - thanks. re narrower being better in snow.... still a bit
> uncertain though. Narrower (more force/area) will 'cut' through snow better
> OTOH, surely Wider tires may provide more friction on ice (I'm guessing that
> the friction coefficient may be greater - ie. coeff x weight = Frict Force)
> .....maybe it's just wishful thinking.
You want narrower tires all around for winter driving.
You don't get more traction on ice from wider tires, because the vehicle
still weighs the same. In effect, you get less traction because the
weight of the vehicle is spread over a wider area, therefore the "weight
per square inch" or whatever is less.
I ran the Michelin non-performance studless (Artic Alpin or something
like that) for a couple of winters and they seemed fine. I didn't wreck
my car, at least. ;)
> I am a bit suprised at your observations... the wider tire should
> have (from theory) better traction on slushy/wet stuff I would have thought
> because there are more 'sipes' (spelling?) exposed. Isn't it these sipes
> that provide the friction - ie traction in slush/ice etc - and the more sipes
> the larger the friction coefficient between tires and road.
The sipes provide traction by changing the surface of the tire to
effectively reduce the surface area of the tire.
-tom!
--
Guenter Scholz - 10 Nov 2006 18:47 GMT
>> I am a bit suprised at your observations... the wider tire should
>> have (from theory) better traction on slushy/wet stuff I would have thought
[quoted text clipped - 4 lines]
>The sipes provide traction by changing the surface of the tire to
>effectively reduce the surface area of the tire.
Aha! didn't know that .... thought that these 'sipes' were kind of like
little 'suction cups' ... sort of. Can't quite see though why these squiggly
'cuts' in the rubber - which the sipes essentially are - would effectively
reduce the tires surface area..... would have thought the opposite in fact.
cheers, guenter
Tom Plunket - 10 Nov 2006 19:23 GMT
> Aha! didn't know that .... thought that these 'sipes' were kind of like
> little 'suction cups' ... sort of. Can't quite see though why these squiggly
> 'cuts' in the rubber - which the sipes essentially are - would effectively
> reduce the tires surface area..... would have thought the opposite in fact.
Well, it depends on the road surface, but if we're talking about ice,
then assume it's "perfectly smooth". Then realize that the sipes allow
the tire tread to "flex", so the tire surface isn't smooth anymore, but
in profile looks more like a saw. At this point, the contact between
the saw-like tire tread and the perfectly-smooth ice has very little
contact area, so the tires can actually cut in.
Again, though, if you have more surface on the tire to begin with, the
number of sipes that need to cut in is increased, and each of them
individually gets less weight, so they don't cut in as well.
I hope that makes some sense.
-tom!
--
Tiger - 20 Nov 2006 21:42 GMT
Wrong on all counts. The sipes are designed to capture the snow or water...
Traction comes from snow on snow... so by trapping snow in the sipes, it
will grab onto snow. On ice, because tires tend to be warmer... it suck the
water from surface and enable traction... sort of like tongue on fire
hydrant.
Guenter Scholz - 20 Nov 2006 22:21 GMT
>Wrong on all counts. The sipes are designed to capture the snow or water...
>Traction comes from snow on snow... so by trapping snow in the sipes, it
>will grab onto snow. On ice, because tires tend to be warmer... it suck the
>water from surface and enable traction... sort of like tongue on fire
>hydrant.
Tiger, makes sense. But that would mean that tires with more sipes, ie
wider tires, would be better in snow/ice. But isn't it commonly accepted
that winter tires should be narrower?
still confused
cheers, guenter
Tom Plunket - 21 Nov 2006 03:01 GMT
> Wrong on all counts. The sipes are designed to capture the snow or water...
> Traction comes from snow on snow...
Huh,
http://www.websitecontentarticles.com/Article/Snow-Tires---A-Canadian-Must-Have/9613
http://www.generaltire.com/generator/www/us/en/generaltire/automobile/general/ne
ws/conti_launch_052005_en.html
http://www.carbibles.com/tyre_bible.html
seem to indicate otherwise. None of the pages that popped up in my
google search suggested that "snow on snow" was the way to create
traction.
-tom!
--
Chas Hurst - 21 Nov 2006 05:16 GMT
>> Wrong on all counts. The sipes are designed to capture the snow or
>> water...
[quoted text clipped - 13 lines]
>
> -tom!
The open tread on snow tires traps snow. Snow has greater traction on snow
than rubber. Sipes do not capture snow or water.