The "BMWs are crap in the snow because they're RWD" thing...
Discussion
kambites said:
smartie said:
couldn't you just drive it backwards everywhere to mimic FWD? 
Well you could, but it'd be ever worse because RWD is better than FWD in the snow. It's the weight distribution that screws up BMWs, not the fact that they are RWD. 
Stu R said:
Urban Sports said:
They are pants in the snow, I used my Astra all day today which was great.
The BMW is cack in the snow.
And it is because it is RWD.
My E38 7 series has been sterling in the snow. We've had shed loads of it over the last couple of weeks and I've yet to slide/wheelspin significantly / get stuck / crash / roll / die. I've navigated roads that many a front wheel drive car has got stuck on too. That's RWD, and I'm no more talented a driver than most other people. I just have decent tyres. The BMW is cack in the snow.
And it is because it is RWD.
however, my dad has just got an m sport 3 series and he won't stop moaning about how crap it is in the snow and drives my mum's daihatsu to work instead.
I suspect to factors at play here:
- type of tyre used - winter tyres make a noticeable difference to traction and braking in current conditions - current Volvo on winters has had no problem in piles of snow in Lancashire today
- weight over the driven wheels - which either helps or hinders traction - my old 911 on winter tyres used to be pretty good in snow
- ability of driver - to apply and control power and braking smoothly - and leave plenty of room for the conditions
- type of tyre used - winter tyres make a noticeable difference to traction and braking in current conditions - current Volvo on winters has had no problem in piles of snow in Lancashire today
- weight over the driven wheels - which either helps or hinders traction - my old 911 on winter tyres used to be pretty good in snow
- ability of driver - to apply and control power and braking smoothly - and leave plenty of room for the conditions
MarJay said:
I wonder what would happen if I put six breezeblocks in the boot of my Bimmer?
Not much because breeze blocks aren't very heavy. 
On principle though, it will help, as it will both move a higher proportion of the weight over the driven wheels, and reduce the tyre-width to weight ratio.
Judging by the idiots I saw in BMW's tonight the problem is a certain faction (NOT all!) of the people who buy BMW's and don't have a clue about the mechanics of driving!
One twunt tonight (3 series) kept going sideways and throttled harder to try and get out of it!
I've got 260 BHP going to my rear wheels and, yes, I can get it to spin on the ice/snow with the slightest over-application of throttle. Less throttle, more control!
Let's be careful out there!
One twunt tonight (3 series) kept going sideways and throttled harder to try and get out of it!
I've got 260 BHP going to my rear wheels and, yes, I can get it to spin on the ice/snow with the slightest over-application of throttle. Less throttle, more control!
Let's be careful out there!
As above, RWD is fine, in fact better then FWD (i'm assuming the biggest problem is people getting up hills, so that's where you need the most help)
The driving wheels are pointing up the hill all the time.
The weight transfer while going up the hill will put more weight over the back wheels.
However more important then either of those things is how the weight is distributed, you need the engine over the driven wheels, in fact in a perfect car the engine would be right at the end of the car that has driven wheels, to get the most weight over the driven wheels.
More important then either of the above is decent tyres and low weight.
The perfect 2WD snow car would have:
Decent tyres (thin, proper compound and tread), low weight, engine in the back, RWD. Like a beetle.
As has been said, BMW's have RWD going for them, but that's it. In evry other way they are poor snow cars. They are heavy, have wide tyres and the engine in the 'wrong' place. It doesn't really have as much to do with driver skill as people seem to be inferring, if you're stuck on a hill and don't have enough traction you aren't going anywhere I don't care how you drive.
Mid-engined cars are the same, in theory good weight balance but in practice the cars are not suited for other reasons.
The driving wheels are pointing up the hill all the time.
The weight transfer while going up the hill will put more weight over the back wheels.
However more important then either of those things is how the weight is distributed, you need the engine over the driven wheels, in fact in a perfect car the engine would be right at the end of the car that has driven wheels, to get the most weight over the driven wheels.
More important then either of the above is decent tyres and low weight.
The perfect 2WD snow car would have:
Decent tyres (thin, proper compound and tread), low weight, engine in the back, RWD. Like a beetle.
As has been said, BMW's have RWD going for them, but that's it. In evry other way they are poor snow cars. They are heavy, have wide tyres and the engine in the 'wrong' place. It doesn't really have as much to do with driver skill as people seem to be inferring, if you're stuck on a hill and don't have enough traction you aren't going anywhere I don't care how you drive.
Mid-engined cars are the same, in theory good weight balance but in practice the cars are not suited for other reasons.
I had an interesting experience recently in a 520D. We were coming back from a trip to south wales, back home to yorkshire and I was driving the bosses 520D, the snow suddenly hit us as we got back to Wetherby where I live. My place is at the top of quite a steep hill and I was a bit dubious we would make it, unfortunatly I couldn't get a run at it either, so I started at the bottom of this hill at a crawl. We were both absolutely astounded when this 520 literally crawled up the hill at about 1 MPH, the back wheels were slipping then locking one after the other on the TC, but the car never actualy stopped, it didn't make a jot of differance what I did with the throttle, it was almost on autopilot not revving above about 1000RPM.
The next morning I was full of confidence that I could get my 120D out of my steep drive in the same sort of conditions, trouble is I had to reverse and I quickly found out TC doesn't work backwards, I had no chance!.
Out of the BM, into a Fiat Panda... straight out no problems at all.
Incidently it's not all about rear wheel drive either. As has been said earlier fat summer tyres are as much to blame. I've got a rear wheel drive Alfa 2000 GTV which has nowhere near 50/50 distribution, more like 65-35, yet with Vredestein snow Tyres and an LSD it works great in the snow and is a barrel of laughs too
The next morning I was full of confidence that I could get my 120D out of my steep drive in the same sort of conditions, trouble is I had to reverse and I quickly found out TC doesn't work backwards, I had no chance!.
Out of the BM, into a Fiat Panda... straight out no problems at all.
Incidently it's not all about rear wheel drive either. As has been said earlier fat summer tyres are as much to blame. I've got a rear wheel drive Alfa 2000 GTV which has nowhere near 50/50 distribution, more like 65-35, yet with Vredestein snow Tyres and an LSD it works great in the snow and is a barrel of laughs too
kambites said:
deeen said:
the poor traction's not cos they're rwd, it's cos the weight is not over the driven wheels.
so mid engined should be fine?
Yup. Although you still have the problem that mid engined RWD cars tend to have rather wide tyres for their weight.so mid engined should be fine?
Still, the Elise has managed fine so far.
The winter tyres are the key crap i've been hearing this winter, by people who have never used them is a bit annoying.
I have a massively overtyred e36, 245 on the front, 275 on the rear, and it won't budge on snow. Winter tyres will make no difference to it at all, it'll still sit on top of the snow.
At one stage, i had some continental snowsport winter tyres in 255/40, and they were no better than any other 255/40s in snow as snow driving is purely on ground pressure, maybe a little better if you had massive clearing grooves like you'd find on off road tyres, but you won't find any off road mud tyres for a regular car unless you start buying rally stuff.
Winter tyres, are good for cold weather. If you track a car, or watch formila one etc, you can't fail to notice that warm rubber is grippier than cold rubber. The warmer it gets, the softer it gets, and the grippier it becomes.
Going the opposite way, cold weather hardens the rubber and it becomes less grippy, so they use a low temp resistant rubber with extra silicon that won't harden as much.
On a freezing cold road, this is what helps the grip, but it doesn't affect the snow performance.
You might now start thinking why other countries can handle the snow with winter tyres if they don't work.
Well, the reason is that the winter tyres are also thinner than the summer spec tyres.
Add the 2 factors together, and you'll cope far better, the soft rubber for cold clean roads, and thin tyres for snow, but just getting winter tyres in the usual size won't pull you up an icy hill.
kambites said:
MarJay said:
I wonder what would happen if I put six breezeblocks in the boot of my Bimmer?
Not much because breeze blocks aren't very heavy. On principle though, it will help, as it will both move a higher proportion of the weight over the driven wheels, and reduce the tyre-width to weight ratio.
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