Having driven a 160hp full time four wheel drive car for the last 13 years, I agree that in the real world (as distinct from "Top Gear" type driving) 4WD doesn't make any difference "if the back steps out" compared with a front wheel drive car. However, in a permanent 4wd car, by sharing the power of the engine through 4 wheels rather than 2, you are less likely to lose traction in the first place, and you are therfore far less likely to have the back step out. By adding 4WD to a car that is normally only rear wheel drive (eg Porsche 911) if loss of traction is detected at the rear, the electronice will transfer drive to the front, thus reducing the tendency for the rears to slip and so bring the car back under control.

The Yeti only puts significant power to the rear when the system detects slip at the front, so if the rear has "stepped out" the ESC will not normally add power to the rear, but will attempt to correct matters by braking one or more wheels.

If you enter a corner faster than the car's chassis can cope with, 2wd or 4wd, you will ultimately lose control and whilst the Yeti's electronics will try to sort it out, there comes a point where you will vist the scenery!

In just the same way, it doesn't matter whether you have 2wd or 4wd, you only have the same amount of rubber in contact with the road when you put the brakes on, so again a 4x4 will not get you out of trouble under braking.

Snow, or slippery off road conditions, present a different set of circumstances, as shown in the various film clips of Yeti's doing donuts. The Yeti's 4x4 system is primarily designed to allow you to maintain traction when off road or in adverse conditions (eg snow) by sharing the drive between all 4 wheels. If you press the loud pedal hard enough, you will overcome the ESC because the car simply develops more power than the braking effort that the electronics are designed to produce.

The bottom line: 2wd or 4wd, neither will get you out of trouble if you're not driving sensibly!

Edited 27 December, 201015 yr by speedsport

Having driven a 160hp full time four wheel drive car for the last 13 years, I agree that in the real world (as distinct from "Top Gear" type driving) 4WD doesn't make any difference "if the back steps out" compared with a front wheel drive car. However, in a permanent 4wd car, by sharing the power of the engine through 4 wheels rather than 2, you are less likely to lose traction in the first place, and you are therfore far less likely to have the back step out. By adding 4WD to a car that is normally only rear wheel drive (eg Porsche 911) if loss of traction is detected at the rear, the electronice will transfer drive to the front, thus reducing the tendency for the rears to slip and so bring the car back under control.

The Yeti only puts significant power to the rear when the system detects slip at the front, so if the rear has "stepped out" the ESC will not normally add power to the rear, but will attempt to correct matters by braking one or more wheels.

If you enter a corner faster than the car's chassis can cope with, 2wd or 4wd, you will ultimately lose control and whilst the Yeti's electronics will try to sort it out, there comes a point where you will vist the scenery!

In just the same way, it doesn't matter whether you have 2wd or 4wd, you only have the same amount of rubber in contact with the road when you put the brakes on, so again a 4x4 will not get you out of trouble under braking.

Snow, or slippery off road conditions, present a different set of circumstances, as shown in the various film clips of Yeti's doing donuts. The Yeti's 4x4 system is primarily designed to allow you to maintain traction when off road or in adverse conditions (eg snow) by sharing the drive between all 4 wheels. If you press the loud pedal hard enough, you will overcome the ESC because the car simply develops more power than the braking effort that the electronics are designed to produce.

The bottom line: 2wd or 4wd, neither will get you out of trouble if you're not driving sensibly!

well put, good post indeed

With regards to Quattro, yes I get it. My understanding of Quattro is a full time 4 wheel drive set up with a torque split between the front and rear of the vehicle at all times for maximum drivability and control. The same as my Range Rover has.

My understanding of the Yeti system is Front Wheel Drive until you get wheelspin, (as you say, pulling away) where is sends power to the rear. Which is not the same thing while cornering as power is going to the front until you spin. You have to lose grip before the 4x4 kicks in.

Are you saying they are the same?

If so, that would clear it up a bit As I said, I thought they were different.

Sorry for needing it spelled out... but I don't see them as the same.

Probably worth having a read of this thread, it explains it better than I can;- http://briskoda.net/forums/topic/184693-haldex-4-vs-torsen-diffquattro/

As I understand it, the Yeti IS full time 4x4, just that it only sends, and I'm no sure on the exact amount, but somewhere between 5 & 10% to the rear wheels ALL the time in normal driving conditions, but as Bahnstormer says, it reacts very quickly if it detects any speed difference between the front and rear axles and between wheels.

Mike

FWIW, and in some ways a reply to original post: I live somewhere that's hilly, cold, and this winter - like last - very snowy. There's a 1 in 7 hill up to the village. Gritting is patchy, and the nearest "main" road has been compacted snow and ice frequently, both this winter and last.

Having driven last winter on a 2wd Civic with 138 HP, which is similar footprint, tyre size and weight to a Golf TDi (i.e. not far off a Yeti 2wd) with non-winter tyres, then this winter (much worse so far) with initially 4wd 140 HP Yeti and summer tyres, then changed to winter tyres (same size; Goodyear SP Winter Sport) my experience is:

2wd+summer tyres+snow and ice = rubbish to dangerously uncontrollable.

4wd+summer tyres+snow+ice = generally quite good, but slips, particularly downhill, and control on very slidy stuff a bit sideways at times but 4wd system generally sorts you out; not got stuck, and not too worried about the journey. However....

4wd+winter tyres+snow+ice = definition of safety, how good 4wd can be in snow, and how vastly better winter tyres are for, erm, winter. Took very hilly compacted snow road home immediately after getting them fitted: two cars in 8 miles, both Defenders. No slips, no dodgy corners, fantastic uphill and cornering traction, and braking surreally good - almost like being on tarmac! Can't recommend strongly enough. Only slips so far have been in icing-sugar-like semi slush cornering when deliberately trying to find limits of grip, and Yeti sorts out these no bother. Intelligent 4wd more intelligent than me probably. Tried (when safe to do so) to get car very sideways: still not done it, car straightens up, keeps going forward. Total entertainment at times! Can't imagine 2wd + winter tyres managing the stuff we've had this year as well, but winter tyres are superb on a Yeti in this winter's snow.

I guess price premium determines whether you'd opt for 2wd or 4wd if you live rurally with likely snow and dodgy driving conditions. I'm sure the lower HP rated 4wd Yeti would do as well as the 140 HP.

Edited 28 December, 201015 yr by Northener

Good post Northener and well put

Regards,

TP

Good post Northener and well put

Regards,

TP

Couldn't have said it any better mesself.

The 4x4/4WD/Quattro helps a lot and reacts way quicker than you or I could! I'm talking milliseconds.

I used to have an Octavia vRS TDI and trying to do a quick getaway in the wet was almost impossible as it would easily result in wheelspin from the FWD. In my current Audi A5 quattro with the same CR170 engine a quick getaway in the wet is a piece of cake; the quattro (same system as on Yeti) works imperceptibly and I'm 'off the line' like a Cheetah.

Transferring this to traction in a corner, again the quattro works imperceptibly and gives superb traction throughout (normal laws of physics apply naturally), but you have the tractive power being put through 4 wheels, not 2, so the amount of power that can be applied before grip is lost is greater. Result? Quicker cornering.

Having thought about what I wrote last night (as above) I checked info on the Quattro system in my Audi A5 and found that it has the Torsen diff (mechanical) system as opposed to Yeti's Haldex (elctro-magnetically operated clutch) system.

Therefore some of my comments about the abilities of a 4WD/Quattro system have to be taken with a degree of caution as they are not based on the Haldex system as used in Yeti.

Explanation of the differences can be found in this thread; http://briskoda.net/forums/topic/184693-haldex-4-vs-torsen-diffquattro/

Edited 28 December, 201015 yr by bahnstormer vrs

The only time my 2WD 1.2 DSG with winter tyres slipped on an ice covered driveway with a slope to one side the interesting thing was that the car carried on in a straight line with no input from me and evident intervention from the electronics. I was expecting one end or the other to slip out of line.

How much this improved stability was down to the extra grip of the winter tyres and how much due to the ESP etc. I cannot tell.

My previous Octavia on summer tyres would probably have struggled more from my experience of driving on ice and snow earlier this year.

Another 2WD car (presumably with summer tyres) on the same driveway had developed an impressive amount of wheelspin and very little progress before gaining the roadway.

Thank goodness the weather justified my purchase of the winter wheels - if we had had the warmest winter for years with no cold spell I would have been in real trouble with SWMBO.

HAPPY NEW YEAR TO YOU ALL

My 2WD 1.2 Yeti with summer tyres was appalling - far worse than my old Octavia TDI with summers.

My Yeti with 4 winter tyres has been everything I ever wanted - one or two incidents of wheel slip but only in slush and very briefly. On ice and compacted snow and even up a fairly steep hill covered in 4" virgin snow no slip at all - just brilliant tyres - I have driven up hills where many other vehicles are wheel-spinning at the bottom!

Unless you intend to drive off real roads I don't believe 4WD is necessary.

I agree with mafuta entirely.

I was lucky enough to get 4 snowtrac 3s on steels to replace

my worse than hopeless premium contacts. That is, worse than hopeless

on snow! No traction, no cornering ability and hope for the best braking.

I knew the winters would be noticeably better because of all the reports

I'd read but could barely believe just how good they were. Mine is a

1.2 2wd yeti and the traction improvement was amazing. I would

seriously back a 2wd yeti on winters over a 4wd on summers for

traction.

As impressive as the newly found traction was, it was actually the

improvement in cornering ability and braking that was truly astonishing.

Tested on the many country lanes around Nuneaton on a variety of

Snow conditions I felt entirely comfortable travelling at normal speeds.

Hard White compact snow which is probably the worst condition

on summer Tyres actually proved the grippiest surface for the winters,

with the ability to corner at 'taking ya mum out for lunch' speeds

and brake harder than you would in normal driving. In short 'stunning'

I am just back from skiing in Northen Italy and I noticed that nearly all cars had winter tyres fitted. I saw two Yetis, both 4x4, both of which interestingly had winter tyres fitted. Temperatues were -3 in the day and -10 at night with compacted snow and ice on the roads. The winter tyres made a massive difference to any car even old 2WD Fiats... I would say that for most use cases 2WD with winter tyres is more than sufficient unless you really do go off road and in that scenario then 4WD would be of use.

I am just back from skiing in Northen Italy and I noticed that nearly all cars had winter tyres fitted. I saw two Yetis, both 4x4, both of which interestingly had winter tyres fitted. Temperatues were -3 in the day and -10 at night with compacted snow and ice on the roads. The winter tyres made a massive difference to any car even old 2WD Fiats... I would say that for most use cases 2WD with winter tyres is more than sufficient unless you really do go off road and in that scenario then 4WD would be of use.

It seems that for general road use that winter tyres on a 2 wheel drive would be sufficient in all but the very worst conditions. The real question I have now is whether it is even worth paying the premium for a Yeti or whether I should buy a more conventional fwd hatch with a more refined ride and drive. A Golf Match1.4 Tsi + DSG is a lot cheaper than a Yeti (which is not even available with the 1.4 TSI + DSG combination) and the new Focus due in March has had very good pre-release reviews.

Decisions, Decisions!!

It seems that for general road use that winter tyres on a 2 wheel drive would be sufficient in all but the very worst conditions. The real question I have now is whether it is even worth paying the premium for a Yeti or whether I should buy a more conventional fwd hatch with a more refined ride and drive. A Golf Match1.4 Tsi + DSG is a lot cheaper than a Yeti (which is not even available with the 1.4 TSI + DSG combination) and the new Focus due in March has had very good pre-release reviews.

Decisions, Decisions!!

Sorry - I missed a good point in that I could get another Octy Estate with the 1.4 TSI + DSG option to replace the '55 2.0 TDi + DSG I have currently, then buy a spare set of wheels with winter tyres!!

It seems that for general road use that winter tyres on a 2 wheel drive would be sufficient in all but the very worst conditions. The real question I have now is whether it is even worth paying the premium for a Yeti or whether I should buy a more conventional fwd hatch with a more refined ride and drive. A Golf Match1.4 Tsi + DSG is a lot cheaper than a Yeti (which is not even available with the 1.4 TSI + DSG combination) and the new Focus due in March has had very good pre-release reviews.

Decisions, Decisions!!

Yes two wheel drive with winter boots would be ok but the extra ground clearance the yeti would give you is worth the extra.

deep fresh snow low car on winter boots stuck

yeti keep moving

Having run 2wd and 4x4 cars on winters I'd still go for 4x4 particularly with Haldex; appears to work extremely well and worth paying a premium for. On top of this is the better ground clearance and high driving position yet get with the Yeti.

TP

Having run 2wd and 4x4 cars on winters I'd still go for 4x4 particularly with Haldex; appears to work extremely well and worth paying a premium for. On top of this is the better ground clearance and high driving position yet get with the Yeti.

TP

+1

Mike

I would just like to add my tuppence worth the the winter tyres debate.

I have a Yeti 4x4 140 Tdi on summer tyres. I also have a Suzuki Swift 1.3 DDis with winter tyres only on the front ( a result of one of the rears being damaged on changeover this winter). I live right up here in the north of Scotland where snow and ice covered roads have been more or less constant since november. I can honestly say that the little Suzuki with only ABS , none of the fancy 4wd, esr , etc etc is just as capable on snowy roads as the Yeti. Having had Subarus for years , my conclusions are that winter tyres are in fact just as effective as 4 wd on summers. Saving up for winters for the Yeti ,that should be really good.

Finally to the chap who says winters on the front only are unsafe - get the lead out of your boots !!

Finally to the chap who says winters on the front only are unsafe - get the lead out of your boots !!

Its nothing to with that, with winters on the front and summer on the back, the back wheels can slide out on a bend long before the fronts will causing massive oversteer or a spin. Similarly the car can quickly swap ends when you apply the brakes. You may be getting the traction advantage with winters only on the front but the handling and braking is less predictable.

Look at the links to vehicle tests with mismatched wheels even at very low speeds on bends.

Finally to the chap who says winters on the front only are unsafe - get the lead out of your boots !!

I liked that comment

Finally to the chap who says winters on the front only are unsafe - get the lead out of your boots !!

I'd like to know why you think this is materially different to having radial tyres on the front and crossply tyres on the rear.

I'd like to know why you think this is materially different to having radial tyres on the front and crossply tyres on the rear.

Gareth, have you watched the videos?

Gareth, have you watched the videos?

From reading Gareth's comment I think that he is pro winters all round and that it is some others that feel mismatched tyres are fine. The problem is trying to convince anyone that 'their' way is incorrect when 'they've been doing it for years without a problem'. Trouble is it only takes the once. I can easily see a situation where those winter tyres on the front lull a driver into a false sense of security and they approach a bend little too fast, arse overtakes front and you mount a kerb where mother and toddler were walking. Yes, I know that is extreme but as I say, it only takes the once.

more snow here today...and low and behold mine was the only non 4x4 car to get up our street'...all the others failed less than half way and promptly slid to the bottom....i had to drive 12 miles to fetch my daughter, and on arrival back it promptly drove straight up with no slipping/flashing lights etc..fwd and goodyear exceallance

2 Wheel drive or 4 wheel drive? Unless you have a diff lock, you will have 1 or 2 wheels driving.....