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Based on past experiences of FWD Accord and 3GTL, FWD with winter tires feels more stable. However, if (knock on wood) the time comes to correct a serious error, you'll see how the SHAWD can get you out of trouble. For example, in the video you posted, had you "touched" the snow bank on the left, the FWD wouldn't be able to help you correct the mistake.
As far as Quebecers driving on winter tires... its not helping at all because they drive like idiots anyways (present company excluded). Other snowy areas in Canada to be careful driving because of idiot drivers is Markham and Brampton, (Toronto suburbs) and I am not even going to explain why.
Kind of a broad generalization concerning quebecers there buddy! Quebec is only up .3 deaths per 100k heads compared with the national average. Similar statistics as B.C with .6 deaths per 100k heads over the average. I'll add that Ontario's record is pretty impressive with -2deaths/100k heads compared with that same average value of 5.8 deaths/100k people. You can't come to the conclusion that mandatory winter tires are ineffective from those stats since Quebecers drive a lot further up north than people in Ontario do. Add the notoriously bad conditions of the roads in Qc and the differences in accidents stats can probably be explained.
All I'm trying to say is that every place has its idiots on the road. I'm sure an idiot equipped with winter tires still has a better chance of avoiding a crash than an idiot with shitty 4 seasons tires.
More weight over the driving wheels improves straight line traction big time.....Which is why fwd vehicles ,with their inherent weight bias over the driving wheels , are significantly better in accelerating on low traction surfaces, versus rwd....Assuming equal tires....
Putting 100 lbs of sandbags spread evenly in the trunk isnt going to turn your rwd car into a menace just waiting to spin tail first off the road......My experience has been that this sort of weight in the trunk has been a noticeable help in getting moving in the winter..in my rwd cars.
The beauty about physics is that it doesn't changed whether you believe one explanation or not. Your diagnosis of a symptom of a problem is incorrect and so your solution for that problem also is incorrect. Understand what weight over drive wheels do first then talk.
The compression of tires, increase of contact patch and increase in grip are all symptoms of having weight over drive tires.
The actual benefit is the increased contact patch. Increase your contact patch depending on the situation instead of creating more weight for the vehicle to deal with. By loading your car you decrease suspension compliance and create a situation for your vehicle to loose traction unpredictably.
Its closed minded bullshit like this which has led to people crashing because the false confidence created by a car that can accelerate fast is quickly nullified when you cannot stop or turn like the car should.
If you believe this bullshit that weight helps why not buy some 40lbs steelies to help with that process too. You'll be adding a shit to of weight to your drive wheels in that case. Just the switch to lighter wheels in the winter had made stopping, cornering, traction and acceleration much more predictable and controllable.
Instead of that BS learn how to be a better driver in the snow. Learn how to vector torque when you have an open diff and get a clue about how cars work before spreading bullshit like this!
A seemingly quick fix for one problem does not eliminate the issue. It causes a whole host of other problem. Again your diagnosis of the problem is flawed so your solution is flawed as well!
Last edited by d1sturb3d119; 10-19-2014 at 09:33 AM.
The beauty about physics is that it doesn't change whether you believe one explanation or not. Your diagnosis of the symptom of a problem is incorrect and your solution for that problem is also incorrect. Understand what weight over drive wheels do first then talk.
The compression of tires, increase of contact patch and increase in grip are all symptoms of having weight over drive tires.
The actual benefit is the increased contact patch. Increase your contact patch depending on the situation instead of creating more weight for the vehicle to deal with. By loading your car you decrease suspension compliance and create a situation for your vehicle to loose traction unpredictably.
Its closed minded bullshit like this which has led to people crashing because of the false confidence created by a car that can accelerate fast, which is then quickly nullified when you cannot stop or turn like the car should.
If you believe this bullshit that weight helps why not buy some 40lbs steelies to help with that process too. You'll be adding a shit to of weight to your drive wheels in that case. Just the switch to lighter wheels in the winter has made stopping, cornering, traction and acceleration much more predictable and controllable.
Instead of that BS, learn how to be a better driver in the snow. Learn how to vector torque when you have an open diff and get a clue about how cars work before spreading bullshit like this!
A seemingly quick fix for one problem does not eliminate the issue. It causes a whole host of other problem. Again your diagnosis of the problem is flawed so, your solution is flawed as well!
^^^^
No need to get personal there.....calm down. Ad hominem attacks are generally not received well here even if your points are sound (which they are).
^^^^
No need to get personal there.....calm down. Ad hominem attacks are generally not received well here even if your points are sound (which they are).
Sorry. I get pissed when there's no proof to backup a claim and its just statements likee, "no you're wrong because I do it this way...". A lot of mis-information gets spread and then we have a bunch of people driving stupid in bad conditions because awd is superior to fwd or rwd. Its a culture of mis-information again and again because someone told me something and I believed it.
Either you prove your point or it is not true. Everything I've tried to state is based on sound information. You have to do the research to find it. Vehicle dynamics have enough and more coverage and the information out there is vast! Search for it and understand it without arguing pointlessly when someone illustrates a blatant fact.
Apologies for getting rude! I just want proper info available so its a resource and not a forum of bad advice.
^^ Always nice to see people being able to admit they may have gone a bit harsh....I appreciate your mature and respectful response. It's what makes Acurazine a great place to hang out.
Could disturbed119 please refer to a scientifically conducted experiment to prove that adding weight to the back of a front engine rear drive vehicle does not help moving off traction. I am open to be convinced otherwise but every single web reference I can find and everyone I have spoken to state otherwise. Sure excess weight behind the axle will hinder braking, cornering, worse gas mileage etc. But this is all secondary of you can't get going or get up that hill. Or is everyone on the same page - adding weight helps initial traction, and hurts otherwise. And also concerning conventional wisdom to specify a narrower winter tire, which invariably happens, is in fact wrong.
No experiments. Just the math and understanding physics.
Mechanisms of Tire grip.
Friction
Mechanical Keying = The ability of a rubber compound to be able to "key" with the road surface at a microscopic level.
Adhesion
With regard to tires, although traction increases with load, it increases less linearly, and the coefficient of friction decreases with load. Meaning, it does not give you more traction but give you more friction with the road surface. A larger contact area reduces the load per unit area, resulting in more grip.
This is why weight give you the impression that you have more traction. There is a point of diminishing returns, such as weight and aerodynamic drag. In this case lets ignore those factors.
http://en.wikipedia.org/wiki/Tire_load_sensitivity
Now what else does weight achieve?
It causes more load which means that your tires dig into the snow packing the snow more densely and coupled with good aggressive tread your vehicle gains more traction. However this can change in different situation which is why your understanding of the area you're driving in is paramount.
Narrower tires create a different contact patch when compared to a wide tire. This contact patch stays exactly the same unless the diameter of the tire is changed.
Also the area of the contact patch does not affect the grip of the tire.
The things that do affect grip are the coefficient of friction of the rubber compound and the load on the tyre. As far as friction is concerned, the formula is relatively simple - F=uN, where F is the frictional force, N is the Normal force for the surfaces being pressed together and u is the coefficient of friction. In the case of a tyre, the Normal force basically stays the same - mass of the car multiplied by gravity. The coefficient of friction also remains unchanged because it's dependent on the two surfaces - in this case the road and the tyre's rubber.
The coefficient of friction is in part determined by the rubber compound's ability to 'key' with the road surface at a microscopic level.
This explains why you can slide in a corner if you change road surface - for example going from a rough road to a smooth road, or a road surface covered in rain and diesel (a motorcyclist's pet peeve). The slide happens because the coefficient of friction has changed.
Possible Scenarios Now the video only give information related to the width of a tire. This is the reason why slimmer tires are recommended in the winter. This type of scenario offers the best handling, braking, acceleration and control. However driving conditions change throughout the season and must be addressed accordingly. So if you are driving on roads which are not plowed yet with thick soft snow that needs to be compacted to generate traction, use slimmer tires with higher tire pressure to achieve the affect rather than increasing load.
On the other hand if you find yourself stuck, what that means is your tires are not compacting the snow enough to generate traction and considering gravity is at work all the time it means that your weight is being offset because your vehicle has bottomed out on the snow. The exact same thing that would happen if you loaded your car up. Same reason why driving offroad in the snow or even in sand requires the creation of a bigger contact patch. In that scenario you would have to approach the issue from another angle. In order to create thick enough of a contact patch to drive on, you can decrease your tire pressure. Without a beadlock it cannot be too low or you'll pop the bead off the wheel however you can go as low as 20 PSI to create the same effect. Then your vehicle will distribute its weight better allowing it to pack more snow in its footprint and allow you to drive out of deep snow by driving "over" it.
The reason you DO NOT want to practice low tire pressure for conventional driving is because roads are plowed. You typically have a good road surface to drive on. With low tire pressure you car is not going to be safe at higher speeds to corner or maneuver. It will however it is safer than driving with additional weight since there is no additional strain on the suspension or other components of the car to deal with the weight.
So based on road surface changes when people get stuck on roads that are not plowed it is because there is too much snow on the surface and the car does not have enough suspension travel to compact the snow. Weight helps but making it seem as though you are generating more traction however a reduction of tire pressure instead allows for better control and allows your car to create a bigger contact therefore distributing the weight over a wider area which is best to be used only in certain situations.
There is not one solution for everything. Each issue must be addressed differently. Snow tires for the most part make life easier. If you have a rwd vehicle keeping the tire pressure on the lower limit is fine and lowering it below that in really bad situations will work.
The actual benefit is the increased contact patch. Increase your contact patch depending on the situation instead of creating more weight for the vehicle to deal with. By loading your car you decrease suspension compliance and create a situation for your vehicle to loose traction unpredictably.
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*editted sentences
How exactly is 100 lbs of sandbags spread evenly on the trunk floor going to cause my vehicle to lose traction unpredictably?...
Using your logic, it would be safer to drive with the gas tank almost empty and remove the spare tire and jack, to improve suspension compliance.....
Also, using your logic , carrying passengers in the back seat and adding luggage to the trunk is a recipe for disaster....Since suspension compliance is decreased......
Now what else does weight achieve?
It causes more load which means that your tires dig into the snow packing the snow more densely and coupled with good aggressive tread your vehicle gains more traction.
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Gee, isnt that achieved by putting weight in the trunk of a rwd vehicle?
I agree that added weight in the back would help a rwd get moving. Wouldn't that added weight straight up murder you while turning though? I guess it wouldn't be too much of a problem on twisty roads since you won't give gas while turning on icy/snowy roads but on highway turns wouldn't the added weight in the back be bad? Losing traction while going 70 is one of the scariest thing ever.
100 lbs spread evenly in the trunk has never caused me any problems with this...The difference between a full tank of gas and running on fumes is close to that....
Im not talking about putting 200lbs of loose weights to roll around in the trunk....
Huh?...Is english your second language? ...."symptoms of" ??
Yes in fact it is. Got a problem with that? "A by product of." Better?
Originally Posted by kws6000
How exactly is 100 lbs of sandbags spread evenly on the trunk floor going to cause my vehicle to lose traction unpredictably?...
Using your logic, it would be safer to drive with the gas tank almost empty and remove the spare tire and jack, to improve suspension compliance.....
Also, using your logic , carrying passengers in the back seat and adding luggage to the trunk is a recipe for disaster....Since suspension compliance is decreased......
I guess I'm lucky to be alive....
Not using my logic. Conventional logic. Passengers and luggage in the car still alter how the vehicle performs. Depending on how you load your vehicle. If you use your vehicle like a taxi, that's great but the fact is what I have stated is how vehicular dynamics work. If you want to stop and move your vehicle effectively that is the way to do it.
Originally Posted by kws6000
Gee, isnt that achieved by putting weight in the trunk of a rwd vehicle?
"With regard to tires, although traction increases with load, it increases less linearly, and the coefficient of friction decreases with load."
What part of that statement don't you understand. Narrower tires will have the same effect and perform better than increasing weight. Read the damn post.
Originally Posted by kws6000
100 lbs spread evenly in the trunk has never caused me any problems with this...The difference between a full tank of gas and running on fumes is close to that....
Im not talking about putting 200lbs of loose weights to roll around in the trunk....
Actually gas weighs more than that. However gas is still a calculated amount of weight placed low in the vehicle to keep your center of gravity in check. Unless your trunk is in front of your rear axle you are still creating a load that is going to alter the handling of your vehicle.
Stop attacking me and instead ask a question. Works better in your favor. Don't agree? Then disprove it. Its idiots like you who fight against facts and figures provided to claim your way is the best way to do it because it "feels" better.
Also the links I've attached go over basic to advanced vehicular dynamics. Learn if you want, chew out my post some more if you want. Either way that does not change the facts. Goodluck to you!
So based on road surface changes when people get stuck on roads that are not plowed it is because there is too much snow on the surface and the car does not have enough suspension travel to compact the snow. Weight helps but making it seem as though you are generating more traction however a reduction of tire pressure instead allows for better control and allows your car to create a bigger contact therefore distributing the weight over a wider area which is best to be used only in certain situations.
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What does suspension travel have to do with compacting the snow?....
There is no seeming about it....more weight over the driving wheels does generate more traction....If this werent the case, why would fwd vehicles with more weight over the driving wheels, have better straight line traction than a rwd vehicle?
Lowering tire pressures to the point of making any meaningful difference in contact patch is totally impractical.....And potentially unsafe....
Actually gas weighs more than that. However gas is still a calculated amount of weight placed low in the vehicle to keep your center of gravity in check. Unless your trunk is in front of your rear axle you are still creating a load that is going to alter the handling of your vehicle.
Actually not...gas is about 6lbs/gallon....
Older vehicles had gas tanks behind the rear axle.....
Even in newer vehicles, adding 100lbs evenly over the trunk floor will not adversely affect handling or braking.
The OP wanted to know about a daily driver in winter conditions.
I hear what you are saying. And if your setting up a car to race then the physics become tantamount so you can setup the vehicle for optimum performance.
However we are talking about daily driving in Winter conditions.
A vehicle may have 400 lbs of extra weight one day and none the next. The road conditions change constantly. Yadda, yadda... So the vehicle is rarely setup ideally, because the conditions of the road and vehicle change constantly.
So one has to choose the best overall all setup for any given set of conditions, which is how the manufacture ships it(minus the winter tires). Sure all the changing variables alter the handling of the vehicle, but there are only so many practical things a person can do. As you point out good proper winter tires are the best thing a person can do for themselves.
The tires will exert a certain down force, measured in Psi This will be directly related to how much weight is being put over the tires and how wide the tires are (contact area).
The front wheels will have more force on them due to the engine weight. More force means better traction. A plethora of variables will be in play determining over all handling under ever changing conditions.
Hence the FWD is preferred over rear in winter conditions as it seems to handle the changing variables better. It will take you places any rear wheel drive would be stuck, guaranteed.
Having driven these conditions for a few years now (lol) in a lot of different vehicles I can attest that FWD is generally better in crappy winters weather conditions than RWD.
But your right in that a person should always be aware of how their vehicle is loaded under various conditions as the handling may change quite a bit!
100 lbs spread evenly in the trunk has never caused me any problems with this...The difference between a full tank of gas and running on fumes is close to that....
Im not talking about putting 200lbs of loose weights to roll around in the trunk....
According to what you said 6lbs per gallon would mean a fully filled tank is well over 100lbs, not close to that, well over that.
You want to go against what the physics says be my guest. You can argue all you want that YOU have never had problems. The fact is that this is bigger than you and your inability to grasp these concepts. Stop arguing with me and read. Don't care about that then that's great, go back to lugging garbage around in your trunk if it makes you feel like you have better traction. This is the same as people cutting springs to lower their cars. Does it work? Maybe. Is it safe or a good way to do it? No. People will always find a shortcut to solve a problem and because you haven't had an issue so far does not change the fact that the practice is not safe.
Thought we might get to a consensus here. In many winter conditions then... a slimmer tire will work better. But if you get stuck a fatter tire or lower pressures are better. Makes sense to me. I off road quite a lot - and airing down is obligatory - in fact below 20psi is where it starts making a difference and usually at 12 to 15psi you won't pop a bead - I never have but it does occasionally happen and you have to be prepared to get it back. We all carry compressors, or use converted a/c compressors. Bead lockers are awesome (3psi...) but illegal on road for some reason). Varying tire pressure on road isn't really practical anyway. And in most circumstances a slimmer tire is going to work better. FWD works far better than RWD as there is more weight on the driven wheels. RWD may need more weight in the back to get better traction. But not too much to avoid significantly hindering handling......and with good winter tires and judicious driving extra should not be necessary.....unless the front rear balance is too far off (2WD pick up trucks?...
10-19-2014, 09:21 AM
