I was told by the tire guy today that if only two new tires, they definitely should go on the back. Opinions? Facts?
Every major tire manufacturer states that, if only two new tires are purchased, they are to be mounted on the rear wheels of the vehicle.
Very few tire retailers would be willing to go against the word of the tire manufacturers who spend millions of dollars annually testing their tires on a variety of vehicles, under a variety of conditions.
Put the new tires on the rear wheels.
The typical FWD vehicle has about a 60:40 weight distribution. The front has about 50% more weight on the tires than the rear. Weight creates traction. Hence, with all else equal the front has a traction advantage anyway. Since the traction of a new tire is better than that of a worn tire, putting them on the front would make the problem worse and could result in the rear losing traction and spinning out under conditions where the front (the steering) still feels fully in control.
Tests on test tracks have proven the theory to be true.
It has always felt weird and counterintuitive to me too. It’s taken a long time for my gut to accept what my brain has been shown to be true. New tires belong on the back.
When you put them on the back, the vehicles handling characteristics are less likely to be disturbed than if you put them on the front…
Not accepting any liability will only capitulate what my shop teacher told me 30 years ago. Older tires are more prone to failure and if you had a preference of tires to fail, for control issues you would prefer the rear. In addition as many cars are front wheel drive it seems to make sense to me to have the best tread where you need the traction. The other side of the story from previous discussions in this forum is your rear end is more prone to sliding out with the worse tread on the rear. I can accept that logic but evidently do not push the limits enough for it to be a problem. Even in rwd vehicles I put the new tires on the front, and if they are so bad as to provide no traction it is time to replace them.
thank you, but then what happens when you get into snow with the least tread on the front, and a front wheel drive car?
Going in the snow isn’t the biggest concern, though. The biggest safety concern is oversteer (a rear-wheel skid), which will probably lead to a crash because it’s hard to recover from unless you’re a trained professional. Having less tread on a lighter rear end sets you up for exactly that.
The back; the main concern here is BRAKING and handling. Costco will not put new tires on the front, unless you also buy a new set for the rear. There are liability issues here too.
In my younger and more foolish days I regularly drove in excess of 100 mph on old tires and suffered a few blowouts at speed. The front wheel blowouts were very easy to control, just keep your foot lightly on the gas and let the friction of the blown tire slow the car to about 40 then brake and pull over. A rear tire will swerve you all over the road and you will be counter-steering all over the place to keep on the road and upright. I read a study many years ago that the most violent drop and swerve was between 55-60 mph. Above that speed centrifugal force of the rotating front tire kept you straight unless you were foolish enough to stomp on the brake.
After seeing the Police chase videos of people driving on sparking rims on all 4 tires I wonder if there is any truth to any philosophy, but will continue in my ignorant ways, thanks for tolerance.
Is not 60% of braking on the front tires? A common statistic? Liability does not necessarily mean common sense.
If you can’t go in snow, you may need a front end alignment. There isn’t much traction if the wheels are not pointing in the same direction, more or less.
Braking is the main reason Costco won’t put new tires on the front.
Generally, cars without ABS will start to skid in the front wheels first. When the wheels begin to slip/skid, their braking force is decreased, because STATIC coefficient of friction is lower than the DYNAMIC coefficient of friction. This means that if the rear begins to skid first, the rear end of the car may swing over to the front to create an uncontrollable situation. If the rear tires maintain their contact with the pavement during hard braking, the car will be manageable even if the front end starts to skid due to heavy braking.
Just ask yourself, do you want to hit that oncomming truck with your door or the front of the car?.
Not many accidents happen because you don’t have enough traction on the drive wheels. What does happen in the usual accident is that something has happened in front of you and you need to avoid it or stop before hitting it.
If you try stopping and you loose traction on the back wheels, you will find yourself looking where you came from and not where you are going. That is usually not a good way to avoid an accident. Keep the best tyres on the back for those life threatening situations and just put up with that occasional case where you might get stuck in the snow. You generally get a second chance if you get stuck in the snow.
Agree; the idea is that if there is too much front braking, the car will not stop straight. That’s the official line and that’s what Costco and others stick to. You may do as you wish, of course.