Hi

I have a g37s coupe automatic.
As I am expecting snow later next month, i am looking for winter tires. Some told me that having two winter tires on the rear is all i need. Is that true? do i need to buy all four or can I just put two on the rear?

 

Well, logically, 2 is better than none, and 4 is better than 2. But 2 should help a lot, and the rear is the place to put them.

Since you don't have AWD, the front tires could still help with braking and front slide, but its the rear that usually fishtails anyway.

 

No, you will want all 4. Not having them on the front means braking and turning will be severely diminished, which are critical.

Buy all 4, if you're on a budget use eBay or craigslist. I got 4 Blizzaks with 10/32nds tread(~85-90% life) for $400 shipped. You need deep tread for snow tires to be effective, and blizzak has the most effective snow compound in the top 50% of the tire.

 

This! The last thing you want is rear traction without the ability to steer or brake. Snow tires make a big difference. Worth the extra money for four.

 

I agree with most here. You'll want all 4.

Also, AWD doesn't help with steering or braking traction to the front. It's mainly for extra "go" traction.

 

I'll have to disagree with that. AWD doesn't help with braking, but it sure helps with steering. In my truck, the first place I will notice that 4WD is turned off is on a curve, where I will be much more likely to lose traction, fishtail or spin. with all 4 wheels going, it keeps the vehicle tracking on course.

 

This is a little off topic, but here is a video showing car hydroplaning with worn rear tires vs worn front tires. Best tires always go on the back, regardless of 2WD, 4WD, or FWD.

 

Get all 4 ... and there is a difference between 4WD and AWD, not apples to apples.

 

You are talking 4WD but that's not the way AWD and Infiniti's implementation works. The front will only activate if you start to slip/spin the tires, other than that an Infiniti AWD will still push you through a turn unless you slip and it engages.

 

Whether its 4WD or AWD, it definitely helps with steering. AWD, maybe even more as the traction control reacts to keep you straight, compared with older 4WD systems that just turn without traction control.

If you ever had a vehicle where you could turn off AWD its easy to see the difference.

 

I see what you're saying, but poorly suited tires on the front will be more of a disadvantage to steering than a lack of AWD.

On these X models, the front axels don't have any power until there's slip detected, so most of the time, the car is RWD. My understanding is that the SNOW mode forces a 50/50 split front to rear only for the first 12-15mph, then it goes back to RWD only until there's slippage.

So yes, with 4WD, I can see there being better steering when in 4WD, but with ATTESA, I'm not sure there's much going on up front. Of course, I could be wrong about all of this...do your due diligence

My ultimate point was that tires that don't have grip, aren't going to suddenly have grip when you deliver power to them (or are they?). Thus, if you need snow tires, put them on all 4 wheels.

 

I don't know about that. AWD keeps the car straight when you lose traction, which is a huge benefit. Snow tires lose traction all the time, and without AWD, you are still spinning.
The thing is, most snow driving is really ice driving, where tread depth hardly matters, and the compound and lugs will add some bite, but traction is still poor.
I think your understanding is correct, except for the 12-15 mph part. AWD should continue as long as there is slip regardless of speed.
And the torque split can be anything between 0 and 50%. the computer is constantly adjusting it.

I've had 3 AWD cars in the last 5 years that work similarly. At first I had my doubts about them, in that they weren't true 4WD. But testing in empty parking lots and in real driving and I am convinced. I will trust my Infiniti AWD over my F150 4WD any day. The reaction time for the front wheels is hundredths of a second, and the computer is constantly adjusting torque to each wheel to keep you straight. It works great. It's actually pretty difficult to do donuts with AWD, even if you are trying.
BTW everyone should be doing testing in empty parking lots. It's important to know what it takes to make your car lose grip and how it reacts.

No doubt 4 is the best. But, I could see going with 2 for someone who wanted to save money and had AWD already. The Denver winter has been pretty icy so far, and my G has regular tires on it, yet it is doing fine. I think snow tires would be even better, but I don't need them. So therefore, 2 is an option.

 

"I think your understanding is correct, except for the 12-15 mph part. AWD should continue as long as there is slip regardless of speed.
And the torque split can be anything between 0 and 50%. the computer is constantly adjusting it."

The car automatically does a 50/50 split in snow mode REGARDLESS of slipping or not up to 12-15mph, after 12-15mph it goes into normal AWD mode. Plus it tampers back throttle response.

 

A complete set is what you should do of +4...
Snow..!! lucky wish it snowed here in LA.. without having to drive far..
lol..

 

Snow tires are the best investment you can make for winter driving. AWD, traction control, etc, etc... the GREATEST factor is the rubber used to contact the pavement. Use a good set (4) of snow tires and you will find yourself glued to the road.