Topic: Feature: Four winter tires – one icy intersection

[Autos_Editor]

Using a front-wheel drive Mazda CX-7 equipped with Continental ContiCrossContact wnter tires, ABS, traction control and stability control, author Michael Clark chose an icy intersection to evaluate braking, traction and stability performance in real-world conditions.

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[Gadabout]

I always like to see articles on winter driving.  People just don't seem to get it.  It's not like there is a lack of info out there.  Hopefully the enthusiast will share with their non-enthusiast friends.

I was at my local Dodge dealer late last fall, and as I stood at reception, I overheard a conversation at the parts counter.  The new owner of a Durango was inquiring about getting winter tires  The response from parts was "The vehicle is 4 wheel drive.  Winter tires are a bit of an overkill".  I was shocked that somebody in the industry was propagating this.  He also stood to make money (well not him personally) selling a new set of winter tires!

I did not think my opinion of Dodge service could get any lower.

[Toe]

"...the tire pressure monitoring system provided the expected low pressure warning."

Why is the warning expected?  Do you not have the sensors installed?  I have Hankook IPikes on OEM rims with OEM sensors, and the TPMS works just fine.  Just like the summer tires on the factory-installed rims and sensors.

[The Mighty Duck]

"...the tire pressure monitoring system provided the expected low pressure warning."

Why is the warning expected?  Do you not have the sensors installed?  I have Hankook IPikes on OEM rims with OEM sensors, and the TPMS works just fine.  Just like the summer tires on the factory-installed rims and sensors.

It's explained right there in the article:

"Speaking of systems, the tire pressure monitoring system provided the expected low pressure warning, due to the required use of the Conti’s in 225/65R17 sizing. The stock fitment of 215/70R17 is a bit of an oddball, though variations in tire size for winter use are not uncommon."

Of course you, running OEM sized-tires on OEM rims would not get a tire pressure warning. But once you change tire sizes, the system gets confused.

[HeliDriver]

^^ Still doesn't really explain anything to me.

Does the Mazda TPMS just compare relative wheel speeds, or does it have dedicated sensors in the wheels?

If it's the former, then why would having winter tires 1% smaller than stock make any difference? Assuming that all four corners have the same size tires, of course.

If it's the latter, and the light came on because there were no sensors installed in the wheels, well... why even bother to mention it in the article?

[BDR]

Most TPMS systems measure the pressure, so if all 4 tires are above or below the vehicle's specs, it will turn on the light, or if one tire is above or below the allowable range. Maybe the Conti's call for less or more pressure than the stock tires, thereby triggering the TPMS. The circumference of the Conti's are 2.2% smaller than the stock size (2276 mm vs 2303), so quite close to the original tires.

On another note, if a vehicle has 215 tires on it, it makes no sense to go to a wider winter tire, they will act like snowshoes do. You want the same size, or ideally, the next size down (in this case a 205/75, which does not exist). 215-70 17 is a bit of an oddball as stated, but I found a Bridgestone Blizzak in that size on the internet.