Strange winter tire design? Less tread depth on shoulders?

[IndyIan]

Canadian tire had a pretty decent sale on their house brand "premium" winter tire, they review pretty good, look like a reasonable tread pattern and lots of siping, so I order a set online before the sale ends.
When I picked them up I thought the tread depth looked a bit odd, but overall a very well made tire. But when I got home I had to measure the tread depth and the middle of the tire is 11/32, but tapers down to just over 9/32 on both the shoulders? And all 4 are identical, so its consistent at least...
Anyone ever seen any new tire with that feature?
I haven't mounted them and can return hassle free for 90 days, which I probably will do as I can't see how starting at 9/32 on the shoulders helps the tire work better?
They are MotoMaster Winter Edge made by Cooper

 

[Vercingetorix]

The Continental VancoFourSeasons I had had less tread depth on the shoulders than in the middle.

 

[hemitom]

I wonder if that is done to create less of a squirmy feel to the steering when the tire is new ? .

 

[atikovi]

It's so when you air them down for better traction they will wear evenly.

 

[Mainia]

My guess it is done to have a sudo "thinner tire" as the center tread will have a smaller contact patch and more pounds per square inch of load pressure on slippery snow and ice. While cornering you will have a thinner contact patch, that is distributed more evenly then a wide tire lifting the inside contact patch area in a linear wedge shape. This new tire will distribute the load across a more evenly loaded contact patch that takes in account camber and body roll in this design.

 

[eljefino]

That's pretty common with tires, not just winter ones.

You may also find that the horizontal tread cuts don't go as deep as the circumferential ones. It helps reduce tread squirm. An added bonus (for the tire maker) is that once your tire wears to 4/32 or so it looks very "plain jane", like it's bald, or just cheap, with all the fancy stuff worn off.

PS those do indeed look just like my wife's Cooper snows which work quite well.

 

[Kalle.J]

Mount them on a rim first? I would not worry about it. Looks decent for a budget.

 

[Rand]

not quite normal but as designed surely.

I have had plenty of new tires that were shallower at the edges than the rain grooves.

 

[supton]

Hottest day of the year here, and we’re buying snow tires. Must be on BITOG… (I can’t say much, I bought a set last weekend)

Nice looking tire. If the price is right, why not try? If you keep records on tire life in general, maybe you can determine if they do last less, or the same?

 

[UG_Passat]

Hottest day of the year here, and we’re buying snow tires. Must be on BITOG… (I can’t say much, I bought a set last weekend)

Nice looking tire. If the price is right, why not try? If you keep records on tire life in general, maybe you can determine if they do last less, or the same?

Salt Lake City area already got a dusting of snow on Monday

 

[IndyIan]

That's pretty common with tires, not just winter ones.

You may also find that the horizontal tread cuts don't go as deep as the circumferential ones. It helps reduce tread squirm. An added bonus (for the tire maker) is that once your tire wears to 4/32 or so it looks very "plain jane", like it's bald, or just cheap, with all the fancy stuff worn off.

PS those do indeed look just like my wife's Cooper snows which work quite well.

Its a new one to me, every tire I've had new has always had equal tread depth in the circumferential grooves?
Well that's good to hear they work well, they will be $95 each with installation, so not bad for a decent tire these days it seems... One of the local used tire guys was shooting for $180 for just a pair of "new" winter tires manufactured in 2009 so I figured these would be better bet!

 

[userfriendly]

My guess it is done to have a sudo "thinner tire" as the center tread will have a smaller contact patch and more pounds per square inch of load pressure on slippery snow and ice. While cornering you will have a thinner contact patch, that is distributed more evenly then a wide tire lifting the inside contact patch area in a linear wedge shape. This new tire will distribute the load across a more evenly loaded contact patch that takes in account camber and body roll in this design.

It's so when you air them down for better traction they will wear evenly.

It has to do with the speed rating of the tire.
Nitto Tire has a video on the subject.

My daughter has those tires in 235/55/20 for her 2022 Acadia.
The price was right and we got bonus Canadian Tire money.
West coast car, the tires work well in heavy rain and corner better than the stock tires.

 

[CapriRacer]

It has to do with the speed rating of the tire.
Nitto Tire has a video on the subject.

Could you provide a link to that video? Not only couldn't I find it, but I'm having difficulty believing that is the reason.

 

[userfriendly]

Could you provide a link to that video? Not only couldn't I find it, but I'm having difficulty believing that is the reason.

I’ll try and find it. It wasn’t just about tread depth, although you won’t likely find a V speed rated tire with a 19/32” tread, but more about the shape of tires as the speed ratings go higher.
The higher speed tires had more rounded shoulder profiles than say a Q-rated winter light truck tire.

I think the YouTube video is called

Nitto Tire Presents: Winter Tire Technology

 

[IndyIan]

I’ll try and find it. It wasn’t just about tread depth, although you won’t likely find a V speed rated tire with a 19/32” tread, but more about the shape of tires as the speed ratings go higher.
The higher speed tires had more rounded shoulder profiles than say a Q-rated winter light truck tire.

I tried to find it too, but no luck.
These are T rated basic snow tires, and with partially sharp edge should profile, which I look for in a snow tire. On summer tires, a nice rounded shoulder profile is ideal for grip and wear, but even on those I've never noticed actually shallower tread blocks on the outside? Like at the first circumferential groove from the shoulder. Always were equal or close enough I didn't notice. On these I could see something was odd to me right away.

 

[CKN]

Salt Lake City area already got a dusting of snow on Monday

The mountains above Salt Lake City got a dusting of snow......at 10,000 feet.

 

[CapriRacer]

I’ll try and find it. It wasn’t just about tread depth, although you won’t likely find a V speed rated tire with a 19/32” tread, but more about the shape of tires as the speed ratings go higher.
The higher speed tires had more rounded shoulder profiles than say a Q-rated winter light truck tire.

I think the YouTube video is called

Nitto Tire Presents: Winter Tire Technology

You have the name exactly right. But it doesn't make a connection between tread depth and speed rating. It does say that a rounder tire performs better in certain conditions and presumably the difference on tread depth could be used to get that. Personally I think there are better ways to achieve that.

 

[userfriendly]

Yep, usually the depth is reduced right across the tread on high speed tires, instead of just the shoulders.

 

[vtec260]

I picked up these tires, too, for my wife's MDX. Switching from all weather Kumho;s (will use as three seasons now) to dedicated winters. Price was good for $140/each for 245 50 20 size. All weathers, IMO, were not bad, but not great for long Canadian winters. Hope these tires wear as well as GT Altimax Arctic which we've used before for 10 winters with no significant performance degradation.