Tyre tread rant - rip off?

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Batman

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#201499 21-Aug-2016 19:09

As I am researching tyres, it seems that the more high end the tyre, the tread "pattern"/sipes that is cut do not go all they way down to the bottom, ie say at 4mm left the "patterns" disappear. Why do they do that? So that by 5mm they turn into semi slicks and by 4mm they become slicks (with only the ribs remaining)?

Thanks for any explanation.

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#1615222 21-Aug-2016 19:23

got a picture of what you mean?

kiwirock

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#1615229 21-Aug-2016 19:43

Hazard a guess.... so you'll keep them in business?

I know there are tread deepth indicators that eventually become one with the surface of the tyre once the rest wears down. But 4mm to go? I know snow tyres are meant to be 4mm or something minimum but a road tyre that's a little more odd. Perhaps something to help visually see if the tyre is starting out wearing evenly or not.

I wonder if it has something to do with the forces those few mm's make on the water and crap in the tread as the tire wears down, effectively changing those forces on the remaining tread pattern.

Sounds like an overly complicated tyre, or a very clever design to make more money of those that like to spend more :o)

Batman

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#1615387 21-Aug-2016 23:00

Jase2985:

got a picture of what you mean?

This tyre is expensive. SIpes don't do down to the bottom

and this is also expensive

and this is the mother of all, so it's a semi slick anyway to start with, soon to be slick within a few hundy Ks

cheap tyres, sipes go down all the way to the bottom of the rib.

Coming to think about it, the studies show aquaplaning when ribs are 3mm or less, so perhaps it warns you at 4mm left ... but really at 5mm you're beginning to see loss of the sipes ... oh well ... I guess the premium brands R&D guys know what they're doing! $$$

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#1615388 21-Aug-2016 23:01

Or perhaps the sipes are just for show and has no function?

As for me I'm interested in sipes because I tend to take my car to unpaved roads, or if roads lightly snowed eg ski fields), then the sipes would help clear junk ... or so I think (you see this sort of patterns in so called "all-seasons" tyres which have more grooves but lousier rubber in general) ... so who knows.

richms

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#1615390 21-Aug-2016 23:17

Because cheap tires are made for people that do not give a crap about grip and want something that will last a long time before the nasty man at the WOF place tells them they need new ones, expensive tires are made for people that care about performance and know that lumps of small areas and high depth will have a lot more movememt when loads are put on the tire and give it much worse performance.

Not rocket science, there are people that would get ones with 30mm of depth if they could find them for their car since that must last a bloody long time, even tho it would be like driving on a bed of erasers or something wiggling all over the place.

Richard rich.ms

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#1615414 22-Aug-2016 07:43

No idea on the pricing, but
http://www.coopertires.co.nz

They promote their tyres as having extra deep treads.

Nothing is impossible for the man who doesn't have to do it himself - A. H. Weiler

Jaxson

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#1615420 22-Aug-2016 07:55

Yeah it's a balance between maximum grip and a long tyre life.

Slicks are more grippy than grooved tyres, unless it's wet...

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#1615459 22-Aug-2016 08:47

joker97:

Or perhaps the sipes are just for show and has no function?

As for me I'm interested in sipes because I tend to take my car to unpaved roads, or if roads lightly snowed eg ski fields), then the sipes would help clear junk ... or so I think (you see this sort of patterns in so called "all-seasons" tyres which have more grooves but lousier rubber in general) ... so who knows.

Not "just for show, or with no function" but not something that should be top of your mind when looking for multi-purpose tires.

In racing where you're pushing tires right to the edge of the performance envelope, the difference siping makes is probably important.
I have a few racer friends who groove and sipe their own tires. It's pretty common with that crowd.
Another off road racer I met buys blanks and cuts his own tread patterns. It's a whole science (or religion) with those guys.

They also discard their tires after a couple of uses, they're not balancing longevity (or looks) against purpose.

The overall tire design you choose - mainly the compound and tread pattern - will have way more effect than siping on "clearing junk".

While sipes supposedly make a bit difference in traction by themselves, they also allow a certain - engineered - amount of flex through the depth of the tread.
That flex allows increased grip and reduced howl while still manufacturing the tread blocks from stiffer, better wearing compounds.

They're not always supposed to be cut right down to the bottom of the tread blocks.

Our snow tires in Canada had lots of sipes extended all the way down. They were also made from soft rubber compound for snow and sub zero temperatures.
They were dangerous on dry summer roads, with too much flex, causing a soft squirmy fast wearing tire and shear at the tread base allowing chunks of tread to come off.
As richms says - like driving on a bed of erasers.

I've seen Jap imports sold here with snow tires still on them - a potentially deadly thing. But a different topic.