[diablo]

When I remember tyres from many years ago I seem to remember that they usually had sipes, the tiny slits which aid traction on wet and icy roads. Apparently invented and named after a John F Sipes - in 1923.

http://en.wikipedia.org/wiki/Siping_%28rubber%29

They caught up tiny shards of stone which I would occasionally remove if servicing the car.

Then they seemed to disappear. Later tyres only had solid blocks of rubber without sipes ??  They only seem to be featured on winter tyres nowadays.

Maybe the inferior rubber of years ago needed them for wet conditions ? Do sipes add to the cost and also lessen longevity ?

That was an interesting read. I just went and inspected my Hankooks and they seem to have what is described as sipes although certainly less and don't cut through the shoulder as much as my last car's tyres which from memory were some sort of Goodyear cheapy. I was always picking out gravel size stones and bits of glass from those.

[Daken76]

Hy Guys,

More about siping is written here: http://www.discounttire.com/dtcs/tireSiping.dos 

This is very interesting to talk about. Even that detail about micro-flexibility is enorm to read.

Check out Everybody to find a Brand which uses that actually.

CU

Greetings from Germany

Daken

Ok, I guess I was thinking more "cuts" than grooves when I mentioned my previous tyres and that last url confirms it. Sipes are cuts. Another look at the Hankooks shows no cuts but instead moulded grooves, although they are thin; perhaps they can perform a similar task.

It will be interesting to get the guru's view.

[Surferdude]

Hi guys, not sure I can answer this one straight away.
I know that in th elast couple of years I have still shown potential buyers sipes in som etyres.
I'll have a closer look through a couple of stock rooms this week.
But I think that, if they ARE disappearing it will be because of the inclusion of silica in tread rubber in recent years.
Silica provides a similar sort of result to sipes. But sipes could be overdone to the extent that shoulder blocks flexed too much and allowed feathering, then uneven wear on the shoulders if there was the slightest alignment problem.
Designers walked a fine line between the benefits of sipes and the dangers of uneven wear, then noise.