Len-
Here is a posting from another list that you might find informative.
-Roland
>To: <shop-talk@Autox.Team.Net>
>Subject: Re: Siping (on street tires)?
>From: "Nolan Penney" <npenney@mde.state.md.us>
>Date: Tue, 07 Dec 2004 06:08:40 -0500
>
>
>I've siped and grooved my own tires for years now. It does work, but
>it's not a perfect cure all for everything, and can be done wrong.
>
>Siping is the cutting of slits, not groves. It is performed with a
>knife. Siping can greatly increase overall traction. Siping does very
>little, if anything, for rain traction.
>
>Siping allows the leading edge of the resulting tread block to raise up
>when under load, helping to create a mechanical bond with the driving
>surface. This is the same sort of mechanical bond that occurs with the
>extremely soft rubber of racing tires.
>
>The downside of this is treadblock instability. Siping produces tall
>skinny treadblocks that flex and roll under load. This tends to reduce
>cornering capability, especially when carried to excess. There is a
>fine balance between increasing traction of a tire with large stiff
>tread blocks, and creating a squirmy tire that can't corner above 20
>mph.
>
>In order to control this, you normally only sipe about 1/8"-1/4" deep
>in the tread blocks. This does mean you'll be siping several times
>during the life of the tire if you want to retain the effect.
>
>You often times see stock siping in all weather tires or snow tires.
>These are the little groves cut into the upper surface of the large
>tread blocks.
>
>Siping done by tire dealers is almost always nothing more then rolling
>the tire over a bladed wheel. This means the sipes are cut willy-nilly,
>with no regard to the existing tread pattern. As a result, the edges of
>the tread blocks are cut, resulting in bits of tire that fling off and
>give no traction benefit.
>
>Grooving tires does a similar effect as siping, but also increases rain
>traction. Grooving is the cutting of groves, with something like a
>grinder or a soldering iron. Because the blocks are now separated by a
>grove, they are even more willing to roll over. You also tend to cut
>groves far deeper. This is most commonly done on offroad tires where
>tread blocks are too large for the type of terrain. They are cut down
>in size, increasing the number of tread blocks. This makes the tread
>blocks more flexible, increasing the lip that catches traction, as well
>as potentially increasing mud clearing capabilities. Done right, and
>you will get much greater traction. Done wrong, and you get the most
>god awful squirmy tire that flings tread blocks off
On Thu, 26 Jan 2006 19:05:10 -0800, The Other Len wrote:
::Les Schwab Tires is offering a service called Siping. To quote a brochure,
:"Siping is done by placing your tires (new or used) on a specially designed
:machine that rotates your tires while making small, virtually invisible 90
:degree cuts in your tread. Only under very close inspection can the SIPES
:even be seen, and you're more likely to tell by your improved driving
:experience than by visual inspection."
::
::Has anyone had any experience with SIPING?
::
::
::(The Other) Len
|