i havent seen any threads on this and i know people have been siping tires since the 1950's.

I just bought a new set of Toyo Proxes 4 tires at Schwab and paid $52 to have the set siped (run through a machine with a blade which slices the tread). Previously I was driving on the Sumitomo HTRZ II's that came with my rims and was experiencing wheel hop and loss of traction on turns, typically at about 30mph, general street driving.

Allegedly, the siping helps with quicker braking and traction on turns. Though it is impossible to compare worn tires of one brand with new tires of another, the new set is a very obvious improvement in cornering and braking. i haven't been able to induce of loss of traction under normal driving and can take 90degree street turns at 55mph+ without even a hint of lateral slip.

I am loving the new Toyos which are obviously better than the Sumi, but just curious what the siping contributes to the equation.

This is a daily driver, no racing.

 

I was under the impression that sipes were meant to increase bite in snow, by giving more edges to cut through the snow. I would guess that the better traction you are feeling is due to the new tires being stickier (either because they're new or better rubber) or a placebo effect.

These are the currently accepted "best" street tires for dry grip in autocross-type racing and, other than the goofy little flame imprints, there are no sipes to be found:

 

If sipes help traction then why don't racing slicks have them?

 

i forgot to clarify that this is my daily driver. I am not racing this car, never have. a track is super smooth and a slick tire provides maximum traction on a smooth surface, obviously.

street roads are coarse, rough, have rocks and dirt, etc...a slick doesn't do as well here, then you add the rain, slicks are no good. We have no snow here but are at the beginning of our heavy rainy season, so i expect the siping will help with that.


here's something i found testing stopping on wet pavement:

http://www.youtube.com/watch?v=HiVxFkqkQEE

 

Expect to trade some dry weather behavior and road feel to get the wet/slippery advantage.

I'd also expect the tire treads to wear more quickly after siping and to generate more heat as you drive, as it appears that the advantage of siping comes from effectively having lots of little tread blocks that squirm a lot more than the large tread blocks that they were cut from.

All in all, I'd generally suggest a top rated all-season tire instead, like this one I just recommended to another member here
http://www.tirerack.com/tires/tires....=yes&tab=Specs


Norm

 

great responses, thanks. i will let you know how it goes with this set but so far i am loving the improvement over the old rubber.

i found the marketing blurb from discount tire here:

http://www.discounttire.com/dtcs/tireSiping.dos

 

I live in the rainy NW and have gotten my tires siped. My conclusion is that it does nothing and is an additional way for tire shops to screw you out of your hard earned cash.

 

i hear you, but it was only $52 on top of $1K+ for the tires so worth a try. that costs less than a tank of gas.

 

That's what I thought too (worth a try) but it didn't do anything at all...and I tried it on a set of tires that I had driven for a few miles so I was aware of how they gripped in the rain before I had them siped.

I just put Ventus V12s on my car...they seem to grip pretty well from what I can tell so far...sadly no goofy flame imprints on them though :-(

 

I've had many sets of light truck tires siped.

It makes a noticeable improvement in wet, frozen, and slippery conditions.

However, I suspect that for "high performance" tires the handling may suffer somewhat under certain conditions.

I hope that helps.

G