&nbsp&nbsp&nbsp I know what siping is, but how does it serve its purpose? What are the benefits of having it or not having it? I was in the tire shop last month looking at some Bridgestone mudders. The sales person told me I would have poor on-road wet and ice traction due to the massive flat lugs on the tire...

 

I've always heard that siping helps wet-road traction.
-Cope

95 F-150 4x4
4.9L M5OD
Front Truetrac Rear Detroit
3.73 Precision Gears
Warn Premiums
4" Superlift Superunner

 

I was told it helps in the mileage-longevity of the tire by have more air space to help keep the rubber cool...Next answer??

kyle

 

Siping will help traction on hard surfaces, especially when wet. The extra traction you'll get on dry pavement won't be noticeable, but if you're rock crawling it will help. It will reduce the number of miles you will get out of the tire, but usually siped tires are less aggressive and will last longer than mudders anyways. Unless it's a newer style snow tire like a Blizzak that combines alot of siping with really soft tread compounds the wear shouldn't be a problem.

 

When a tread block, or some part of the tire, comes down to contact the road, rain water needs somewhere to go. With little or no siping the water can't move (or be channeled) out of the way fast enough, and it will essentially prevent some part of the tire from making contact with the road (thus we have dangerous hydroplaning).

The downside is that the more siping you have, the less tread you have touching the road for any given sized tire. Dry traction suffers (but this is more of a sports car's problem).

The more horizontal siping you have on a 4x4's tire, the more edge surface area you have to gain forward or rearward traction over obstacles.

In both the cars' and trucks' applications the increase in siping effectively decreases the amount of tire rubber you have in the tread blocks. This means tires of the same compound with more siping wear faster - there just isn't the amount of rubber to do the cornering and mileage of a less-siped tire.

Load carrying tires seem to tend to have more verticle (or lengthwise) siping. They need the siping to channel water in bad conditions, but need the constant lengthwise tread to support the loads, and ditribute the weight, they carry. On some truck/SUV tires you'll see the sideways, or horizontal, sipes are nearly non-existant on the outside edges. This is to give a more supportive, longer lasting tire to trucks since trucks put more stress on the outward edges of the tires in turns. The bad part is, of course, water can't be channeled out that side as easily with that design.

Massive flat lugs on a big tire, as the original poster inquires about, give forward traction (via the edges) on rocks and some mud terrains, but they hinder in two ways:

1.) They spread the load out over a larger surface area, thus not allowing the downforce (due to gravity) in any one area to dig in as much as a thinner, or smaller lugged, tire might.
They will also act to be like the pontoons on a pontoon boat in the water, especially when the tread gets low. They'll do this somewhat even when new since they distribute the weight on the water across a sled-like (or boat-hull-like) surface (instead of the more knife-like surface of a thinner tire).

2.) They don't have the many edges that many smaller lugs will have, and these edges are the traction needed on ice (it sure ain't the rubber to ice contact doing it...).