Talk:Contact patch

I agree with the below. These statements in this article seem to be trying to indicate something true, but are too condensed to be of much use.

Under normal conditions on dry pavement, creating a larger contact patch does create some more traction (useful for racing and extremely high traction requirements) but doesn't give you much of an advantage for regular driving because there is already so much traction between the tire and dry pavement that it's already entirely sufficient. In this case creating a larger contact patch just creates unnecessary flexing of the sidewalls and more rolling resistance, which is detrimental to gas mileage and to life of the tires, and perhaps to handling.

On softer snow and sand, and depending on the design of the tire and characteristics of the vehicle, a wider contact patch can both increase or decrease overall traction. In soft snow, a wide contact patch on non-driven tires can create unnecessary rolling resistance because they have more snow to compact and/or move out of the way. This makes more traction necessary on the driven tires to compact all that snow, making you more likely to get stuck.

Higher PSI (smaller patch) can help on tires with deep tread and/or studs because it can sink into the soft snow and provide traction against each tread piece. Narrow tires (small contact patch) can make less snow to move/compact. But again, on smooth tires and smooth ice, making a nice big contact patch can increase traction overall.

So on a rear-wheel drive vehicle in moderately deep, soft snow for example, you probably want big fat soft back tires and narrow hard front tires (but not so narrow that you sacrifice steering traction either).

Tons of variables here so I'll leave any edits up to someone else more eloquent than me. —Preceding unsigned comment added by 68.187.198.37 (talk) 19:10, 20 July 2008 (UTC)[reply]

Contact patch size and traction

"A larger contact patch does not mean more traction on a normal road, but might on snow or mud."

Then why do race cars have wide tires? The tire article currently says "Dry traction increases in proportion to the tread contact area."-AndrewDressel (talk) 14:48, 5 May 2008 (UTC)[reply]

Basically force due to friction is the product of contact force (mostly vehicle weight) and coefficient of friction (depends on road + tyre materials). Contact area is not important. Second-order effects such as pressure distribution, surface patterns, loose surface will have small effects. I guess narrow race tyres might catch fire - same energy over a larger area gives lower temperature. OTOH drag racers wheelspin first to make tyres sticky by heating them. Narrow tryes can slice through thin snow to contact the road beneath ! --195.137.93.171 (talk) 23:56, 21 October 2011 (UTC)[reply]

My hypothesis is that statement applies up until stresses on the tread exceed the strength of the rubber. A larger contact patch allows lower pressure to support a given weight, and distributes traction forces over a larger area. This reduces the stress on the rubber, increasing the total force that can be applied. It probably also allows a softer rubber with a higher coefficient of friction to be used. Disclaimer: I'm a civil engineer hypothesizing outside my area of expertise. --Triskele Jim 17:57, 23 December 2013 (UTC)[reply]

As opposed to?

The lead for the article introduces it as applying only to pneumatic tyres. For non-experts in the subject (like me), what would be equivalent terms for other tyre or wheel types, or times when it is used for other tyre or wheel types? I've marked the article as incomplete for this reason. — Sasuke Sarutobi (talk) 13:49, 23 December 2013 (UTC)[reply]