For Maximum Off-Road Traction; Wide or Skinny tires?

[trd_4runnin]

I run 255/85 16 in the KM2 flavor and love the performance of the skinny tire. Lighter weight and better clearance and breaking. As far as airing down.... I do not air down to widen the contact patch, I air down to LENGTHEN the contact patch.

Overall it is a personal preference and my vote is clear!

Here is a video from this weekend at the Toyota Jamboree. I went up this clim in just over a minute and the guy behind me did it in over 4 minutes and he was running 35s on an older FJ Cruiser.
YouTube - 4runner on Barnwell MVI_3115.MOV

Lengthening the contact patch and and widening the contact patch are both examples of INCREASING the contact patch. I don't really see how one vs. the other would provide any benefit over the other.

I'm glad you like your 255s but again the clearance and weight aren't what the poll is about. It's about off-road traction. A video of two different sizes in two different tires on two different vehicles does little to sway anyones opinion.

 

[jujew]

Easy tiger!

Lengthening the contact patch and and widening the contact patch are both examples of INCREASING the contact patch. I don't really see how one vs. the other would provide any benefit over the other.

Well then, lemme explain the benefit of longer vs wider. A longer tread provides a more tank like tread grip. It's that simple. Would you prefer a contact patch that is square or a contact patch that is more rectangular with the width running front to rear?

On to your next points...

I'm glad you like your 255s but again the clearance and weight aren't what the poll is about. It's about off-road traction. A video of two different sizes in two different tires on two different vehicles does little to sway anyones opinion.

I understand what this poll is about. It is about opinions on tire size. My opinion is that skinnies are better for what I do. The purpose of the video was simply to provide a reference, not to convince skinny is better than wide.

And if you think clearance and weight do not have an affect on traction then you should do a bit more research before you mislead others. If your tires are too big for your set up and the rubbing prevents articulation then that would have an affect on traction. If the tires are too big and heavy then you are likely to break CVs and a broken CV does not improve traction.

It would appear you took offense to my previous post and I'm sorry of my opinion ruffled you.

 

[trd_4runnin]

Easy tiger!



Well then, lemme explain the benefit of longer vs wider. A longer tread provides a more tank like tread grip. It's that simple. Would you prefer a contact patch that is square or a contact patch that is more rectangular with the width running front to rear?

You aren't running tracks like a tank, so again I think the comparison here doesn't really make much sense. I see what you are saying but I think the difference is negligable. Even if you air down strictly for increased length, that is still an increase in contact patch and if an increase in contact length would help, then it doesn't make sense that a increase in contact width would not also help.

...I understand what this poll is about. It is about opinions on tire size. My opinion is that skinnies are better for what I do. The purpose of the video was simply to provide a reference, not to convince skinny is better than wide.

And if you think clearance and weight do not have an affect on traction then you should do a bit more research before you mislead others. If your tires are too big for your set up and the rubbing prevents articulation then that would have an affect on traction. If the tires are too big and heavy then you are likely to break CVs and a broken CV does not improve traction.

I'm sorry but in my opinion, you are throwing in things that are complete variables and are using them just to aid your point. The poll is about traction and should stay with just traction. To me, that means that we are assuming a vehicle is perfectly capable of running both sizes, and which one would provide better traction.

..It would appear you took offense to my previous post and I'm sorry of my opinion ruffled you.

Definitely no offense taken here. This is a poll about tire sizes on an online forum. You said nothing offensive of any kind directed at me so it would be silly of me to be offended. I definitely, however, don't appreciate you saying that I was misleading anyone as we just have two different ways of looking at things... by your standards stock tires are better than your 255/85s as they fit better and weigh less.

 

[jujew]

I'm glad no offense was taken. And I agree that the difference between stock to 285 or 255 is not that big a difference, if at all, performance wise.

To answer the question posted in the poll: Which has more traction, one would have to determine which has more friction/or larger contact patch. Easily determined by inflating several different size tires to the same psi and taking an impression of the contact patch. Done.

But that takes the "opinion" out of it.

I was replying to the post as "which tire do I prefer". I think in the end it is less what size tire and more driver capability. Heck, this past weekend at Barnwell I saw a lil truck on 29s on a 3 rated trail. He was schooling some of the other guys with 33s and up.

 

[trd_4runnin]

I'm glad no offense was taken. And I agree that the difference between stock to 285 or 255 is not that big a difference, if at all, performance wise.

To answer the question posted in the poll: Which has more traction, one would have to determine which has more friction/or larger contact patch. Easily determined by inflating several different size tires to the same psi and taking an impression of the contact patch. Done.

But that takes the "opinion" out of it.

I was replying to the post as "which tire do I prefer". I think in the end it is less what size tire and more driver capability. Heck, this past weekend at Barnwell I saw a lil truck on 29s on a 3 rated trail. He was schooling some of the other guys with 33s and up.

Pretty much agree with everything here. Until someone has ran the same line, on the same trail, in the same vehicle, with the same tires, in 2 different sizes then it's kinda all up in the air with me. I went with 285s and with my fender flares I think they look a lot better. They impressed me a lot on my last trail line, but I think that was more a KM2 thing then a size thing.:hatsoff:

 

[jujew]

Gotta love the KM2s!

 

[LINY4Runner]

Km2 ftw!

 

[trd_4runnin]

Km2 ftw!

Can't wait to upgrade to 315/75/16 KM2s!

 

[LINY4Runner]

Can't wait to upgrade to 315/75/16 KM2s!

I'm not sure I'm going to...you may lose a decent amount of flex to tire rubbing

 

[JeremyH]

The argument for skinny (see Chris's link) is that the wider tire spreads out the load reducing the amount of "bite" the tire has on irregularites.

A wider tire has the ability to conform to the rock surface easier because the material between the edges will be more malleable than a skinnier tire (assuming the thicknesses of the rubber in both tires is the same). Also, a wider tire, when aired down, will create a larger bulge which will help protect the bead of the tire and keep it on the rim.

Look at most competition rock buggies and you'll notice that there is not a single one of them running anything narrower than 12.5" wide. Here's a video of this year's King of the Hammers competition (going on this weekend) and shows a good mixture of desert racing and rock crawling:
http://vimeo.com/9059027

At about 6:45 they get to the rock crawling section of the course (and again at around 11:00)....you'll notice that none of the vehicles in this race are running skinny tires.

BTW, for those of you interested, here is the live feed of the event:
http://www.pirate4x4.com/king-of-the-hammers-2010/index.php

The main event starts on Friday.

Heck, this past weekend at Barnwell I saw a lil truck on 29s on a 3 rated trail. He was schooling some of the other guys with 33s and up.

The trails out there were built for short wheelbase Jeeps and Zuks....anything with a slightly longer WB will excel on those trails...even if he's got smaller tires. Drive that same truck up Airstrip or Dewoody and see how it compares against a SWB vehicle.

You've gotta compare apples to apples....