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  #1  
Unread 26th November 2017, 02:06 AM
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Default Road Tyre vs A/T Tyre Off Road

To those who are set in their ways, do as you please. I doubt what I am going to say will sway your opinion. I make the following comments based on tens of thousands of kilometres of outback travel, and on terrain from gibber to rocky outcrop, mud, gravel and of course sealed road. Everything but sand and ice really.

I came to the conclusion after all those trips across the continent that to get a puncture, you really had to be unlucky. On one trip, we headed of down the Birdsville Track. It had just been re-opened following heavy rain. We were in 2WD vehicles and were the first vehicles to hit the track once it was re-opened. It was very muddy in places, especially the first half of it.Further on, my mate who was running all terrain tyres got a puncture. I was running road tyres, in this case 265/50's. I never got a puncture.

Of all the trips I did, from the Simpson, Sturts Stony, Tanami and other desers, and the Oodnadatta and Strzlecki Tracks, Buchanan "Hwy" (the West Australians have an evil sense of humour) and so many other tracks across the continent, I never got a sidewall puncture. Until I went to an all terrain tyre. Then I got a puncture on every single trip I did, without fail.

I came to the conclusion all terrain tyres are the most over rated thing you can get for your car. And while I have been stuck twice on my road tyres, my situation had nothing to do with tyres and everything to do with diffs. Yes, ultimately an all terrain tyre will hold a marginal advantage in off road traction, but nothing like the advantage the road tyre has over the A/T tyre on road. And even with a dedicated off road car, you still spend a far greater time on road than off. At least most people do.

So if there is minimal traction advantages, and punctures at best a lottery of luck (I am keeping L/T construction tyres out of this. They have issues of their own) at best, I would suggest spending money elsewhere on things that will make a real difference. I am. I'm spending money on getting a diff locker. I will only have to buy it once and unlike all terrain tyres, It won't adversely affect driving on road, and will do far more off road than an A/T tyre could ever hope to. Happy to do a side by side comparison after the car is back on the road with the new diff.
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Unread 26th November 2017, 10:27 AM
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I quite agree with what you write. I started with BFG AT's, then Grabber AT's and now have some Nokian AT's...the last ones being the less agressive by the looks.

A 4x4 tire specialist on forum4x4.org is allways telling everybody that the sidewalls are all equivalent in strength, what I don't really believe but he is probably right.

But how do you explain you had no puncture with road tires and so many with AT tires ? Did you drive differently thinking they are stronger ?

And for the traction, for sure a better transmission/suspension makes a bigger improvement over tires
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Unread 26th November 2017, 11:08 AM
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I checked for myself the difference in sidewall thickness with thumb and finger. Not particularly precise, but the difference was big enough to notice. Road tyres need a stiff sidewall for cornering. I suspect, depending on the brand, that a/t tyres might be biased more towards sand driving and have a soft sidewall for bagging out when aired down. I drove no differently. I had no sidewall punctures on road tyres.
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Unread 26th November 2017, 01:28 PM
MiddleAgeSubie MiddleAgeSubie is offline
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There are two problems with your comment, Rally:

1/ It is one person. And your car is known to be not quite like the Subarus on dealer lots.
2/ Some AT tires have sidewalls that are far stronger than any street and many AT tires. You just lump all AT tires in one group.

You cannot seriously claim that a street tire has a stiffer sidewall than an LT-metric, 3-ply sidewall AT tire. In fact, my oversize KO2 corner just as well, if not better, than stock street tires. They do at par with the performance 255 55 18 street tires on the TB even though they are 225 65 17.

I can see how a 2-ply sidewall AT tire gives you no advantage over a GOOD street tire. Even here, however, your opinion would be of little use to me, if I were starting now. How in the world do I figure which street tire has good traction off-pavement? The street tires I have used off-pavement have been a joke compared to AT tires when it comes to handling and cornering. Next is longevity. All tires see their lives shortened off-pavement, but this is especially true of street tires. My Sumitomo on the B9 Tribeca looked like they were coming from a war theater at 28,000 miles. The Nitto 420S on the Tribeca are exceptional on road but a joke on dirt. None of my five sets of AT tires has suffered any chips or comparable damage and all have handled well (ATS) or great (KO2, Toyo Open Country ATII, Conti Terrain Contact AT).

So, I do not doubt that SOME street tires can do just as well as SOME all-terrain tires, but you cannot pass this as a universal conclusion (all street tires are same--or better!--than all AT tires).

So...
1/ one buys LT metric, 3-ply sidewall AT for strength. This is especially needed on a Subaru, which does poorly in rock and thus low pressures are essential and thus the aforementioned tires are essential, too. The Subaru needs some momentum where a Wrangler, Toyota, or Nissan can crawl. I am not driving narrow or rocky spots (see pics) on street tires, thank you. Further, the KO2 do great on road, performance wise. If one is driving narrow, mountain trail one should upgrade pads and fluid anyway; with upgraded brakes, the heavier, oversize tires are not a problem on road. Sure, they are harsher and make a bit of noise.

2/ One buys P-metric AT tires, like my brand new Conti Terrain Contact AT, for handling and cornering on dirt road coupled with less damage to tires from the ordinary crushed rock and gravel found on such roads. Instead of wondering which exactly street tire might happen to perform on dirt. On road, these mild AT tires behave just as well as very good street tires, so why not?

3/ Personally, I am beyond the one-tire suits it all approach. Now, I am getting beyond one car suits it all either, lol.

Pics:
examples of terrain I want the KO2s for
Attached Images
File Type: jpg 5.jpg (73.3 KB, 15 views)
File Type: jpg 6.jpg (81.1 KB, 15 views)
File Type: jpg 8.jpg (16.0 KB, 13 views)
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Unread 26th November 2017, 02:03 PM
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Please re read where I said I am not including LT construction tyres. My experience goes back 30 years and pre-dates my Subaru times. It includes comparisons with full size 4WD’s with experienced drivers, and in one instance a club off road driver trainer. It is not just my experience, although mostly it is. On numerous outings with others, new to the off road experience we have done off road trips without puncture. Last weekend was a good example. Gen 4 Outback, totally standard on no name street tyres. Spent all day on a particularly difficult track, especially for a novice, negotiating steep rocky conditions, water crossings and mud. Good opportunities for punctures and similar to where my at’s geolanders were punctured. He did get stuck once due to inexperience. However, I jumped in the car and drove it out. On the same trip, an SG on a/t tyres also got stuck due to inexperience and I drove that out as well. I have driven in more severe conditions but I reckon the majority of people on a/t tyres would not have. I don’t believe any a/t tres will grip on road as well as my 002’s or even come close. And I still maintain better diffs are a better solution, especially the locker going in my car shortly.
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Unread 26th November 2017, 02:23 PM
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I see no problem taking my car, as is, to the places shown in your photos. Would be a good drive though!

On street tyres here. Too much for some of the A/T tyres cars. The 2 before me took 3 goes at least, including the club driving instructor. The other was a Pajero. Neither had a trailer. I was out first go.


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Unread 26th November 2017, 02:26 PM
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You have to take the driving skills as an important factor too, the most important in fact !
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Unread 26th November 2017, 02:32 PM
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True. But in the photo above, one of the cars that took 3 goes was the clubs off road driving instructor. But remember one of the points I made above. Most of the people on off road tyres will not enjoy the marginal traction advantages because they either won't go to places that require it or their diffs will be the weak link and negate that small advantage.
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Unread 26th November 2017, 04:02 PM
MiddleAgeSubie MiddleAgeSubie is offline
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I cannot see that picture.

Yes, most people with AT or even MT tires do not need them any more than many people with Wranglers or trucks and big lift and tires do (most only go to the mall).

Yet, I still fail to see the point you are trying to make. Modern all-terrain P-metric tires like my Conti AT or the new Geolander GO15 have no downsides on road and yet guarantee good performance and tire integrity off-road.

How exactly does someone who is just starting figure out which street tire might have good dirt road traction? And how does one know which street tire will resist chipping?

If you want to go on shallow thread street tires on a narrow mountain trail, it is your choice. A Subaru can be pretty poor even in snow, its favorite element, on the wrong street tires. Similarly, if you want to expose your weak sidewalls to rocks, it is your choice. A stock Subaru on street tires and street pressures has close to no chance of climbing the small step on the first picture I showed you unscathed. And how long will aired down street tires last in that environment? Best case, they will all be chipped up. The Sumitomo tires of the B9 never saw anything that challenging and still looked like the craters of the Moon.

So, I still do not understand your advice or its target audience. If all all-terrain tires today were like my two sets of the old Geolander At-s, an awful tire in corners or hard braking, I would understand. But modern ATs do great on road.
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Unread 26th November 2017, 04:14 PM
MiddleAgeSubie MiddleAgeSubie is offline
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Btw, I am not trying to convince you. I just want to ensure that whoever comes across this on the internet has more info on which to base a decision.
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