Tread wear and off-road performance

[ColoradoMike]

Sorry if this has been discussed, but I can't find the answer I want.
What are you guys' thoughts on how much tread wear affects performance on the trail?
Note: I do not have any interest in a religious war about brands; I don't care who loves and who hates KO2s.
But here's my deal:
I have one-year-old KO2s (315/70/R17), 15,000 miles, on my Rubi XR.
It looks to me like the spare (which has never been used) has tread depth of about 15/32. The tires on the rig seem to be at about 9 or 10/32. That means I have lost about 1/3 of the depth between the lugs.
Do you guys imagine that means my traction on the trail, particularly rocks, is down by a third? Like, my rig is going to be 33% less capable trying to climb the slippery rocks of French Creek on Holy Cross? (I ask because I'm getting ready to go do Holy Cross, and I imagine that trail is going to be a stout challenge for my mostly-stock Rubi XR. So I don't want my capability significantly diminished.)
It sounds like KO2s claim to have a tread life of about 50,000 miles, though at the rate I am going, I am going to be down to 4/32s after about 30,000 miles.
I hate to replace tires too soon, wasting money and materials, but I don't want to take my rig to a hard trail and be doomed by reduced traction.
So, how much reduction in tread depth do you tolerate before you feel compromised on the trail and before you replace them?
Thanks-

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[AcesandEights]

No, it doesn't mean your traction is impacted that much. It would only mean that if the "rocks", or the surface of the "road" needed to fill that space of 15/32" It's more likely to use that void, not in rocks but, in mud, soft(er) sand or dirt. That's where the voids allows the terrain to fill it, but it's never at more than a couple 32nd"

 

[Upnarms]

It will matter more when you get into mud or anything that will fill in the tread quicker than the higher/newer tire. Btw, you should do 5 tire rotations so your spare gets rotated in and you get 20% more life out of your tires. That's a wasted spare just dry rotting in the back imo.

 

[ColoradoMike]

It will matter more when you get into mud or anything that will fill in the tread quicker than the higher/newer tire. Btw, you should do 5 tire rotations so your spare gets rotated in and you get 20% more life out of your tires. That's a wasted spare just dry rotting in the back imo.

Thanks. And yeah, as for the 5-tire rotation…. I mean, it means that at your first rotation, you end up with 3 tires on your rig with 6,000 miles of wear and one tire that is mint. Whether that’s okay is a whole other religious argument that we don’t need here.
I’m just wondering how sensitive people are to tread depth reduction as it relates to off-road performance. And I’m getting the sense that mine are probably fine for another season. Holy Cross will tell me if that’s true next week, I imagine.

 

[Upnarms]

If you are airing down properly, your increased surface area of the tire with even half worn tread should work fine. And just from my experience doing the 5 tire rotations, the 5k or so miles of wear is a non issue, you won't even notice it. Think of using the brand new spare if you had a flat now and it would be a lot more significant.

Have fun and good luck at holy cross

 

[stumblinhorse]

It all depends on what off road means to you. Worn tires work better in rocks than newer. They work worse in mud and dirt. The work worse in snow. just dirt forest service roads there is no difference.

 

[RubiSc0tt]

Good info here.
One thing worth mentioning: You could air down a little bit more to help with contact patch, but not too much otherwise it'll just get floppy and not be able to grip.

Just a point of reference:
On my 98 TJ, I had the original BFG KO's that were down to the bars. These would not pass inspection. I used them for one last wheeling trip as I was getting tires the following week. I was down to probably 5psi on a difficult trail (east coast rock crawling, but still) and those things would not give up. They crawled and clawed every inch, and I never lost traction. This was with a 3.5" Long arm kit, open front and ARB locked in the rear. I was amazed. I wish the Gen1 MTR's I had on it after were half that good.

IMO, if you are not seriously off roading, wear them down to the wear bars. If you are serious about traction off road, there are better tires.

All that said, I think this is solid advice. If you're able to, and you wheel frequently enough- you could certainly get another set of wheels and run trail wheels/ tires and save the BFG's for the street/ road. I know a few people who do that, sadly I don't get enough wheeling in to be able to justify the extra cost.

 

[ColoradoMike]

It all depends on what off road means to you. Worn tires work better in rocks than newer. They work worse in mud and dirt. The work worse in snow. just dirt forest service roads there is no difference.

These are going to be big, wet, muddy rocks in a difficult creek crossing. ? I think this trail would be pushing a 7 on the Moab scale, except without the benefit of that dry, grippy Slickrock.

 

[stumblinhorse]

These are going to be big, wet, muddy rocks in a difficult creek crossing. ? I think this trail would be pushing a 7 on the Moab scale, except without the benefit of that dry, grippy Slickrock.

Muddy rocks probably you will notice no difference between newer vs older tires.

 

[ColoradoMike]

Muddy rocks probably you will notice no difference between newer vs older tires.

Right on. The only excuse for failure will be driver error!

 

[stumblinhorse]

Right on. The only excuse for failure will be driver error!

But don’t let my opinion stop you from getting new tires! I don’t want that on my conscious! I have had 30 sets of tires in the last 20 years!

 

[Ratbert]

Right on. The only excuse for failure will be driver error!

Yeah, right. I haven't tackled it yet, but Holy Cross should be pretty damn challenging.

 

[ColoradoMike]

Yeah, right. I haven't tackled it yet, but Holy Cross should be pretty damn challenging.

Want to come next Sunday, 7/23?
So far it's me and one other guy-another forum member. The Funtreks guide ranks Spring Creek as one notch tougher than Holy Cross, and my rig made it through Spring Creek (mostly) unscathed. So I'm confident that it's doable.

 

[Ratbert]

Want to come next Sunday, 7/23?
So far it's me and one other guy-another forum member. The Funtreks guide ranks Spring Creek as one notch tougher than Holy Cross, and my rig made it through Spring Creek (mostly) unscathed. So I'm confident that it's doable.

Maybe? They're taking out half of my thyroid tomorrow, so we'll see how well that recovery goes

 

[ColoradoMike]

Maybe? They're taking out half of my thyroid tomorrow, so we'll see how well that recovery goes

Oh man, good luck with that! And yeah, let me know if you end up feeling up for it.

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