MT/R (vs KM2) update/observations and questions

I've now put somewhere around 6,000 miles on the MT/Rs. Based on what experience I have with these tires so far, it's been a mixed bag. Forgive me if this is a shitty way to organize this.

Also I want to note any comparisons I make with the KM2s are based on the 33x12.50x15 KM2s with 4.30 gears and 35x12.50x15 MT/Rs with 5.29s.
I am generally pretty religious about tire rotation, pressure, and alignment.

Off-road, the Kevlars have been fantastic.

Pros
-They seem to have better traction on the rocks.
-Better self-cleaning abilities than the KM2s.
-They have very rarely picked up/retained stones in between the tread blocks unlike the KM2s which seemed to happen frequently.
-Rock rash, and tearing/chunking of the tread blocks also seems to be less than the KM2s.

On-road, they are just 'okay', which is where all the negatives about this tire come in.

Cons
-Louder than KM2s but still tolerable.
-They seem to wear much faster than the KM2. (The KM2 had the same or less wear with twice as many miles)
-At time to rotate the tires (5k-6k miles) I noticed an odd wear pattern that was identical on the front driver and front passenger (pictured below), wear on the rear tires were fine. KM2s however, had perfect wear all around.
-Less on-road traction, especially in wet conditions.

On that last point, I don't know for certain if this is at least in part due to the regear to 5.29s? In dry conditions, I sometimes noticed a slight 'chirp' when accelerating out of a sharp turn, which I don't ever recall happening with KM2s. I have also had several occurrences where the MT/Rs would produce little or no traction when accelerating (even slowly) from a full stop... didn't have this issue nearly as much with KM2s. I haven't had the MT/Rs in snow/ice conditions yet so I can't compare this aspect.

Here is my tread wear on the rear tire after 6,000 miles.
New spare:


Rear tire:


And can someone explain what is going on with this uneven wear on the front tires?? As I mentioned, the wear is identical for driver/passenger. In the tighter tread, the smaller blocks have significantly more wear than than all the other tread blocks on the tire. The wear seems almost perfectly even across the individual blocks. It was suggested that it has to do with the 1" spacers I have on the front, but I had the same spacers and suspension with the KM2s and had zero issues. So, WTF?





No regrets getting the MT/Rs. In all, I think if I wanted a tire to beat the shit out of on the rocks and still use it for DDing, I'd stick with the KM2s. If I had the cash and the storage space, I'd keep a set of MT/Rs for real wheeling and a set of BFG AT/KOs, Duratracs, all seasons, etc. for DDing and the easier trails.

And pics just because.





http://www.youtube.com/watch?v=ByWM4qgnh-o

 

Btw..your old KM2s are still holding up great. I should get them measured for comparison..

 

Did you get them rotated somewhere along the drive?

The front ones did seem a bit janky with that funky wear going on

 

Are you running the same air pressure you ran in the KM2's? If so, you may have too much air in them, causing the center tread to wear faster. It would also explain the poor traction on road. The bigger the tire, the less air pressure required.

 

Nice, man. One more pro for the KM2 (in my mind) is the weight. One of the main reasons I run them is because they are the lightest mud tire on the market. Which is perfect for us IFS guys looking to run 35s/37s with as little rotating mass as possible, to minimize breakage...

My rear KM2s also chirp (or peel out) on corners if I apply too much throttle. Since we have the same tire size gear ratio, my guess is the gears are to blame... but it's hard to tell for sure.

Your front tires are cupping, dude... That sucks. Cupping could be caused by an unbalanced tire (Did you get the tires balanced when you rotated them?) but most likey indicates a mechanical vibration. Since you're seeing this wear on your front tires, I'm very confident it's a mechanical vibration. You'll want to check ball-joints, bearings and the shocks. I just about bet you the shocks are dying as a result of the spacers... Most of the cupped out tires I see come in at work are a result of old or worn out shocks. It may be time to get a new front suspension, man. As for this not happening with the 33" KM2s, I don't know exactly why, but maybe it's because the larger/heavier tires have magnified the stress put on the shocks, and they're deteriorating more quickly than they were with the lighter/smaller KM2s...

 

This is also a good point. I run 28 psi in the front, and 26 psi in the rear.. and I still chirp!!! I could probably get away with 24 or 25 psi in the rear with my hacked up bed...

But his front tires are definately cupping. Over-inflation can worsen the effects of mechanical vibrations on the tires, but I don't think air pressure is the culprit in this case.

 

MTRs love rocks
MTRs love pavement
MTRs love mud
MTRs love dirt roads
MTRs love snow
MTRs hate ice

That's my review

 

Damn.

Ball joints were replaced under the recall about 1.5 years ago.

Which bearings should I be checking and how?

So do you think I should just swap the 883s and spacers with some new 882s or do you think I need new shocks as well?

I initially left the pressure out as a factor since over-pressure normally results in a bowing, across the tread type of wear, unlike this every other lug on one side of the tire deal.

I basically did the chalk test when I tried to find the ideal pressure which seemed to be around 29 (about 3-4psi less than the 33" KM2s). And as mentioned the rear tires and all the other lugs on the front tires are wearing even.

 

And tires were balanced when I got them installed and also got an alignment (twice).

I noticed the cupping while I was in Colorado the other day (so around 5k miles), drove home (so total around 6k miles on the tires) and stopped in at Discount who said they won't touch a damn thing that has spacers. I'll go to the tire shop across the street tomorrow.

 

I'd stick with the 883s but maybe new shocks??

 

re: Slodgetto's post

When I rode in 45acp's truck I didn't notice any mechanical vibration, odd noise or the likes. The thing rides like butta.

 

X2

 

I havent really had the chance to test out my mt/r's yet
I did notice that the tires seem to have an odd contact patch though. when i drive up and down my new driveway, the concrete coats the tread white; it seemed like the outer edge hardly made contact with the ground.

But, like I said, I havent had the chance to mess with them yet; with PSI and such...I suspect that's what's causing my problems

 

Yeah thats cupping.

 

I noticed that too at first. Chalk test, an alignment helped, chalk test, I guess a little bit of a break-in, and chalk test pretty much takes care of it. I'm sure tire/wheel width combos play a role in that too.

 

Took the truck in to the shop today. Upper ball joints have play and need to be replaced, partially due to the fact that they rub the coils when the suspension is fully extended. They want $435 for parts/labor. At that price I might as well get aftermarket UCAs and do the work myself. Any suggestions on which UCAs?

 

Cam burg and TC are pretty much the same. Burgs are cheaper..

Those are the only two brands I'd get personally

 

That tire wear is from bad alignment. Improper to to be exact. I have it too. I ja a half inch of toe out.

 

i disagree with the above cupping causes.... cupping on the front tires is common with lifted vehicles. basically.... with the stiffer front suspension when u turn at lower speeds, the suspension isnt compressing as much with weight transfer. this causes the inner edge lugs on the tire to kinda fold and bend aggressively as they hit the pavement.... u can hear the rubber "scuffing" the pavement on some trucks when turning slowly. my duratracs are starting to do it do. and i guarantee im more religious about tires and alignment than anybody here. my alignment is perfect and my tire pressure are too. very hard to get around this cupping with aggressive tires. only way to prolong tire life is to rotate all the time. not just front to back either. i move my fronts in an x backwards and the backs forwards straight.... but like i said hard to get it to stop

 

i like my burgs man.... just gotta keep em clean and lubed...