FlatlanderWB

I'm trying to choose between the two. I'm primarily interested in a tire that will stick to the rocks for serious rock crawling. Its not a daily driver. But I don't have a trailer and the trails I do are 8 to 12 hours of interstate driving away. So the tires have to be safe and stable for 75 MPH Interstate driving.

Size 37X12.5 R17. Plan to mount them on Interco Birddog 17X9 wheels. Birddog wheels because the manufacturer claims that they can be aired down to 4 to 10 psi and still hold a bead. Four Wheeler magazine testing seemed to confirm this. I like to rock crawl at less than 10 psi. With a 37 even 5 psi sounds really good if it really does hold a bead well. I don't want to deal with true beadlocks.

Sidewall puncture resistance is important. I wheeled with BFGs in the 90s and lost 3 over those years to sidewall punctures. One on Wolf's Run near Las Cruces, NM, one on Behind the Rocks in Moab and one on Blanca Peak in CO. If there isn't a tire shop near the trail that can replace the tire then my outing is over because I can't risk another ruined tire which would leave me stranded on the trail.

I like the soft rubber the IROKs come with because I feel the soft rubber will have more traction on the rocks. I am willing to put up with the higher cost and shorter tread life if they really do significantly outperform on the rocks and are safe and stable enough for long Interstate drives. Do they significantly outperform the MT/R on the rocks? Are they safe and stable on the Interstate? How resistant are they to sidewall punctures? Do they air down well or are the sidewalls too stiff?

The MT/R with Kelvar are supposed to have good sidewall puncture resistance, are less expensive, should be safe and stable on the Interrstate and are much easier to find when a replacement is needed. Are they really more resistant to sidewall punctures? How do they stick to the rocks compared to the IROK? Do they air down well or are the sidewalls too stiff?

Any other tire/wheel I should be considering? Any comments/suggestions appreciated.

D3ADLY

I've seen Iroks perform in person. Between the two I'd choose Iroks hands down. I think you'll get a more aggressive traction in almost any off road condition. Sidewall strength, I'm unsure of. I'd be willing to put money on it that they're built pretty tough though.

Invest2m4

I've been really disappointed with my 37" MTRs in the rocks. The tight center tread pattern and hard compound just doesn't get traction.

In terms of Iroks, I assume you mean the bias ply version? If so, those would definitely work better offroad. If you're talking radial, I think you need to broaden your tire search. The iroks are stiff and need to be aired way down, so you better hope the bird dogs work. Certain sizes of iroks have been known to burp air as well.

TheDirtman

its more the fact you are running a D rated tire and too stiff a sidewall and extra belts that don't allow the tire to mold around the rocks and grip. The MTR/K does not have a hard rubber compound and the C rated tires have great grip in the rocks.

To the op if you cant take a cut tire then you should not be on the trails as there are not tires that are indestructible that you can still run down the highway. That being said the Irok may be a better off road tire vs the MTR/K but will not ride as nice on the road.

Invest2m4

A little bit goes a long way in compound hardness. The below is data from a tire test. I see the numbers and confirm the performance off-road. The D rating may not be ideal, but I get a full pattern when aired all the way down.

SoK66

Having run both, IROK in radial, no way I'd go with IROK. MTR/k much better rock tire, off the charts better on highway, although neither are great in that regard.

FlatlanderWB

Lots of interesting thoughts and perspectives!

Back in the 90s BFG had a "Moab" MT. It was just like their regular MT but with softer rubber. I got a set of 33s and did a lot of trails with them. They seemed to work very well but it was very hard to find a Moab replacement when I punctured a sidewall. So when I went to 35s I just got the regular BFG MTs. There were several obstacles that I walked up with the softer 33" Moabs that I struggled with or didn't make with the 35" regular BFG MT. So I'm a strong believer in the softer rubber.

When I started this thread I was thinking radials. I really hadn't considered Bias Ply tires. But now I notice that Bias Ply seems to be more sidewall puncture resistant than the radials and may conform better to the rocks than the radials. The IROK Bias Ply 36x13.50-17LT (a 36.8" diameter) has an 8 ply body and 4 ply sidewall and weighs 66 pounds while the Radial 36x13.50R17LT (a 36.0" tire) has a 10 ply body and 3 ply sidewall and weighs 84 pounds. So the Bias Ply has one more sidewall ply than the radial, 2 less body plys and weighs 18 pounds less. I read somewhere that 1 pound in tire weight is equivalent to 10 pounds of load in the Jeep. So 18X4X10=720 pounds equivalent sprung weight???? And they are cheaper. I'm not concerned about long tread life and it doesn't need to be a great highway tire, just safe and stable enough to get me to and from trails. So the bias ply is looking better and better.

Ringer

One thing to keep in mind is that the 36's are a more rounded or balloon shape, where the 37's are more flat. I am running 37x14-17 bias Iroks and am very happy with them. I run them at 5 psi off road and they wrap around everything. So far I have not had any sidewall issues. They do get flat spots, but smooth out after the first few miles. I can cruise 80mph with zero vibration. I am running them with Hutchinson beadlocks and 10oz of beads in each.

In the past I have run lots of different tires from MTR's, TSL's, BFG MT, Hercules Trail Digger, Yokohama MT, etc. my next tires will either be Irok's or Creepy Crawlers.

FlatlanderWB

I like the idea of a flat vs rounded look.

The Interco specs are a little confusing to me. The 36x13.50-17LT and 37x14.00-17LT are both shown to have a 36.8" diameter. But the tread width on the 13.50 is shown to be wider than on the 14.00 (11.8" vs 10.6"). Is this true?

Thanks for sharing your experiences!

Jp3792

I had issues with my 39/13.50/16 iroks. They were round and id get death wobble in 15 different directions. Bias ply are not the greatest for comfort.