Let's Talk Big Tires for Rock Crawling

[Crowdog]

I just got back from 4 days of rock crawling in Moab. My new Teryx performed beyond my expectations. I am running 26.5" Pit Bull Rockers and they grip real well on the rocks, but I am seeing more and more UTVs running LT tires and would like to explore this a bit more. Pit Bull was originally going to make 27.5x14 Rockers, but they no longer have a timeline on making them. The 26.5" Rockers are basically a 27" tire, so I would like to look at something that is 29" or 30" tall.

Here is my current setup: 26.5" Pit Bull Rocker XORs on 14" wheels.

And here are some other tires I spied over the week:

Reid is running a BFG Mud Terrain. I think he said 28" x 15".

Casey Currie is running 27x14 General's. Looks good for desert, but I'd like a little more height for the rocks. 14" is cool though since I could use my DFR Baja Cripplers.

32"x15" Super Swampers! A little too big and heavy for my liking. But Damn!!!

Brett is running Super Swampers as well. Tire width is awesome for rock crawling, but I would like them a bit taller.

Jagged is running 30x9.50R15 BFG KM2's. Really like the look of these. Wondering how they would do for rock crawling on a light vehicle like a UTV. Maybe some cutting and siping?

Raceline came out with their SxS MT last year, but I haven't seen much about these. They are available in 28x10-14, 28x12-14, 30x10-14, 30x12-14.

Other than Raceline or a mud tire, it sure doesn't look like there is much available with a 14" wheel.

Thoughts?

 

[Darryl89]

Great discussion topic Jon, you are hitting on something I have been watching and have a lot of interest in.
The KM2s seem to have worked pretty good at Moab. I think one real big bonus is the large diameter having a lot less rolling resistance and allows the tire to attack the ledges and rocks from a higher point as well as giving more ground clearance.

One problem I'm seeing is, not too many manufacturers are interested in making 15 inch beadlock wheels. Vision makes 15 inch wheels as you show in one of your photos, but when I talked with DWT, they just looked at me strange when I asked them about building 15 BL wheels.

Brett said he was only running 2-3 psi in his tires at Moab, pressures like that really need beadlocks.

 

[Crowdog]

Brett said he was only running 2-3 psi in his tires at Moab, pressures like that really need beadlocks.

The Super Swampers have a stout sidewall and both sets I saw there did not show hardly any side bulge even at super low PSI. Super Swampers do look super heavy though.

I would really like to see what some siping would do to some of these LT tires. Even cutting out some of the lugs as well.

Reid was running pretty high PSI in his BFGs the first three days (he didn't check until day four at Area BFE). I followed him quite a bit and I wish he would have had something below ten for the first couple of days so I could have observed more. From my perspective, my Pit Bulls had better traction for sure. But his BFGs had the edge in tire circumference (crossing the Golden Crack) and ground clearance. Reid is running 15" OMF beadlocks. If you want a beadlock, I think OMF is about your only option. Thankfully they are good as well!

 

[Crowdog]

Here are some other LT and large UTV tire choices that may work:

* Raceline Wheels new SxS MT Tire - Available in 28" and 30"
* Firestone Destination M/T 235/75R15 - 29.1â€X7.3â€
* Good Year Dura Trac 235/75R15 - 28.9â€X7.5â€
* BF Goodrich KO 215/75R15 (27.8â€X7â€) or 235/75R15 (29â€X7.6â€)
* BF Goodrich 30x9.50R15 Mud-Terrain T/A KM2 (also LT215/75R15 & LT235/75R15)
* Maxxis MT-754 Buckshot 235/75R15 - 29"X9.5
* Nexen Rodian MT LT235/75R15 - 28.9"X9.2"
* General Grabber AT2 30X9.5R15

 

[Brian B]

Remember the first really loose hill climb a few miles into KOH Jon? Go back and look at the videos from that section. The UTV's on LT tires struggled bad there while we cleaned that section on Pitbulls!

I do not believe UTV's have the weight required to flatten out the footprint on a lt tire.

 

[Rusty5150]

I run the 27" BFG's and I only run around 8 psi and they still don't really flex the side wall.

 

[JoeyD23]

I am sold on the tall LT tires! Reid's aka Team Green's BFG's worked awesome in the rocks and he didnt even drop the pressure all that low I dont think? Casey's aka IM0T0's General Tires started to hook up really good as they began to break in.

Not only do the BFG's look awesome but they worked great!!! As the power increases in UTV's I think we are going to start seeing the use of more of these LT and taller tires.

I am planning on using the same KM2 and OMF wheel set up that Jagged X has on my next build!

 

[Crowdog]

I spoke with Bones over at OMF. They are working on what will be their "standard" 15" billet center wheels now. Should be ready for prime time here within a month.

I have used billet center OMFs for a while now and absoultely love them. Once you have invested in a set, you can switch to a new vehicle with just a new center. I have had the same set of wheels run on a Rhino, RZR, Commander and Teryx!

Would really like to know what the 15" OMF + 30" KM2 weighs out at. Jagged?

 

[Darryl89]

I spoke with Bones over at OMF. They are working on what will be their "standard" 15" billet center wheels now. Should be ready for prime time here within a month.

I have used billet center OMFs for a while now and absoultely love them. Once you have invested in a set, you can switch to a new vehicle with just a new center. I have had the same set of wheels run on a Rhino, RZR, Commander and Teryx!

Would really like to know what the 15" OMF + 30" KM2 weighs out at. Jagged?

The 30X9.5-15 KM2 weighes 41lbs. Not sure what the OMF weighes....

Awesome that OMF is going to be building these, I think they will pick up some new customers...me for one...

 

[Crowdog]

The 30X9.5-15 KM2 weighes 41lbs.

Any idea on a BFG A/T KO 30x9.50x15? Guessing 5lbs less per tire.

 

[Darryl89]

Any idea on a BFG A/T KO 30x9.50x15? Guessing 5lbs less per tire.

38lbs per tire...

BFGoodrich All-Terrain T/A KO

 

[Darryl89]

Specs for the KM2's is here...

BFGoodrich Mud-Terrain T/A KM2

 

[Crowdog]

Only three # difference. For three extra pounds, KM2 looks to be a better choice then.

 

[Darryl89]

Only three # difference. For three extra pounds, KM2 looks to be a better choice then.

I agree. And if you watch the rock climbers up in Moab and at the WERock events, many of them will run the KM2s.
Granted, you may have to drop to 2 or 3 psi like Brett was running, but then you can turn right around and pump them up to 25psi and run desert as Jagged X was doing.

I'm not sure that the problem the guys had on the first hill at KOH was just from LT tires, but if that is so, then siping and cutting the tread can help that.

 

[Crowdog]

Pit Bull makes 31/1050R15 Growler LT. Measures out at 30.5", but comes in at 52 lbs. The 10.50" width would be nice for the rocks.

Time to look into lower gearing. What are the options for a Teryx???

 

[tatum]

When I first got my rhino I was running a ITP mudlite tire in a 28x10x12 that would climb almost anything.I think they make them in a 30 inch tire and they are light weight and very flexible.They are not a radial and arent great for fast desert riding but I think for something like Moab the would work really good.The tractor type tread would allow me to climb some narly loose hills with out spining the tires.
In believe if you can keep the weight down then it would save you from lower gearing.

 

[tatum]

Just weighed one of my old tires.25lbs and lugs are super tall.

 

[Darryl89]

In believe if you can keep the weight down then it would save you from lower gearing.

I'll disagree with you there Hans, gearing is a function of diameter, not weight. Horsepower will be affected by weight (rotationg mass calculations) whereas changing gearing will be the most effective way to address tire diameter.
There is no doubt, larger diameter tires have many benefits in the desert and in rock crawling. Save the smaller diameter tires for short course work.
As for the weight of the tires, yeah, it would be great for the tires to weigh less, then it would take less horsepower to spin them, but lighter usually is directly related to durability and strength.
You and I have had this discussion before, I respect your opinons and acheivements in SCORE, but for my use, feel 8 ply tires add a benefit of durability, flat protection and so on.

It was interesting to see the different tires in use at Moab last week, it did seem that both the UTV specific versus the LT tires showed different benefits.

Arctic Cat has 4.0 gearing in their 550 and 650 Prowlers, it appears those could be changed out into the XTZ (which has 3.1 gearing) to pick back up some of the loss of effective gearing...
Maybe it's time for some aftermarket companies to look into different gearing sets for other brands...

 

[Zerofield]

I would go with a TSL Irok's for a rock crawling tire...they just don't have come in smaller the a 35"

Next to that BFG KM2's.

 

[Crowdog]

I found out that the 31/1050R15 Growler LT comes in radial or bias. The radial is 52 lbs. Bias ply is 45 lbs.