Testing 30-inch Tires at Prairie City SVRA
By Jon Crowley
We last did a tire review back in 2012 (see 30-inch Tire Review). At this time, ourRZR XP 900 was our test mule and we tested GBC Mongrel, ITP UltraCross, ITP BajaCross, Maxxis Big Horn and STI Roctane. Since then, not only has the UTV market exploded, but also the number of tire manufacturers. Since so much has changed, we decided that it was time for a new look at the 30-inch tires.
We decided to use our Polaris GENERAL as the test mule this time around. The GENERAL has a Racer Tech 2-inch lift and 2.5″ FOX RC2 shocks from Shock Therapy. The lift gave us just enough clearance at full-bump for the bigger tires (stock are 27-inch) and the bigger shocks let us drive it like a race car without worrying about g-outs and getting out of shape in rough terrain. We also added 3/8″ Factory UTV UHMW skid plate to protect the underside of the car while bouncing through the rocks.
After contacting the tire manufacturers about doing a new UTV tire review, we got seven different tires for us to test. To be most fair, we should have used the same wheel for each tire, but that would have proved cost-prohibitive for me. Take that into account as not all wheels weigh the same. We also opened it up to both 14-inch and 15-inch wheels. A 14-inch wheel weighs less than a 15-inch wheel but tire weights vary between the two as well. This is why we give a tire only weight, plus a tire + wheel weight. In addition, six of our wheels were beadlock, while the Arisun Aftershock XD was mounted on a traditional wheel which weigh less. Not completely fair, but that is what we have.
The first thing we did was weigh and measure each tire. Although horsepower of today’s UTV has increased significantly over the last few years, rotating mass still greatly affects performance, drive train durability and suspension. But what you gain in performance with a lighter tire and wheel can also be given away in durability. But then again, heavy tires don’t automatically equate to durable tires, so take it all with a grain of salt because it is very difficult to come up with a repeatable test for durability.
30-inch Tire Specifications:
|Tire||Ply||Tire Weight||Tire + Wheel Weight||Mounted Height||Tread Depth||Mounted Width||Max Load||DOT||Price|
|Arisun Aftershock XD –30x10R14||8-ply Kevlar||34.2 lbs||48 lbs||29 1/2″||1/2″||10″||615 lbs||No||$199.95|
|BFG Baja T/AKR2 – 30×9.50R15||N/A||38.2 lbs||55 lbs||29 1/4″||1/2″||9 5/8″||N/A||No||$258|
|GBC Mongrel – 30x10R14||10-ply Nylon||35 lbs||50.6 lbs||29 5/8″||1/2″||9 5/8″||936 lbs||Yes||$205.77|
|GMZ Ivan Stewart Edition – 30×9.50R15||8-ply Nylon||39.4 lbs||57.8 lbs||29 1/2″||3/4″||10 1/2″||1000 lbs||No||$239.95|
|MRT RACE – 30x10R14||8 Ply Kevlar||38.2 lbs||52 lbs||29 11/16″||7/16″||10 1/4″||1280 lbs||No||$286|
|Sedona Rock-A-Billy – 30x10R14||8-ply Nylon||36.2 lbs||51 lbs||29 9/16″||1/2″||10 9/16″||616 lbs||No||$229.95|
|STI Chicane RX – 30x10R15||8-ply Nylon||38.8 lbs||54 lbs||30 1/8″||7/16″||9 9/16″||937 lbs||Yes||$211.21|
** Price – Most manufacturers use suggested retail (MSRP) while a few use Minimum Advertised Price. The column above is not an apples to apples comparison for that reason. In many cases, you can find these tires for less than what is listed.
** Ply – Today’s ply ratings do not count the actual number of body ply layers used to make up the tire’s internal structure, but indicate an equivalent strength compared to early bias ply tires. UTV tire manufacturers are hot on advertising this number, but don’t take it to mean a higher number is always the stronger tire. And in the case of the BFG KR2, ply is not even listed.
Arisun Aftershock XD
Arisun Aftershock XD – Xtreme armor with Aramid protects against flats utilizing two layers of reinforced nylon, then a third belt of Aramid composite material that wraps around the shoulder and is sandwiched between another layer of nylon to protect against punctures, cuts and abrasions. Closely spaced lugs produce a smooth ride over hard surfaces with siped knobs that grip when climbing over rocky terrain.
BFG KR2 – The BFGoodrich Baja T/A KR2 UTV tires are engineered with race-proven CoreGard technology and designed to meet the specific performance demands of todays high-performance UTVs. Mud-phobic side bars to release compacted mud and stone ejectors to clear out rock paired with a proven race winning tread design offer superior performance in soft dirt, enhanced traction in the mud, and improved braking in loose, rocky dirt. The KR2 is currently available in the 30×9.5×15 size. More:BFG Baja T/A KR2 UTV Tire
GBC Mongrel – Now four years after its 2012 debut, the new 10-ply rated Kanati Mongrel radial tire features a re-engineered carcass and sidewall all while keeping the tire weight to a minimum. With the growing size and increasing horsepower of modern sport UTVs, Mongrel tires are sure to remain the preferred choice of professional and recreational drivers. Read more:New 10-Ply Rated Kanati Mongrel UTV Tire from GBC Motorsports
GMZ Ivan “Ironman” Stewart Edition Tire – GMZ engineers went to work creating a durable 8ply DOT radial construction that will hold up to Ivans punishment. With an addition of an innovative shoulder lug that extends down the sidewall that will help deliver extra traction in soft terrain and was also designed to deflect rocks and avoid sidewall punctures. With our specially engineered compound and 100% natural rubber used we were able to create a tire that can deliver the power to the ground, keep you in control at all times and most important pass the Ivan IRONMAN Stewart test. More:GMZ Race Products Inc unveils Ivan “Ironman” Stewart Edition Tire
MRT RACE – MRT RACE 30x10R14 8 Ply , 1280lbs Load Rating. Engineered as a Do Everything rugged Tire. Race, Rocks, Trail and Road. Delivering Kevlar Triple Armor Belt No Flat Technology and special compound to increase grip and wear. Complemented with the proven “RACE” tread, this tire will provide traction and protection in all surfaces. Quality When You Need It!
Sedona Rock-a-Billy – Designed to match the high horsepower, high-speed requirements of today’s side by sides, the Rock-a-Billy is an 8 ply, puncture-resistant radial with a tread compound designed to outlast, out-grip, and out-perform the competition. An aggressive tread design with integrated side lugs grip in extreme riding conditions and also feature integrated rock ejectors and a built in rim guard for added protection. So no matter what the terrain: rocks, hard pack, or trail: the Rock-a-Billy is ready to take you there. More:Sedona Tire & Wheel Introduces the Rock-a-Billy Tire
STI Chicane – The Chicane RX tire combination results from STIs years of hands-on experience and proven testing that has produced a broad line of high-performance tires and wheels. Featuring a unique split-knob non-directional tread design, the Chicane RX line is DOT marked and ready to hit the road for powerful performance and high-mileage value. The designs 8-ply carcass offers the perfect mix of durability, light weight, and smooth ride flexibility. More:STI Announces the All-New Chicane Tires
Rock Crawling Test
We tested all seven tires at Prairie City SVRA in a variety of situations. Tire pressure was set at 12 psi. While we feel all of these tires would benefit from lower air pressure in a pure rock crawling scenario, 12 psi is a pressure that is used for wider terrain flexibility (e.g. desert and rocks like you would see at King of the Hammers).
As seen in the video below, all five tests we conducted on manmade obstacles that varied in difficulty and type of test.
Rock Crawling – River Bed
The “River Bed” has large boulders scattered along a slight uphill. Ground clearance is key, but we paid close attention to tire flex to gauge how stiff the tires were. More flex not only can give you more gription, but also helps absorb some of the bouncing.
Rock Crawling – Pyramid Descent
The pyramid was used for both climb and descent. We paid close attention to sidewall flex and traction.
Rock Crawling – Sand Covered Concrete Climb
The sloped concrete was covered with sand and was driven at slow speed to test tires traction.
Rock Crawling – Top of the Stair Step Climb
The stair steps were also a great illustration of the tires ability to gain enough traction to climb both front and rear at the same time without much of a bump. A few climbed right up real smooth, while others needed varying levels of a run at the double step obstacle to get up.
Less than an inch separates the shortest and tallest of the seven tires, so ground clearance did not play much of a role in our tests. That is something to consider if 1/2″ more ground clearance would make a difference in your situation.
Test Feedback – Short Course (hard pack):
Rock-a-Billy tires were the best looking tire with the sidewall bite and he gaps in-between for softer terrain like mud. Had decent flex, but would perform better at a lower PSI in the rocks.Arisun Aftershock XD – surprisingly good for rock climbing. Also, the kevlar belts provide great durability. The tire had very stiff side wall and carcass, but combined with the closer treads it gripped well on the rocks.
GMZ Ivan “Ironman” Stewart – Very stiff sidewalls and carcass and the forward thrust was decent on the rocks. This tire seems very stout and should perform better at lower PSI.
STI Chicane RX – Good sidewall flex, but spins/slips in the rocks more than I would like.
GBC Mongrel – Forward bite was decent crawling up slick and dirty rocks, nice sidewall flex which allowed the tires to absorb the rocks.
BFG Baja T/A KR2 – Excellent tire overall with great sidewall and tread flex, plenty of traction on both slick and dirty rock. One concern I have is pinch flats since there is so much sidewall flex. We did not experience any flats with any of the tires, but it is very tough to test durability over seven different tires equally.
MRT Race – This is a very good tire with medium flex, the traction overall was fairly good, about an 8 out of 10 in my opinion. The side and forward bite were decent on both slick and dirty rocks. Kevlar belts are a plus.
- BFG Baja T/A KR2
- MRT RACE
- Arisun Aftershock XD orGBC Mongrel
Rock-a-Billy – Tires spun a bit more than I would have liked on the sand covered concrete. Great looking tire with aggressive sidewall.
Arisun Aftershock XD – This tire had lot of grip on the slick rock and the tire went where you pointed it. Overall a good tire on the rocks. Like that these tires contain aramid fibers (Kevlar).
GMZ Ivan “Ironman” Stewart – Seems to have a stiff side wall and tire, we got a lot of wheel bounce out of it and we had more spinning on the smooth rocks than I would have liked to see. Aggressive looking tire with deep lugs. I think this tire would do better in the desert and better in the rocks at a lower PSI.
STI Chicane RX – Needs a little more bite maybe due to rounded profile. Sidewall has decent flex.
GBC Mongrel – Needs a little bit more grip, the rounded tops and sidewalls don’t seem to have as good of traction, they slide around a little bit.
BFG Baja T/A KR2 – Good grip on the slick rocks, good sidewall flex, did great crawling over the big boulders, and had a smooth ride due to the sidewalls flex. Great overall performance.
MRT Race – Little bit more wheel spend than I would like on the smooth rocks. Decent sidewall flex made it a smooth ride.
- BFG Baja T/A KR2
- Arisun Aftershock XD
- MRT Race
Short Course – Hard Pack
We tested all seven tires at Prairie City SVRA on the track that is used for VORRA and Nor Cal Rock Racing. The track condition when we tested was dry and hard packed in all cases except on the outside of some of the corners. The track has one fast uphill jump, a few smaller rollers, several fast sweepers and a few hard corners.
Several laps were taken on each tire, and although we didn’t do any specific timing or measuring, we paid close attention to tires ability to steer, handling under hard braking, drift predictably and accelerate.
BFG Baja T/A KR2
STI Chicane RX
Arisun Aftershock XD
GMZ Ivan “Ironman” Stewart
Test Feedback – Short Course:
Rock-A-Billy – Braking performance and acceleration were adequate. However, the side roll and side bite were a little marginal on the slippery course. Overall, it seems like a solid performer.Arisun Aftershock XD – There was some front end push and difficulty steering the front end. I could never pick the same line due to the steering difficulty. The rear end hookup and the side bite were both decent, but the bite was sketchy with the square edge.
GMZ Ivan “Ironman” Stewart – Lots of side sliding and it was tough to get forward grip. I found myself constantly fishing for traction. Seems like a very stout carcass that could handle a lower air pressure to give more sidewall flex without compromising durability.
STI Chicane RX – Not enough side grip, it liked to slide and keep sliding. The steering input is a little positive but they wash around. Tire performed better in the small amount of loose terrain on this track.
GBC Mongrel – Predictable tire on hard pack and runs through the ruts pretty good, on the soft stuff you can hang it out a little bit, I get a little more sidewall flex in the corners, I would prefer more forward and side bite.
BFG Baja T/A KR2 – This was a very predictable tire with tons of forward grip and side bite, a very flexible sidewall, and it handled deviations in the track well. Overall, this is an awesome tire.
MRT Race – Very predictable handling, good forward bite and side handling. These tires do great in both the hard pack and especially in soft dirt. Great turning and breaking. Overall an awesome tire.
- BFG Baja T/A KR2
- MRT RACE
- Sedona Rock-A-Billy orGBC Mongrel
Rock-a-Billy – This tire preformed well under acceleration and braking. The sidewall looks pretty cool, and overall its a pretty decent tire.
Arisun Aftershock XD – A lot of push in the front end, and you had to keep the corner steering. You couldn’t push it into the turns as hard, if you jumped on the gas the back end would have a tendency to come around on you.
GMZ Ivan “Ironman” Stewart – Tire tended to slip and slide on the hardpack. Not much sidewall flex.
STI Chicane RX – On the hardpack course, this tire had lots of wheel spin, making a lot of dust. It pushes through the turns and I couldn’t get the front end to turn.
GBC Mongrel – It was a little squishy going into the turns, and broke traction fairly easily. Decent tire, if you peddled it, it would point you in the right direction and go.
BFG Baja T/A KR2 – This tire was the first we’ve seen today that actually had flex in the side wall at 12 psi. It was very predictable, If you turned it went, if you stabbed the throttle, it went. Overall a very nice tire with great steering capacity.
MRT Race – Good traction, cornering, and steering. These tire go where you want them to and don’t slip around much. Overall a great tire.
- BFG Baja T/A KR2
- MRT RACE
- GBC Mongrel orSedona Rock-A-Billy