Pro Comp Xterrains

Pro-Comp X terrain
All Mud Tires are not the same!
http://www.procomptires.com
By
Don Ferguson

I have never been a big fan of a MUD tire, and I'll tell you why. Â Most of the old style mud tires made way too much noise, did not handle well on a hard road surfaces, had a bad ride, and you could not get good tire mileage out of a mud tire. Times have changed! (And so have I).

There are a lot of tires that look alike, and most tires have tread that look somewhat the same, but that?s where the similarity stops. I know, I have been Testing Tires for some 30 years. As the owner of two Off-Road stores, we sold 4x4 parts, wheels, and Tires. Most customers would come in and asked for a tire by name, because they had them in the past or a friend told them about them. Other customers would ask me what tire I though they should use. That is a hard thing to do, telling a customer what tire he needs. There are so many variables and most tires were not multi-use.

I have been on the leading edge of rock crawling for years, even when many thought it was too rough on vehicles, parts & tires. Tires are as important as your suspension. The right tire can take a really bad spot and make it look like you know what you are doing. If you have ever been out on a trail with me you know what my tire choice was, and has been for the past ten + years, even the same tire size. 33x12.50?s. Â I have a back condition and the thought of walking out is not an option for me. I wont run a tire on my Jeep that I don?t believe in. Pro-Comp changed my thinking

I always mount & balance the tires & wheels we test. The tire machine I own is 20-year-old Coats 40/40. It works very well, but when I tried to mount the 35x12.50 Pro-Comp X terrains, the old Coats ground to a halt. You can tell how strong the sidewalls and safety bead are by how tire installs and how it sets on the safety bead when you try to put the air in. I had to use a tire hammer to assist in installing them on the old Centerlines, and Kevin had to help when it was time to air them up. Installing 5 of these tires was a real job. I always start out with 32 psi. to make sure that the bead sets right. The balancing was too easy, the first tire did not need weights, and there was no tread run out (how true the tread runs on the rim). So on it went. It was the same for the rest of the tires. With the tires on and re-torqued, it was time for the test

Kevin and I had to work at getting in the Jeep, it was much taller with the 35?s in place of the well-worn 33?s I was used to. We started out on the long dirt road that my shop is on. Its surface is a bit choppy; with lose dirt on top of a hardpack. The take off was crisp, the Detroit locker and the tread of the X-Terrains made for good grip. I tried a couple of quick, sharp turns back and forth to get a feel, the Jeep steering was very responsive. (I like these tires) When we got to the pavement we stopped and made a right turn. Take-off at low rpm was good, 1st, 2nd, 3rd, 4th, we?re Doing 50+?(something was missing?) THE NOISE! We both looked at each other at the same time said, ?Where?s The Noise?? Â No noise, not even a little. (Wow) I tried a quick turn back and forth, the tires felt strong without that swaying feeling so common in a lot of big tires.

It was now time to set the tire pressure to the vehicle. A note about tire pressure, the correct pressure will not the same on every vehicle. The tire pressure on the sidewall is what is recommended for the weight listed on the tire. The correct pressure will not be the same on my 2900lb. Jeep as on Kevin?s 5800lb. Ram Charger. Every time you change tires or wheels, check the tire?s footprint, by using chalk or crayon, by marking the tread from inside to outside with a line, then drive straight down the road for a ? to a ? mile, no dirt or water. Check the amount and area of marker that is worn off. All the way across, the pressure is right. This might take some time if you don?t have on board air. This procedure sets the air pressure so the tire has tread contact across the full surface of the tire for longer tire life, and better traction and braking without the tire being under-inflated. We started with the tire pressure at 32psi. Yellow tire crayon was applied across the to the tread on both front and back tires. We then drove straight down the road ? mile and stopped to look at the tread pattern. The tire crayon was wearing off in the center 1/2 of the tire so we dropped the pressure down to 20 psi. The process was followed again; crayon was wearing off in the center 3/4 of the tire. Down to 15psi. The front was good but rear need to go down a little more, we tried 12psi. for the rears. We got it! After a short drive down the road at 55mph, the Jeep felt more stable with even more tire on the ground. We went back on dirt for more testing, turning was good, stopping from 50 was great. My jeep was turning into a pre runner (not really but it sure felt good). Â

Off Road - Locking the Super Winch Hubs, we took off the down the trail and came to our track, a sharp turn, up hill, then a very hard right turn, and further up the hill the dirt was very loose but the Pro-Comps performed very well. I did not need to use 4-wheel drive; the Detroit Locker in the rear and tire combo was all I needed. I stopped and dropped the tire pressure down to 10psi. Front & Rear and got to the real test. (I just wish Santiago canyon. Or The Panamints were still open, On Both of these trails my Jeep broke trail and ran them first).

WET ROCK Â & WATER, Tires at 10 psi. - Â The trail I was on has good climbs, side hill, big rocks and the Jeep had no trouble only had to use the ARB on the big rock part of the trail. I tried really big wet rocks and Hi-centered myself. Turing the steering wheel right or left, in forward or reverse, it made no difference. But I found that when I turned tight, to the right in 2nd gear the Jeep started to move in a clockwise direction and then I was able to drive off. We came out of the riverbed straight onto two- four foot slick rocks (now remember the tires are wet and covered with sand). Â I drove over with no slip, none. I got out of the Jeep to look at the rock, you could have drawn a picture of the tread marks and they would have matched the tread perfect, just black marks and no sign of slipping. Excellent wet and dry traction on the rocks.

SAND with the tires still at 10 psi. - Â The only sand we have close is river sand. Super dry, very deep. The take off was not great, I though I was digging in, but when I brought the rpm up, off I went. Side-hilling on sand and Super Hi speed take offs worked well. Good to Very Good in the sand.

LIGHT MUD Tires at 15psi. front, 12 in the rear. I could not find deep mud, which did not break my heart; I once toured a monster truck and ran my share of mud bogs. (Yuk) - This mud was old lake bottom, black clay. Trying to do a burn out in 4-wheel drive made for a super fast take off, the amount of bite was unreal. I had to run 2wheel drive to make the tires spin. The tread was self-cleaning with little RPM?s,
In the mud I would say the Pro-Comps worked better then most

DEEP MUD Â - When I got home it started to rain & rain then rained some more. There is a road behind my home that turns into a mud pit that I have never been able to go through, let alone pull some one out of. Every year someone trys, and gets stuck, and they walk over for help. And that day was no different, here came a guy, walking from a ? ton Chevy with big wheels and tires. He said that he had been out there for 2hrs trying to get out with no luck, I hooked up the tractor and pulled him out. It starts to rain some more. Its now about 7pm and the Kern County Search And Rescue gets a call, some one is in the mud and guess where? I am a member of the Kern Co. Search And Rescue and I am close, so off I go, not looking forward to winching someone out. (Did I tell you I don?t like mud?) There is maybe 2 miles of muddy road to where this guy is stuck, he made it to where the ? ton went down, but here the clincher, this guy drove a 2001, 5 series BMW 4 door down this road, and is now almost door handle deep. The Jeep made it to him with ease. I got out my 30-foot long tow strap found the tow ring on the Beemer and used a clevis to make the connection. Â I got back in the jeep after telling the guy to keep the tires just turning and the steering wheel straight. I started pulling in reverse and thought the Jeep was going down with the Beemer. I stopped and pulled forward to unhooked the strap from the Jeep, turned around, with the jeep doing what I asked of it, then backed up and rehooked, this time leaving ? the strap loose so I could get going before the Beamer tried to suck me in. Thinking that this pull was not going to work, I told the other driver I would try this once and if it did not work, to lock it up and I would give him a ride. Back inside the Jeep and strapped in, I brought the RPM's up to 3000 and dropped the clutch, the CenterForce gripped and so did the X-terrains. The next thing I felt was a very hard tug but we were still moving, the tires were throwing mud everywhere and my wipers were useless. I towed the Beemer all the way to the pavement without further incident, unhooked him and went home. When the next day dawned, I went outside dreading the cleanup, looked at the Jeep and the only thing that was clean was the tires. The rest of the clean up job took some 5-hours. Â
DEEP MUD, THE BEST? I still don?t like mud. Â Â
Interesting Facts. Â The X-terrains are a directional tire. Â If you buy a set, and I would highly recommend them to anyone that does the serious four wheeling, you will either need to get two spare X-terrains or a regular Mud Terrain tire as a spare. Â These tires are not intended to be run backwards. Â Pro Comp informed me that even the sidewalls are directional and this is part of the reason for the superior performance off road and for the quiet ride on the street. Â My suggestion is that IF you want to run an X-terrain for a spare that you mount the tire to run on the right hand side of the vehicle as statistically speaking, the right side tires are more likely to go flat more than the left side. Â Â Â Â Â Â Â Â Â Â Â