Subscribe to a magazine

August 2008 4x4 Truck Tech Questions - Tech Line

Willie Worthy | Writer
Posted August 1, 2008

Send Us Your Questions

Where To Write
Address your correspondence to:
Four Wheeler
6420 Wilshire Blvd.
Los Angeles, CA 90048.

All letters become the property of Four Wheeler, and we reserve the right to edit them for length, accuracy, and clarity. The editorial department also can be reached through the Web site at www.four Due to the volume of mail, electronic and otherwise, we cannot respond to every reader, but we do read everything.

Is Tire Cutting A Groovy Deal?
Qusetion: Have you ever "cut tires," and can you recommend a good tire knife for cutting tires? I have set of 33x13.50R15 Mickey Thompson bias-ply Baja Claws. They have always been good tires, but where I live, the mud is like super glue. I have two sets of tires and wheels for my Jeep, and I only use the Claws off-road.

Like I said, the mud is like super glue, and it sticks to everything. I've never encountered mud like this, until I moved here. It's heavy, it's thick, and it doesn't seem to have any problem adhering to even the most aggressive mud tires. I've seen Boggers, SSRs, and even the mighty IROK tires get caked. No tire seems capable of shedding this stuff! I have a Chevrolet 350, and with my foot on the floor, it seems this stuff will not clear out.

Does tire cutting help with mud? I'm thinking of cutting out the smaller lugs (leaving the center for sidehilling), to open up the tread. I'm open to any suggestion you might have.

I just have never wheeled in anything like this mud. It's pure Northern Arizona sludge. I've tried every trick I learned up North (Washington state). I've tried applying Armor All to the tires and I've even tried Pam (it kind of works till it wears off). I even painted my tires, which was the ultimate cheat back home. This mud just sticks to everything! Would cutting some of the lugs out help?
Jason Rowley
Grand Canyon, AZ

Answer: An inexpensive low-wattage tire groover such as the ones that Speedway Motors ( sells for 40 bucks would take a long time to cut out the blocks and just about kill your arm before you were done. You would really need the company's Transformer version that costs about $360. Plus, it is a lot of work.

Second, what makes you think that by cutting a few blocks out, you can make a better design mud tire? You could cause more problems than you gain. The Claws work in mud better than most tires. Try running them backwards. They make a lot more noise but bite harder and may clean out better. I run them in the sand dunes backwards (but I hate mud, so I don't play in it). Boggers are most likely one of the best mud tires on the market even they fail in the stuff you have, which, by the way, is what geologists refer to as "caliche." It is what glues other minerals together to form certain types of rocks such as sandstone. When in Moab, I don't go out in some areas if it has rained because of this type of mud.

As for the IROK, it was not designed as a mud tire, but an all-around tire that would work for just about anything. I know because I was one of the five people that had a hand in its design. They do, however, work pretty well in most types of mud.

The only answers are (1) stay off the dirt roads in mud season (besides it really tears up the road), (2) run the tires at very low air pressure, and (3) use lots of wheel speed, as the extra flex and high speed will help clean them.

I have cut tires, but only some 1/4-inch-wide strips, not big blocks out. My Claws are cut a bit to improve side traction, and I have cut both my Pro Comp M/Ts and my XTs just a bit to make them better in the snow. On the M/Ts, all I think I gained was to make them a lot noisier going down the highway and chunk off pieces of rubber.

Wants Heat Insulation For Stripped-Down TJ
Qusetion: I have a '98 Jeep Wrangler that is slowly becoming nothing but a trail rig. I say that because I have started stripping the luxuries like the stereo, all the speakers, the back seat, the airbags ... and the list goes on. Recently I removed the carpet and the insulation from the whole interior. I know there are products out there that I can roll onto the floor to protect it from rusting. My question is, do any of these products insulate the floor to keep the drivetrain from burning my feet?
Eric Callen
Irwin, PA

Answer: I recommend you start off by trying to reduce as much heat transfer to the floor as possible. Two heatshields-one between the muffler and body, and one for the catalytic converter-will make a world of difference. Flowmaster (, I believe, sells some. Try to keep a 1-inch air gap between the shield, muffler, and body. I have used both heavy aluminum and stainless steel in the past. You will have to figure some type of a bracket that attaches to the floor to hold it in place. I have even gone as far as to take some exhaust tubing that has a larger diameter than that of the exhaust pipe, split it in half lengthwise, and then tack-weld it over the main exhaust pipe about a half inch above it to provide an air gap. It's a bit of work to do this, but the results are worth it, especially if the exhaust pipe comes anywhere close to the body.

The next step is some good quality insulation. My feeling is that you want to keep the heat away from the floor, so the insulation needs to be on the underside of the floor. You're going to want to glue the insulation to the body, so it has to be, like, super-clean of grease and oil. Soap and water just won't get it clean enough; use something like Gunk, clean it off with water, and then use a brake cleaner on the metal where you want the insulation to stick. You're going to want to use the silver foil type stuff that has a self-adhesive backing. Sources of material that I have used are Koolmat (, ThermoTec (, and Dynamat ( Let me stress again that the surface has to be clean for it to stick on properly. I suggest that you make some paper patterns for the area that you want to cover and put on the insulation in small sections, as it will make it much easier.

Most of the spray-on/roll-on bedliner materials will help somewhat too. On my flatfender Jeep, I sprayed on Herculiner on both sides of the floor and then sanded the underside fairly smooth before applying the insulation. I made heatshields for the exhaust system. It's all been on for about four years now, and it works so well, I could drive the Jeep in bare feet if I needed to.

Load More Read Full Article