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2008 Jeep Wrangler JK Rubicon - Trailrunner

Posted in Features on January 1, 2011
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1250-1300; ME fin < AF, OF < L finis
End, utmost limit, highest point
Finished, consummate, perfect

"Fine" accurately describes Trailrunner, our two-door JK project. It not only turned out well, the older definition "end" or "finished" also describes the project. Our Trailrunner project is complete and on the trail.

We started out to build a two-door JK Rubicon that could not only crawl, but haul on dirt roads while exploring the backcountry. You've read in the last two installments how we did this, with the U-turns and replacements made to make the Jeep work.

With the Teraflex Elite LCG suspension installed the JK was working well, except that with our short 2.5-inch coils we needed straight control arms. Thunder Mountain Truck Outfitters of Logan, Utah, builds very nice solid aluminum arms. We installed our Teraflex ends in a set of four Thunder Mountain long lower control arms. The arms are straight and don't hit the frame during up travel. They're very strong and should hold up well to the pounding they may be asked to take.

Our beefed up OE Rubicon 44 front end was holding up okay, but we somehow felt it was a Frankenstein monster of tubing, plate, and gussets added to make a very weak part work. There is absolutely no excuse for this piece of frontend garbage being used by Jeep on an otherwise stellar vehicle.

To fix this, we installed a new Dynatrac ProRock 44 front end. Designed to fit JK and TJ Wranglers perfectly, the ProRock 44 immediately cures JK front end woes. JK owners can finally say good-bye to bent front housings for good. This is not a welded-up and braced housing. It is a new housing designed from the ground-up to handle tough trails, big tires, and loaded Jeeps.

The new ProRock 44 has big improvements in strength and ground clearance, but reuses our stock (and aftermarket) JK Dana 44F internal parts. It also uses OE JK outer knuckles and brakes. Everything went together easily. Dynatrac has its beefy bracketry in stock positions so there are no surprises or problems when installing the ProRock 44. If you would like bracketry changed a bit to suit your application, Dynatrac will do that, too.

When we removed our OE Rubicon 44 front end and started disassembling it, we were surprised to find the two lower ball joints were shot and the uppers were going fast! Remember, Trailrunner had seen only 6,800 miles of easy on-road use before we got our hands on it, and only about 70 miles of off-road driving afterwards. That's all it took to do in the ball joints. These are more weak parts in the JK front end.

Dynatrac has a solution for the weak factory ball joints, too. Its ProSteer ball joints provide (much) higher strength, longer life, and can be rebuilt without special tools. They are an absolute must-have addition to JK Wranglers.

PhotosView Slideshow

We mounted a set of 37x12.50R17LT Mickey Thompson Baja Radial MTZ tires on 17x8 Black Rock Viper alloy wheels. The MTZ tires are relatively quiet on pavement and shine off-road. We've used these tires on other vehicles in snow, mud, sand, rocks, and dirt. They work. The tough three-ply sidewalls and side biters protect the tire from sharp rocks on the trail. The compound grips, but tire life is good for an aggressive tread design.

We can't thank John Williams, owner of Impulse Off-Road in St. George, Utah, enough for the help he's given us dialing in Trailrunner. The use of his lift alone saved us hours of work and made things much easier. John is also a gear guru and set up our 5.38 Sierra gears in the ProRock 44 perfectly.

Our Trailrunner JK can really move on graded roads and trails, but still works in the rocks. It is fast, slow, fun.

PhotosView Slideshow


Currie Enterprises
Corona, CA 92880
Huntington Beach, CA 92647
Phoenix, AZ 85043
ARB 4x4 Products
Renton, WA 98057
Off-Road Evolution
Fullerton, CA 92833
JKS Manufacturing
Alliance, NE 69301
American Expedition Vehicles
Wixom, MI 48393
Poly Performance
San Luis Obispo, CA 93401
Anaheim, CA 92806
West Chester, PA 19380
RCV Performance
Loves Park, IL
Murray, UT 84107
Tom Wood's Custom Driveshafts
Ogden, UT 84404
West Coast Differentials
Rancho Cordova, CA 95742
PSC Motorsports
Azle, TX 76020
Warn Industries
Clackamas, OR 97015
JB Conversions
Sulphur, LA 70664
MasterCraft Safety
Santee, CA 92071
Impulse Off Road
Expedition One
Ogden, UT 84401
Kilby Enterprises
Burbank, CA 91504
Misch 4x4 Products
Coffeyville, KS 67337
Valley Center, CA 92082
Houston, TX 77066
Black Rock Wheels
Ontario, CA
Gainesville, FL
Queen Creek, AZ 85242
Thunder Mountain Truck Outfitters
Logan, UT 84321

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