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TNT Motorsports' Rear Disc Brakes - Dakota Stoppers
Installing TNT Motorsports' Rear Disc Brakes.
If there's one universal truth in hot rodding, it's that going fast is cool. But stopping fast is better. We worked with TNT Motorsports in Houston, Texas, to develop a bolt-on rear disc brake kit for two-wheel-drive Dodge Dakotas, based off of their existing 4x4 rear disc kit. If the name TNT sounds familiar, then you've been paying attention to what goes on in the Viper circles-not only does TNT manufacture a host of go-faster goodies for Vipers, but they hold the world's fastest quarter-mile time in a Viper with a 9.67 second pass at 148 mph.
The kit comes complete with new, custom two-piece rotor assemblies, single-piston floating calipers, new rubber brake hoses, new wheel studs, and all the hardware needed to install them.
The kit is fairly straightforward, but it's not for the beginner. While the rear disc kit installed with the prototype 4x4's stock five split-spoke wheels, it didn't clear the solid spoke aluminum wheels on our truck, necessitating new wheels and tires. Both styles of factory wheels are cast aluminum 15-inch wheels. We don't know what the difference is on the inside surface behind the spokes, but something was different, because the calipers didn't clear on our stock wheels.
The rotors, as they usually come from TNT, are a vented design with solid non-drilled surfaces, but we had them drilled to match the Stillen Sport Rotors we installed a few months ago on the front of the truck.
To install the disc brakes, you first have to remove the axles, necessitating draining the differential to gain access to the C-clips, which retain the axles. Then remove the spider gears. You also have to re-route the rear brake lines, as the calipers have a rubber line that attaches to the inside of the leaf spring on the kit-supplied bracket. You could bend the existing hard line that runs from the T-fitting in the center of the axle housing to the stock wheel cylinder, but you'll have to trim off several inches from the cylinder end and straighten out several curves. After starting this, we decided it'd be better, and easier, to just replace the entire hard line between the T-fitting and the new rubber lines for both wheels. The stock emergency brake cable is retained, and doesn't need any modification. The rear anti-lock brakes also won't be affected, as that system is controlled by a separate exciter ring in the differential.
To solve the wheel clearance problem, we contacted Weld Racing and ordered a set of their 17-inch, right/left directional Tomahawk forged billet alloy wheels and fit them with BFGoodrich Comp
T/A tires. We didn't need to go larger than 16-inch wheels to clear the brakes, but we wanted a lower sidewall profile to take advantage of the truck's improved performance, while still being able to fill the wheelwells. With the massive wheelwells Dodge trucks have, this is harder than it sounds! We ordered the wheels "backwards" from the tires to achieve the look we were after-we chose a tire with the overall height of the stock 15-inch tires, so it wouldn't throw our speedometer off. Once we had a close overall height, we then ordered a wheel in the size needed. When it was all said and done, the tires we settled on were P255/60ZR17s, which mount on wheels with a width of 8-9.5 inches. We'll be dedicating a future article to determining proper wheel and tire sizes as a result of this.
The Weld Racing wheels are different from other billet aluminum wheels due to a new manufacturing/forging process. Rather than take a chunk of billet aluminum and carve a wheel out of it, Weld has invested upwards of a million dollars for a forging press that takes a billet of aluminum and presses it into either a wheel center or a rim, using enough pressure to crush Superman. The two forged halves are then welded together. The result is one of the strongest, lightest wheels on the market. The benefits for us are that we can have the look and style of a billet aluminum wheel, yet it's strong enough that we don't have to worry about bending the rim on rough roads or while carrying payload during our daily commute. Traditional billet aluminum wheels can be much softer, and, as a result, many are damaged beyond repair by pot holes and other road hazards. You'll only have to buy one set of Welds.
We also took the opportunity to refill the differential with Red Line synthetic lubricant. We've talked to enough race teams who have chassis dyno'd synthetics to know that when you have to replace the oil in your rearend or trans, you may as well step up and upgrade to synthetics while you're doing it.