The Right Tires And Wheels When you swap from five- or six-lug axles to eight-luggers, you must change wheels. Depending on your brake choices, you may also need to shift from 15-inch wheels to 16s or 16.5s, which also requires new tires. The truck used for this article had 15x8s with 33x12.50 tires before the axle swap. The front calipers and backing plates had been ground slightly for the 15s to fit, but the rear disc brakes required 16s for proper clearance. Everything this truck needed to cure its wheel and tire dilemma was available through Tyres International. In addition to having an incredible selection, Tyres offers one-stop shopping and will deliver your tires mounted and balanced on your wheels. You can even order your lug nuts and locks from the company. This truck called for some serious meats on all-business wheels: 36x12.50R16 Super Swamper TSL radials on 16x10 American Racing type 767 steel wheels. The increase in tire height lifted the 14-bolt to maintain the ground clearance the truck had with the 12-bolt and 33s. The radial Swampers are a hair quieter on pavement and offer the same traction off-road as their steel-belted brethren. A GM Corporate 14-bolt is found under 3/4- and 1-ton two- and four-wheel-drive trucks, making them fairly common. They were also used under dualies and vans, but these have different overall widths from regular pickups and Blazers, and the spring perches are in different locations. If you're doing a swap on a '73-'87 truck, Blazer, or Suburban and are looking at one that's not bolted in a truck, the rearend you want is 72 inches from end to end (measuring from the end of the axle-retaining bolts) and 66 1/2 inches from wheel flange to wheel flange (with drum brakes), and the leaf-spring centering-pin holes are 42 3/4 inches apart. For '67-'72 trucks, Blazers, and Suburbans, you'll need one 70 3/4 inches wide, 66 3/4 inches from flange to flange, and 40 inches from pin to pin.A GM Corporate 14-bolt is found under 3/4- and 1-ton two- and four-wheel-drive trucks, mak A 14-bolt is a heavyweight in more than one way; it tips the scales at about 525 pounds fully dressed with drum brakes. That does wonders for axle droop but makes it a serious pain to install. Gary Valencia positioned the rearend on jackstands (using an engine hoist) to lower the truck onto the rear.A 14-bolt is a heavyweight in more than one way; it tips the scales at about 525 pounds fu If you've located the correct rearend for your GM truck, the springs will sit perfectly on the perches. The axle tubes are larger in diameter than a 10- and a 12-bolt, so new U-bolts will be required. Valencia whacked off the excess thread on the U-bolts once the nuts were torqued to 150 lb-ft.If you've located the correct rearend for your GM truck, the springs will sit perfectly on One of the drawbacks of a full-floating rear axle is that the drum brakes are challenging to service. You must remove the axleshafts and two interlocking hub nuts just to pull the drums. To avoid this and increase the braking power of the truck, this GMC was fitted with an ORU disc-brake kit. The original hubs were used for this swap so the lugs were driven out and the hub and drum separated.One of the drawbacks of a full-floating rear axle is that the drum brakes are challenging The tires still hit, badly. This truck has a 6-inch Pro Comp suspension lift and no body lift. The body is less than perfect, so a Sawzall came to the rescue. The majority of the rubbing was on the front of the fenders, so cutting at the line shown here ended that problem. At the rear, a little metal needed to be shaved at the bottom on each side.The tires still hit, badly. This truck has a 6-inch Pro Comp suspension lift and no body l Here's an example of nicer metal trimming. The front of the fenders were whacked in line with the prerunner bumper, but the trailing edge of the fender openings were swept back. A rolled lip makes it look factory.Here's an example of nicer metal trimming. The front of the fenders were whacked in line w A Detroit Locker from Reider Racing was used in the 14-bolt. The unit for this rearend is a little different from other Detroits. The locker (lower left) functions exactly the same as a Detroit for other applications, but it replaces only the two side gears and four pinion gears inside the original carrier. For most other axles, Detroits replace the whole carrier.A Detroit Locker from Reider Racing was used in the 14-bolt. The unit for this rearend is Another gear-installation kit from Reider Racing was used by Valencia to set up the 14-bolt and check all vital statistics. In addition to the parts provided in these kits, ORU installed new inner and outer axle bearings and seals to complete the rebuild on the front and rear axles.Another gear-installation kit from Reider Racing was used by Valencia to set up the 14-bol The original shocks bolted right up to the mounts on the new rearend. Because the 14-bolt is heavier, however, there will be more axle droop and you should check for adequate shock length. The mounts on this rearend were tweaked pretty badly, so Valencia cut and replaced them with custom brackets that ORU offers.The original shocks bolted right up to the mounts on the new rearend. Because the 14-bolt Mauricio Natera installed all of the disc-brake parts on the 14-bolt, including a custom spacer, new backing plates, rotors, and calipers. The rotors are the same diameter as the front, and the calipers are GM units. Valencia installed Pro Comp braided-steel brake lines from the calipers to custom-bent hardline mounted on the axlehousing.Mauricio Natera installed all of the disc-brake parts on the 14-bolt, including a custom s luminum ORU diff covers were used front and rear. They add fluid capacity to the axles and dissipate heat more quickly than steel. They also look a heck of a lot better. There was some question about their durability on tough rockcrawling trails, which is addressed in our "So What?" sidebar.luminum ORU diff covers were used front and rear. They add fluid capacity to the axles and The brakes were finished front and rear with a Pro Comp braided-steel line kit. These hoses are extra long to allow for plenty of axle movement and are DOT legal. The 3/4-ton swap didn't require any special lines because the 1/2-ton calipers were retained up front, and Valencia bent new hardlines for the rear and used the junction block off the 12-bolt.The brakes were finished front and rear with a Pro Comp braided-steel line kit. These hose The final step in an axle upgrade is to connect them to your 1/2-ton truck's transfer case. One route is to have your original rear driveshaft shortened and have the axle end replaced with one that holds a 1350 U-joint (the 1/2-ton rear used a 1310). The 1350 U-joint is larger and stronger. The best option is to have an all-new driveshaft made. This one is from Denny's Drive Shaft Service, and it features sealed U-joints and an extra-long slip joint. Denny's also provided a new output for the NP205 that accepts a 1350 U-joint.The final step in an axle upgrade is to connect them to your 1/2-ton truck's transfer case A new shaft from Denny's was used up front. While it used the stronger sealed U-joints and heavy-duty steel tubing, it retained the 1310 U-joint and CV joint. This truck has a four-speed, which made this shaft relatively short and, with a 6-inch suspension lift, created the potential at full suspension droop for greater front driveshaft angle than the larger 1350-series joints can operate at.A new shaft from Denny's was used up front. While it used the stronger sealed U-joints and SOURCES Off Road Unlimited (Burbank) 300 N. Victory Boulevard Burbank CA 92504 818-848-2020 www.offroadunlimited.com Denny's Driveshaft 1189 Military Road Kenmore NY 14217 716-875-6640 www.dennysdriveshaft.com Tyres Intl. 4637 Allen Rd Stow OH 44224 800-321-7123 www.tyres1.com Warn Industries 12900 S.E. Capps Road Clackamas OR 97015 800-910-1122 www.warn.com Reider Racing 877-465-5729 www.reiderracing.com Explorer Pro Comp 800-776-0767 « | 1 | 2 | View Full Article By Cole Quinnell Enjoyed this Post? 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