I have a ’98 GMC K2500 that I use as my daily driver and tow rig. I would like to get some 17-inch wheels for it (I have a set of nearly new 17-inch tires in the garage), but I do not understand why the wheels I find are not hub-centric. I know the factory wheels are hub-centric because I have to pry them off the hub, but it seems to me this would be important on a truck that sees cargo hauling duty. Is it important for the wheels to be hub-centric?
A hub-centric wheel is aligned on the hub by the center hole, whereas a lug-centric wheel is aligned by the lug nuts. Your 2500 uses eight lug nuts, so, no, you do not need hub-centric wheels to replace your factory wheels. OEMs use hub-centric wheels for better alignment of the wheel to the hub and to aid with braking, but it doesn’t aid in load carrying capacity. A properly rated wheel will support the load whether hub or lug centric. Most aftermarket wheels are not hub-centric since OEMs use different hub diameters yet universal lug diameters.
More Tons Mean More Fun
I have an ’85 Chevy Silverado 1⁄2-ton and want to make it a 1-ton. I recently was told that the 1⁄2-ton frame is not strong enough for the 1-ton drivetrain. I noticed in the Aug. ’11 issue that you had a ’75 Chevy K-10 with a 1-ton drivetrain [“Ultimate Revival”]. Is there anything that I have to do to the frame in terms of making it stronger or any other part of the truck?
This is a great question, Tyler. To help us provided you with the most thorough answer, I consulted with the fullsize GM experts at Offroad Design, www.offroaddesign.com. Offroad Design makes a host of upgrades for GM wheelers, and the Watson family has piloted their fullsize trucks everywhere from Baja to the Hammers to multiple Ultimate Adventures. Here’s what they had to say.
“There are lots of 1⁄2-ton trucks, Blazers, and Suburbans with 1-ton axles, and in general they hold up OK. The 3⁄4-ton and 1-ton frames have thicker material and are stronger, but they’re not perfect either. There are a few weak spots on all the frames that are a problem no matter what axles you’re running. The steering gearbox area is number one, as they all crack there. Another area to watch is the engine crossmember. They often crack too. And last but not least, the rear upper shock mounts tend to crack the frame eventually as well.
“With those areas fixed, we find that over time and with a lot of flexing cycles, the sheetmetal of the cab will start to fatigue and crack before the frame becomes a problem. Ideally you should look at a rollcage, extra crossmembers, and possibly some frame boxing to keep the frame totally rigid, but don’t be afraid to build the truck and use it. You can always just add the extra strength as you can and as you need it.
“There is a lot of fun to be had with what you have. I do recommend spending some time checking your truck over between trips just to catch small problems before they become big problems, but that’s standard procedure for anything you use off-road.”
5.0 for More Go
I have a ’93 Ford Ranger extended cab 4x4 with the 4.0L and five-speed transmission. It has an 8-inch suspension lift with a 3-inch body lift. I would like to swap in a 302ci but am having trouble finding the right adapters to bolt the engine to the transmission. I am not exactly sure about the whole process. Any info would be greatly appreciated.
You’re in luck, as the 302ci engine is a very popular swap among Ranger and Bronco II enthusiasts. While the complete conversion is pretty involved, there are a few aftermarket companies that can help you out. The transmission adapter you’re looking for is PN 712541from Advance Adapters, www.advanceadapters.com. Advance Adapters can also provide you with the engine mounts and other miscellaneous adapters that you’ll need for the project.
Remember that wiring, cooling, intake and exhaust routing, and your suspension will all need to be addressed when you squeeze in the V-8. Depending on whether or not your truck will see the street post-conversion, you will need to check your state’s emissions codes to make certain that your swap is legal and up to code.
On the Clock
In the July ’11 issue the feature “Chevy Function” has a caption that says the truck owner clocked the transfer case to adjust for the angle of the front driveshaft. What does this mean? I have a ’91 Chevy 4x4 1⁄2-ton, and I am planning on doing a solid-axle swap just as the guy in the article did. I got a lot of info from that article and will use it as I do my build. What does it mean to clock a transfer case? Will I need to do it to mine? Any help will be greatly appreciated.
Clocking a transfer case simply means to rotate or change the position of the transfer case, just like changing the hands of a clock. The output yokes on the transfer case are where your driveshafts connect, and in many cases clocking the case will lower the yokes so as to decrease the driveline angles. In this case the factory NP241 transfer case was clocked down (lowered). This was done to lessen the angle on the front driveline.
As you increase the degree at which your driveshaft operates, you raise the chances of driveline joint damage and wear. How tall you plan on making your Chevy and the type of travel you expect both play factors in making your front driveline live. If you’re planning on doing a similar build as the Chevy featured, then I would say yes, plan on clocking your NP241. You will need a clocking ring, which simply bolts to your factory transfer case. A good source for clocking rings is North West Fab Works. The company offers a variety of clocking rings for New Process/New Venture, Dana, and BorgWarner. You can check out the full list of clocking rings at www.northwestfab.com.