Coil Confusion
Q It seems like a lot of the tube cars in your magazine use coilover or air shocks instead of a traditional leaf springs or coil springs. What is the advantage to using a coilover instead of a coil spring and separate shock, like I have on my TJ? What about air springs? Are they better yet?
Gene S.
via 4wheeloffroad.com
A The trend toward coilover shocks and air shocks has definitely taken the off-road world by storm the last 10 years, but while the coilover shock should give you more performance tuning capability, I'm not sure it is always the best choice. Understand that the coil spring supports the weight of the vehicle, whereas the shock controls the movement of the suspension to keep if from bouncing out of control. Leaf springs are dirt-simple. Little to no additional links are required to locate the axle, and they are relatively cheap. However they do have approach and departure angle faults and require additional mounts for shocks and the possibility of requiring a traction bar of sorts.
A separate coil-spring and shock setup, such as what your TJ came with, is great. It will require three, four, or five links to locate the axle, depending on what fits and what type of performance you desire. However, you also need mounts for the coil springs and mounts for the shocks, which can start taking up a lot of room under your chassis and along your axlehousing.
Coilover shocks are simple to mount, requiring as little as two tabs on the chassis and two on the axle. But as with the coil spring, you will also need suspension links to control and locate the axle movement. Unlike the coil and leaf spring design, a coilover shock integrates the shock and spring mounting in one so it must be strong enough to support and control the weight and movement of the suspension. Also, most coilover shocks are rebuildable, allowing you to adjust spring rate, valving, and pressure to fine-tune your suspension. But this comes at a cost. An average coilover shock with springs is over $300 each, whereas leaf springs can be less than half that. Also a coilover shock needs to be charged with nitrogen. This can be done when purchased, but every time you adjust your valving you need to recharge the shocks, so purchasing a nitrogen tank is suggested.
Air shock is commonly used to describe a charged shock with a large shock shaft that replaces both the spring and the shock. These seem like a great upgrade: simple, less expensive, and easy to use. But they are not as tunable as a coilover, and most air shocks are an emulsion-style shock, where the oil and the nitrogen charge can mix, making them less than perfect. Imagine an air shock as a Swiss Army knife, a coilover as a giant Snap-on toolbox, a coil and shock setup as a small Craftsman toolbox, and a leaf spring as a hammer, a screwdriver, a pliers, and an adjustable wrench. Each of these tools can get the job done, and some are better than others but also cost more.
161/2 problems
Q For my 16th birthday my uncle gave me a '58 Studebaker pickup that was placed on a '73 Dodge W200 4x4 frame. The truck came with 161/2-inch rims, which I have found makes tires hard to find, and the tires I have found are somewhat expensive. In your magazine I found that I can get 15-inch rims with the 8-on-61/2 bolt pattern. I was going to buy a set of them, but when I talked to a guy who also wheels a Dodge truck around my area, he said that the steering setup on a Dodge axle knocks the wheel weights off of the inside of the rim. Is this true? If so, is there a way I can change the steering setup so that the weights won't get knocked off? Or should I just get a set of 16-inch rims and live with the price difference in tires? I'm 18 now and leaving for college, so I do not have a lot of money lying around. A somewhat cheap fix would be very helpful.
F.D.
via 4wheeloffroad.com
A Wow, that is one sweet-looking truck! My first advice would be to get some 17-inch wheels and tires. Many new trucks come with 17-inch wheels and the 8-on-61/2 bolt pattern (Dodge and Chevy), so the selection of 17s increases every year. I don't like the idea of going to 15-inch wheels on your 1-ton axles, as there are a bunch of clearance issues.
If that purchase is outside your price range, why not check out some 38x12.5-16.5 Super Swamper SXs tires? These are really tough-looking, have a very aggressive tread, and will bolt onto your rims. I'm not sure what size tires you have now, but judging from the photo, you may be close to 38s currently.
If these tires are too expensive, the next best bet is to search for military surplus tires. Places like Boyce Equipment (www.boyceequipment.com) and 100Dollarman (www.100dollarman.com) both sell used military tires, and many of the Humvees ran 161/2-inch tires in a 36- or 37-inch size. These tires aren't bad, but the 37s are usually the better of the two.