What Is This BS?!
Q What is backspacing, and how do I measure it on the wheels I currently have so I can get new ones?
A Backspacing is the distance from the back edge of the rim to where the wheel mounts to the axle. To measure, lay your wheel down with the outside (the side you see when it’s mounted on the truck) toward the ground. Lay a flat bar across the wheel, and measure from the inside of that bar to the surface that mounts to the axle. This is your backspacing.
Offset is the distance from the centerline of the wheel to the wheel mounting surface of the wheel. If the mounting surface is toward the outside of the wheel from the centerline, it is considered positive offset. If it is on the axle side of the centerline, it is negative offset.
One confusing factor is that the width of a wheel is measured from inside the wheel mounting bead on one side to inside the wheel mounting bead on the other side.
The trend for a long time has been to get wheels with very little backspacing and/or negative offset. I think it is important to try and run as much backspacing as possible, as this reduces the stress on your wheel bearings. This is complicated by tire size, where the tire swings as you turn, and whether the tires will clear suspension components and steering.
Give Me Liberty (Lift)
Q I have a ’12 Jeep Liberty Sport and I want to put a lift kit on it, but I can’t find one anywhere.
A Daystar (www.daystarweb.com) has a spacer kit for the Liberty that will give you 2 inches of lift.
Q I just bought a Warn winch off my girlfriend’s dad for my Chevy. It has cable on it and works fine, but I wasn’t sure if there was a best setup for a winch in deciding on cable or synthetic rope.
A No, there is not a best. Cable guys love the resilience of metal cable. It is less affected by dirt and grit like rope can be, and it lasts a long time. But it is heavy and can kink and be damaged. Plus, metal cable can rust and get sharp wire frays that can stab hands.
Synthetic winch rope guys like the light weight and ease of use. Being lighter, it is easy to throw and drag through deep mud. But UV rays can reduce its life expectancy.
I run both, I appreciate both, and I realize both can be dangerous if not used appropriately. Always wear gloves no matter which you decide on.
4-Link 4 Weight
Q I know that a four-link suspension flexes better than a leaf-spring suspension. My question is will a four-link have the same load carrying capacity as the leaf-spring suspension it replaces in a truck? Thanks.
A The load carrying capability of a suspension is determined mostly by the spring rates of the suspension. A coil spring and a leaf spring can both carry a large capacity. The four-link suspension is simply a way of locating and controlling the movement of the axle: The spring holds the weight, and the shocks control the movement.
Though a four-link suspension can flex very well, it doesn’t always flex better than a leaf-spring suspension. A lot more is determined by the geometry of the link suspension and what is being used for springs. A lot of big trucks have a linked suspension and use airbags as the spring, so yes, it can support a large capacity of weight. Going to a higher spring rate can often reduce the ability for the suspension to flex. I think we’ll see an air-spring suspension in the next few years on Chrysler’s heavy-duty trucks, similar to what the automaker offers on its half-ton. But I’m not sure if it will go up to the 1-ton and beyond, or just the 3⁄4-ton.
I think most companies go to leaf springs for load capacity because they can build them with a progressive spring rate. This means the springs flex less as weight is added. Coil springs are not usually built this way and are more difficult to build with a progressive rate, as the wire diameter/wrap needs to vary over the body of the coil. Leaf springs allow a better range of load weights, whereas coils are designed more for a smaller range of capacity.
Nuts, I’m Confused
Eight Is Enough
Q I just read the Drivelines section of the Aug. ’12 edition of your magazine and noted in the “Ram 1500 All-New For ’13” item that “Chrysler is aiming for best-in-class fuel economy for its light-duty Ram . . . engines will be available with an eight-speed automatic transmission.”
It seems like eight speeds for an auto tranny is just too many. The environmental waste associated with making all those extra gears would more than negate the ever-so-slight fuel savings. I really feel there’s no excuse to have more than five speeds for an automatic or manual transmission. I mean, come on, we’re not talking commercial big rigs here. All these speeds fix one problem but create another.
A I ran your question by the experts at Ram Truck and received this response:
The Ram Torqueflite 8 transmission (8HP45) offers eight gear ratios in a transmission package that has similar to lower weight and size and actually fewer parts than most competitive five- or six-speed transmissions.
This is enabled by modern simulation programs that can identify innovative geartrain designs that give the desired ratios and efficiency.
The First gear ratio of 4.71 allows more efficient torque multiplication versus leaving the torque converter open longer during launches, while on the other end a 0.67 Eighth gear ratio allows low-rpm cruising at highway speeds.
The small and even steps between these eight ratios allow for imperceptible, nonbusy shifting even with eight gears.
The fuel economy gains from the transmission are achieved not only by having the eight evenly spaced ratios maximizing the use of the engine torque curve, but also by having a best-in-class transmission efficiency due to its unique design.
Unlike the other six- and eight-speeds on the market, the TorqueFlite has only five clutch packs and only two of those are open in each gear, which greatly reduces drag.
Chief Engineer RWD Automatic
Transmission, Ram Truck
I recently drove the ’13 Ram 1500 with the eight-speed transmission (“First Drive: Ram 1500 Refresh,” Dec. ’12). Not only do I think it’s going to work out great, but I really hope it finds its way into the Jeep Wrangler behind the Pentastar V-6.
The goal of a multispeed transmission is for efficiency. It keeps the engine in its optimal rpm range almost all the time. The multiple gear options keep the engine from revving or lugging, thus improving fuel economy. The low First gear of the transmission is perfect for off-road use, and it helps get heavy loads moving from a stop. The multiple overdrive gears allow the engine to rev calmly at highway speeds when less power is needed.
Imagine riding a bicycle. A single-speed bike is great when you’re a kid with a lot of energy, but as you get older you realize a multispeed bike allows you to get moving from a stop, climb hills, and speed along open road or trail without overworking your legs and lungs.
Mike, you bring up a good point about the value of complexity. The fact is the manufacturers of the world are constantly striving for better and better products, and oftentimes this means more complexity. For example this eight-speed transmission is very neat and works well but it is completely computer controlled. There is no mechanical shifter. Of course, most vehicles have been using drive-by-wire throttles for years, so a drive-by-wire transmission isn’t really that unusual. Plus, these controls allow the transmission to shift smoothly and hold the best gear for the vehicle at any given situation, but still allow driver override if need be. In addition, the transmission has intelligence to learn from output speeds and wheel speed sensors what the axle gear ratio is. This allows it to compensate and adjust shift patterns accordingly, which is perfect for guys like us who like to change axle gearing when going to larger tires.
It is human nature to have a fondness for older technology, but though a carburetor and three-speed manual transmission worked great in the 1940s to the 1970s, the computer age is not going away. The OEMs are constantly striving for the next best thing, be it eight-speed transmissions, small engines with turbos, or direct-injection gasoline engine technology. Luckily, there are still plenty of off-road enthusiasts who work at these OEMs and they can apply technology to make their trucks work great off-road as well as on-road. And never fret—there are plenty of old trucks out there with fewer gears and less high-tech powertrains you can rebuild to be your perfect 4x4.
Since your question seems relevant to many readers I’m picking you as this month’s Nuts, I’m Confused winner, and I will send you an Ultimate Adventure 2012 shirt.
Confused? Email your questions about trucks, 4x4s, and off-roading tech using “Nuts, I’m confused” as the subject and include a picture (if it’s applicable). Digital photos must measure no less than 1600 x 1200 pixels (or two megapixels) and be saved as a TIFF, an EPS, or a maximum-quality JPEG file. Also, I’ll be checking the forums on our website (www.4wheeloffroad.com), and if I see a question that I think more of you might want to have answered, I’ll print that as well. Otherwise drop it old-school style with the envelope addressed to the address below. Letters published in this magazine reflect the opinions of the writers, and we reserve the right to edit letters for clarity, brevity, or other purposes. Write to: Nuts & Bolts, 4-Wheel & Off-Road, 831 S. Douglas St., El Segundo, CA 90245 fax to: 310.531.9368 Email to: firstname.lastname@example.org