Okay, it's not that simple, which is why companies like Superlift Suspension Systems serve as a source of appropriate lifts for your application, along with an encyclopedia of information to make sure you've got the right combo. Technology has come a long way in providing a safe, functional lift for 4x4s. Gone are the days when a few extra inches of height for off-road clearance turned highway driving into an exercise in figuring out how long it takes the wheels to catch up to your steering. But a missing link remains for the end user - not a mechanical link, but an informational link. You slap on those giant knobbies, lift your 4x4 to accommodate them and let loose a whole series of reactions you hadn't counted on. It's that old physics thing about every action triggering an equal reaction.
To anticipate those reactions or to ensure that an initial action eliminates those nasty, little buggers, we went straight to Bret Lovett at Superlift to take a look at some typical scenarios. He's been involved with off-roading since he could walk and with Superlift for 31 of the company's 33 years.
Since most readers of Off-Road Adventures probably don't fit into that first category, Lovett concentrated on category two - the daily driver/weekend off-road rig. "Making the right decision for your lifestyle, vehicle and budget is not really that complicated." he insists. "Whatever you want to do has probably been done many times before. It's a matter of doing the research, then verifying your choices with experienced fellow off-roaders, etc."
We start with the obvious - what size of tire do you want to run? You decide on "X" tire size which will require "Y" amount of lift to allow for enough fender clearance as the suspension articulates. The lift will vary depending on the stock wheel backspacing (the distance from the inside lip of the wheel to the wheel mounting surface that bolts to the hub). According to Lovett, most suspension manufacturers list maximum tire/backspacing data in their literature or on their websites. Also, many tire/wheel suppliers will let you mount one up and fit-check the combination. Even so, it's still good to understand the mechanics:
The next consideration is what your stock vehicle gives you to work with. "I need to stress the point that any given vehicle's powertrain, drivetrain and chassis has a limited degree of factory 'overbuild'," notes Lovett. "If you want to run 38-inch tires on an older Ranger, forget it. Subjected to serious off-roading, the factory parts will not survive if the Ranger is shod with anything taller than a 32-33-inch tire."
Beefing up the platform won't necessarily solve all your problems. "You're just moving the fuse - there will always be a weak link," Lovett says. "The key is for that weak link to be easily repairable and relatively inexpensive, like a locking hub." Lovett has firsthand knowledge of breaking things, seldom at a convenient time or place, so he knows about weak links.
One of the primary questions when you're juggling an off-road build with a budget is, "What do I need to do this right, and if I skimp what are the tradeoffs?" Lovett uses a Jeep JK Rubicon as an example of possibly exceeding the vehicle's gearing ability with over-sized tires.
"It's common knowledge that the Dana 44, the stock gears on the Rubicon, will handle 33-inch tires. When you install a lift and upsize to 35-inch meats, an axle shaft upgrade may be in order depending on the terrain and your right foot tendencies." The Dana 44 will live with the tire upgrade, especially with hardened shafts, but Lovett questions the quality of life.
"With 35-inch tires you won't be a happy camper with the stock 4:10 axle ratio. The taller tires effectively raise the final drive ratio which takes the little six-banger out of its optimum power band." Lovett's solution to offset this domino effect is installing 5:13 axle gearing.
"The rule of thumb," he says, "regardless of the vehicle (unless it's diesel powered), is that a three-inch increase in tire diameter is tops unless you want to spring for an axle gear ratio change and possibly heavier axles."
In terms of budget, Lovett stresses research as a more valuable asset than a checkbook. "Throwing money at something doesn't ensure success," he frankly points out. Of course it helps to deal with a company like Superlift that provides a full range of lifts, along with the technical ability and real-world experience to provide help through the process.
If you're hungry for your own real-world research, check out Superlift's website (www.superlift.com) or the company's 1254-acre ORV Park in Hot Springs, Arkansas (www.orvpark.com). Every year, Superlift hosts organized events like the annual 4 Wheel Parts Wholesalers/Superlift Customer Appreciation Run. The first 100 registered vehicles get in free and Superlift brings along a few modified Jeep platforms for prospective customers to drive on the trail (with a co-pilot). That way you can tap into Superlift's savvy to feel your way through the big wheels/big lift process, so you'll be happy with the end result.