Our project '07 Toyota Tundra has been lifted for over a year now, and we've thoroughly enjoyed its on- and off-road manners afforded by the Pro Comp suspension, wheels, and tires. The only drawback to its aggressive stance and imposing stature has been a severe shot to our wallet each time we need to refill the fuel tank. In stock form, our Tundra averaged between 17 and 19 mpg of gas on the highway and 15 to 16 mpg around town. After the lift installation, and since we didn't regear the rear axle to accommodate the new 35-inch-diameter tires, that figure dropped to 15 mpg highway and 13 mpg in the city. Needless to say, it hurt a lot to gas up this truck once the price at the pump jumped to $4.69 this year, even though we loved the looks of admiration we received from other motorists.
We could have regeared the truck and found more efficiency in the engine with some choice modifications, but since our truck is leased and about to go back to the factory we chose to lower it on low-profile rubber to regain some mpg and find out what it's like to own a dropped Tundra. We took the truck to 4 Wheel Parts in Laguna Hills, California, to have the lift kit removed and a new Ground Force drop kit installed.
The kit (part number 9852) dropped the front suspension 2 inches via shorter coil springs and lowered the rear suspension 4 inches via new leaf-spring packs and dampers. An optional C-notch is available for the rear framerails to increase axle travel, and it's something we highly recommend installing if you can. We couldn't cut up our truck due to the terms of our lease and found that just a few hundred pounds of weight in the bed was enough to sack out the rear suspension over bumps and ruts. With this kit, towing and hauling is a pretty rough deal without the notch.
When we removed the 35-inch Pro Comp wheel-and-tire package, we replaced it with a premounted and balanced package from Rimz One. We went with Rimz One as a source for our wheels because the company was able to select the right-size tires and wheels with the right backspacing and mailed everything mounted and balanced directly to us quickly. After the install, the package was right on the money and we had no tire-clearance or wheel-fitment issues. The shop even made sure Toyota's tire-pressure sensors went on the new wheels correctly. The new tires are from Toyo Tire's Proxes S/T lineup measure 305/35R24 or about 32 inches in diameter when mounted on our new 24-inch Driv Tremor wheels with 6.88 inches of backspacing. Here's a look at our Tundra's newfound stance.
What's In The Box?
This is a pretty simple kit to install. Ground Force includes new hardware to go along with the replacement springs, bumpstops, and shocks. The factory control arms and spindles are retained up front. Our new rolling stock comes courtesy of Rimz One and consists of Driv Tremor wheels and Toyo Proxes S/T rubber.
 |  |  1.After raising our truck...  1.After raising our truck in the air, the staff of 4 Wheel Parts removed the wheels and disassembled the front suspension. We'll essentially be putting the front end back to stock specs but with shorter coils provided in the Ground Force drop kit. To get the ball rolling, front antisway bar and tie-rod ends were disconnected from the lower control arms, and then the Pro Comp coilovers and lift spindles were removed (inset). |
 |  2.Next, we grabbed the pile...  2.Next, we grabbed the pile of stock Tundra suspension parts and readied them for reinstallation. |  3.The black spring on the...  3.The black spring on the right is the stock coil spring, and next to it is the new, shorter coil from Ground Force. Although the new coil is only approximately 1 inch shorter than the original part, it will settle after a few hundred miles of driving to a 2-inch drop in ride height. |
 4.A spring compressor is not...  4.A spring compressor is not mandatory for removing the soft stock coil springs from the front coils, but it is for installing the Ground Force coils. |  5a.Here is the stock suspension...  5a.Here is the stock suspension re-assembled with the new springs. |  5b.The sway bar, tie rods,...  5b.The sway bar, tie rods, and control arms were all reconnected. |
The Rolling Stock
We rolled the 24s up next to our 20s, and you can really see the difference between the two combos. The 35-inch tires and 20-inch rims really ate into our fuel economy by increasing the final drive ratio of the truck, moving the operating rpm of the engine away from its peak torque curve. At a 70-mph cruise on the highway, the engine was only turning 1,700 rpm and required more throttle position to maintain speed on slight grades. The new 24s are nearly 3 inches smaller in diameter, which is similar to the stock tire diameter. Not only will our speedometer be more accurate with the new wheels, but we'll be gaining in the fuel economy department by putting the gearing and motor back into its sweet spot.
Tread Design: Toyo's Proxes S/T tires have a directional tread pattern designed to channel water to the outside of the tire during wet weather driving. We found the tires to offer excellent lateral grip during high-speed cornering, while maintaining a smooth, quiet ride. The low-profile sidewall gave a stiffer ride with a performance-oriented feeling, which was appreciated after months of driving on the huge-sidewall off-road tires we had on our truck.
 1a.Our old rear suspension...  1a.Our old rear suspension consisted of a 4-inch lift block sandwiched below the factory leaf pack |  1b.The pack is comprised of...  1b.The pack is comprised of four progressive leaf springs plus an overload leaf that only contacts the rest of the pack when the bed is loaded down with cargo. |  2a.Ground Force includes a...  2a.Ground Force includes a replacement spring pack with three springs and a new overload leaf, plus a slim angle cut shim that goes below the pack to aid in correcting the pinion angle of the rear axle. |
 2b.Shorter bumpstops are also...  2b.Shorter bumpstops are also provided since the 4-inch drop the springs provide will put the axle within inches of the rear framerails. We suggest adding a C-notch to the framerails if you intend to drive on anything but perfectly smooth asphalt. |  3a.Here's a look at the difference...  3a.Here's a look at the difference in length between the stock shock absorbers and the new units from Ground Force. By purchasing a complete kit like this one, you don't have to guess what the right-length shock might be. Ground Force has done the work for you. | 
3b. |
 4.Like we said before, lowering...  4.Like we said before, lowering this truck 4 inches really diminishes the amount of usable suspension travel available. This photo shows that even with the suspension cycled downward to its maximum droop position, there's not much travel. Once it's set on the ground and the weight of the 5,000-plus-pound truck is applied, gravity will shorten the travel to just a couple of inches. A C-notch will really help out here. |  5a.The professional crew at...  5a.The professional crew at 4 Wheel Parts really knows how to accessorize a truck the right way. Here, note that antiseize compound is being applied to all the lugnuts before installing the new rolling stock. This will aid in removing the wheels later on. | 
5b. |
 6.And finally, the truck is...  6.And finally, the truck is moved over to the shop's four-wheel alignment rack to bring the suspension back within factory specs. This is paramount in making the truck drive straight, handle properly through the corners, and keep those expensive tires from wearing out prematurely. | | |
The Final Word
Mention that you're thinking of putting 24s on your truck around your buddies and they might think you've lost your mind and are building a donk. A few years ago it sounded ridiculous, but now that manufacturers are building bigger trucks with huge wheelwell openings and contoured fenders, big wheels actually look just right on a truck like the Tundra. We're getting just as many looks now that our truck is lowered as we did when it was lifted, and we're getting better mileage. This truck's cornering prowess has increased substantially, and without the usual rubbing and tire-cutting that comes with an ill-conceived drop and tire combo. The only drawback to our approach here is that we couldn't notch our rear framerails, rendering our truck useless now in terms of towing capability.