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Big Toys

Posted in How To: Suspension Brakes on November 14, 2005 Comment (0)
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In the classic 1985 film Back to the Future, Michael J. Fox's character, Marty McFly, had a bunch of wacky adventures while traveling back in time in a stainless steel DeLorean, but the most significant part of that film to my brother and me was the sweet lifted Toyota pickup that Marty dreamed of having.

I've come to find out the same holds true for many other Toyota owners. Just after that film came out, Toyota developed its first Independent Front Suspension (IFS) for 4x4 trucks. As with most OEMs, the folks at Toyota were trying to open the 4x4 trucks to a larger market, and figured that these better-riding suspensions would help them stay in the forefront of the minitruck shopper. Luckily Toyotas already had a cult following of owners ready and willing to modify their 4x4s, and when this new suspension showed up, the aftermarket was quick to support it. We often dream of traveling back in time like Marty just to get our hands on an 1985-or-earlier solid-axle Toyota, but if you already have an IFS Toy, then consider these options when you are ready to take it up to the next level. As with most IFS suspensions, we would rather see you choose a kit for maximum performance and travel instead of one that just gives you major height for big tires.

Since those first A-arms made it under a 'Yota, the design of the suspension has changed in many ways. The 1986-1995 pickups and 1986-1990 4Runners all used upper and lower A-arms (with torsion bars as the spring) and leaf-sprung rear suspensions. These stock suspensions give about 7-9 inches of travel up front.

Then in 1990 the 4Runners received a coil-sprung strut and coil-sprung rear suspension, and the Tacoma followed suit in 1995 with the same front suspension and a leaf-sprung rear suspension. With the 2003 4Runners and 2005 Tacomas the suspension style stayed the same, but all the components got slightly larger.

Adjusting the torsion bars for 1986-1995 trucks can be the cheapest suspension mod. It is possible to simply crank up the torsion-bar preload, which in turn raises the truck, but you are effectively putting the truck on stiffer springs, and the ride quality and torsion-bar longevity will greatly suffer. Plus you still need to do something about the rear suspension. A better option is going to a larger-diameter aftermarket torsion bar, such as those offered by Sway-A-Way or Downey. Though it may seem counterproductive to go to a thicker torsion bar, think of it like a tire - a stock torsion bar that has been cranked up for more height is like a 30-inch tire at high air pressure - very hard to ride on. On the other had, a thicker torsion bar that has not been cranked up excessively is like a 36-inch tire with low pressure - it's just as tall as the 33, but rides much better. You can crank up the big torsion bars for even more height, but you will eventually ruin the ride quality again. Another bonus of the aftermarket torsion bars is that they will take more abuse from off-roading than the stock units without losing their spring rate as quickly, if at all.

If you own a Toyota Tacoma, different stages of suspension are available to you. The most basic entry-level kits include a spacer that goes above the factory coilover and is similar to a body lift, but instead of going between the body and frame it goes between the frame and the front spring and shock. Revtek, Tuff Country, Downey, Cornfed Suspension, Donahoe Racing, and many others all offer versions of this type of suspension. These spacers usually offer between 1 and 3 inches of lift by effectively preloading the suspension. However, they also reduce the downtravel of the suspension and can give a slightly rougher ride. As with any suspension kit, we would prefer one that doesn't use lift blocks for the rear suspension, as they apply more leverage to springs and can cause spring wrap. Rather, choose a kit with an add-a-leaf or, better yet, a new spring pack and slightly longer shackles.

The next stage of suspension for both 1986-1995 torsion-bar trucks and coil-sprung Tacomas is a suspension kit where the lower A-arm mounts are dropped below the frame, the differential is moved down, and either a spacer for the knuckle that fits between the knuckle and the stock upper ball joint (left) or a completely new knuckle (right) is incorporated to drop the front tires. Most 1986-1995 kits use the knuckle/ball-joint spacer, while some Tacoma kits come with a new knuckle. Luckily both kits usually have new steering mounting points either on the spacer or new knuckle that keep the steering close to the original position. We would choose the new knuckle kit over the spacer since the spacer adds another fastener which could loosen. However, by going to a new knuckle on the Tacoma, you often need to remove the factory unit bearing from the stock knuckle and it's not uncommon that they cannot be reused due to damage during removal. Plus, both versions will add considerably more leverage onto the stock upper A-arm mounts. In addition, by lowering the differential you are only gaining ground clearance by going to a larger tire.

We've had great results with the Total Chaos Caddy kit. It uses 3-inch-wider A-arms and longer Toyota T-100 shafts and CVs. This kit can be used with either aftermarket torsion bars or coilover shocks. It's also offered with either the stock ball joint or high-angle uniballs. For longevity, we would go with the ball joints--for performance we would choose uniball. Another option is the steering idler-arm upgrade kit and differential substructure truss, both of which help keep your frame and steering happy during dune jumping.

Some of the best options for Tacomas replace the front coilover shock to get more lift, as well as better spring rates and damping. Downey Off Road had one of the first on the market, but there are now many options such as those from Sway-A-Way, Donahoe Racing, and Bilstein. We recently spied this preproduction mockup for the 2005 Tacoma that utilizes a Total Chaos upper A-arm with uniball and a Donahoe's coilover shock. When considering a kit, choose one that uses a new rear spring pack.

We would like to investigate the new Downey Grand Slam Kit, which has been redesigned for 1986-1995 torsion-bar trucks. Downey first addressed the suspension by designing an upper A-arm, that changes the angle of the upper ball joint so at full droop it doesn't bind. However, this means that at full compression the stock upper ball joint will be maxed out before anything else. Downey offers a modified Mega-travel ball joint that is machined to allow more travel on compression without significantly reducing strength during droop. As an added bonus, Downey decided not to lower the front differential as most suspension kits do, but this required addressing the axleshafts. The original kit used slip-splined halfshafts that would change lengths during travel, but the new kit will utilize custom turbo Porsche inner CVs and chromoly shafts similar to those used in many desert race buggies. Plus the new kit will have 2-inch-wider chromoly upper and lower A-arms to give a larger arc to help with camber changes during travel.

If there is one place Toyotas shine, it's in the rocks. However, we rank IFS on the rocks next to "pink lam jumpsuits and toebells." The IFS suspension just cannot keep pace with a solid axle as far as strength and articulation, and though a skilled driver can go very far up the trail with IFS, swapping a straight axle is often a better idea. The first company to the market with a solid-axle swap was All Pro Off-Road; its leaf-sprung suspension was installed over many Toyota front axles on 1986-1995 Toys. Nowadays there are more than a handful of new companies entering the SAS (solid axle swap) market. Marlin Crawler, a long-time dual transfer case and Toyota accessory company, has entered with brackets and springs, as has Sky Manufacturing and Front Range Off-Road. In addition, Front Range offers a solid-axle swap kit for Tacomas using leaf springs. All Pro is currently working on a kit that uses coilover shocks. Sky Manufacturing is offering a kit to put full-width Dana axles under 1986-1995 Toyota trucks. There are also many custom fab shops such as 4-Wheelers Supply or Demello Off Road that will custom-build your solid-axle swap such as the one in our 2001 Ultimate Tacoma. Since the 1986-1995 frame design is very similar to the pre-1986 solid-axle 4x4s, it is much easier than other makes when going to a solid axle. Additionally the IFS steering box is often reused for a crossover steering conversions when going to a solid axle since it rotates side to side rather than front to back. The crossover design reduces bumpsteer compared to the stock solid-axle truck's steering. The Tacoma-era trucks were built on a new frame and so proper care must be taken to replace any crossmembers or supports that help stiffen the frame from the factory. Additionally we have found that if you are doing abusive four-wheeling, such as jumping, then the frame should be reinforced wherever you expect bumpstops to hit.

Sources

Bilstein
Poway, CA 92064
858-386-5900
http://www.bilsteinus.com
Sway-A-Way
Chatsworth, CA 91311
818-700-9712
www.swayaway.com
Total Chaos Fabrication
Corona, CA 92880
951-737-9682
www.chaosfab.com
Tuff Country
West Jordan, UT 84088
800-288-2190
www.tuffcountry.com
Donahoe Racing
Anaheim, CA 92806
Front Range Off Road Fabrication
Fort Collins, CO 80526
www.frontrangeoffroadfab.com
Downey Off Road
Santa Fe Springs, CA 90670-3221
www.downeyoff-road.com
4-Wheelers Supply
www.4wheelers.com

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