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The 2024 Toyota Tacoma's New Coil Spring Rear Suspension Explained

Dec 07, 2023Dec 07, 2023

Toyota is busy spreading its new TNGA-F global truck platform beneath the more rugged members of its lineup (and Lexus's), and it now underpins the newest Tundra full-size pickup, Lexus LX600, new global Land Cruiser, three-row Sequoia SUV, and, now, the new-for-2024 Toyota Tacoma midsize truck. With the new Tacoma pickup's adoption of TNGA-F comes a switch to a more modern rear suspension; still using a live axle, the Tacoma now offers coil springs instead of old-school leafs, just like the larger Tundra. Unlike the Tundra, the coil-sprung rear end isn't used across the Tacoma family—only certain models get the modification, curiously, though given how the same design's been received on the Tundra, that might be a good thing.

There are benefits to switching over to a coil spring suspension system for the rear of any truck. You'll gain more rear articulation as the leaf attachments can drastically limit travel (at least with stock leaf components), along with a better unladen ride—coil springs have a very consistent rate through their full travel. Oh, and by separating axle locating and suspension duties (leafs both locate the axle and cushion it), you can get more consistent axle behavior in addition to that smoother ride.

What do we mean? Well, using a multi-link setup to hold the axle in place and coil springs to control its movement can result in less of a tendency for the axle to steer the rear end around. Leafs stretch, which can move the axle fore or aft throughout the springs' compression or expansion. (Remember, with leaf springs, the axle is rigidly bolted to the leaf pack.) The trailing eyelet is also not fixed in place and attached to a moving shackle. If you have one wheel going into bump and the other going into droop (or rebound, if you want to get engineery about it), the bump side of the axle will move rearward while the droop side doesn't. This movement is allowed by the rear shackle while the fixed front eye uses the compliance of rubber or urethane to twist within its bracket and why this phenomenon can occur despite using a live axle rear end. Without those, the rear suspension couldn't work and trying to "stiffen up" those components would make an already harsh ride even harsher if you were to eliminate that compliance in either end of the leaf spring.

The aftermarket, of course, has a solution, though it's one not often deployed on the OEM side: Using a "floating" axle where the housing is allowed to stay in place by using a linkage system (like a ladder bar set) and a pair of roller perches replaces the rigid and welded ones on the housing. This is a common modification in the aftermarket for trucks and muscle cars (especially in drag racing), not so much on factory trucks.

While the switch to a coil-sprung rear axle might seem like a good thing—and it is, generally—the design carries one key drawback relative to good ol' leaf springs: Managing towing and loads. Now, this isn't universal, as some manufacturers use coil springs in their trucks' rear axles (Ram, notably, on the 1500 models) and deliver strong towing figures and solid towing feel. Toyota's own Tundra, which is in its first generation with a coil-sprung rear axle, behaves more like a first-try effort. at this past year's Truck of the Year evaluations, we found the rear ends of multiple Tundra variants noodled around when saddled with a heavy load, sashaying about far more than their leaf-sprung predecessors. We noted that the TRD Pro model felt "overwhelmed" by our trailer testing, while features editor Scott Evans declared "It seems clear Toyota has never done a coil-sprung rear axle with a heavy trailer before," before adding "Ram got this right straight out of the box 12 years ago."

And while Ram may have figured out the coil-spring thing with its 1500, across the halls in Stellantis' engineering quarters, their counterparts at Jeep have struggled like Toyota, with the midsize Gladiator pickup using the design and suffering from weird towing behavior.

For all of the benefits of having a better driving feel by going coil sprung, the benefit of the leaf spring pack is that it's a progressive suspension system. What we're talking about here is where each leaf of the pack takes more of the weight as the pack flattens out. It may not look like it, but there is just enough separation between each leaf of the leaf pack to allow for movement and bending of the pack. To ensure smooth movement, most manufacturers will place hard wearing pads between each leaf. The first leaf is the primary leaf, the one that bears the vehicle weight. When the primary leaf contacts the leaf under it, that leaf is now starting to bear the load along with the primary leaf of your pack and this progression continues through each leaf of the pack.

The easiest way to visualize this is to think of a single sheet of paper over a gap versus a stack of papers over the same gap. A single sheet of paper might hold up a one pound weight, but add more weight and it will start to sag. Add a second sheet of paper to it and that sag reduces as both sheets are now bearing the load. You can add a thicker piece of paper to reduce that sag without changing the height of the stack dramatically. Again, that's merely a visualization. However, by adding a leaf to the pack or changing a leaf to a thicker version within the pack will increase its weight capacity, something the aftermarket has done for decades. At the same time, you can also see why a leaf spring suspension is much harsher when a truck is unladen, it still takes a lot of force to make the suspension "work."

This is probably why—besides possibly cost—Toyota is only fitting certain higher-spec 2024 Tacoma models with the new suspension design. Entry-level and lower-spec Tacoma SR, SR5 Xtra Cab, and TRD PreRunner trims keep the leaf design, as they're more likely to be used for actual work (or so we imagine Toyota thinks), while the more off-road- and premium-oriented TRD Sport, TRD Off-Road, Limited, Trailhunter, and TRD Pro variants get the coils. (The TRD Pro also gets standard air-shock-equipped front seats, dubbed IsoDynamic Performance Seats, which should further smooth out the ride, at least to the front-seat occupants.) There are a few notable call-outs in that group, though—the Trailhunter is equipped for overlanding, or car camping, and so if we run on the assumption that the coils won't tow as well as the leafs, Toyota appears to be prioritizing off-road capability over towing for that version, even though some overlanders like towing trailers to their campsites... and the SR5 crew cab, historically the Tacoma's volume-selling configuration, gets the coils, too.

We'll hold final judgment on the Tacoma's new coil-sprung rear end until we sample it for ourselves (and tow with it!), but it's worth mentioning again how Toyota still has work to do on the same basic design on the larger Tundra. If Toyota can quell the design's towing issues for the Tacoma, great—if not, it appears that, for now, those looking to buy a midsize Toyota truck and more comfortably tow or haul heavier loads should keep their eyes set lower, on an SR, SR5 extended-cab model, or TRD PreRunner.

Towing speculation aside, what makes the multi-suspension aspect of the new Tacoma so wild to think about is the fact that the TNGA-F is a global platform, and that switch forced Toyota to adopt the rear coil spring system on the Tundra. Toyota has never mentioned whether switching the Tundra to leaf springs was even a possibility. So, for now, we're left wondering whether the Tacoma's dual suspension options is Toyota's response to customers disappointed with the Tundra's towing, or simply a cost decision, or some blend of both. We've reached out to Toyota to find out why, but at the time of publication, the Japanese brand hadn't given us any answers to our questions on the Tacoma and Tundra leaf spring swap out.