Toyota makes great looking trucks. Keeping the sheetmetal healthy might be the most visible concern, but powertrain components are most critical. Skid plates and rock sliders will protect the soft underbelly and smooth skin of the rig, while a heavy-duty set of bumpers can provide improved approach and departure angles while protecting the ends from trail damage.
Skid Plates
The crossmember and C-channel frame design on the Tundra allows for very easy installation of skid plates from the tip of the front bumper to the rear of the transfer case. This can be accomplished by anyone with access to a break and a drill, using 3/16" mild steel plate, but it's much, much easier to just buy them from
Skid Row. Their plates are bombproof and have been abused by plenty of Tundra owners on the forums here, with great success--they were actually designed in part from input by one of the TS forum members. The pieces are very reasonably priced--the price largely reflects the cost of the raw material (3/16" mild steel). The front skid plate uses existing threaded holes in the frame (8.00mmx1.25mm), which are easily damaged during oil changes or a salty winter. The holes can be drilled (5/16", cobalt bit) and tapped to accept a 3/8" Grade 8 coarse thread bolt, install with washer and lock washer to prevent backout. Fine thread works better but fine thread is also harder to source.
Behind the transfer case, the exhaust and forward section of the driveshaft are the only parts to be damaged. While it's not necessary, a belly skid will protect the pipes and shaft, and allow the truck to be skidded across an obstacle without hanging on anything you'll need to drive home. A belly skid can be made with a sheet of 3/16" plate, 4' wide and extended from the rear lip of the Skid Row t-case skid to just behind the driveshaft carrier bearing (DCB). The bolts securing the DCB crossmember can be used to secure the tail of the plate, while nuts must be tack-welded to the inside of the C-channel frame rail to secure the rest of the plate. With two breaks and careful measurement, a belly skid will fit over the rear lip of the S/R t-case skid and can be notched for the rear section of the driveshaft to provide clearance and maximum protection. A belly skid designed this way will protect the entire exhaust system forward of the muffler, and the forward third of the gas tank. The belly skid should be reinforced from side to side with vertical supports to prevent deformation if the entire weight of the truck rests on the belly, and holes should be drilled in the plate to provide drainage as appropriate. Again, use 3/8" Grade 8 coarse thread with washer and lock washer to secure the skid.
Anything that says "baja look", "rock crawler look", "offroad look", or is made of formed aluminum sheet, or sticks out like an underbite so everyone can see that you have a skidplate, is probably a dress-up toy not a skid plate and will not protect the truck from anything in the field.
Rock Sliders
Rock sliders (aka rock rails, sliderz, etc) are a sort of outrigger to the frame, hard-mounted either via bolts or welding, that look like a step or nerf bar but can support the entire weight of the truck from the outermost point on the slider, and can be used as a pivot to turn the truck around an obstacle without damaging the body. They are made from tube, either square or round, with several supports linking the main rail (stringer) to the frame. The stringer is usually positioned just below the pinch weld, in order to protect the weld and provide support to the body if the sliders flex upward during use. Most sliders have a ladder construction, where a second bar (spreader) is attached to the stringer with several supports to either provide more protection for the body, a place to stand, safer use as a pivot in a turn, a kickout to move the tire away from the obstacle the slider is riding, or all of the above. Sliders can be made of any type of steel, the design is much more important than the material. Material provides a way to save weight--higher cost but lighter tube can be substituted in areas which will not take a direct impact, for example supports to the frame and supports between stringer and spreader. A great deal of weight can be shaved off by switching alloys if you're willing to pay the higher material cost (as much as 8$/ft), but consider if youre willing to risk significant damage to a thin-walled tube from either poor design or simply the intended use of the slider. For a truck which will rarely use the sliders but still needs protection, light weight/high cost material may work, but for most trucks standard 0.120 wall mild steel structural tube (square or round) or 1-1/4" sch40 pipe (O.D. @ 1.66") works
great.
Many manufacturers now make sliders for Tundras.
Search the forums or ask your local 4x4 shop. If you want to make your own (not terribly difficult to do a decent job), there are plenty of good ideas
here, at 4x4wire.
Bumpers
Bull Bars
Bull bars (ARB Sahara Bar, TJM's similar offering, other "ranch hand" type bumpers) offer a great deal of forward protection, and if designed and built properly will operate in conjunction with the vehicle's air bags and crumple zones. ARB tests and guarantees their bumpers with the OEM safety equipment, other manufacturers may as well, but NEVER ASSUME when it comes to your safety...always ask if it's not directly advertised. Overbuilt bumpers won't crumple the way Toyota intended for the OEM bumper, and will transfer the shock of impact to the occupants rather than absorbing the impact through deformation. Also keep in mind that "overbuilt" isn't necessarily obvious--a large, imposing bumper may have a mounting system which works in conjunction with the OEM crumple zones at the front of the frame, and a simple "roo bar" may be mounted directly to the frame without any impact protection at all. The best old, original, massive chromed bumpers were mounted on springs or had a deformable rubber chunk between the bumper and the frame. A bull bar may also provide a place to stand on the front of the truck, a reference point for the front end and corners when driving, a push bar, or protection from roos, deer, moose, and the odd bull. A good bull bar will have a place to mount a winch and some lights, provides more clearance for larger tires and a better approach angle, works in concert with the OEM safety features when it needs to, and allows the driver to fend off rocks, trees, animals, bad drivers and wandering shopping carts. A bad bull bar is unreasonably heavy, doesn't work with the OEM safety features, sticks out too far, is too wide, doesn't provide additional tire clearance, can't be stood upon, doesn't clearly indicate the front or corners of the vehicle, can't mount a winch, doesn't protect the headlights, and cannot be easily modified. There are several manufacturers of (imho) bad bull bars for Tundras, and no manufacturer of (imho) a good bull bar. There are
decent bull bars, including ARB and a new offering from Road Armor, which can mount a winch and lights, can be stood upon, work with the safety features and provide more access to the front of the tire. Last communication with Road Armor suggests that they are very willing to modify their design to suit a particular owner's needs for clearance, width, mounting hardware or other features. Though the ARB part is powdercoated, it can be modified very easily and a spray-on bedliner makes a great sealant, protectant and accent to the powdercoat. Decent bull bars can be transformed in to good bull bars either from a willing manufacturer or by a determined owner, and shopping carts can be pushed to around 30mph before they become completely unstable and result in a skid plate check. Shrockworks and a couple other quality fabricators may be offering Tundra bumpers in the near future as well.
Prerunner Bumpers
Prerunner bumpers (so named because they're found on long travel desert race trucks and prerunners) are generally tube constructions intended to minimize weight and maximize functionality, and completely replace the stock bumper. Since a prerunner bumper is almost always a custom creation, winch mounts, light tabs, antenna tabs, stingers, hitches and other features can be easily added. The approach angle possible with a prerunner bumper far outstrips that of the stock and bull bar bumpers, and the tube frame can be skinned with aluminum, steel, or even plastic to provide forward and corner protection, depending on the intended use (rocks, racing, both). The minimal bar construction allows the most access to the front of the tire, but also tends to provide the least protection in a collision. Decent prerunner bars are easy to design and build. Bad prerunner bars offer no protection whatsoever to the radiator and other critical forward OEM components. Since these are usually custom built, good is completely subjective. Almost any shop can build a good prerunner bumper if you have a general design in mind and they have a tubing bender. Some manufacturers even offer bolt-on bumpers which feature the clearance, light weight and custom options of a prerunner bumper combined with the protection and forward structural design of a bull bar. Ask your local 4x4 fabrication shop about a prerunner bumper. Prerunner bars (tube constructions which mount over the stock bumper but do not replace it, and look like a prerunner bumper without having to actually buy a real one) are a nice looking way to mount enough lights to impress the mall valet but are otherwise completely useless as they are just another form of bolt-on brush guard and often do more extensive damage to the truck in a front impact than a stock front end. Prerunner bumpers aren't just mounted on prerunners, they perform extremely well on trail rigs--note the front of many buggies are essentially prerunner bumpers with stingers.
Rear Bumpers
Rear bumpers also come in two general varieties, replacements for the OEM part which offer more protection or features, and high-clearance pieces which integrate quarterpanel protection with the bumper and usually require significant trimming of the rear quarterpanel. The former are offered by a variety of manufacturers (usually 4x4 shops) as completely bolt-on pieces and can be anything from a thinner, sturdier version of the OEM bumper to elaborate, lightweight tube constructions. The latter are almost exclusively custom designs but share features such as integrated receivers, quarterpanel protection under and around the sheetmetal and tied to the frame, swingout tire or fluid carriers, light or antenna tabs, tow hooks or loops, shackle mounts, and over half a foot of improved vertical clearance all the way to the rear tire. Cost for a custom rear bumper is highly dependent on where material is sourced (recycler or new) and who does the work (you, somebody else, or both). Bring pictures or drawings to your local 4x4 shop and find out what they can work up.
Water & Dust
Differential Breathers
One of the quickest, easiest and cheapest mods to the truck is extending the rear differential breather. When the gears are turned, the differential heats up, and the air expands. The breather allows the pressure to equalize through a planned route, preventing gear oil from being forced through the axle seals. This applies to every geared system on the truck; front differential, transmission, transfer case and rear differential. In a water crossing, the gear cases will cool down, and a submerged breather will allow water, mud or other debris to enter the differential. On a Tundra, the front differential and transfer case have breathers extended from the gear case to the rear left wall of the engine compartment, down next to the engine. Look for two silver caps on the end of black hoses. On the rear axle, the rear differential breather is located on the top of the housing, left of center. Again, look for a silver cap. The breather assembly can either be removed and replaced with a threaded hose barb, or the cap can be pulled and a larger hose attached over the breather flange. The hose (fuel line from the hardware store works great) can be routed up the brake line and then run to any high point on the vehicle. The engine compartment and the rear taillight are two good spots to end the breather. The end of the hose can either be turned down, take a stock breather cap, or even a small filter with a hose barb attachment.
Snorkels
Nobody makes a snorkel for a Tundra, yet. The intake is in the passenger side wheel well and is fairly well shielded, similar to the new FJ Cruiser. The bottom of that intake tube is the maximum fording depth, better to measure your own vehicle since lifts, bumpers and other modifications will change the depth. For a slightly different type of snorkel setup, there is enough room to fit a tube down the engine compartment next to the frame rail and up through the bed; the STS turbo systems mount this way as well. Aluminum tube and gels can secure this type of snorkel with a cut to the left rear of the airbox, and the OEM intake tube/hole would need to be sealed.