What is track width (TW)?

EMS - 4 September 2024 - 12:56 am

Why Track width Matters

Track width plays a crucial role in several aspects of vehicle performance:

1. Stability

A wider track provides a more stable base for the vehicle. Think of it like a person standing with their feet close together versus far apart – the wider stance is inherently more stable and resistant to tipping over. The same principle applies to vehicles. A car with a wider track is less prone to rollover, especially when cornering at high speeds or traversing uneven terrain.

2. Handling

Track width also influences a vehicle’s handling characteristics. A wider track typically allows for more responsive steering and reduced body roll when cornering. This is because the wider spacing of the wheels provides more leverage to resist the centrifugal forces that cause a vehicle to lean outward during a turn.

3. Off-road capability

For off-road vehicles, a wide track is often desirable to improve stability on rough, uneven surfaces. A wider stance helps prevent the vehicle from tipping over when navigating large obstacles or steep inclines. Many dedicated off-road vehicles like Jeeps, Toyota 4Runners, and Ford Raptors feature relatively wide track widths to enhance their rugged capabilities.

4. Aesthetics

While not a performance factor, track width does influence a vehicle’s visual proportions and stance. A wide track can give a car an aggressive, planted look, while a narrower track may appear more elegant or streamlined. Many sports cars and performance vehicles intentionally utilize a wide track to convey a sense of capability and purpose.

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Factors That Influence Track Width

Several design considerations go into determining an appropriate track width for a given vehicle:

1. Intended use

The primary factor is the vehicle’s intended purpose. A Formula 1 race car, which prioritizes cornering speed and downforce, will have a much wider track than a compact city car designed for maneuverability in tight spaces. Off-road vehicles also tend to have wider tracks than their on-road counterparts to aid in stability on rough terrain.

2. Size and weight

The overall size and weight of the vehicle also play a role. Larger, heavier vehicles generally require a wider track to maintain stability, while smaller, lighter cars can get away with a narrower stance. This is why semi-trucks have extremely wide tracks compared to passenger cars.

3. Suspension design

The type of suspension used on a vehicle can influence its track width as well. Some suspension designs, like double wishbone or multi-link setups, allow for a wider track within a given vehicle footprint compared to simpler designs like the MacPherson strut.

4. Tire size

The size of the tires also factors into track width. Wider tires require a correspondingly wide track to fit within the vehicle’s bodywork and to maintain proper suspension geometry. High-performance cars often utilize very wide, low-profile tires to maximize grip, necessitating a wide track.

Track Width vs Wheelbase

It’s important to distinguish between track width and wheelbase, as the two are often confused:

Track width is the distance between the centerlines of the left and right wheels.
Wheelbase is the distance between the centers of the front and rear wheels.

While both dimensions influence a vehicle’s handling and stability, they serve distinct purposes. Wheelbase is the primary determinant of a vehicle’s longitudinal stability and ride quality, while track width is more concerned with lateral stability and cornering behavior.

A vehicle with a long wheelbase will typically have a smoother ride and be less prone to pitching forward or backwards during acceleration and braking. A short wheelbase allows for a tighter turning radius but may result in a choppier ride.

In contrast, a wide track improves lateral stability and reduces body roll, while a narrow track may feel more nimble but less planted in corners.

Most vehicles aim to strike a balance between wheelbase and track width that is appropriate for their intended use case and design goals.

How Track Width Varies Across Vehicle Types

Track width specifications vary widely across different vehicle segments, reflecting their diverse performance requirements and design constraints. Here are some typical track width ranges for common vehicle types:

Vehicle Type	Typical Track Width Range
Compact Cars	55-60 inches
Midsize Cars	60-65 inches
Full-size Cars	62-67 inches
Sports Cars	60-65 inches (front), 61-66 inches (rear)
Crossovers/Small SUVs	60-65 inches
Midsize/Full-size SUVs	65-70 inches
Pickup Trucks	68-74 inches
Semi-trucks	80+ inches

*Note that these are general ranges and individual models may fall outside these bounds.

Sports Cars and Track Width

Sports cars and performance vehicles often feature some of the widest track widths relative to their size. This is because lateral grip and stability are paramount for their handling-focused mission.

For example, the Porsche 911 GT3, a high-performance variant of the iconic sports car, has a front track width of 64.2 inches and a rear track of 62.6 inches despite its compact overall footprint. The Chevrolet Corvette, another sports car benchmark, features a 66.1-inch front track and 66.3-inch rear track in its latest C8 generation.

Many sports cars also have a slightly wider track width at the rear compared to the front. This “staggered” setup helps put power down more effectively and can aid in high-speed stability. The massive rear tires needed to handle the power output of supercars like the Ferrari 488 or McLaren 720S necessitate an extremely wide rear track.

Pickup Trucks and SUVs

Pickup trucks and SUVs generally have some of the widest track widths of any passenger vehicles, often exceeding 65 inches. This is due to their larger overall size and weight, as well as their need for stability when hauling heavy loads or traversing off-road terrain.

Full-size pickup trucks like the Ford F-150 and Ram 1500 boast track widths of around 68-69 inches in front and 67-68 inches in the rear. Their heavy-duty 3/4-ton and 1-ton siblings are even wider, with track widths approaching 74-75 inches to handle their immense towing and payload capacities.

Similarly, large SUVs like the Chevrolet Tahoe and Ford Expedition have track widths in the 68-70 inch range to provide a stable platform for their truck-based underpinnings and spacious interiors. Even car-based crossover SUVs tend to have slightly wider tracks than their sedan counterparts to accommodate their higher ride height and center of gravity.

Modifying Track Width

In some cases, vehicle owners may wish to modify the track width of their car or truck to improve handling, accommodate larger tires, or simply for aesthetic reasons. There are a few common ways to increase track width:

1. Wheel spacers

Wheel spacers are plates that fit between the wheel and the hub, effectively pushing the wheel outward and increasing track width. They are a relatively simple and inexpensive way to widen the track, but they also place additional stress on the wheel bearings and suspension components if used in excess.

2. Offset wheels

Wheels with a lower offset sit further outboard than stock wheels, increasing track width. This is a popular modification in the aftermarket scene, as it allows for a wider stance without the need for spacers. However, excessively low offset wheels can cause tire rubbing or require fender modifications to fit.

3. Suspension modifications

More involved modifications like extended control arms or revised suspension pickup points can be used to increase track width from the factory mounting locations. This is typically reserved for dedicated race cars or extreme off-road builds.

It’s important to note that increasing track width can have negative consequences if done improperly. Pushing the wheels too far outward can place undue strain on suspension and steering components, accelerating wear and potentially compromising safety. It’s crucial to research the appropriate amount of track width increase for a given vehicle and use high-quality, properly engineered components.

Additionally, significantly increasing track width may render a vehicle illegal for street use in some jurisdictions. Many areas have laws restricting how far the wheels and tires can protrude from the body. It’s important to check local regulations before modifying a vehicle’s track width.

Track Width in Motorsports

Track width takes on additional significance in the world of motorsports, where every millimeter counts in the pursuit of lap times. Race cars in various disciplines often push the boundaries of track width to extremes in order to maximize grip and stability.

Formula 1

In Formula 1, the FIA (Fédération Internationale de l’Automobile) sets strict rules on vehicle dimensions, including track width. As of the 2022 season, F1 cars are limited to a maximum track width of 2000mm (78.7 inches). This is a significant increase from the 1800mm limit used from 2017-2021, and reflects the sport’s focus on increasing downforce and cornering speeds.

The wider track also allows for larger floor area, which is a critical component in generating downforce in current F1 designs. Teams will always push right up to the regulatory limits on track width to maximize aerodynamic performance.

NASCAR

While NASCAR stock cars appear superficially similar to their road-going counterparts, they are purpose-built race machines with significantly wider track widths. The current Generation 6 NASCAR Cup cars have a track width of 2540mm (100 inches) — over 20 inches wider than even the widest production pickup trucks.

This extreme width, combined with the cars’ relatively short wheelbase, gives them incredible stability in high-speed corners. The wide stance also allows NASCAR teams to run very aggressive camber angles for improved grip.

Rally and Off-road Racing

In off-road motorsports, a wide track width provides critical stability and balance on rough, uneven terrain. Rally cars like the Subaru WRX STI and Ford Fiesta WRC feature track widths around 1800mm (70.8 inches) — considerably wider than their street-legal versions.

This allows them to tackle jumps, ruts, and high-speed gravel corners with greater control and less risk of rolling over. The same principles apply to off-road endurance races like the Baja 1000, where trophy trucks with massive track widths exceeding 90 inches dominate the field.

FAQ

1. What is the difference between track width and wheelbase?

Track width is the distance between the centerlines of the left and right wheels, while wheelbase is the distance between the centers of the front and rear wheels. Track width primarily affects lateral stability and handling, while wheelbase influences longitudinal stability and ride quality.

2. Why do race cars have such wide track widths?

Race cars utilize very wide track widths to maximize grip, stability, and aerodynamic performance. A wider track allows for larger tires, increased lateral stability, and more aggressive suspension setups. In disciplines like Formula 1, the regulations on track width are pushed to the absolute limit to gain every possible advantage on the track.

3. Can I increase the track width of my vehicle?

Yes, track width can be increased using methods like wheel spacers, offset wheels, or suspension modifications. However, it’s important to carefully research the appropriate amount of track width increase for your specific vehicle and use properly engineered components. Excessive track width increases can cause tire rubbing, suspension wear, and potentially compromise safety.

4. What is a good track width for a daily driver?

For most standard passenger vehicles, manufacturer track width specifications are more than adequate for daily driving duties. Typical track widths range from around 60 inches for compact cars to over 65 inches for full-size trucks and SUVs. Wider is generally better for stability, but excessively wide track widths may negatively impact maneuverability in tight spaces and increase tire wear.

5. Are there any downsides to a very wide track width?

Extremely wide track widths can have some drawbacks, particularly on road-going vehicles. An excessively wide stance may make a vehicle more difficult to maneuver in tight spaces and can lead to increased tire wear due to scrubbing in turns. In some cases, significantly increasing track width may also render a vehicle illegal for street use due to laws restricting how far the wheels can protrude from the body.

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