Bigger Wheels and Tires - Where Performance Begins And Ends

There's also the matter of looks. With modern automobiles being visibly larger than their forerunners from 10 to 20 years ago, designers had to upsize the wheel arches to accommodate the larger tires, which – in most cases – require larger wheels. One exception to said rule of thumb comes in the form of highly capable off-road machines.

Take, for instance, the Bronco Raptor's 37- by 12.5-inch rubber and 17- by 8.5-inch wheels. By comparison, Cadillac advertises the zero-emission Escalade IQ with  24-inch wheels and 35-inch rubber shoes. Also worthy of note, the Honda Civic LX ships with 16-inch steelies mounted with 215/55R16 tires, resulting in a diameter of 25.3 inches.

Can you extract more performance from your vehicle by going bigger with the wheels and tires? While the answer isn't a clear-cut yes or no, we're glad to explain the advantages and drawbacks of a larger wheel-tire combo, beginning with acceleration and speed.

Acceleration and speed

Imagine two vehicles with the very same peak output figures and similar curb weights. One is equipped with the manufacturer's recommended wheels and tires, whereas the other uses slightly smaller wheels and tires. Which of the two vehicles can get to 60 miles per hour (97 kilometers per hour) quicker?

Considering that bigger wheels and tires equal more circumference, certain people would be tempted to believe that bigger is better. Truth be told, it's the other way around. To understand why the smaller wheels and tires are theoretically superior in this regard, we first have to bore ourselves with physics and math formulas.

Or do we? Think of changing a vehicle's tire size as changing the effective gear ratio. Going small doesn't necessarily mean quicker, though, because there is a tradeoff between wheel spin, wheel inertia, and the driving force available at the contact patch.

A smaller overall diameter will give you more driving force and less polar moment of inertia, hence better acceleration. Be that as it may, smaller tires also imply a greater possibility of wheelspin. The downside to downsizing is a lower top speed, which is certainly going to hurt one's lap time on a fast circuit such as Autodromo Nazionale di Monza. Speaking of which, Kevin Magnussen recorded the highest top speed for a Formula 1 car at Monza in 2024, clocking 357.1 kilometers per hour (221.9 miles per hour) in the Ferrari-powered Haas VF-24.

If you're curious why Formula 1 switched from 13- to 18-inch wheels for the 2022 season, part of the reason is none other than official tire supplier Pirelli, which became involved in F1 to enhance its visibility and prestige. The closer a racing car's tires are to a road car, the better for the Italian tire manufacturer. But that's not all, no siree!

Coming courtesy of BBS, these 18-inch wheels are joined by slightly larger tires, boasting a diameter of 720 millimeters while retaining the front and rear widths of the old 660-millimeter tires. Also worth mentioning, the sidewall offers less flex than before, making suspension design a great deal more important from the standpoint of both race- and qualifying-trim performance.

Handling and braking

When it comes to handling, larger also implies wider. The bigger the contact patch of a tire, the more grip you have. A tremendous disadvantage to larger tires and wheels is more unsprung mass, referring to the parts that aren't supported by the suspension of a vehicle. A heavier wheel-tire combo also requires more work from the combustion engine or electric motor to turn said wheel and tire. In other words, it will cost you time on a racing circuit or on a drag strip.

This is where lightweight alloys and carbon-fiber wheels enter the scene. Ford Motor Company and GM's Chevrolet division come to mind with their carbon-fiber wheels for the S550-generation Mustang Shelby GT350R and C8-generation Corvette Z06. In the Shelby's case, Ford quotes 18 pounds (8.1 kilograms) per corner as opposed to 33 (15) for the standard aluminum wheels. As for the Z06, the largest automaker of the Detroit Big Three promises a reduction in unsprung weight of 41 pounds (18.6 kilograms).

Carbon wheels are the very opposite of affordable. When the Voodoo-powered GT350R was brand-spanking new, replacement wheels retailed at $3,433 each for the fronts and $4,053 each for the rears. Big yikes, indeed! Over at General Motors, the build & price tool reveals that four carbon-fiber wheels add $11,995 to $15,500 over the standard aluminum wheels. Forged aluminum wheels, on the other hand, can be had for $495 or $1,495 per set of four.

In theory, upsizing further enables better braking performance, for the larger contact patch of a wider tire resists the forward motion better. But in the real world, you should also consider investing in larger brakes, for larger wheels and tires make it possible to fit larger rotors and calipers.

A good example in this regard is the S650-generation Mustang with the EcoBoost four-cylinder turbo. The pony car comes with 17- by 7.5-inch wheels and 235/55 tires, flaunting 320- by 30- and 12-millimeter rotors with twin- and single-piston calipers. Optionally, customers are presented with either 18- by 8.0-inch or 19- by 8.5-inch wheels.

With the 19s, the Dearborn-based automaker upgrades the Mustang EcoBoost to 390- by 36- and 355- by 28-millimeter rotors with six-piston calipers up front and four for the rear.  Swept area? That would be 467 and 402 square centimeters, respectively, by default as opposed to 768 and 523 square centimeters for the Performance Package's brakes.

Fuel economy or driving range

Obviously enough, larger tires automatically mean worse fuel economy or driving range. Our internal combustion example is the sixth-generation Bronco two-door with the 10-speed box and 2.3-liter turbo, which produces either 275 horsepower and 315 pound-feet (427 Nm) with regular unleaded or 300 horsepower and 325 pound-feet (440 Nm) with premium-grade dinosaur juice.

17-inch wheels and 32-inch tires are standard, with the Environmental Protection Agency claiming a combined fuel economy of 20 miles to the gallon or close to 11.8 liters per 100 kilometers in metric vernacular. The optionally available 35-inch rubber included in the Sasquatch Package helps the Ford Bronco a lot off the beaten path, but combined gas mileage is a bit worse at 18 miles per gallon or 13.0 liters per 100 kilometers. Oh, and by the way, the 35s are mud-terrain tires while the standard 32s are all-terrain tires.

Supposing you're in the market for a Tesla Model 3 with adequate straight-line performance, you can't go wrong by choosing the Long Range All-Wheel Drive. 18-inch wheels are standard, while 19s are optionally available for an extra 1,000 buckaroos, with both wheel designs boasting all-season tires. However, be warned that picking the larger wheel-tire combo will drop the combined range by 36 miles. To the point, from the standard 341 miles (549 kilometers) to 305 (491) on a full charge of the battery.

Off-road capability

Back in the ol' days of the personal automobile, 4x4 vehicles came with skinny tires. Nicknamed pizza cutters by the off-road community, narrow tires make a lot of sense in certain scenarios. In muddy conditions, for example, a thinner tire cuts through the mud more effectively than a wider tire of the same diameter. Contrary to popular belief, skinnies are good on rocky terrain as well because narrower tires offer increased deformation depth. Still, remember that wider tires offer quite a few more benefits, including better puncture resistance and traction.

When driving over sand, thinner tires can stretch out more when deflated for a larger footprint. The lower rotational resistance and greater contact pressure for more focused grip also help. Looking at the bigger picture, there is no definitive winner in the skinny-versus-fat debate. At the end of the day, a heavy truck running fat tires will give you relatively similar contact pressure per square inch to that of a light truck with narrow tires.

If your off-road vehicle can handle tires with a larger overall diameter and more sidewall than stock, go for it. Increased ground clearance does come at a cost, though. Not only do you shift the vehicle's center of gravity, but you also have to consider that upsizing puts more stress on the steering, CV joints, shocks, engine, and diffs.

Having addressed the meat and potatoes of how tire and wheel size affects performance, we should also talk about representative cases. The first two of three real-world tests star a Skoda Octavia and a rather spicy Honda Civic with bigger tires and wheels. A video from Driven District is the final representative case, with the YouTuber testing whether lighter wheels improve the acceleration of an Abarth 124 Spider.

16- versus 17-inch wheels on a Mk3 Skoda Octavia

Back in December 2016, a gentleman by the name of Zoltan Varga uploaded a YouTube video of a third-gen Skoda Octavia with the 1.8-liter TSI. The Czech station wagon was first tested from 60 to 150 kilometers per hour (37 to 93 miles per hour) in third gear on 16- by 7-inch Borbet BL5 wheels mounted with Dunlop Sport Maxx RT tires measuring 205/55R16, with each corner weighing precisely 17.6 kilograms (38.8 pounds).

For the larger setup, Zoltan used 17- by 7-inch Skoda Teron wheels and 205/50R17 Dunlop Sport Maxx RT tires, with each wheel and tire weighing 19.8 kilograms or 43.6 pounds. The uploader notes that his car had 26 more liters of gasoline (about 20 kilograms) in the tank while testing the 17s. Over three runs, he recorded 10.78, 10.94, and 10.80 seconds with the 17s, resulting in an average time of 10.84 seconds.

How did the smaller and lighter wheel-tire combo fare? Zoltan ran 10.90 seconds on the first of four acceleration tests, but he ultimately posted a best of 10.21 seconds for an average of 10.62 seconds. Due to similar widths and negligibly different sidewall heights, Mr. Varga reported no substantial difference in the car's handling.

15- versus 17-inch wheels on an EK Honda Civic

Speed Academy's Dave Pratte knows a thing or two about extracting performance from one's driving and car. He used a 1999 model year Honda Civic Si Coupe to demonstrate how big of a difference 17-inch wheels make over 15s on a circuit where handling and being in the right gear are more important than outright speed and acceleration.

Equipped with Nankang AR-1 semi slicks measuring 225/205 by 15 inches and 235/215 by 17 inches, respectively, the K-swapped Sport Injected was tested on 15- by 7.5-inch Konig Hypergram and 17- by 8-inch Konig Dekagram flow-formed wheels. Otherwise put, it's a true back-to-back comparison. The 17s weigh 6 more pounds than the 15s, although the wider contact patch makes a world of difference in the twisties.

Almost an inch and a half in overall diameter translates to longer effective gearing for slightly worse acceleration. Even so, Dave prefers the 17s for a number of reasons, beginning with said wheels and tires allowing him to use second in places where he couldn't on the 15s. Front grip also feels better, there's less understeer,  and he didn't need fifth on the front straight before preparing for the corner. Lap times? Make that 1:22.5 on the 15s and 1:22.0 on the 17s around Toronto Motorsports Park's 11-turn road course.

Factory versus lightweight wheels on an Abarth 124 Spider

Unsprung weight is a big deal in racing applications. The question is, can you improve a road-going car's acceleration by swapping the factory wheels with lightweight units? Driven District is much obliged to answer with a black-painted Abarth 124 Spider wearing 205/45 by 17-inch Bridgestone Potenza RE050A tires.

17-inch OZ Ultraleggera matte-bronze wheels tip the scales at 16 pounds (7.25 kilograms) each, whereas the standard wheels weigh 22 pounds (9.97 kilograms) each. Driven District tested the 124 Spider with said wheels in relatively similar weather conditions on the stock tires from 35 to 70 miles per hour, 30 to 70, and 30 to 75 miles per hour in third gear exclusively.

The Dragy recorded 5.84, 6.62, and 7.84 seconds on the stock aluminum wheels. Switching to the OZ Ultraleggera wheels resulted in 5.72, 6.32, and 7.5 seconds, respectively. Put differently, a grand total of 24 fewer pounds (10.9 kilograms) of unsprung weight improved acceleration by 0.12 seconds from 35 to 70 miles per hour, 0.3 seconds from 30 to 70 miles per hour, and 0.34 seconds from 30 to 75 miles per hour.