Pros, Cons, and Safety of Riding the Dark Side: Car Tires on Motorcycles

John Melendez
Jul 10
7 min read

a motorcycle rear view — An example of "darksiding"

What Is Riding the "Dark Side"?

Riding the Dark Side refers to mounting car tires on motorcycles, typically on the rear wheel but sometimes the front. This controversial practice, known as "darksiding," has sparked debates among riders, with some praising its benefits and others warning of risks. This article explores the pros, cons, and safety considerations of darksiding, drawing from online discussions, blogs, and social media trends.

Why Riders Choose the Dark Side: Five Key Arguments

The decision to ride the Dark Side often stems from practical and financial considerations, particularly for high-mileage riders. Here are five compelling arguments in favor of using car tires on motorcycles, based on insights from riders and online forums.

Cost Savings and Affordability

Car tires are significantly cheaper than motorcycle tires. A high-quality motorcycle tire can cost $150-$300 and last 5,000-20,000 miles, while a car tire, such as an Arizonian Silver Edition, might cost $73 with a 50,000-mile warranty. For riders who log tens of thousands of miles annually, the reduced cost per mile is a major draw, especially for touring or commuting on heavy bikes like the Honda Goldwing or Yamaha FJR1300.

Extended Tire Longevity

Car tires are designed for heavier vehicles and longer lifespans. Riders report getting 20,000-50,000 miles from car tires on motorcycles, compared to 5,000-15,000 miles for motorcycle tires on heavy cruisers. This longevity reduces maintenance frequency and costs, appealing to long-distance riders who prioritize highway stability over aggressive cornering.

Enhanced Load Capacity

Motorcycles, especially touring models, often carry significant weight from riders, passengers, and gear. Car tires typically have higher load ratings than motorcycle tires, providing extra capacity for heavy bikes like the Kawasaki Vulcan 2000 or Honda VTX 1800. This makes them suitable for riders who travel with substantial cargo or ride two-up frequently.

Improved Traction in Certain Conditions

Some darksiders claim car tires offer better traction in wet or gravelly conditions due to advanced rubber compounds and tread designs. Riders on forums like mcdarksiders.forumotion.com note that car tires, such as the Michelin Pilot Exalto, provide a wider contact patch in straights and leans, enhancing stability on highways or rough roads. This is particularly valued by riders in regions with variable weather.

Smoother Ride Quality

Car tires can provide a smoother ride, especially on long highway stretches. Riders on platforms like GL1800Riders report that tires like the Michelin Alpin offer a comfortable, stable experience, reducing vibrations over potholes or train tracks. This is a significant advantage for touring riders who prioritize comfort during extended trips.

The Case Against Darksiding: Five Critical Concerns

Despite the enthusiasm of darksiders, many riders and experts argue that car tires on motorcycles compromise performance and safety. Here are five arguments against riding the Dark Side, grounded in online discussions and technical analyses.

Compromised Handling in Corners

Motorcycle tires have a rounded, U-shaped profile designed for leaning into turns, allowing the contact patch to adapt dynamically. Car tires, with their flat tread and sharp sidewall angles, resist leaning and can feel sluggish or unstable in corners. Riders on Reddit’s r/motorcycles note that darksiding reduces nimbleness, particularly on sportier bikes like the Honda VFR 750, where precise handling is critical.

Reduced Traction During Lean

When a motorcycle leans, a car tire rides on its edge, reducing the contact patch to as little as one-third of the tread width. This diminishes grip, especially in hard turns, as highlighted in a RideApart video demonstrating minimal tread contact at lean angles. For riders who enjoy twisty roads or aggressive cornering, this loss of traction is a significant drawback.

Incompatibility with Motorcycle Rims

Car tires are designed for wider car rims, not the narrower rims of motorcycles. This mismatch can lead to improper bead seating, increasing the risk of tire failure under stress. A detailed analysis on thetruthaboutcars.com explains that the bead shape and ply-wrappings of car tires are not suited for motorcycle-induced stresses, potentially compromising air seals and structural integrity.

Legal and Insurance Risks

In many regions, using car tires on motorcycles violates safety regulations or manufacturer recommendations, as noted on roaddirt.tv. This can result in legal consequences or voided insurance coverage in the event of an accident. Riders on Harley Davidson Forums have expressed concerns that insurance adjusters may deny claims if a car tire is found on a motorcycle, adding financial risk to the practice.

Unpredictable Performance on Irregular Surfaces

Car tires perform poorly at low speeds on rough or uneven roads. A rider on vtxcafe.com described the flat profile of a car tire as akin to “riding with an uncooperative passenger,” causing the bike to fight ruts or ridges. This unpredictability can be exhausting and hazardous, particularly for riders in areas with poorly maintained roads.

Double Darksiding: Front and Rear Car Tires

The practice of “double darksiding”—using car tires on both the front and rear wheels—is far less common and more controversial. While rear car tires are widely debated, front car tires are rarely endorsed, even among darksiders. The front wheel is critical for steering and stability, and car tires lack the rounded profile needed for precise control during leans and turns. A post on vulcanforums.com mentions “double darksiding” as mounting a rear motorcycle tire on the front and a car tire on the rear, indicating that even darksiders avoid car tires up front due to handling concerns.

Using a car tire on the front wheel exacerbates the handling issues seen with rear darksiding. The flat tread profile hinders quick steering inputs, making low-speed maneuvers and tight turns difficult. Additionally, the risk of sidewall contact during leans increases, as car tire sidewalls are not designed for road contact. Most darksiders on forums like indianmotorcycles.net stick to motorcycle tires for the front, citing safety and performance as non-negotiable. Given these factors, double darksiding is generally imprudent and rarely practiced, even by those who embrace rear car tires.

Important Safety Considerations: The Ultimate Argument

Safety is the paramount concern when evaluating riding the Dark Side. While darksiders report millions of miles without incidents, the practice introduces risks that cannot be ignored. Motorcycle manufacturers, including Honda and Harley-Davidson, explicitly recommend against car tires, citing their incompatibility with motorcycle dynamics. The Rubber Manufacturers Association has also issued warnings, as noted on gl1800riders.com, emphasizing that car tires are not engineered for the stresses of motorcycle use.

One major safety issue is the reduced grip during leans, particularly at high speeds or on wet roads. A YouTube video by FortNine illustrates how car tires roll onto their sidewalls in hard turns, drastically reducing traction. This can lead to loss of control, especially for riders unprepared for the altered handling. Additionally, the weaker sidewall integrity of car tires, as highlighted on rideapart.com, increases the risk of blowouts or flats, which are catastrophic on a motorcycle due to the lack of stability compared to a car.

Legal and insurance risks further compound safety concerns. In jurisdictions where darksiding is illegal, riders face fines or penalties, and insurance companies may refuse claims, leaving riders financially vulnerable after an accident. Maintenance challenges also arise, as many tire shops refuse to mount car tires on motorcycle rims due to liability concerns, as discussed on rabaconda.com. This can leave riders stranded or forced to perform risky DIY installations.

However, darksiders counter that real-world experience—millions of miles ridden on car tires without widespread reports of crashes—suggests the risks are overstated. The Iron Butt Association, known for long-distance rallies, permits car tires, noting no data links them to increased crashes. Still, the lack of crash statistics may reflect underreporting rather than safety, and the absence of controlled testing leaves uncertainty.

Ultimately, safety depends on the rider’s style, bike type, and riding conditions. Darksiding may be viable for straight-line highway cruising on heavy touring bikes, but it’s risky for aggressive cornering, rough roads, or high-performance riding. Riders must weigh these factors against cost savings and ensure compliance with local laws to minimize risks.

Is Riding the Dark Side Right for You?

Riding the Dark Side offers tangible benefits—cost savings, longevity, load capacity, traction in specific conditions, and ride comfort—but comes with significant drawbacks, including compromised handling, reduced traction, rim incompatibility, legal risks, and poor performance on irregular surfaces.

Double darksiding is largely inadvisable due to severe handling issues, particularly on the front wheel. Safety remains the ultimate consideration, with risks of reduced grip, tire failure, and legal consequences outweighing benefits for many riders. For those considering darksiding, thorough research, careful tire selection, and an honest assessment of riding style and conditions are essential.

Stick to motorcycle tires unless the benefits align with your needs and you’re prepared to manage the risks.

Altus assumes no risk on any of this content! Blog article disclaimer

Remember: Ride safe. Ride far. Be Considerate. And have Fun!

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Since 1997, Altus Scooter & Motorcycle Parts™ has been the driving force behind cutting-edge fuel delivery systems for scooters, motorcycles, jet skis, and small boat outboard engines.Our products include a full line of high-quality replacement fuel pump assemblies, plain fuel pumps, ECUS and fuel filters.