Which Harley-Davidson Model Has The Biggest Gas Tank?

Very few motorcycle brands can claim to evoke the same sense of freedom and adventure as a Harley-Davidson motorcycle does. As one of the oldest, most popular motorcycling companies in the world, Harley built its reputation on big-bore V-twin cruisers and touring machines, all of which cemented its image as the maker of bikes for cruising highways, small-town main streets, and long-distance touring. Carrying forward its legacy, Harley, today, continues to sell a variety of motorcycles across various categories, ranging from tourers, cruisers, and trikes to adventure tourers and sport models.

Irrespective of the type of Harley one rides, there's one very practical factor that often separates a carefree ride from a frustrating one: fuel capacity. Having to constantly check if you have enough fuel to reach the next gas station isn't something most motorcyclists want to think of while enjoying a thrilling cross-country ride. Small fuel tanks have never been an issue with Harleys, given the company's focus on big-bore cruisers and tourers. In fact, Harley-Davidson motorcycles are known for their high-capacity fuel tanks. We found that the largest fuel tank capacity offered on a stock Harley-Davidson (as of 2025) is 6 gallons (22.7 liters). However, that same model of tank is shared across multiple motorcycles. We also discovered that the smallest fuel tank currently offered on a stock Harley-Davidson motorcycle is 3.1 gallons (11.7 liters), limited to some of its Sport models.

If your goal is a brand-new Harley with the biggest fuel tank, you have to look at models from the company's "Grand American Touring" and three-wheeled "Trike" lineup. All models from the Grand American Touring lineup — including the Road King Special, the Street Glide series, and the associated CVO models — come with a 6-gallon fuel tank. These machines offer roughly 40-45 mpg, giving them considerable range. As for the Trike models, all three 2025 model year offerings — the Freewheeler, Road Glide 3, and Tri Glide Ultra — feature a 6-gallon fuel tank. All of these machines also offer between 40 and 43 mpg. 

Harley's adventure tourer models — which include the Pan America 1250 and the CVO Pan America — feature a slightly smaller 5.6-gallon (21-liter) fuel tank. However, these models do have slightly better fuel efficiency numbers, which could help bring their range closer to that of the Trike and Tourer models, so if your main concern is getting the most miles between fuel stops, any of the Harley models mentioned above will serve you well.

Harley's trademark Cruiser motorcycles, which include machines like the Low Rider, Breakout, Fat Boy, and Heritage Classic, all come with a 5-gallon fuel tank. The Street Bob is an exception in this lineup, with a smaller 3.5-gallon fuel capacity. The smallest fuel tank on the current Harley-Davidson motorcycle lineup (3.1 gallons) is found on the company's Sport models, like the Nightster and Sportster.

The 6-gallon fuel tanks that some Harley-Davidson motorcycles sport scratch the upper limit of fuel tank capacity on the company's lineup. While this is a big enough capacity for most motorcyclists and long-distance tourers, for people wanting even more single-tank range, the only option is to opt for even larger fuel tanks made by third-party vendors. While several 3rd party mods center around increasing the tank capacity of Harleys with smaller fuel tanks, there are some companies that make fuel tanks that exceed 6 gallons in capacity.

Remmotorycle, a motorcycle-focused e-commerce company, lists a massive 6.3-gallon (24-liter) fuel tank that is designed to work with Harley Davidson Softail models launched since 2018. The product is simply called the "Large Capacity Softail Fuel Tank" and is made to order.

The largest Harley-Davidson-focused gas tanks we could find were from HogWorkz, which makes two 6.6-gallon (25-liter) fuel tanks. The company currently sells two models in this category: a Stretched 6.6 Gallon Gas Tank and a Stretched Bodyarc 6.6 Gallon Gas Tank, both of which fit a variety of Harley tourers produced between 2008 and 2025. The company states that the fit of these tanks also means that the stock seat would need to be replaced with a new one.

With a price tag between $470 and $650, upgrading to larger fuel tanks isn't what we would call affordable — and this is excluding the fitment charges, as well as the cost incurred for making additional modifications like changing the seat.