Installing aftermarket tires is a common way to modify and personalize motorcycles. They can provide an entirely new look for a bike as well as a performance gain if you choose the right set. New tires look good on a scooter, sport bike, cruiser, and basically all types of bikes.
That said, new tires are one thing, but different size tires are another thing entirely. There are some important points to consider before you change your motorcycle's tire size. Factors like the contact patch, tire clearance, tire grip, and unsprung weight all play a part in how well a tire would work for your bike.
Can I put wider or narrower tires on my motorcycle?
The short answer is yes. The long answer is also yes, but you have to consider a few things and you have to know what you're doing.
Tire size is always a balance between acceleration and cornering grip. This is why manufacturers equip motorcycles with a certain size tire. The size of the stock tires has been carefully considered against the capabilities of the bike as well as the weight and other factors. However, this doesn’t mean that there’s no room to change tire sizes. It only means you have to think about how you approach the changes carefully.
Now, smaller displacement motorcycles can handle slimmer tires, while bigger bikes are better equipped for wider tires, up to a certain point. Changing tire sizes will affect unsprung weight, which refers to the components of a motorcycle that are not supported by the suspension system. The brakes, wheels, and tires make up the unsprung weight, and any changes to these will affect handling and cornering abilities, for better or worse.
It’s worth noting that different-sized bikes will have different-sized rims. With wider tires on a rim meant for a narrower tire, the geometry of the tire changes to fit the rim. This results in a more rounded tire profile and a smaller contact patch than is ideal. Wider tires are also heavier, so when equipped on smaller motorcycles, it can negatively impact performance and fuel consumption.
While wider tires tend to work better for bigger bikes, It should be said that not all motorcycles can handle wider tires on a smaller rim, no matter how powerful they are. However, assuming a proper fit, the larger contact patch from wider tires can enhance road grip, disperse more heat, and use more tread, leading to improved handling and a longer lifespan for the tires.
As for narrower tires on a larger rim, the contact patch sits closer to the centerline. Slimmer tires reduce weight, which may be good for handling and performance, but they can't handle as much power. When you put a significantly narrower tire than the bike is designed for, it can be good for a while, but the sheer force of gripping the road can wear out the tread very quickly.
When changing tires, you also have to consider the bike's clearance for width and diameter. If the tire size you're looking at hits the frame, swingarm, or other components, that's an automatic no-go. Only fit tires that can comfortably clear every part of your bike. The owner’s manual usually includes the dimensions for these parts, or you can look them up online.
So, you can change your motorcycle's tire size—that is if you weigh the pros and cons and put in the necessary research to determine the proper fit. For best results, check with your motorcycle and tire manufacturer to find out which tires are compatible with your stock rims and bike.