If you have ever seen a folding bike, one of the first things you notice is the fact that their wheels are much smaller than a standard road bike. For example, your standard Brompton comes with 16" inch wheels, and there are some folding bikes available with 12" wheels. Although this helps with the folding nature, allowing them to be more compact, how does it affect the performance?
The difference in wheel size between a folding bike and a regular-sized bike - Image from I Love Biking SF
Do small wheels on a bicycle affect speed?
This isn’t such a simple question to answer because it all depends. A small wheel is able to spin at a higher RPM (revolutions per minute) because of the smaller circumference, meaning it would take more effort to get to the same speed on a bike with larger wheels.
It would be quicker to accelerate from a dead stop with a smaller wheel, but once moving, the extra size and weight of a larger wheel will give you more momentum giving you a higher top speed.
Do small wheels make the bike easier to manoeuvre?
Yes. Smaller wheels are more responsive to the steering which makes the bike more manoeuvrable. This helps on tight turns and wet surfaces. However, larger wheels have better traction, due to more rubber connecting with the floor.
Are small wheels better for hill climbs?
Small wheels are lighter, making climbing easier. You’re able to accelerate quicker and build up and maintain speed on hills. The lower RPM of the smaller wheel definitely helps here. The higher traction of the larger wheel will help with grip but you’ll have to put more effort to achieve the same RPM as the smaller wheeled counterpart.
Are small wheels better for long journeys?
The unique selling point for the majority of folding bikes is the fact that they are perfect for commuting. They seem to be sold as the ideal urban transport, perfect for taking on and off public transport, perfect for any city worker. But if you plan on cycling long distances then comfort is paramount. Larger wheels definitely have the advantage here as smaller wheels have a steeper angle of attack when it comes to rough terrain. Any bump in the road, or curb, or rock that you cycle over will be felt more on a bike with smaller wheels.
Image taken from - Evo.com
There are a lot of pros and cons when it comes to having smaller tyres on your bicycle. The reason the majority of folding bikes have smaller wheels is that they are designed to fold up into a compact size. They aren't designed for fast, off-road competition. If you want a bike that is high performance both on and off road then perhaps a folding bike isn’t for you. However, if you think the smaller wheels are a hindrance to the rideability of a folding bike then you are mistaken.