Condensed answer: If the pump is designed for balls, it could lack the adapters needed for the Schrader and Presta valves found on bike tires. As a result, the pump will be useless for bike tire inflation.
If the pump comes with the needed adapters, you will be able to add some air to the inner tube, but it will be difficult to reach high air pressure.
Additionally, the pump could leak. For that reason, it’s recommended to get a dedicated bike and/or floor pump that can do everything.
Non-Compatible Adapters
Standard ball pumps are equipped with a needle end that slides into the air valve of the ball.
The inflation valve is made of strong rubber. Once the needle is in the valve, it allows the transfer of air from the pump to the body of the ball. When the needle is pulled out, the rubber valve closes automatically.
Bicycle tires have completely different valves. The most common options are Schrader (the one you find on cars) and Presta (French valve).
Some ball pumps have removable ends that will allow you to install a Schrader adapter because those are a lot more common. In that case, you will be able to pump some air into a bike tire with a Schrader valve, although it will be difficult to reach high PSI.
It’s also possible to install a Schrader to Presta valve adapter on the tire and pump even a tire with a Presta valve. That said, it won’t be possible to reach the high PSI that a road or a hybrid tire needs for proper operation.
FAQ: What happens if a tire operates at lower than recommended air pressure?
There are three main downsides:
1. Increased chance of getting a flat tire. (The tire is too soft to push away external objects, and there’s a greater risk of a flat caused by the rim itself a.k.a. a snake bite.)
2. Increased rolling resistance (The tire rolls slowly and less efficiently.)
3. Greater chance of rim damage
Ball Pumps Have Low PSI Threshold
The vast majority of pumps specialized for the inflation of balls cannot operate with high air pressure.
Most models are limited to about 15psi or 1 bar. Meanwhile, the typical mountain bike air pressure ranges from 22psi (1.5 bar) to 35psi (2.4 bar).
In the case of road bikes, the situation is even worse because road tires are narrow and operate with extremely high air pressure between 90psi/6.2bars and 120psi/8bars.
A basic ball pump won’t reach that air pressure without breaking or leaking.
Structure, Build Quality
Many ball pumps have weak, plastic bodies. After all, they’re designed to be carried around and have a fairly simple purpose.
Meanwhile, dedicated bike pumps (portable and floor versions) are built to last a long time and come with strong aluminum shafts and seals that can sustain the high air pressure that a bicycle tire might need.
Inefficient
The pump stroke of a ball pump is much shorter than that of most dedicated bike pumps. Or in other words, each pump pushes a very small amount of air into the tire. As a result, it takes more time and effort to reach greater PSI.
The Ideal Scenario
If you want a portable pump that will be efficient for both bicycle tires and balls, it’s recommended to get a dedicated telescopic bike pump with a needle adapter. The needle adapter usually mounts to the Schrader end of the pump.
A ball pump may fail when it comes to bicycle tires, but even the cheapest bike pump can inflate pretty much any ball with a needle adapter.
Ideally, you will also have a large floor pump with a manometer at home. Floor pumps are much more efficient than portable bicycle pumps thanks to the large barrel and the leverage that they provide.
The manometer allows you to monitor the air pressure of the tires and take notes on how they perform at different values.
