Comparison Kraissmann TRF 121 vs Aspiring Storm 3

The maximum pressure provided by the pump or compressor — in other words, the highest tyre pressure that can be achieved using this unit.

In most models, this figure is from 2.5 to 10 atm, and in mechanical pumps (manual and foot, see "Type") pressure of more than 10 atm is practically not found at all. This is due to the fact that even for heavy trucks, the optimal tyre pressure is usually about 5 – 9 atm (depending on a number of parameters — there are special formulas and tables for calculations); and in passenger car tyres, a pressure of more than 2.5 atm is extremely rarely used. However, there are compressors with higher pressure parameters — 11 – 15 atm, 16 – 20 atm and even higher. The meaning of such characteristics is mainly in the "power reserve": a higher working pressure contributes to faster pumping. However, be careful not to over-inflate the tyre and damage it.

The capacity of the compressor (see "Type") is the maximum amount of air that it can pump into the tyre in a minute.

Higher performance reduces the time required to inflate the wheel; on the other hand, this parameter directly affects the dimensions, weight, power consumption and price of the compressor. So it is worth choosing according to performance, taking into account real needs. So, for a “duty” tyre inflation in a passenger car, a compressor with a low operating speed is quite enough — up to 20 L / min inclusive. And if the speed of full pumping is also important for you (for example, after replacing the rubber) — you can choose a unit for 21 – 40 L / min. In turn, models with more solid characteristics — 41 – 60 L / min and more — are intended mainly for heavy equipment like SUVs, trucks, tractors, etc.

Separately, it should be noted that this parameter is NOT suitable for calculating the exact inflation time (even if the exact volume of air in the wheel is known). The fact is that the actual performance of the compressor is always lower than the claimed one: the figures in the characteristics are indicated for free air outlet, and when pumping the wheels, the pumping speed will inevitably be lower due to the resistance of the nipple.

Rated power consumed by the compressor during operation.

This parameter primarily affects the features of connecting the unit to the on-board network through the cigarette lighter socket. Such a socket has restrictions on load power, and these restrictions are different for different cars; and even in the same car, different connectors — the cigarette lighter itself and a separate socket of the same format — can differ in allowable power. However, most of these connectors can easily cope with units with a power of up to 100 – 120 W; but if you get a more powerful compressor, you should clarify the possibility of using it with a specific cigarette lighter (the easiest way to do this is according to the documentation for the car). If the device is planned to be powered through "crocodiles" or from a 230 V socket (see "Connection"), you can not pay much attention to the power consumption.

Also, more powerful compressors, usually, have a greater capacity and/or maximum pressure, but there is no strict relationship here.

The length of the cord with which the compressor is connected to a power source — a standard car socket DC 12V (so-called cigarette lighter) or directly to the battery terminals. It is believed that the length of the cable should not be less than two metres to avoid inconvenience in operation.

The length of the hose through which air is pumped into the tyre. The larger it is, the more convenient the device is to use. But it is rare that the compressor is left far from the wheel, especially if a pressure gauge is placed on the device, which must be periodically checked. For domestic use in cars, a one and a half metre long hose is enough. Powerful and performant models can be equipped with a hose of 7 metres or more, but these are more solutions for commercial use in car services.

In theory, the higher the capacity, the longer a cordless tool can last on a single battery charge. However, in practice, everything is far from so simple. Firstly, ampere-hours are a fairly specific unit; its features are such that only batteries with the same voltage can be directly compared by the number of ampere-hours. If there is a difference in voltage, you need to convert the capacity into watt hours and use them for comparison. Secondly, the actual autonomy of the tool depends not only on the properties of the battery, but also on power consumption and other performance characteristics. Thus, it is possible to compare different models in terms of battery capacity only with the same supply voltage and similar capabilities.

The time it takes to fully charge the battery that comes with the tool from a standard charger (when using other batteries or a “non-native” charger, this time can vary in one direction or the other).

Ability to operate in power bank mode. This feature is found only in models with built-in batteries: it allows the battery to be used for charging/powering a smartphone or other external gadget. Thus, a compressor with a Power Bank function can serve as an additional external battery, which can be crucial during power outages. The design may include both a USB-A port and a more modern USB-C port.

The presence of backlight pressure gauge in the design of the device.

This function requires a power supply, so it is found mainly in the corresponding type of device — compressors (see "Type"). Its purpose is generally obvious: thanks to the backlight, you can easily see the readings of the pressure gauge in low light conditions and even in complete darkness. Such an opportunity when working with a compressor is useful — and not only at dusk and at night, but even in the daytime: many garages, boxes and other places where you have to service a car are very sparingly lit, and even during the day the pressure gauge scale may not be visible without additional illumination.