A guide to air compressors for bicycles
A great addition to the home workshop, an air compressor assists with cleaning and inflating.
A great addition to the home workshop, an air compressor assists with cleaning and inflating.
Look to almost any professional workshop or race mechanic setup and you’ll likely see, or at least hear, an air compressor in use. The job of an air compressor is simple – compress air for pressurised release – and it does so with a motor (or motors) that forces air into a constrained space (a tank).
When it comes to working on bicycles, air compressors are most commonly used for two key tasks. Firstly and perhaps most beneficially, they’re the perfect tool for drying things off after they’ve been washed, or for blowing grit out of tight crevices (such as derailleurs and brakes, but take care). I hate being without one for this task.
Secondly, they’re an effortless blessing for tyre inflation, namely setting up fussy tubeless combinations that can require a sudden and sometimes high-volume burst of air (using a pump or filling a tubeless canister can be tiring!)
Best of all, air compressors are not as expensive as you may think. In this first of a two-part feature, I’ll cover the basics for getting set up with an air compressor. The second part focuses on the inflator tools required to get compressed air into a bicycle tyre.
Air is air, and in that sense, a low-cost air compressor is likely to work out perfectly fine for the casual home user. And there are a myriad of effective low-cost options given that air compressors are considered a tool for DIY projects. However, there are some critical elements to know and consider.
Most importantly, the ability to get a sudden blast of air requires a tank (aka receiver) to be pressurised, and for this, the compressor must have a tank. There are a number of affordable “electric inflators” or “compressor inflators” (more on these at the bottom of the article) on the market that lack this critical feature. Beware.
Talking of tanks, typically the more you spend the bigger the compressor and attached tank will become. Generally speaking, the bigger compressors and tanks offer comparable filling pressures to smaller options (and therefore the same initial blast of air), but that increased capacity means there’s more air to use before the pressure drops. Plus, the motor won’t need to top up the tank as often.
This can be a critical thing if running power tools or a paint gun, and it’s handy to have if blowing water off a whole bike (or bikes). However, having a large tank capacity is not critical for tyre filling, tubeless tyre seating, or just drying a chain.
At an absolute minimum, a 12 litre (3 gallon) compressor should suffice for tyre seating and filling needs. Those wanting to dry off a bike should consider a more common low-cost 24 L (6 gallon) size. While heavier users, or those looking to run other air tools, may benefit from something with at least double this capacity again. If you’re keen on running air tools such as paint sprayers, nail guns, grinders, or impact wrenches, you should look at the required CFM (cubic feet per minute) and match it to a suitable compressor.
Almost all consumer-style compressors are powered by standard household 110/240 V outlet power. Some newer (and more expensive) models can be powered by the same Lithium-Ion batteries that power big brand power tools – these are a nice option if you need something portable.
The smaller 12 L compressors start from about US$60 / AU$90, and larger ones can be had for not much more. There are a number of generic brands available online for impressively low prices, but my advice is to at least buy the compressor from a hardware, automotive, or tool store that’s going to offer a stress-free experience in case of needing to use the warranty – it is an electrical appliance after all. This article is intended for an international readership and so I won’t provide specific store links to suggested compressors (but hey, at least you know this isn’t an affiliate link money grab).
Few people have endless workshop space and so size is always going to be a factor. Obviously the larger the tank, the larger the footprint of the compressor. Those tight on space should look at “pancake” style compressors (often 24 L / 6 gallons, such as this) which typically offer a reduced footprint through a vertical-based design.
It’s important to note that many air compressors, especially the cheapest oil-free ones, are noisy little buggers when they’re filling. The noise can be well above unhealthy levels in confined spaces, so it’s worth considering whether such noise can be tolerated by the ears you own along with those belonging to your cohabiters and neighbours.
Spending more doesn’t just mean more capacity; it can also afford a quieter compressor. Brands such as Chicago (sold in Australia), Senco, Makita, California (sold in the USA), and Fortress (Harbour Freight’s brand, sold in the USA) offer “silenced” models that are noticeably quieter and more pleasant to be around. After owning a couple of low-cost noise machines, I bought myself a Chicago Silenced a number of years ago and my hearing thanks me to this day.
You can talk over these silenced compressors while they’re running. In my opinion, they’re worth the additional expense, but I also have a propensity to spend more on tools than most are comfortable with.
It’s also worth noting that compressor designs vary greatly and there is a wide range of oil and oil-less compressors on the market. For cleaning purposes, an oil-free compressor is superior and will blow air that doesn’t have oil particles. If you’re using a more industrial-style oiled compressor then you’ll likely need to add oil and water filters.
OK, so you’ve got the compressor, chances are you’ll need a few other items. You can buy an “air compressor accessory kit”, but in my experience, you’ll be left with a bunch of junk you don’t need.
Instead, I’d recommend buying a quality hose that suits your needs, a blow gun for cleaning and drying purposes, and a way to inflate tyres (more on this in the dedicated air inflator feature). You’ll likely also need a way to connect all these pieces: quick connect couplers are the way to go here.
Firstly, there’s the air hose. You’ll need one that’s long enough to go from at least the air compressor to the furthest point of where you’ll be working on bikes. The most common hose type is a low-cost spiral hose that works like an accordion to give you extra length while remaining compact when not in use. Assuming you have a wall or ceiling to mount to, then a superior (albeit far more expensive) option is an automatic air hose reel that works exactly like an auto-retract garden hose reel – these are neat and provide plenty of reach.
Commonly the air hose will come with fittings on either end, often including a quick-release coupler for easy interchange of air tools. You’ll likely need to purchase “male” adapters (aka plugs or fittings) that thread into your air tools and that match the provided quick-release coupler. There are a few different standards of coupler fittings and it’s important you don’t mix-and-match them. These fittings are often region-specific and you’ll find that what’s common in the USA will be different to the go-to in Europe.
The three most common fitting types are Ryco (aka Automotive), Nitto (aka Japanese), and Milton (aka Industrial, and what most of the cycling-related tools come fitted with).
Most consumer-available tools and compressors use 1/4″-sized threads for fittings, but care must be taken to check whether you need BSP (British standard) or NPT (American standard). Tools from USA-based companies are likely to require NPT fittings, while those from elsewhere in the world will typically need BSP. It can be confusing, and sourcing the opposite can be difficult in certain regions. While it’s not ideal, speaking from (accidental) experience, I’ve found that you can often achieve a leak-free fit by mixing NPT and BSP.
Using an air compressor to aid in cleaning and drying requires a way to focus a blast of air, and a low-cost tool called a blowgun is what’s needed here. The cheapest blow guns work fine, while more expensive versions can do a better job of offering more airflow control and a higher-pressure blast from a refined tip shape. Cheap options should cost you around US$10, while even an expensive one should be under US$30. Just a quick safety warning here, these tools can be dangerous if used incorrectly and for that reason, safety codes often dictate a low outlet pressure to be used. I can assure you that the vast majority of bicycle shop and race mechanics use such a tool without a low-pressure limiter, but it is advised to wear safety glasses.
And finally, there’s the tool that you’ll need for inflating bicycle tyres: a tyre inflator tool. Of course, I tested almost all of the popular options and so there’s a dedicated shootout article for just this.
Once you have the compressor it’s important to follow the manual for setting it up – there are subtle differences between many popular compressors.
Most compressors allow some form of adjustment to the filling pressure that controls when the motor stops adding air to the tank. For bicycle purposes, I’ve found that using an approximate 90-100 psi line pressure (the pressure coming out of the compressor) is a good compromise between easy tubeless inflation and not over-taxing the tool.
Compressed air will cause water to pool at the base of the tank and it’s important to bleed this semi-regularly, especially given most air compressors use a steel tank that can rust if ignored. Because of this, it’s a good idea to put the compressor in a place that’s relatively easy to access.
Almost all brands warn not to leave a filled compressor and that you should empty the tank between uses. While you should always follow the advice of the brand, I will say that most workshops leave theirs filled. If your compressor is unlikely to receive regular use then empty it.
And as a final important safety point, it’s always recommended to wear safety glasses when using an air compressor. Debris can spray in all directions during cleaning and unexpected things can happen when working with tyres.
As mentioned above, there are numerous products on the market that share similar naming and purpose with a traditional air compressor. Below is a brief guide on what these are and why you should and perhaps shouldn’t consider them.
Designed as an electric replacement for a hand pump, these small devices were first popular amongst mountain bike and cyclocross race mechanics and have since boomed in popularity.
An increasing number of industrial tool brands, such as Milwaukee, Bosch, Ryobi, Dewalt, and more offer a pump like this. Then there are the generic options such as the Xiomi Mijia pump. And the smallest example of all is the bicycle-specific Fumpa pump (a product I personally use on an almost daily basis).
Many of these offer an accurate way to reach the desired tyre pressure with little manual effort and in a portable package. However, all of these lack a filling tank and so they’re just about useless for setting tubeless tyres or drying off components.
These are much like the electric inflators above but typically draw on an external power source to power them. In most cases, these go off 12 V power and are intended as an emergency pump that can be plugged into your car.
Like above, these almost always lack a filling tank and as a result, they’re pointless for when a compressor is typically most handy.
Tubeless tanks are bicycle-specific air chambers that are manually pressurised with a floor (track) pump – think of them as an air compressor where you’re the motor. Tubeless tanks can be bought as a separate accessory or as an integrated component of a tubeless floor pump.
These tanks are often filled to 120-160 psi before allowing you to release the contained air for seating stubborn tubeless tyres. They’re often an effective tool for the task and I know of a few people who choose to use this for seating tubeless tyres instead of switching on a noisy compressor.
They’re portable, don’t require electricity, and don’t make noise – all things that make them ideal if you don’t have a dedicated workshop space. However they can be rather tiring to fill, and it can quickly get tedious if the tyre bead isn’t seating straight away. Also, they’re of little use for drying components due to limited air volume.
Air blowers are most commonly used for cleaning electrical components or grooming pets, Metrovac is one such example. Many of these look like paint sprayers but instead blow a surprisingly large volume of warm air. These are a good option if you simply want a tool to assist with drying off freshly cleaned parts. They’re often quieter to use than an air compressor and come with far fewer safety caveats. Leaf blowers, hairdryers and similar tools can also be used in these circumstances depending on your patience levels. Obviously, none of these air blower devices are suitable for tyre inflating purposes.
If you’re keen to get an air compressor set up for your cycling needs, be sure to also check out our feature on the best tyre inflators for air compressors.