Ring Automotive Air Compressor RAC900

Automotive Air Compressor RAC900 by RING


This post is about the RING Automotive Air Compressor RAC900 which is an excellent pump for inflating anything with a Schrader valve, (e.g. car tyres, bicycle tyres, etc.) or balls, airbeds, etc. (3 Inflation Adapters are supplied). It has to be powered by a 12 volt (30 amp peak) supply such as a car battery (not provided).

The Background To My Purchase

A few weeks ago I passed a friend in the street who was inflating his car tyres on his driveway with a RING Automotive Air Compressor RAC900. He was eagerly showed me his new tyre pump which was powered by his car battery. He explained that it had the advantages over other tyre pumps because it:

  • inflated tyres very quickly,
  • had a built-in pressure gauge,
  • was very well-engineered with lovely brass parts,
  • came with a long yellow curly plastic pipe to reach all tyres on a car,
  • was very quiet compared to other 12 volt air compressors I have heard,
  • was “Made in England”, Leeds in fact.

He told me he had bought it from a local automotive shop J. G. Bestwick Ltd. However they had to order it for him since they didn’t stock it.

I was impressed with what I saw.

Away from a petrol station I still used a foot pump. I once bought a cheap air compressor to inflate tyres but it was too noisy. I felt inhibited from using it at home on the driveway in case I disturbed my neighbours. So I got rid of it.

The one my friend showed me was a RING Automotive Air Compressor RAC900 for heavy duty work. See it at the RING web site. Here is the INSTRUCTION MANUAL.

I couldn’t wait to get one and found I could make a considerable saving buying it on-line through Amazon.

The Quality Of The RING Automotive Air Compressor RAC900

Most tyre pumps connect to the valve on the tyre with a quick release mechanism having a rubber insert which, when squeezed by a lever, swells and seals against the thread on the valve. These are usually OK when new but deteriorate with usage until they leak causing loss of applied pressure.

With the RING Automotive Air Compressor RAC900 the hose is attached by screwing the brass Schrader valve attachment onto the valve until it seals against a sealing ring. The valve attachment has a push and turn mechanism to allow the tyre to be deflated when the pressure is too high while the compressor is still attached to the wheel valve. The compressor comes with an instruction label attached to the pipe but it may rip off easily.

The gauge, with its brass push-together & quick-release coupling for joining to the yellow hose (shown below), is mounted at one end of a short black pipe while a Schrader valve connector is mounted at the other.

Ring Automotive Air Compressor RAC900
Coupling between yellow hose and gauge.
Ring Automotive Air Compressor RAC900
Female part of coupling on the gauge.
Ring Automotive Air Compressor RAC900
Male part of coupling on the yellow hose.

The take off from the compressor is via a short black high pressure hose. This then connects to the long yellow flexible coiled hose which can be stretched to reach distant tyres.

Keeping The RING Automotive Air Compressor RAC900 Pipe Connectors Clean

The connector coupling the two pipes is a quick release type and very well made with a back-pressure valve in it. The back pressure valve prevents a tyre deflating when it’s connected to the yellow hose but disconnected from the black hose, or the compressor is turned OFF. You can see it below:

Ring Automotive Air Compressor RAC900
The female brass connector on the yellow hose.
Ring Automotive Air Compressor RAC900
Looking at the back pressure valve inside the brass connector on the yellow hose.
Ring Automotive Air Compressor RAC900
The male connector on the black hose.

Prevent Ingress Of Dirt In The Pipes

It would be difficult to remove dirt from inside the connectors, so keep dirt out of them. Once inside it may prevent them sealing when coupled. This is one of the arguments against this device.

Connecting The Air Compressor RAC900 To The Car Battery To Give It Power

The pump’s compressor is driven by a powerful looking 12 volt electric motor. It can draw up to 23 amps from the battery. This is too much current for a cigar lighter socket, commonly fused at only 15 amps. So, don’t connect the wires to a cigar lighter plug.

To use it with a car the bonnet must be open and the battery cover removed to expose the battery terminals.

The cable has an in-line 30 amp fuse and connects to the car battery with two substantial spring clips coloured BLACK and RED thus:

  • The BLACK clip attaches to the NEGATIVE (-ve) battery terminal (the one connected to the car body on most modern cars),
  • The RED clip attaches to the POSITIVE (+ve) battery terminal.

See images of battery connections below:

Spring Clips Connected To The Car Battery
The Compressor’s Spring Clips Connected To The Car Battery
RAC900 30 Amp Fuse (Cover Removed)
RAC900 30 Amp Fuse (Cover Removed)

There is an ON/OFF switch at the motor end of the casing with a nice translucent rubber dust cover over it. I don’t know if it is completely waterproof.

The compressor and motor have four rubber feet at the corners which rest on the ground and absorb vibration. The unit also has a nice handle allowing the unit to be balanced in the hand when picked up. See featured image.

Below the compressor is connected to a car tyre:

RAC900 Tyre Pump In Action
RAC900 Tyre Pump In Action

The Inline Tyre Pressure Gauge

Here you can see a close-up of the inline Tyre Pressure Gauge:

The Inline Tyre Pressure Gauge

It measures psi (pounds per square inch), BARs and kg/cm2

Carrying Bag For The Air Compressor RAC900

All of the parts can be kept in this nice bespoke bag with two compartments, a large one for the compressor and smaller one for the pipes and Inflation Adapters:

Ring Automotive Air Compressor RAC900 Bag
Two Compartment Bag Closed
Two Compartment Bag Open
Two Compartment Bag Open

Details Of The Inflation Adapters Supplied

Below are the three Inflation Adapters included for inflating balls, airbeds, paddling pools, etc.:

Inflation Adapters

Here are the sizes of the adapters A, B & C in the picture:

  • A – Narrow End 8.5mm, Broad End 11.3mm, Length 13.5mm,
  • B – Narrow End 5mm, Broad End 12.2mm, Length 40mm,
  • C – Diameter 2mm, Length 32mm, open ended with 1mm Hole 5mm from end. Inflate balls with this adapter.



15 responses to “Automotive Air Compressor RAC900 by RING”

  1. Skyler avatar

    Thank you for sharing a great article. People can use air compressor most effectively with these detailed guidelines in long-lasting. Hope to see more tips in the future. Everyone can go through http://aircompressorjournal.com/ to learn more about air compressor. Many thanks

    1. Marc Smith avatar
      Marc Smith

      Great post, thanks Colin. Was looking for an air compressor for home when I came upon your post. Found some reviews on http://www.thediyhubby.com/air-compressor-reviews/ and purchased a Porter Cable portable air compressor to run my nailer and inflate tires.

  2. Linda avatar

    Colin, my yellow hose has got a couple of holes in it, can I buy a new hose and if so where from?

    1. Helpful Colin avatar

      Hi Linda,

      Sorry to hear your yellow hose is damaged and needs replacing. You could try binding the hole with several layers of good PVC electrical tape if the pipe is clean and the holes are somewhere away from the connectors on the ends.

      Buying a replacement part can be hard work in this modern world. I think it would be best to contact Ring Automotive direct.

      You could contact them over the internet via their web site: http://www.ringautomotive.com/uk/content/contact-us
      There you will find a contact form.

      If you are in Europe you could email exportsales@ringautomotive.co.uk for help.

      Away from an internet connection you can contact Ring Automotive this way:

      Contact us by phone or fax
      UK Sales – Calling from the UK
      Tel: 0113 213 2000
      Fax: 0113 231 0266

      International Sales – Calling from overseas
      Tel: +44 113 213 2000
      Fax: +44 113 231 1887

      Office Hours: Mon-Fri: 8.00am – 5.00pm
      Contact us by post
      Ring Automotive
      Gelderd Road
      LS12 6NA
      United Kingdom

      Kind regards, Colin.

  3. bill avatar

    Hi Colin can you tell me what the brass fitting is on the top of the compressor it leaks air Thank you

    1. Helpful Colin avatar

      Hi Bill,
      There are rules governing the construction and use of compressors in the UK, e.g. Compressed Air Safety. See page 7, section 14, Safety Valves. So I’m sure it has a Safety Valve and that is it.
      If so then why is it operating and discharging air?
      1. Maybe there is a blockage in the pipework between the compressor and the vehicle tyre, or a problem with the tyre valve. If so pressure will build up and the safety valve will operate to release the excess pressure. Disconnect the pipe from the tyre and ensure that air passes through all the pipework freely and the Safety Valve closes so that no air comes out of it. If the pipework is OK check what is faulty with the tyre you’re trying to inflate. Try inflating another tyre. Are you seeing a pressure reading on the pressure gauge provided when connected to a tyre (you should)?
      2. Maybe the Safety Valve is faulty, i.e. stuck in the open position. In this case I would contact the supplier and discuss with them. Your compressor may still be under guarantee so you may be able to get it replaced.
      WARNING: Tampering with the safety valve or hose connection at the compressor is likely to invalidate any guarantee and may introduce safety issues so I will not recommend it.
      Regards, Colin.

  4. Bill avatar

    Thanks Colin will check it out if no joy will contact the manufacturer

  5. Steve Dean avatar
    Steve Dean

    What is the thread size and type on the compressor body please. The one that the black rubber flexible hose is screws to, Many thanks, Steve

    1. Helpful Colin avatar

      Hi Steve,
      I’m sorry I have not replied until now. I’ve had to measure the thread size.
      Having measured it I think it is M10 × 1.0 parallel (not tapered).
      How have I determined that?
      I unscrewed the black pipe from the compressor head and measured it. The thread has Loctite on it so it doesn’t look clean in these photos.
      Diameter of Thread
      Pitch of Thread
      Parallel Thread
      From the pictures you can see: The diameter is 10.0 mm, The pitch is 1.0 mm and in the jaws of my calipers it looks fairly parallel.
      I’m not 100% sure its a metric thread but it was made in recent years within the EU. My next best guess would be an NPT (National Pipe Thread), but I can’t see a taper on it.
      I hope this helps.
      Regards, Colin.

      1. Steve Dean avatar
        Steve Dean

        That is absolutely brilliant Colin, could not have asked for more. As you say metric seems the most likely ( rather than NPT or BSP). Thank you.

  6. Cathy avatar

    Hi Colin, can you advise whether the engine should be running when using the Ring 900. I don’t want to end up with a flat battery.

    1. Helpful Colin avatar

      Hi Cathy,
      The power consumption of the RAC900 is 280 Watts. That’s equivalent to 5 car headlamp bulbs of 55 Watts each. This is much more than a cigar lighter which is often 180Watts. And it’s continuous throughout the time you’re pumping the tyre.
      The average car battery may have a capacity, when new, of 50 Ampere Hours, i.e. if you connected a device that would draw 25 amps (and the RAC900 draws 23 amps) the battery would be drained in 2 hours.
      So there you have it. Pump tyres up without the engine running, to charge the battery, for two hours continuously and you will flatten the battery. Do it for a few minutes just to raise the pressure by a couple of pounds per square inch when you check your tyre pressures, and you have a good battery that’s charged, and you’ll be OK without running the engine. That’s what I do on my drive at home and I’ve never had a problem. However if you find yourself in the middle of nowhere with a completely flat tyre and you hope you have a slow puncture and you want to drive it to a nearby garage, then turn the engine on. You might be pumping for quite some time. You’d probably want to overinflate it a bit so it would take longer to go flat again too.
      I hope that answer is good enough.
      Regards, Colin.

  7. Cathy avatar

    That’s fantastic, thanks Colin

  8. Stephen Israel avatar
    Stephen Israel

    Hi Colin
    Can you recalibrate the pressure gauge, as our old compressor I think is now running 10psi over the real psi level?
    Kind regards

    1. Helpful Colin avatar

      Hi Stephen,
      Short answer – Not that I’m aware of.
      I’ve always noticed that pressure gauges attached to pumps give incorrect readings. I suspect the dynamic pressure in the pipe from the pump is greater than the static pressure in the tyre.
      When I’ve finished inflating the tyre to a higher pressure than required I measure the pressure with a gauge I trust. One like a cylinder with a piston that is pushed out after the pressure has worked against a spring. Then I let the pressure down bit by bit until it is correct. Those gauges have a shaped knob on the end to press the tip of the valve in to let air out. These are called pencil gauges, e.g. pencil gauge
      Regards, Colin.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.