Ring RAC630 12V Digital Tyre Inflator, Air Compressor with Auto stop, Tyre Pump with LED Light, Case and Adaptor Set

Great little unit. Does what it says. I do need to keep referring to the instructions on how to use it.Can never get the unit to start inflating the tyre. Once working works well.

In use, you plug the 12V connector into the 12V receptacle in your car (e.g. in a VW Golf Mk5 this is under a cover in the centre console) after optionally starting the engine running to avoid drain on the car battery. You then take the unit itself around the car connecting the pressure hose to each tyre valve in turn, either setting the pressure as required, or using the last pressure that you set, automatically (this makes cars that use equal pressure around all tyres especially easy to do). You press the "power" button to start each inflation after using the + & - buttons to set your target pressure if necessary.Pluses:Very quick to get pressure into the tyre, if topping up by say 4psi you'll have the tyre up to pressure in 15-20 seconds. It can take longer to pack the thing up neatly than it takes to do all the tyres!Auto-shutoff when the tyre come up to the pre-determined pressure you'd set.You can switch units of measure between PSI (pounds per square inch)/Bar/and Kpa (kilopascals). You can usually find your car's ideal pressures printed on a sticker either on the driver door frame (when opened), or inside the car's filler flap. You use the "M" button to cycle through the settings.It has a multifunction light. White as a work light, flashing red as hazard warning, and flashing Morse code "SOS" if you want extra drama.Power lead is sufficient to reach all corners of the car from the driver's door for a typical car like the VW Golf. The unit may need feeding across the front seats to the other door for estate cars and "blunder buses" (4x4 and MPV).It remembers the last pressure you set. Especially handy if your car uses the same pressure on all tyres.It could really help people who have limited strength or endurance, such as elderly motorists, provided they are able to walk and stoop around a car doing the tyres!Minuses:Inflation hose is quite tricky to screw onto the tyre valve, although it gets easier with practice it is still fiddly. My bike track pump goes on properly every time.Power lead is a flattish profile (I assume to avoid being pinched if a car door closes on it) and feels flimsy. Time will tell whether it survives.Pressure shown is not necessarily accurate (this is mentioned in the leaflet with the pump), so it is necessary to confirm pressures against a gauge known to be accurate. This can involve spending another £10 just to check that the pump has done its job! The discrepancy I saw was 1.5psi after inflating from 26 to 30psi (I'd hoped for better than that and was glad to have another gauge to cross-check). Looking around at group tests online, the reviewers seem pretty sanguine about a discrepancy of 1psi. If the pump consistently underreads by a given amount, I may just set it to overinflate by .5 or 1psi to compensate. Either way the reading is about as dodgy as your typical garage or filling station air pump, and possibly better, just for perspective. TireTek Premium Tyre Pressure Gauge - Large Dial  is a decent gauge that also allows you to depressurise an overinflated tyre without reconnecting the pump.The instructions are pictograms. They're not bad provided you have a clear head, about "Informative Level 2" on the scale from 1- Ikea to 10 - Chinglish.Summary:For heavy users I don't think this tyre inflation pump will stay the course but, for me, who never obsessively tinkers or fiddles with cars, and only really checks pressures before long trips, or when faced with taking a small group around in the car (when the pressures should all be increased), or when stuck at the roadside (cross fingers...) it will more than suffice.I bought this after helping an elderly friend use their tyre inflator and realised how quickly and effortlessly they can get all the pressures balanced, and it also saves the problem of going to a service station where, even if the air pump is free, you're inflating warm or hot tyres and will find you have under-pressure tyres when they cool down. This pump also reads far more accurately than most of the forecourt air pumps I've ever used, because of course they endure terrible abuse.It isn't madly noisy. What noise it makes doesn't last long because it is pretty quick at topping off tyres.If there are pumps that can guarantee accuracy in pressures and their readings, then this is obviously a compromise. Is it worth the price? Well, considering that you'll be budgeting for a better-calibrated tyre gauge as well as this unit, or indeed any pump below £100, you would have to go considerably upmarket, which makes this pump considerable value for money. For me, it has enough minus points to make it 4-star, but with that said, it is competing in a space filled with other 4-star machines (e.g. Michelin) that all make the same compromises.

< Reason for the purchase >My wife used to ask me every other month to bring her car to a garage to pump tires. I just got tired of it and wished to do it home somehow.I read Amazon users review thoroughly and decided to get this one.< Delivery >I clicked Amazon purchase button at noon time on 20-Jan-2012 with a standard delivery condition, and it was 11:40am 21-Jan-2012 when a delivery van arrived my home. It was a good start.< First use on 22-Jan-2012 >- I used to pump tires only at garages, so it was my very first time to use this kind of self-pumping tool.- Instruction guide is so straightforward that I could learn how to operate it instantly.- I firstly worked on my own car (Nissan) for OJT so I do the trick on wife's car next.- A battery plug fit the 12V socket easily on the first try.- Also very easy to connect the air tube to tire.- A digital indicator quickly showed a front tire pressure at 26psi, whereas the car manual states it requires 33psi.- I set a target pressure at 33psi by pushing + button on the unit.- Even for setting a target pressure that should be only a business inside a unit with no influence from air pressure, I needed to push + button pretty hard for some time to increase the set value. The same story to reduce it.- According to other user's review I knew it could be pretty noisy, and I found it was true. Due to also a strong vibration I needed to hold it by hand during the whole work- If it was kept sitting on a hard ground, the vibration should damage its own life time. Although a power cable is long enough, the air tube is very short. If it was technically possible, the length should be swapped so we can keep sitting it inside a car.- It took 15-20sec until a pressure rose up to 33psi (it counts every 0.5psi).- When it reached 33psi, it still kept pushing air for another 5sec until it automatically stopped (I guess it's for a safe margin, a smart guy).- I completed the job on 4 tires in less than 10min for the 1st test in my life (could be around 5min from next time).- I was quite happy, except dirty fingers.- Needless to say I was very successful on my wife's car, too (Toyota).- She was very happy, just wondered how much such a handy tool could be.- I told her the price, then she returned in a kitchen to cook a nice dinner for me.< Summary >- Very high cost performance- Noisy & hard vibration, but it does work perfectly- Can make your partner happyEnd of report :-)