Portable Air Compressor/tyre inflator

animad36, Aug 4, 3:21pm
Before I head to town and get completely overwhelmed by an enthusiastic sales assistant, can you point me toward an appropriate unit that is easy to use, preferably will operate on 12 V, and will inflate tyres up to 65 psi. Emphasis on the easy to use part!

mber2, Aug 4, 4:03pm
any automotive store and look for the one that plugs into the cig lighter if you want cheap or pay between $15-$50 for battery connection ones

tweake, Aug 4, 4:33pm
what size tire?
if you have a 4wd don't waste money on the small pumps.
the rule of thumb is buy the biggest one you can fit.
if you get one thats to small it takes to long, it over heats and dies.

use they are all much the same.

i recommend to get a separate pressure gauge and know how to reduce pressure with it.
typically you pump more pressure than you need. thats because they pump hot air. once the air in the tire cools down the pressure will drop.
then you can adjust to suit.

gpg58, Aug 4, 5:18pm

animad36, Aug 4, 5:22pm
Good advice, thank you. Yes, 4 WD tyres and light truck I think they are called, on a horse float. 65 psi printed on them, and 50 psi on the 4WD tyres

animad36, Aug 4, 5:24pm

andrewcg53, Aug 4, 5:30pm
That will be the max pressure rating Your 4x4 tyre pressure will be on the door jam of your car and a horse float is 28-32psi

animad36, Aug 4, 5:33pm
oh gosh, now this is why I rely on the garage so much. Thank you, I will do some more question asking!

tweake, Aug 4, 5:37pm
i would grab the combo deal.
the deflater is a bit over kill but it can come in handy at times.

the other is a bit to small.
typically your going to spend at least $200 on one thats big enough.

tweake, Aug 4, 5:43pm
you won't run that much pressure.
but horse float can get up in weight enough to need to use 50psi or so depending on the tire used.

going by the factory specs is a waste of time because you don't have factory tires. it might close enough for similar tires but theres a huge range of specs in 4wd tires.

i would suggest working it out from the max pressure at max weight rating.
its a little complicated but it will get you in a better ballpark and get you thinking about your load weights.

mack77, Aug 4, 7:42pm
You run the risk of your 65psi 8ply rated tyres delaminating if you run them at pressures less than 40psi, even when lightly loaded. The pressure required will depend on how many wheels there are on your house float and how heavy the horse is.

andrewcg53, Aug 4, 8:33pm
A 8 ply tire is designed to run at between 12-32psi it is the tyre size and number that determines the weight the trailer/horse float can carry

tweake, Aug 4, 9:03pm
maybe 30 years ago.
32psi in a lot of tires with fully loaded trailer will be bulging, looking like you have flat tires. you run whatever pressure you need to get correct contact patch and depending on if its an overloaded trailer you may need 65 psi.

we had trouble with ours because tire shop put 30 psi in them, expect they have a max of 90psi and we typically have 70-80psi in them with full loads.

my old ute tires where 30-35 psi, some of the newer tires we run are 40 -50 psi.

and 12 psi you would be poping tires off the bead. cook the tires if under 20 psi.

andrewcg53, Aug 4, 9:37pm
It is tyre size and number that determinants the weight a trailer can carry and most 4x4s run a tyre pressure of 29-35psi and this is cold pressure as you drive your tires warm up increasing psi often to over 40psi.

andrewcg53, Aug 4, 9:39pm
Also 90 psi rated tire is not 8 ply

tweake, Aug 4, 9:43pm
no. its the number of tires and the load capacity of each tire, of which there is a maximum weight limit at a maximum pressure.

tweake, Aug 4, 9:46pm
i had to look it up, they are 8 ply tires. 195/50R13C 8PR

andrewcg53, Aug 4, 9:58pm
That is a radial tyre not an 8ply tyre and has an N load rating and 8ply tyres have a D load rating

tweake, Aug 5, 9:30am
ROFLMAO

kazbanz, Aug 5, 4:32pm
can I ask you WHY you need to pump up many tyres to up to 65psi?
if its just the need to sometimes top up then a decent 12v unit I feel will be the go.
But if its regularly inflating tyres then IMO I'd buy a 240v compressor. even a little single cylinder job would be fine for that purpose.

mack77, Aug 5, 10:04pm
I believe that the above statement is incorrect. A "195/50R13C 8 ply rated" tyre typically has a load/speed code of 104N. The 104 is the code no. for the max. load that the tyre can be subjected to and is 900kg. The letter "N" is the code for the speed rating of the tyre and is 140kph. Although it is a radial tyre the tyre manufacturers print on the tyre that it is "8 ply rated", which indicates that the max. pressure is 65psi, which is necessary for a 900kg load; (this is the sum of the static and dynamic loads that the tyre is subjected to). The letter "C" just indicates that is a commercial tyre.
I stand by my statement that you should not run 8py rated tyres at less than 40psi even when very lightly loaded. I will be very surprised if you will find any tyre dealers or tyre manufacturers that will disagree with me.

s_nz, Aug 5, 10:45pm
I have allway's just used the dirt cheap 12V ones. If you are just looking to top up tire pressures at home, and arn't in too much of a hurry. I have only had one die so far. (that said, I don't have any high volume 4x4 tires)

The 4wd targeted tire compresses & deflator's are intended for "airing down". Essentially where you decrease the pressure in the tires to improve off road performance on soft surfaces by increasing the size of the contact patch, and decreasing ground pressure.

For example, let your tires down from 36psi to 15psi before driving on the beach, then pump them back up to 36psi for proper handling on the open road on the way home. As you can imagine, pumping up 4 large volume 4x4 tires at the end of the day with a tiny pump will take a very long time, and will wear the pump out fast.

Regarding ease of use, smaller pumps plug into the cigarette lighter. (super cheap auto has medium size 25LPM one that does this too). Larger pumps come with crocodile clips and required lifting the bonnet to connect to the battery terminals.

Also there are two styles of connections for the tire valve. Lower end pumps tent to have a plastic latch on methord. mid range pumps tend to have a brass thread that winds onto the valve. High end pumps sometimes have a metal clip on fitting like you find at some petrol stations

pico42, Nov 2, 3:57pm
Connect to your battery, connect the hose, turn it on and you are go.
https://www.arb.com.au/air-compressors-tyre-accessories/air-compressors/