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Improving small car tyre compressor ? Possible or not?
balidey - 18/2/15 at 02:09 PM

I have a small 12v Michelin car tyre compressor / inflator as a 'get me out of trouble' machine.
Needed it the other night and apart from being bloody noisy it took my tyre from 15 psi upto about 22 psi quick enough, but would not go any higher. I had set the cut off to 30psi and I left it bloody ages. Even re-set it a couple of times, but would not budge above 22psi.

So, has anyone else got one of these items? Do they actually go above that sort of pressure? Is there any way of improving them at all? I have not taken mine apart yet, but if its likely just a dry seal or o-ring then I don't mind having a fiddle with it.

Any comments from the font of all knowledge? (that’s you lot if you hadn't guessed).

britishtrident - 18/2/15 at 03:41 PM

quote:
Originally posted by balidey
I have a small 12v Michelin car tyre compressor / inflator as a 'get me out of trouble' machine.o
Needed it the other night and apart from being bloody noisy it took my tyre from 15 psi upto about 22 psi quick enough, but would not go any higher. I had set the cut off to 30psi and I left it bloody ages. Even re-set it a couple of times, but would not budge above 22psi.

So, has anyone else got one of these items? Do they actually go above that sort of pressure? Is there any way of improving them at all? I have not taken mine apart yet, but if its likely just a dry seal or o-ring then I don't mind having a fiddle with it.

Any comments from the font of all knowledge? (that’s you lot if you hadn't guessed).



These little compressors are always going to struggle as pressure increases but it sounds like your is worse than any I have encountered.

Typical these devices contain a very crude single cylinder reciprocating compressor with a layout not unlike a model aeroplane engine.
The compressor is generally so crudely made that it will be pretty well impossible to upgrade by improvingn the valving or reducing the clearance volume. The clearance volumed is the much the same as the compression ratio in a piston engine but has an even greater effect on the performance.


There is a gap in the market for a better quality and a slightly larger 12v compressor.

luke2152 - 18/2/15 at 05:39 PM

Bike pump (track pump style) can be had for less then 20 quid and is just as quick as a 12v compressor albiet with a bit more effort and will deliver as much pressure as you could ever want. Takes me 10 mins to fill 4 trailer tyres from dead flat to 40psi

joneh - 18/2/15 at 05:48 PM

If you decide to upgrade, I got one of those Ryobi 18v compressors that uses the drill battery. Easily hit 120psi which freed my seized brake pistons

Edit: based on what trident mentioned below it easily does my Jeep tyres and the wife's polo.

[Edited on 18/2/15 by joneh]

britishtrident - 18/2/15 at 07:18 PM

There is a difference between generating a high static pressure and delivering a sufficient volume of air at that pressure to fill a tyre.

To inflate a completely flat tyre from flat to 20 psi or so a £10 ebay air horn compressor would do the job much quicker than the cheapo reciprocating types.

whitestu - 18/2/15 at 07:25 PM

I've got a chep one from Lidl which seems to work fine and has no problems reaching 34psi for my car. I pumped 4 tyres from under 20 to over 30 psi one after the otherthis week and it coped quite well.