What is required from a compressor to blow up a 4x4 tyre

[Retro Pedro]

Started to get the gear together to change my own tyres and was wondering what measurements from a compressor I should be looking at to be able to blow up a large 31" 4x4 tyre from completely flat. I'm thinking that it must be the amount of air that can be released instantly is the governing factor or does a standard 50 litre tank compressor has what it takes. Thought I saw reference to Cfm somewhere but not sure.
Am I thinking down the right line that it's relative to the amount of pressure that can be built up in the tank prior to releasing the compressed air that is the governing factor. My old 1980s compressor as a cut off switch at 8 bar which I don't think is that much so I'm thinking should I be looking for a compressor with a larger pressure threshold.

[Drift]

I have one of these and rebeaded loads of my mud tyres with it, at 32"
http://www.ebay.co.uk/itm/T-Max-4x4-ADV ... 3f14dde99e

Takes about 5 mins but pops them on the rims every time and I keep it in the back for airing down if needed on laning trips, also did all the picasso's tyres the other week as well and my new Recip

And they can be hard wired into the car.

[Big Dav]

The compressor I use has a pressure switch set to 8 bar and I'm quite sure it would be able to bead a tyre although I haven't used it for such a job.
I would imagine that if tyre paste has been put around the tyre bead it should 'pop' easier.

[Drift]

I have even used on of those Michelin circular type car tyre compressors to fit a 32" tyre to a rim, took a while but worked.

[Retro Pedro]

Sounds promising guys - thanks for responses. I had it in my mind that it needed a large release of air to pop the tyre onto the beads. Once it had done that, then the gradual pumping would suffice.
I understand that I have to brush tyre soap onto the tyre rims and valve to soften to assist fitting and also wire brush the wheel rim and brush on sealant to help form a permanent seal when the tyre is pressurised.
Touching on the valves, my son in law used to be a tyre fitter many moons ago, and he reckoned alot of off roaders used to ask for the short motorbike valves to be fitted on off road tyres. Apparently, being shorter - I think 13/14mm mark, they reduced the risk of the valves getting bent about in the mud etc. Seemed logical to me, but I'd never given it any thought.

[Drift]

Short valves would be okay but Ive never had any issues plus most off road cars tend to have bigger offset wheels so the valves are inside the dish so to speak and pretty well protected anyway.

[colley]

Or do this

http://www.google.co.uk/url?sa=t&rct=j&q=top%20gear%20blowing%20up%20a%20tyre&source=web&cd=1&ved=0CDMQtwIwAA&url=http%3A%2F%2Fwww.metacafe.com%2Fwatch%2F2324576%2Finteresting_tire_repair_technique_using_gas_and_a_lighter%2F&ei=yBtlT5OwCOek0AWZ2YGlCA&usg=AFQjCNFVxGYV0ttjvR6jmok5dWa0d0w5iQ