Air compressor for tubeless tyres
neil_uk
Posts: 289
I've been looking at a cheap air compressor with the following specs...
180W motor
Air Delivery 3.8CFM at 40 PSI, 2.4 CFM at 90 PSI.
Max pressure 115 PSI
Air tank capacity 4.5 ltr
Air outlet size 1/4"
...and to be honest.... that means absolutely nothing to me! So what I'm wondering is - will this do the job of blasting tubeless tyres onto rims?
Cheers guys
Neil
180W motor
Air Delivery 3.8CFM at 40 PSI, 2.4 CFM at 90 PSI.
Max pressure 115 PSI
Air tank capacity 4.5 ltr
Air outlet size 1/4"
...and to be honest.... that means absolutely nothing to me! So what I'm wondering is - will this do the job of blasting tubeless tyres onto rims?
Cheers guys
Neil
0
Comments
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if you use proper ust/tubeless/tubeless ready tyres, a track pump will do the trick, if you convert regular tyres you are asking for trouble in my experience.
as for the compressor, can you post a link please?0 -
Hi, I've tried the track pump method which I can get away with but it's really hard work. Plus I fancy buying a new gadget!
The compressor is on ebay - PRO MINI PANCAKE PORTABLE AIR COMPRESSOR 4.5l
Neil0 -
had a look and it seems ok as it is for use with air power tools .but i couldnt say properly, i use compressors at work but they are contained in a plant room.
try and find out what flow a co2 cartridge pushes out as that is deffo enough to inflate a tyre, if the compressor is slow it wont have the burst of air required to inlate a non sealed tyre as the air will escape instead of popping the tyre onto the rim.0 -
Ok... so..... there's a genuine innnovations co2 pump that shoots 30litres per minute. The compressor shoots 3.8 cubic feet per minute..... jeez it's too late to do the maths lol.
Neil.0 -
I just tried an online conversion site and according to that -
3.8 cubic feet per minute = 107.6 litres per minute!!! surely that can't be right... is it?
If so, that is more than enough :shock:0 -
just dd the same conversion and you are correct, it doesnt sound unreasonable for a power compressor to be atleast 3 times as powerful as a co2 cart. looks good, might even get one myself!!0
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Yep, I think I'll go for it!0
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The reservoir size is more important than the actual air output. If you have a decent sized reservoir, then that will adequately supply enough air to inflate the tyre far faster than the compressor can manage. A 4.5 litre reservoir is pushing the limits of what is practical for tyre inflation, common thinking is that you need at least a 6 litre reservoir, and preferable a proper 24 litre unit.
You'll also need to lay your hands on a valve-head (like those attached to track-pumps) and air-pipe to affix to the compressor to connect it to the tyre valve.0 -
interesting, had to design a compressor for a uni project,
the CFM is the flow rate of the air exiting the tank and the PSI is the pressure, they are really designed for powering air tools, tanks are also called buffers and do just that, they are a buffer between the compressor unit (piston/values/crankshaft) and the output of air, they therefore prevent any irregularities of flow and pressure,
tank size doesn't really matter, the compressor unit will turn on and off when the tank is emptying using a pressure release switch,
i did some rough calcs and based on the volume of a bike tyre being 0.135 cubic feet (i used the volume equation for a torus with radius of the tyre 2.5 cm and radius of the wheel to centre of the torus 31 cm)
then with the 3.8 CFM flow rate at 40 PSI you will fill up the tyre in just over 2 seconds to the pressure of 40 PSI,0 -
:? erm.... so I guess it's a yes to the compressor then? lol
Seriously though - cheers for the tech info!
I've just killed my track pump which has a good quality valve head, just as well I kept it
Neil0 -
Thanks mate - will do!
Neil0 -
Far be it from me to argue with a scientist......but
In an ideal world, I'd completely agree with your comments, however tyre inflation (and in particular tubeless tyre inflation) has very little to do with the ideal world :?
If you have UST rims and tyres, then you can (easily) inflate using a track pump, because they're designed to provide a partial seal from the very start of inflation.
If on the other hand you're using a tubeless conversion kit and standard tyres, then the make-up of the rim/tyre leads to an awful lot of air escaping as you try to inflate. You need a very-high flow rate initially to cause the tyre to partially inflate, ballooning enough to move the beads out towards the rim sidewall and to begin the bead seating process.
I've emptied a 24 litre air receiver with the compressor running full pelt without seating the tyre. I've also managed to inflate one using just a track pump.
The air receiver provides a high volume high flow reservoir of pressurised air with which to begin the inflation process. Once this has started, then any size of compressor (or hand pump) will be more than adequate!
At the end of the day, you pays your money and makes your choice. You may be lucky, you may not. If I were to purchase a compressor, then I'd go for a 24 litre version (Screwfix sell one for £90)0 -
I tend to run the compressor at only 50psi, that way I'm (far less likley ) to blow the tyre off the rim :shock:
This probably (definitely!) doesn't help, but there's still more air in 24 litres at 50psi than in 4.5 litres at 120psi (or whatever the mini-compressor's maximum rated pressure is)
I'm sure the mini-compressor will be more than adequate most of the time, and will be so much easier than a track-pump!0 -
OK... I can see the attraction of buying new things (of course), but why do you need a compressor. Why not just use CO2 cartridge pump.
On my tubeless (UST), whilst I can get them to inflate with a track pump it was often bloody hard work. Now I just use a CO2 cartridge for the first inlate and they always inflate first time, every time with no need for soapy water and takes about 2 seconds :P0 -
if you do use co2, make sure you deflate the tyre to rmove the gas then pump up with air0
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Ahh yes... you've just reminded me... haven't reinlated mine from scratch for a while.
You're correct, the sealant goes stringy with CO2. The way I did it was to inflate to seal first (with the sealant in). Then deflate and pump up with track pump a few times to get rid of the CO2. No problems with re-pumping once sealed the first time. Joes has been fine with this method but I had forgotten that stage. So it does take longer than 2 seconds :oops:0 -
sheepsteeth wrote:if you do use co2, make sure you deflate the tyre to rmove the gas then pump up with air
Exactly.0 -
A £10 Argos track pump every time for me, I like the sport. Almost every time it's involved almost giving up, sitting down, having a cup of tea then retrying and succeeding. The non-UST 2.4" Nic was the hardest, simply getting it vaguely full of air before it leaks out again was crazy.0
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S_J_P wrote:I tend to run the compressor at only 50psi, that way I'm (far less likley ) to blow the tyre off the rim :shock:
This probably (definitely!) doesn't help, but there's still more air in 24 litres at 50psi than in 4.5 litres at 120psi (or whatever the mini-compressor's maximum rated pressure is)
ok, you say you drain a 24 L tank but the compressor is running full pelt, how do you know the tank has drained 24 L if the compressor is running full pelt? or do you turn the compressor on, fill up the tank with 24 L of 50 PSI compressed air and then turn the motor off?0 -
Start with the compressor on, and tank at 50psi in high hopes
Attach air hose to tyre valve, and open air-feed valve fully 8)
Inrush of air tries to spread bead strips by partial inflation of the tyre so that they make a semi-seal with the rim-strip and from there inflation hopefully follows rapidly
However sometimes the partial seal doesn't happen (despite lashings of soapy water, having "conditioned" the tyre to the rim for 24 hours previously, banging the tyre, playing the bead by rope/strap around its circumference, hanging the tyre rather than sitting it on the ground etc etc etc). In these instances the air merely passes through the tyre, and out between the bead and the rim :roll:
In these instances, the initial significant inrush of air (from the receiver) is insufficient to balloon the tyre sufficiently to gain a partial seal and the air flow abates, and then settles down at the 3.8cfm (or whatever) that the compressor can manage alone :evil:
The smaller the receiver the more often this is likely to happen, as the reservoir of high-pressure air is smaller, and the time to exhaust it is lower. With a large receiver you do at least have time to whack the tyre a few times, squeeze, press, compress and generally fiddle about before the airflow abates!
EDIT:
Do bear in mind that this is the exception rather than the rule!
I've fitted a number of tyres tubelessly using both rim-strips and UST rims using a track pump, but when you need a compressor, you want one which'll do the job!0 -
if i ever get round to doing tubeless i will definitely do it at my dad's work.
compressor running at 9 bar, with a tank big enough to run a workshop and bodyshop, all using air tools
should do the job :twisted:0