AIR COMPRESSOR

Many of you have been waiting for this compressor to go on sale:


Now it has!

KIlo for kilo, the best and fastest 12 volt air compressor;

Quote: Originally posted by mtgoat666

Udo, Get the Viair. Looks like you are shopping harbor freight junk.

Quote: Originally posted by 4x4abc

Quote: Originally posted by mtgoat666   Udo, Get the Viair. Looks like you are shopping harbor freight junk. most Viair are also junk expensive junk

I love my 'cheap' MV-50... fills 16"x 32" tires fast (3 minutes=15 psi gain). It hasn't failed (except once when I accidentally P-nched the tub while it was running)!

I had the Harbor Freight one but the fuse got so hot it would melt (not blow)... It was a tiny bit faster doing about 6 psi per minute... But with the fuse case getting so hot, it wasn't easy to fill all four without a break. The MV-50 has no such issues and was under $85.

Quote: Originally posted by 4x4abc

Quote: Originally posted by mtgoat666   Udo, Get the Viair. Looks like you are shopping harbor freight junk. most Viair are also junk expensive junk

Quote: Originally posted by mtgoat666

We are all waiting on the edge of our seats for you to enlighten us… what brand/model gets the seal of approval from Herr 4x4?

Quote: Originally posted by mtgoat666

Udo, Get the Viair. Looks like you are shopping harbor freight junk.

Quote: Originally posted by David K

I love my 'cheap' MV-50... fills 16"x 32" tires fast (3 minutes=15 psi gain). It hasn't failed (except once when I accidentally P-nched the tub while it was running)! I had the Harbor Freight one but the fuse got so hot it would melt (not blow)... It was a tiny bit faster doing about 6 psi per minute... But with the fuse case getting so hot, it wasn't easy to fill all four without a break. The MV-50 has no such issues and was under $85.

Quote: Originally posted by pacificobob

The one specification missing from many underperforming compressors Is CFM@ a given psi. Eg: 60psi. 90psi.

Quote: Originally posted by PaulW

Quote: Originally posted by pacificobob   The one specification missing from many underperforming compressors Is CFM@ a given psi. Eg: 60psi. 90psi. == = The industry standard is to measure an quote the cfm at free flow. CFM at a given pressure is meaningless unless the volume the flow is pushing into is defined. Some do it by specifying a tire size.

Quote: Originally posted by PaulW

Quote: Originally posted by pacificobob   The one specification missing from many underperforming compressors Is CFM@ a given psi. Eg: 60psi. 90psi. [/rquote] == = The industry standard is to measure an quote the cfm at free flow. CFM at a given pressure is meaningless unless the volume the flow is pushing into is defined. Some do it by specifying a tire size. It would be great if the Nomads with various compressors also posted the actual time it takes to inflate their tires in real time. With 16" truck tires (Tacoma, etc.)... I measured the Coleman brand pump that plugs into a cigarette lighter: 2 psi per minute. The next two, clip directly to the battery terminals: Harbor Freight pump: 6 psi per minute (but melted fuse holder) MV-50: 5 psi per minute. For sand, I lower to an average of 15 psi (12-18) based on tire type, sand type, and the humidity. My current tires' street pressure is 34 psi. 3-ply sidewall tires need to go to 10 psi to float where 'cheaper' tires only need to drop to 15-18 psi. To go from 15 psi to 34 psi (19psi added): Harbor freight: just over 3 minutes per tire MV-50: almost 4 minutes per tire Coleman cig. lighter: almost 10 minutes per tire

Quote: Originally posted by David K

To go from 15 psi to 34 psi (19psi added): Harbor freight: just over 3 minutes per tire MV-50: almost 4 minutes per tire Coleman cig. lighter: almost 10 minutes per tire

Quote: Originally posted by 4x4abc

Quote: Originally posted by David K   To go from 15 psi to 34 psi (19psi added): Harbor freight: just over 3 minutes per tire MV-50: almost 4 minutes per tire Coleman cig. lighter: almost 10 minutes per tire what is your tire size David? with that I can give you the volume of air in the tire only with that we can start comparing

Quote: Originally posted by David K

The photo I posted (of the box image) is in your link, so yes.. the same one. Mine inflates my 265/75-16" Tacoma tires at the rate of 5 psi per minute (going from 15 to 30 psi, in 3 minutes).

Quote: Originally posted by PaulW

Quote: Originally posted by pacificobob   The one specification missing from many underperforming compressors Is CFM@ a given psi. Eg: 60psi. 90psi. == = The industry standard is to measure an quote the cfm at free flow. CFM at a given pressure is meaningless unless the volume the flow is pushing into is defined. Some do it by specifying a tire size.

Quote: Originally posted by 4x4abc

all I can find are complicated formulas for tire volume no go even if I used a simplified formula I only get the nominal volume nobody has been able to tell me yet how many times I have to force the nominal volume into the tire to reach a certain pressure

Quote: Originally posted by Maderita

Quote: Originally posted by 4x4abc   all I can find are complicated formulas for tire volume no go even if I used a simplified formula I only get the nominal volume nobody has been able to tell me yet how many times I have to force the nominal volume into the tire to reach a certain pressure Here's a link to charts for the volume of tires by their size: https://tireplay.com/tire-weight-by-size-with-volume/ The values are in metric (cubic meters), so that will need converting to cubic feet. https://www.metric-conversions.org/volume/cubic-meters-to-cu... Add another volume of that amount for every 14.7 psi of increased pressure. 1 atm = 14.7 psi; 2 atm = 29.4 psi; 3 atm = 44.1 psi, 4 atm = 58.8 psi For ease, use the following converter. example, 35 psi = 2.386 atm https://www.checkyourmath.com/convert/pressure/psi_atmospher... If you'd rather do the math: for psi to atm, multiply by 0.068046 I chose a common SUV/light truck size, 265/75R16 The chart shows 0.17 cubic meters. Converted to cubic feet = 6.0035 At 35 psi, the volume of that tire is 6.0035 x 2.386 = 14.4 cubic feet There are so many variables when it comes to filling tires, that this info may not be of much value. The atm measurement is based on sea level at 0 degrees C. (32 F.) The output of 12v compressors slows as the pressure backpressure increases. 12v compressors have varying air output depending upon input voltage. A compressor is significantly faster and more powerful with the engine running (13 volts to 14v), vs. engine off and the battery at 12.2v to 12.6v. Even the shape of the wheel, across bead surface to bead surface must play a role in the total volume.

Quote: Originally posted by 4x4abc

best info in years! Thank you!