BajaNomad

AIR COMPRESSOR

Udo - 4-27-2024 at 10:48 AM

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;

Tioloco - 4-27-2024 at 11:06 AM

If you are going to be relying on that in a remote place and need reliability, buy 2

4x4abc - 4-27-2024 at 12:22 PM

maybe for your moped

Maderita - 4-27-2024 at 12:32 PM

Udo,
Appreciate your posting of the sale price. Always good to know best pricing on gear.

However, the quality control, reliability, and design of this compressors is poor. It is easy to pull up the negative reviews on the Harbor Freight web page.

Specifications can deceive. The "duty cycle" is not mentioned. A high percentage duty cycle is important when filling multiple offroad tires, particularly in desert temperatures. I prefer 100% (continuous duty). When it comes to air flow rate, HF shows 1.35 CFM, but they neglect to state at what PSI, rendering that spec as worthless. One must assume that it is at zero PSI.

The yellow coiled air hose is convenient. Until it breaks, which it will over time. Even some of the top brands come with a plastic air hose. I carry a high-quality rubber hose, with the appropriate fittings. HF compressor owners have reported that they were unable to change hoses due to incompatible fittings. It was said that the fittings are not NPT and may have a proprietary thread.

mtgoat666 - 4-27-2024 at 02:03 PM

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

4x4abc - 4-27-2024 at 04:11 PM

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


most Viair are also junk
expensive junk

woody with a view - 4-27-2024 at 07:33 PM

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

Udo, I’ve had this for five years with zero issues. Pay triple if you wish or just get a solid unit. Some people here continue to be special ed.
https://www.amazon.com/VIAIR-30033-300P-Portable-Compressor/...

David K - 4-27-2024 at 09:00 PM

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.

mtgoat666 - 4-27-2024 at 09:00 PM

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


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?

4x4abc - 4-28-2024 at 08:06 AM

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?


why would I do that?

Lee - 4-28-2024 at 08:53 AM

Got 2 ViAirs, small and big, 20 years old, still works well. At the time it seemed like it was the brand to buy.

Deciding factor wouldn't be ''sale price,'' but specs.

DK's MV50 looks good for about $30. more.

Udo - 4-28-2024 at 01:35 PM

I've had mine for about 15 years. I have used it many times. I love the high volume. I did have to replace the yellow air hose that came with it.
Quote: Originally posted by mtgoat666  
Udo,
Get the Viair. Looks like you are shopping harbor freight junk.

PaulW - 4-29-2024 at 07:33 AM

Compressor offerings have changed drastically since the last one I bought.
If you search Amazon for 12v portable compressors you will find laterally dozens of choices from low flow to extreme flow at high pressures..
Yup, the old Harbor freight one David has (2.02 CFM)works but the one Udo (1.35CFM) notes will also do the job.

For what it is worth Here are my compressors.

Honda - Viair 85P (1.83CFM) - Had it for a long time and it is ok for the small tires. Not price competitive to comparable offerings these days from Amazon.

21' Jeep Rubicon 37" tires - Tozalazz double unit (11.65 CFM). Will inflate 4 tires from 15 to 40psi in 10+ minutes. See Amazon for the specs and the reviews. I have had it for several years and now days there are more comparable choices.

18' F150 with stock tires - GSPSCN (2.47CFM) Another double compressor but with moderate flow. Again go to Amazon and see the specs and read the reviews.
All compressors mentioned are made in China.

BTW my last VIAIR failed and it is not possible to get it repaired. Just a China made thing and a seller named VIAIR. Probably all compressors named are the same, meaning not repairable.

bajajoaquin - 5-11-2024 at 06:59 AM

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.


The MV50 has been the inexpensive standard over at the Expo forum for a long time. There’s also a lot of chatter about the new dual-head version.

PaulW - 5-11-2024 at 07:23 AM

MV-50
Flow up to 2.54 CFM at 90 PSI. (72 lpm)
I found that after all these years it is still available at
https://superflowair.com/products/mv-50-air-compressor-1
Look at it and see if it looks the same.

David K - 5-11-2024 at 09:34 AM

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).

pacificobob - 5-11-2024 at 11:03 AM

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

RFClark - 5-11-2024 at 03:18 PM

Places not to save $$$ if you go off road.

Tires
Gas cans
Winches
Tow straps
Li ion jump starter
Air compressors
Fire extinguishers
Emergency beacons
First aid kits

Things you think you’ll never need.
Dead man
Air bag jack

PaulW - 5-11-2024 at 04:35 PM

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.

David K - 5-11-2024 at 05:28 PM

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.


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

chippy - 5-12-2024 at 06:18 AM

With this- https://www.alltopusa.com/collections/air-compressor/product...

and this- https://ezflate.com/products/ez-flate-hyperflex

I can inflate all four e rated tires (Toyo Open Country RT/Trail 255/80r17) from 18psi to 35psi in about 7 minutes.
Deflate in a couple of minutes.

Udo - 5-12-2024 at 10:51 AM

Hey, David...Mil gracias for the compressor time ratings. I AM HAPPY THAT YOU TOOK THE TIME TO MEASURE IT.


rquote=1266622&tid=99920&author=David K]
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

4x4abc - 5-12-2024 at 03:57 PM

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

lencho - 5-12-2024 at 05:23 PM

Quote: Originally posted by 4x4abc  
what is your tire size David?

with that I can give you the volume of air in the tire

Oh, that could be useful information! Where do you get that info, do you calculate it?

David K - 5-13-2024 at 05:42 AM

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


Just look up, in this thread:
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).

pacificobob - 5-13-2024 at 07:20 AM

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.


Physics

4x4abc - 5-13-2024 at 09:17 PM

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

lencho - 5-14-2024 at 06:30 AM

Quote: Originally posted by 4x4abc  
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

Pretty meaningless anyway, considering that the backpressure is continuously rising during the process.

Personally, I'm in no rush; whether it takes 10 minutes or 30* to air up, is less important than reliability: a fast compressor is worthless if it fails.

* Or as one friend used to say, "one beer or three". QEPD,(Cirrhosis).

Maderita - 5-14-2024 at 02:26 PM

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.

4x4abc - 5-14-2024 at 07:36 PM

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.


best info in years!
Thank you!

Maderita - 5-14-2024 at 08:22 PM

Quote: Originally posted by 4x4abc  
best info in years!
Thank you!

de nada Harald.
I'm no math whiz, and I had to dig into my memory from Scuba classes 54 years ago!

Btw, 1 atmosphere / 14.7 psi = 33' of water
A typical 80 cu.ft. Scuba tank will fill 5 of those same tires from 0 to 35 psi.