| Pages:
1
2 |
chippy
Super Nomad
Posts: 1699
Registered: 2-2-2010
Member Is Offline
|
|
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
Elite Nomad
Posts: 6334
Registered: 4-26-2008
Location: Black Hills, SD/Ensenada/San Felipe
Member Is Offline
Mood: TEQUILA!
|
|
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 |
Udo
Youth is wasted on the young!
|
|
|
4x4abc
Ultra Nomad
Posts: 4202
Registered: 4-24-2009
Location: La Paz, BCS
Member Is Offline
Mood: happy - always
|
|
| 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
Harald Pietschmann
|
|
|
lencho
Junior Nomad
Posts: 85
Registered: 1-16-2005
Location: Tan lejos de Dios y tan cerca de EU
Member Is Offline
Mood: Somnoliento
|
|
Oh, that could be useful information! Where do you get that info, do you calculate it?
"I can normally tell how intelligent a man is, by how stupid he thinks I
am."
"...they were careful of their demeanor that they not be thought to have opinions on what they heard for like most men skilled at their work they
were scornful of any least suggestion of knowing anything not learned at first hand."
Cormac McCarthy, All the Pretty Horses
"Be kind, be patient, help others." -- Isabel Allende
"My gas stove identifies as electric." Anonymous
|
|
|
David K
Honored Nomad
Posts: 64547
Registered: 8-30-2002
Location: San Diego County
Member Is Offline
Mood: Have Baja Fever
|
|
| 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
Super Nomad
Posts: 2255
Registered: 4-23-2006
Member Is Offline
|
|
| Quote: Originally posted by PaulW |
== =
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
Ultra Nomad
Posts: 4202
Registered: 4-24-2009
Location: La Paz, BCS
Member Is Offline
Mood: happy - always
|
|
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
Harald Pietschmann
|
|
|
lencho
Junior Nomad
Posts: 85
Registered: 1-16-2005
Location: Tan lejos de Dios y tan cerca de EU
Member Is Offline
Mood: Somnoliento
|
|
| 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).
"I can normally tell how intelligent a man is, by how stupid he thinks I
am."
"...they were careful of their demeanor that they not be thought to have opinions on what they heard for like most men skilled at their work they
were scornful of any least suggestion of knowing anything not learned at first hand."
Cormac McCarthy, All the Pretty Horses
"Be kind, be patient, help others." -- Isabel Allende
"My gas stove identifies as electric." Anonymous
|
|
|
Maderita
Senior Nomad
Posts: 640
Registered: 12-14-2008
Location: San Diego
Member Is Offline
|
|
| 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
Ultra Nomad
Posts: 4202
Registered: 4-24-2009
Location: La Paz, BCS
Member Is Offline
Mood: happy - always
|
|
| 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!
Harald Pietschmann
|
|
|
| Pages:
1
2 |
![[*]](images/xmbforum/default_icon.gif){kind=icon}
