Tires...how low do you go and what do you use to re-inflate???? (1 Viewer)

[TOBASH]

30psi is too high for the road, I run 20 on the road with 37 MTR's, and get even wear. 10# with non bead lock 15x8 wheels off road. I have a 20# CO2 tank with regulator set at 150psi for quick air up's.

I worry about your statements as the whole Ford/Firestone saga started because Ford told buyers to inflate to 20 PSI despite the fact that Firestone listed 30PSI as the preferred pressure. Combined with Ford's weakened A-arms, many people had blow-outs with roll overs and roof collapse. Some died, some were crippled, some were just seriously injured.

I would stick to manufacturer's suggested specks ON ROAD unless you have a killer roll cage. Off road is more of a fielder's choice because of less of a risk of blow-out at speed, but you still need a killer roll cage.

MHO. Your mileage may vary.

Best,

T

 

[bikersmurf]

Re tank/no tank. The 'Furnas' Pressure switch I am running shuts the compressor off at 150 PSI. 150 PSI in a converted propane tank will bring 4 33x12.50 tires from 12 PSI to the 21 PSI I was running on the street with air to spare. The down side is that cheaper air line running under the hood in an area 200 deg + will sound like a gun shot after sitting at the Peace Arch for 3 hours on a hot summer day... Not good, unless you want to have the SWAT team swarm your vehicle.

 

[AKcruzr]

I worry about your statements as the whole Ford/Firestone saga started because Ford told buyers to inflate to 20 PSI despite the fact that Firestone listed 30PSI as the preferred pressure. Combined with Ford's weakened A-arms, many people had blow-outs with roll overs and roof collapse. Some died, some were crippled, some were just seriously injured.

I would stick to manufacturer's suggested specks ON ROAD unless you have a killer roll cage. Off road is more of a fielder's choice because of less of a risk of blow-out at speed, but you still need a killer roll cage.

MHO. Your mileage may vary.

Best,

T

Ford also used underrated passenger tires on SUV's, and the plant that manufactured them had a high rate of failures and was closed. The only(knock on wood) tire issues I've ever had (5 flats) were caused by the PO of my wife's FZJ80 putting Duncrap passenger car tires on a heavy 80 series. That issue was promptly remedied with LT tires. Bigger tires require less pressure to get a flat foot print and long tread life. There is a method of calculating the pressure for oversized tires based on vehicles GVWR and the manufacturers load rating/tire pressure on the side of the tires. I've utilized this calculation to get 70,000 miles on a set of 315 BFG AT's mounted on a lifted 89 Suburban, I would change the rear tire pressure when it was loaded and/or towing a trailer. If my method is flawed, why did the old HMMWV's run 20psi front 25psi rear on a 6400lb curb weight vehicle. They ran 36' tsl tires with a 45psi max pressure rated for 3640lbs. I put MANY a mile in those vehicles and never had a tire issue. The newer up-armored HMMWV are 7100lb curb weight and run 35psi front 45psi rear with 37" MTR or Baja TA load range E rated radial tires with a max of 65psi.

Your mileage will definitely vary

 

[Tools R Us]

... The other issue is heat. Compressing air creates heat. Any volume of air compressed to the same pressure is going to create the same amount of heat no matter what size the compressor. ...

Agree. Smaller compressors are less efficient, so heat more than the bigger, shop type. It's best to mount, use them in the coolest place, with the best airflow possible. This effects both performance and life, under the hood is the worst place for them.

Hot air is less dense, as it cools will contract, netting less pressure in the tires. Best to later recheck/adjust pressure. I have done this enough to know what to expect, so simply overshoot the fill to compensate.

They draw a lot of amps, so should always be used with the engine running, if not the voltage will quickly fall off, reducing performance and putting a big load on the compressor motor. Also, good to increase idle speed to put the alternator in it's best output range.

 

[Pin_Head]

A lot of those cheap a$$ compressors I was always bad mouthing turned out to be OK after I stopped abusing them.

First it was those cheap a$$ German compressors, then it was the cheap Japanese junk, then cheap Korean and Taiwanese, then it was the cheap Chinese, now it is those cheap Bangaladesh junk! Is there a pattern here?

 

[White Stripe]

Some people seem really concerned about uneven wear due to too high street pressure. But personally I can live with a little uneven wear. I run 40 psi on the street, I can definetly tell a difference on engine load if I run 25psi. I have run 8psi at 65mph for about 20 minutes, the tires were warm after that. But it rode nice if you didn't mind the balloon feel. It was a bit sketchy.

 

[dancar]

I'm surprised no one has mentioned the 4 psi rule -

Start with about 25psi, drive for an hour or so then check the pressure, if the pressure has gone up MORE than 4 psi, your starting pressure was too LOW, add more air NOW. If your pressure has gone up LESS than 4psi, then your starting pressure was too HIGH, drop 2 psi now.

Same applies for off road conditions - obviously much lower start pressure.

As for re inflation - there is a compressor available here in Aus with 160L/min (9700in3/min) for $100, all review are great.

 

[DSRTRDR]

Reliability of the air pump is probably my main concern................I do realize the cheaper ones do probably run hot. I appreciate all the good input. Think I will start at 15 psi and adjust from there...................I have been running the tires at 30 psi on the road with very even wear.

the MV-50 can get hot - and then it shuts itself off

in my experience, it's easy going for 4 tires of 33" or 35" size, so perfectly fine for your average wheeling outing

when we tried to air up two trucks, though, my MV-50 shut off after 4 35"s and 3 33s - that took a while to cool off for the last tire

 

[DSRTRDR]

as far a tire pressure on asphalt: I run around 33-35psi - up to 38 on long distance trips

 

[Tigerstripe40]

I have 35x1250x15 Goodyear Wrangler MT/R's (the previous tread pattern) and I run 10psi on the trail, 30psi on the street.
I've been runnign cheapy steel rims since day one, never lost a bead.
I air back up with a 15# CO2 tank w/ power tank brand regulator and hose setup. I can air up all 4 of my tires to 30psi in under 5 minutes.

 

[tls3601]

SO Pin maybe the MV90 is a better choice than the MV50......I don't care if they take a couple more minutes to inflate from 13-15psi to 30. I currently have 15X33X12.5 tires on her now.

 

[Tools R Us]

I'm surprised no one has mentioned the 4 psi rule -

Start with about 25psi, drive for an hour or so then check the pressure, if the pressure has gone up MORE than 4 psi, your starting pressure was too LOW, add more air NOW. If your pressure has gone up LESS than 4psi, then your starting pressure was too HIGH, drop 2 psi now.

Same applies for off road conditions - obviously much lower start pressure.

As for re inflation - there is a compressor available here in Aus with 160L/min (9700in3/min) for $100, all review are great.

That method works OK for high speed stuff. Road surface has little/nothing to do with it, if run at too low of pressure at speed, a tire can be overheated/damaged just as easily on dirt as on pavement.

The airing down that most are talking about is related to wheeling, so the pressure is adjusted to the conditions, traction, comfort, etc. When aired down, should only be driven at low speed, at higher speeds, it's easy to roll a tire off of the rim, damage tires, etc, regardless of road surface.

 

[Tools R Us]

SO Pin maybe the MV90 is a better choice than the MV50......I don't care if they take a couple more minutes to inflate from 13-15psi to 30. I currently have 15X33X12.5 tires on her now.

IMHO, observation, no. Two MV50s are much cheaper and will out perform a MV90. This:

The MV units are great, but in my experience would own two MV50s over one MV90. Running two, (one on each side) will net faster times, if one were to die, still could air up, cheaper, etc.

Or with 33" tires, will likely be happy with one MV50, most are. It is a pretty cheap test: http://www.amazon.com/gp/product/B0..._m=ATVPDKIKX0DER&pf_rd_r=05J5FE0AP8BRRPF637CJ

 

[Mace]

I really like the MV50's. I actually run one in my 60 as an ARB compressor with a 1 gal tank.

Also, With beadlocks, 8 psi or lower. ~ 10 psi without beadlocks. Unless it's sand, then as low as I can beadlocks or not.

Old Hummers had Bias tires, they had very stiff sidewalls, and were MUCH more comfortable at lower pressures.

 

[65swb45]

A lot of those cheap a$$ compressors I was always bad mouthing turned out to be OK after I stopped abusing them.

First it was those cheap a$$ German compressors, then it was the cheap Japanese junk, then cheap Korean and Taiwanese, then it was the cheap Chinese, now it is those cheap Bangaladesh junk! Is there a pattern here?

You've obviously already subscribed to the new world order!

 

[Pin_Head]

You've obviously already subscribed to the new world order!

Not really. I'm just watching the parade go by. It just means I am old enough to remember when the Germans and Japanese were making cheap tools. It also means that when it comes to manufacturing stuff, you don't stay on top for long.

 

[65swb45]

The fastest option, good if you don't wheel often. If you do, the refill run around/payment becomes painful.
t

Yeah, my imput on this is definitely biased by the fact that a. there are half a dozen places between home and my shop that'll refill the tank for ~$12, and I refill <once a year since I consistently run underinflated tires to begin with.

From time to time I carry the MV50 with me as a backup, but with MVS, it's sometimes hard to keep track of which rig it's in.

 

[Pin_Head]

I don't know if anyone noticed, but the newer MV50 / MF1050 compressors have a standard quick disconnect fitting now instead of the weird / proprietary one. It is still awkward because it is a male fitting.

 

[Mace]

I swapped mine out for a conventional one any way.