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10-06-2014, 04:55 PM
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#1
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Senior Member
Join Date: Dec 2013
Location: Durango, CO formerly Seattle
Posts: 177
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Airing down your tires - when and how much?
After writing my question yesterday about portable air compressors, I realized I don't know much about airing down tires. My main concern is rough, washboard roads that threaten to loosen my fillings with my tires at 65#. How much should one air down to smooth out the ride?
We have a 2WD rig so I doubt I'll be trying any sand dunes. But I would like to do something like drive to the Racetrack in Death Valley without feeling like I'd gone 10 rounds with Mike Tyson at the end.
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Bardo
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2005 RB-50 5.4L V8 E250 "Blanca"
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10-06-2014, 05:38 PM
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#2
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Senior Member
Join Date: Nov 2010
Location: California
Posts: 1,012
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Re: Airing down your tires - when and how much?
I air down to 35psi for washboard, 45psi for rocky terrain and 20psi for deep sand. DV washboard is a killer at any PSI unless you go fast.
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2006 E350 6.0PSD 5R110, SMB 4X4, RB-50, ARB lockers front/rear, Aluminess galore, AMP steps.
Callsign KK6GIY
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10-06-2014, 05:40 PM
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#3
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Site Team
Join Date: May 2007
Location: Turlock Ca
Posts: 10,409
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Re: Airing down your tires - when and how much?
I usually go to about 30-35 up front and 40-45 rear on washboard but my van is heavy.
viewtopic.php?f=3&t=8726
viewtopic.php?f=3&t=9075
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2006 Ford 6.0PSD EB-50/E-PH SMB 4X4 Rock Crawler Trailer
Sportsmobile 4X4 Adventures.......... On and off road adventures
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10-06-2014, 08:32 PM
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#4
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Senior Member
Join Date: Oct 2010
Location: Sacramento Delta, CA
Posts: 1,024
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Re: Airing down your tires - when and how much?
+1 on Tapatio's advice. You gotta go fast. Experiment with the speed until your tires are effectively bridging the humps. But be careful to slow down before turns.
It would be good to have BajaSportsMobile's advice on this topic.
__________________
2002 E350 ext.; 160K; 7.3L; 4R100 (w/4x4 deep pan & filter); 4x4 conv. w/2007 F250/F350 coil frnt axle (oppos. dual Bilstein press. shocks cured DW) diff chg from 3.55 to 3.73 (bad!); BW1356 t.c. (bad!); LT265/70R17/E Michelin LTX M/S2; Engel MT60 Combi Fridge-Freezer; 4 BP 380J pv panels; Auragen 5kw AC gen. in top alt. position; Webasto Dual-Top; Voyager top. 1995 5.8L EB Bronco, bone stock.
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10-06-2014, 09:22 PM
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#5
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Senior Member
Join Date: Jan 2009
Location: Corvallis, OR
Posts: 5,300
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Re: Airing down your tires - when and how much?
As low as too can go without de beading or getting hot. My M55 tires tolerate 8psi just fine, even up to 20 miles on highway.
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2000 E450 dually V10 wagon
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10-06-2014, 10:15 PM
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#6
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Senior Member
Join Date: Apr 2007
Location: Seattle, WA
Posts: 1,061
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Re: Airing down your tires - when and how much?
Quote:
Originally Posted by Tapatio
I air down to 35psi for washboard, 45psi for rocky terrain and 20psi for deep sand. DV washboard is a killer at any PSI unless you go fast.
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Same here. I generally went right to ~35 psi for the rough stuff, and down to ~20 psi for soft sand.
I've recently calculated that my front tires (305/70R16) can generally go with lower pressures, as they carry less weight (4000÷2 lbs) than the rears (5500÷2 lbs). So for the fronts, I'm now playing with 35-40 PSI highway, and 25 PSI when aired down.
-- Geoff
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10-14-2014, 08:38 PM
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#7
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Senior Member
Join Date: Feb 2009
Location: PNW or maybe Baja Sur
Posts: 381
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Re: Airing down your tires - when and how much?
Hmmm, 2WD. Reduced tire pressure depends on the size and type of tire.. I have the 245 stock tires on slightly wider than stock rims and for good bad baja roads at lower speeds 30psi in front, 35 back is as low as I roll. If in sand one can go lower, but then the what if we swerve or hit a large something turning and roll the tire concern looms...
Those with the 4WD big meats can easily go lower....but even 35 front and back is pretty good on washboard as long as you go slowly....there is the go fast float school of thought, but when it goes wrong (harmonics, rocks, or slippery) it is a drag..at least from a baja out there point of view. Each road is different..You can and should always experiment.
Have fun with it!
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Pac NW and warmer places
1995 E250 EB 5.8 2WD on to a new owner
2006 E350 EB Elect Top 2WD
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