Date: Sat, 9 Aug 2008 20:23:44 -0700
Reply-To: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Subject: Re: Trailer loading and tire pressure testing
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=response
hi mike.
I never go as low as 15 or 20 psi unless it's for going on sand or
something.
I also liked that guy's rule of thumb that if the pressure goes up more than
10 % after a run, and that would have to mean getting the tire warmed up on
a warm day .....if it does that it was underinflated in the first place.
Never heard that one before........but I like the concept, and it makes
sense.
LOL ! . ..thanks for the humor on the 'resemble that remark' - make me
laugh- thanks !
I needed that.
scott
fwiw.....
for years old american cars would specify tire pressure like 22
psi.........or in the 20's for sure ......for a smooth ride I suppose.
Back in the 50's and 60s .........and even then that was unrealistic.
----- Original Message -----
From: "Mike Elliott" <camping.elliott@gmail.com>
To: "Scott Daniel - Turbovans" <scottdaniel@turbovans.com>
Cc: <vanagon@GERRY.VANAGON.COM>
Sent: Saturday, August 09, 2008 1:55 PM
Subject: Re: Trailer loading and tire pressure testing
> Hi Scott,
>
> Hmmm. The chart at http://tinyurl.com/6lg2oy says that 15 psi correct for
> 670 lbs per tire. I'm way under that, even. The tires are rated to 1360
> lbs at 50 psi.
>
> Maybe you're right -- I should ignore the chart and just put 25 psi into
> the tires.
>
> You wrote, "I think you're 'trying to hard' or being obsessive."
>
> I resemble that remark!
>
> --
> Mike "Rocket J Squirrel" Elliott
>
>
>
>
> On 8/9/2008 1:43 PM Scott Daniel - Turbovans wrote:
>
>> i think you said the max inflation pressure listed on the side of the
>> tires was 35 psi ?
>>
>> anything like 15 or 20 psi sounds way way too low for a 13 inch tire to
>> me.
>> I'd do 25 psi cold, and not worry about it.
>>
>> I heard another 'trucker's rule' about hot tire pressures.
>> 'never let air out of a hot tire' .............the idea being, I believe
>> , is that you don't now how low it will be once it's well coooled off.
>> So I just set them at something reasonable cold,
>> and drive.
>> If things are harsh or bouncy, then I let some out, 3 psi at a time say.
>> works for me !
>> I've towed trailers and vans and cars just countless times, for decades.
>> I think you're 'trying to hard' or being obsessive.
>> I suggest put 24 psi in them cold.......nice even # that.........and head
>> on out.
>> Super that you did a test drive !
>> I always carry a spare tire for trailers or anything towed too.
>> scott
>>
>>
>> ----- Original Message -----
>> From: "Mike Elliott" <camping.elliott@GMAIL.COM>
>> To: <vanagon@GERRY.VANAGON.COM>
>> Sent: Friday, August 08, 2008 12:35 PM
>> Subject: Trailer loading and tire pressure testing
>>
>>
>>> Hi all,
>>>
>>> I don't to join the legion of unskilled trailer haulers who find
>>> themselves in a terrible jam because they were dozing in Trailering 101.
>>>
>>> So if anyone wants to check my work to see if I overlooked something,
>>> that
>>> would be helpful.
>>>
>>> TRAILER: 270 lbs. (Small fiberglass-bodied single axle utility trailer.
>>> Empty weight: 270 lbs. This was derived from weight on tongue = 30 lbs,
>>> weight on one tire 120 lbs. It's safe to say that the other tire had as
>>> much weight on it.)
>>>
>>> PAYLOAD: 218 lbs.
>>>
>>> TOTAL COMBINED WEIGHT: 488 lbs.
>>>
>>> The rule of thumb seems to be to have 10% to 15% of the gross weight on
>>> the tongue, so I balanced the load to get 55 lbs on the tongue.
>>>
>>> TIRE PRESSURE
>>>
>>> Too much pressure = bouncy ride, too little = hot sidewalls and possible
>>> kablooey. Each tire is carrying (488 - 55)/2 = 240 lbs. These tires are
>>> ST175/80R13, and according to the load inflation chart at
>>> http://tinyurl.com/6lg2oy 15 psi is more than enough. Refer to the chart
>>> if you don't believe me -- these are beefy tires for such a little
>>> trailer. Heck, 15 psi is good up to 670 lbs per tire.
>>>
>>> So I aired each tire to 15 psi and took the loaded trailer for a 7 mile
>>> ride, half of it on the freeway. At the end of the ride, the sidewalls
>>> of
>>> the van's tires (aired to spec) had risen to 97F (ambient here is around
>>> 76F), and the sidewalls of the trailer tires read about 90F. This
>>> suggests
>>> that the tires are not underinflated, which is in agreement with the
>>> load
>>> inflation chart.
>>>
>>> However, the pressure in each tire had risen to 20 psi, a 33% increase.
>>>
>>> A list member had p-mailed me a couple days ago about a tire pressure
>>> rule
>>> of thumb: if the pressure goes up more than 10% after a fast 5-mile
>>> drive,
>>> the pressure is too low.
>>>
>>> So...according to the rule of thumb, the tires are underinflated.
>>> According to the chart, they are nowhere near being underinflated.
>>> According to the comparison to the sidewall temps of the van's tires,
>>> they
>>> are not underinflated. Anyone want to comment on that?
>>>
>>> Oh -- by the way, the trailer towed like a dream. No side to side
>>> oscillations which indicate that there is too much weight to the rear,
>>> and
>>> no excessive bouncing. It followed along like a little sweetheart.
>>>
>>> --
>>> Mike "Rocket J Squirrel" Elliott
>>> 71 Type 2: the Wonderbus
>>> 84 Westfalia: Mellow Yellow ("The Electrical Banana")
>>> 74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
>>> KG6RCR
>>
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