Trick Question - RIB

I will offer a box of chocolates to the first best answer:

Friday I leave Lake Havasu at 6:30 am Pacific time, temp is 89 degrees and the RIB's tubes are firm. Trailer has just been serviced with new tires and repacked wheel bearings.

After approximately 550 miles I arrive in Alburquerque NM at 4:30pm Mtn Time, temp is 90 degress RIB's tubes are firm.

Today, Saturday I leave Alburquerque at 6:15am temp is 70 degress and RIB's tubes are firm.

At approximately 2:30pm after driving 450 miles I am 75 miles west of Oklahoma City, OK temp is 75 degrees wind is out of the south steady at 24mph and I notice through the rear view mirror that the RIB's tubes are soft and flexing in the wind. I stop to inflate the tubes.

At approx. 4:00pm Central time I arrive in Oklahoma City and tubes have softened some but not alot.

What gives and causes the fluctuation and will the tubes change again in the 580 mile drive tomorrow to Pickwick Lake MS ?????

Altitude. Pressure differences. Ever see a bag of potato chips at 12,000 feet? Send me a PM and I'll give you my address for the candy!

Giggitoni said:

Altitude. Pressure differences. Ever see a bag of potato chips at 12,000 feet? Send me a PM and I'll give you my address for the candy!

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Yes, it will keep changing for the same reason stated above.

Easy. While leaving Lake Havasu the tubes were rigid from the boat's proximity to water with inflation retained by excited readiness. The hope for virgin water stimulation maintained PSI through the day and the over-nighter at Albuquerque, and when it became obvious that, after 1000 miles of no water in sight, there was going to be no play today either, well......

Hose her down before going through OKC and when 40 starts following the Arkansas River a while, she'll stop loosing air. Once she smells the Mississippi, they'll steadily stiffen-up all the way to Pickwick.

Giggitoni well done but my warp sense of whatever also liked Heal Hustler's comment, however after much deliberation my result is Giggitoni.

The PM is on its way.

Please, I'm not looking for chocolate, send it to HH! I'd rather have you join us in the Delta or SF Bay Area soon.

As an aside to your RIB story a friend of mine in the Bay Area bought a brand new Alegro bus a couple years ago and took it to Pismo Beach for the break in trip. Everything was perfect except the queen size mattress, they hated it. Replaced it with a sleep number air mattress and went on another test trip and loved it.

Their next trip they left Los Gatos and drove straight to Ebbets Pass around 8,000 feet elevation. His wife went to get the camera out of the bedroom and he almost wrecked the bus when she screamed at the top of her lungs. They deflate the mattress before climbing mountain passes now.

CPseudonym said:

Everything was perfect except the queen size mattress, they hated it. Replaced it with a sleep number air mattress and went on another test trip and loved it.

Their next trip they left Los Gatos and drove straight to Ebbets Pass around 8,000 feet elevation. His wife went to get the camera out of the bedroom and he almost wrecked the bus when she screamed at the top of her lungs. They deflate the mattress before climbing mountain passes now.

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Great story, Craig! I can just see it happening!:lol:

My comment on the potato chip bag was from experience. I was traveling to a job in Colorado and had a bag of snacks on the passenger seat next to me. I was east-bound on I-70 just about to enter the Eisenhower Tunnel near Silverthorne (about 12,000 feet) when the bag of chips let go. I had chips all over the dash and the noise completely shook me up. I pulled over at the Loveland ski area on the other side of the tunnel. I was laughing and eating chips at the same time. Quite a day!

That's funny Ray! I'd a peed myself if that happened to me.

Good thing you weren't a pilot!

FlyWright said:

Good thing you weren't a pilot!

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Airlines warn about deflating(or was it inflating) the seat lumbar support when landing. Can the seat explode?

Internal temp can be pretty important too.


Blow a rib up in direct sun, let it sit, top it off, toos it in cool to cold water in the shade anf the tubes deflate quite a bit too.


I would guess 20 degrees and sunshine intensity drop would have an effect more than five hundred or so feet of altitude change....8000 maybe. if you went through a high pass and it vented then its a possibility too.


The new gas cans also....they seem to be pretty dangerous the way they deform so badly. I hope the emergency vent kicks in before mine gets any rounder some day and decides plastic isn't THAT strong.

Giggitoni said:

My comment on the potato chip bag was from experience. I was traveling to a job in Colorado and had a bag of snacks on the passenger seat next to me. I was east-bound on I-70 just about to enter the Eisenhower Tunnel near Silverthorne (about 12,000 feet) when the bag of chips let go. I had chips all over the dash and the noise completely shook me up. I pulled over at the Loveland ski area on the other side of the tunnel. I was laughing and eating chips at the same time. Quite a day!

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I have had chips and a pop can once even explode on me in the helicopters.
New rule on the list is don't fly with a can of coke....what a huge mess....

BruceK said:

Airlines warn about deflating(or was it inflating) the seat lumbar support when landing. Can the seat explode?

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Bruce, The problem arises when a sealed air chamber like an inflatable lumbar or neck pillow is taken to an area of lower atmospheric pressure. This can be via a mountain climb or an airplane climb. It's worse in unpressurized planes but can still be a problem in a pressurized aircraft. As the surrounding air pressure decreases, the pressure differential increases between the trapped gas and the surrounding air. The pillow/bag of chips/intestinal gasses will be released if the differential grows too large for the vessel holding the trapped gas.

Take a water bottle as an example of the effects on descent. At altitude, you drink half the water and reseal the bottle. When descending, the bottle will crush in as the air pressure around it increases causing a pressure differential.

I was towing my RIB one summer day. The temp was in the 90's and the tubes were firm. Drove through a summer thunderstorm and the temp dropped 20 degrees. Noticed the tubes were all floppy. Half hour later the temp was back up and the tubes were firm again.

I kept an eye one the tubes in the rearview mirror as we drove. I've had to stop on the side of the road at times to adjust the pressure (both up and down depending on the situation).