Author Topic: Tyre pressure and weather change.  (Read 603 times)

PaulF

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Tyre pressure and weather change.
« on: January 17, 2018, 09:50:01 PM »
One thing that I have noticed on a small wheeled scooter is that it does not take too much change in temperature to get your tyre psi out of the recommended range.  In winter I had no real problems as the days and nights stayed pretty well the same but now that summer is here the range is much greater.  One day might be 25 celsius (77 F) and then change to 35 celsius (95 F) the next.  I did a quick test yesterday to see how much the tyre pressure would also change when riding in the heat.  My scooter tyres were 22 psi front and 26 psi for the rear and that was measured with the scooter in the shade.  After a 25 minute ride I checked the pressures again and they were almost at the recommended psi with the front 24 and the rear 29.  The next two days will be at 41 celsius (106 F) so I will drop a bit more pressure out of the rear.

Stig / Major Tom

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Re: Tyre pressure and weather change.
« Reply #1 on: January 18, 2018, 08:08:26 PM »
Thank goodness for the fat air we have here in the Midwest.
Molecules are too fat to escape the tire/bead apparently ..I fill when scooter tire hasn't been run, the let her go wherever she wants after that -  go years without adding.
I figure whatever pressure is lost at 25°F is offset by the stiffer tires at those temps.
Stig
« Last Edit: January 18, 2018, 10:30:59 PM by Stig »
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hypophthalmus

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Re: Tyre pressure and weather change.
« Reply #2 on: January 18, 2018, 08:32:55 PM »
The recommended tire pressure is for when the tire is cold, before it's ridden.

Tires always heat up when you ride from the constant flexing, and the pressure will increase a bit. So the recommendations represent the bottom of the operating range.

If the pressure is much too low, they can heat up to the point of self-destruction.

As far as never adjusting your pressure goes, you're alive to tell about it, but it sounds like a bad idea to me. The pressure can drop pretty substantially. And it's a good idea to check it frequently anyways for the development of leaks.

de dee

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Re: Tyre pressure and weather change.
« Reply #3 on: January 18, 2018, 09:11:20 PM »
  I use to think about that .,  leaving Canada at 40 below 0 driving to Miami  to 90 F.  checking the temp.  did not find much difference,  always thought it was rolling temp. or sitting in the sun one side hotter so I don't bother any more, 

CROSSBOLT

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Re: Tyre pressure and weather change.
« Reply #4 on: January 21, 2018, 01:43:25 AM »

I know this pressure change is because of tire heat. Just sayin'....



All things considered, the trip was about 410 miles round instead of 520. Hey, I'm old. Cut me some slack! DT ran like a station wagon both ways. On the fill up there it showed only 66. something mpg which is not that good but it has only about 5000 miles since new. My Samsung tablet went into the no charge mode Friday so no pictures of the event. I did get it to charge Saturday night so I have one to share once I get cooled off. Low 90s all three days. One thing about the Steelmate TPMS wothy of note it really shows how enormous the pressure gain is on a hot day. The front will gain 3-4 psi and the rear gains 6-7 psi! Noticed no change in handling but it seems that N2 would be worth a try. Alabama highways are really nice and smooth! At least where I travelled.

Karl
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Forbes1964

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Re: Tyre pressure and weather change.
« Reply #5 on: January 21, 2018, 04:07:08 AM »
I’m not sure about the variation in pressure caused by temp changes in Scooter tires. But I do know that at the Ford Dealership where  I work, on the first days the temperature drops below 40 degrees, we get a rash of customers coming in wondering why their low tire pressure light is on and asking what it means. I feel like saying: Hint, maybe it means you have low tire pressure. But I need my job. [emoji23].
Some know what it means. And while it’s aggravating to have to pause and CLIMB  down from the hood of one of the 4 inch lift kit equipped F250’s just to inflate a customer tire, I can’t get angry with them because there are few other places where they can get FREE AIR. I remember when you could get free air at ANY convenience store. But those days are long gone. [emoji22]


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CROSSBOLT

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Re: Tyre pressure and weather change.
« Reply #6 on: January 21, 2018, 01:21:07 PM »
I really get it, Forbes! Stuff like that on top of what you suffer at the hands of the dealer policy.
Karl

Three motorcycles 1960-1977 (restored a 1955 BSA)
Agility 50
Yager 200i
Downtown 300i
Navy tech, Ships Engineer, pilot and aircraft mechanic

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