cold weather and tyre pressures

[simon the viking]

I thought I had a puncture on Saturday when I wheeled my bike out of the shed as front tyre was very soft. So left bike and went in the car to work. I took the inner tube and dunked in water no bubbles anywhere even the valve I had suspected.

When I fitted the tube a week ago I fitted it in the kitchen where it was warm and perhaps I didn't inflate it as much as I should have.

My question is with it being in the shed could the cold reduce the tyre pressure so much. Anyone else encountered this problem

 

[Linford]

I always notice a drop in pressures when it cools. Similar thing...on my motorbike, regular pressures are 41 in the back and 36 in the front...notice a big difference in handling when it gets cold and this is always down to a drop in the tyres, and when on the race track, cold pressures pre ride set to are about 30psi...so gaining another 1/4-1/3rd (ish) when the tyres are brought up to temp during the track sessions.
My roadie is dropping to about 60psi between rides right now and I normally run 110/120psi

 

[the_mikey]

May be a leaky valve, I recently replaced a tube because the valve was leaky, it went from 110psi to 50psi in 3 days.

 

[simon the viking]

May be a leaky valve, I recently replaced a tube because the valve was leaky, it went from 110psi to 50psi in 3 days.

I did wonder about the valve but no bubbles when I dunked it but I must admit the jury's still out on the valve

 

[simon the viking]

tyre hasn't gone down since i checked tyre, rim and valve and then blew the tyre up Saturday night and commuted on the bike this morning.... so very puzzled

 

[Easytigers]

I know it sounds obvious but was the locking nut fully screwed down?

 

[simon the viking]

I know it sounds obvious but was the locking nut fully screwed down?

Thats what i'm thinking..... oops!

 

[machew]

Working in a industry that takes its tire pressure very seriously, the documentation that I have for checking tire pressure states

Tire temperatures can rise in excess of 200˚F (93˚C) above ambient during operation. A temperature change of 5˚F (3˚C) produces approximately one percent (1%) pressure change. It can take up to 3 hours after a flight for
tire temperatures to return to ambient. A tire/wheel assembly can lose as much as five percent (5%) of the inflation pressure in a 24-hour period and still be considered normal. This means that tire pressures change on a daily basis. Even a tire which does not normally lose pressure can become damaged by FOD or other outside factors that can suddenly increase pressure loss. These are all reasons why it is important to check pressure daily or before each flight

When tires are going to be subjected to ground temperature changes in excess of 50˚F (27˚C) because of flight to a different climate, inflation pressures should be adjusted to worst case prior to takeoff. The minimum required inflation must be maintained for the cooler climate; pressure can be readjusted in the warmer climate. Before returning to the cooler climate, adjust inflation pressure for the lower temperature. An ambient temperature change of 5˚F (3˚C) produces approximately one percent (1%) pressure change.
All tires, particularly bias tires, will stretch (or grow) after initial mounting. This increased volume of the tire results in a pressure drop. Consequently, tires should not be placed in service until they have been inflated a minimum of 12 hours, pressure rechecked, and tires re-inflated if necessary

 

[simon the viking]

Working in a industry that takes its tire pressure very seriously, the documentation that I have for checking tire pressure states

Tire temperatures can rise in excess of 200˚F (93˚C) above ambient during operation. A temperature change of 5˚F (3˚C) produces approximately one percent (1%) pressure change. It can take up to 3 hours after a flight for
tire temperatures to return to ambient. A tire/wheel assembly can lose as much as five percent (5%) of the inflation pressure in a 24-hour period and still be considered normal. This means that tire pressures change on a daily basis. Even a tire which does not normally lose pressure can become damaged by FOD or other outside factors that can suddenly increase pressure loss. These are all reasons why it is important to check pressure daily or before each flight

When tires are going to be subjected to ground temperature changes in excess of 50˚F (27˚C) because of flight to a different climate, inflation pressures should be adjusted to worst case prior to takeoff. The minimum required inflation must be maintained for the cooler climate; pressure can be readjusted in the warmer climate. Before returning to the cooler climate, adjust inflation pressure for the lower temperature. An ambient temperature change of 5˚F (3˚C) produces approximately one percent (1%) pressure change.
All tires, particularly bias tires, will stretch (or grow) after initial mounting. This increased volume of the tire results in a pressure drop. Consequently, tires should not be placed in service until they have been inflated a minimum of 12 hours, pressure rechecked, and tires re-inflated if necessary

Thanks for that very informative. From those figures It was too much of a change... must of been operator error

 

[biggs682]

Thanks for that very informative. From those figures It was too much of a change... must of been operator error

sounds like it

 

[ColinJ]

The Combined Gas Law says

Where p is pressure, V is volume, and T is temperature. Bicycle tyres probably don't stretch/shrink much with a few degrees change in temperature so treat V as constant. The temperatures would be 'absolute' or 'Kelvin' so add 273 to the Centigrade value.

(I can't do subscripts) p1/T1 = p2/T2 so if the tyres were at 100 psi indoors at 20 C and the shed were at 0 C, then 100/(273+20) = P2/(273+0).

Rearranging that ... P2 = (100 x 273)/293 ~= 93.2 psi (which fits machew's rule of thumb, above).

 

[machew]

The Combined Gas Law says

Where p is pressure, V is volume, and T is temperature. Bicycle tyres probably don't stretch/shrink much with a few degrees change in temperature so treat V as constant. The temperatures would be 'absolute' or 'Kelvin' so add 273 to the Centigrade value.

(I can't do subscripts) p1/T1 = p2/T2 so if the tyres were at 100 psi indoors at 20 C and the shed were at 0 C, then 100/(273+20) = P2/(273+0).

Rearranging that ... P2 = (100 x 273)/293 ~= 93.2 psi (which fits machew's rule of thumb, above).

Gad it fits rule of thumb as that is part of the technical documentation that is supplied with the tires that we sell.