Tire differential pressure retainment rates?
08-01-10, 01:52 PM
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Tire differential pressure retainment rates?
Hey guys, quick question.
I've only been back into cycling for a few months (I used to cycle as a kid so I didn't pick up any technical knowledge).
It seems my front tire has much poorer retention of pressure than my rear tire.
After sitting for a week (foot injury last weekend), I checked my tire pressure, and my rear was still at 120psi but my front had dropped down to 80psi (down from 120psi as well).
The rear tube is about 5 years old and the front tube is about 1 month old. Is this common? I've noticed it when I ride as well. Every couple days my front needs refilling but my rear stays good for weeks.
I've only been back into cycling for a few months (I used to cycle as a kid so I didn't pick up any technical knowledge).
It seems my front tire has much poorer retention of pressure than my rear tire.
After sitting for a week (foot injury last weekend), I checked my tire pressure, and my rear was still at 120psi but my front had dropped down to 80psi (down from 120psi as well).
The rear tube is about 5 years old and the front tube is about 1 month old. Is this common? I've noticed it when I ride as well. Every couple days my front needs refilling but my rear stays good for weeks.
08-01-10, 01:59 PM
#2
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Slow leak in front. Replace tube.
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Il faut de l'audace, encore de l'audace, toujours de l'audace
1980 3Rensho-- 1975 Raleigh Sprite 3spd
1990s Raleigh M20 MTB--2007 Windsor Hour (track)
1988 Ducati 750 F1
08-01-10, 02:01 PM
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The only difference I know of that isn't related to slow punctures is that latex tubes lose air much more quickly than butyl ones. Having said that, dropping to 80 in a week doesn't sound like a big deal. Whatever the cause thou, you should really pump your tires up before every ride anyway - it's by far the best flat protection strategy IMO.
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08-01-10, 02:06 PM
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Ultralight butyl rubber tubes also lose air faster than the heavier weight versions.
08-01-10, 02:21 PM
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40 psi drop for a butyl tube in one week is not normal. Don't tempt Murphy, replace the tube. But before you do, very carefully check the inside of the tire for any bits of wire poking through.
08-01-10, 02:23 PM
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find the leak and patch it.
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08-01-10, 03:00 PM
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I've never had a tube that didn't lose at least 40 psi in a week! Depends on the tube I suppose.
08-01-10, 03:15 PM
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Before you replace the tube, pump it back up and be sure you've closed the Presta valve completely. If the pressure continues to drop, I'd replace the tube. If it doesn't drop, you probably didn't have it closed tight.
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