Slow leak in front tire

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rideon67

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I've had the new 09 about 3 wks now & yesterday when I picked it up from the first service the tech told me the tire pressure was down. This concerns me because they also found the pressure way down when I test rode it and it needed a couple psi when I checked it a week or so ago. Coming from a tube tire system on the XS11 I just got used to the pressure never going down so hardly ever checked it. I realize checking it once a week or so isn't a big deal, but I like to keep it simple and not needing to check is pretty fool proof

1) Are these tubless tires more prone to losing pressure thru the aluminum cast wheels? If so, how much would be within the "acceptable" range? By acceptable I mean significant handling changes.

2) Where would be a good place to start looking for the leak other than the obvious places around the stem and bead?

3) Is there a treatment for these rims that makes them less porous?

 
It's not on common to lose some pressure. It seems I read somewhere that one percent per month is normal. I have had some than never lose any and others that need a few pounds pretty regular.

 
The only way that you should not be checking your tire pressure on a regular basis is if you have a tire pressure monitoring system installed, and then you're checking the pressue constantly. ;)

Seriously, tubes, no tubes, car, bike. You can't expect them to hold air forever.

 
Mine fluctuates. I could loose close to none, other times I could loose about 3-5psi per month. I check them about every other week. This week they were spot on.
Pretty much the same experience here, and just about the same with every set of tires I have had on so far. Sometimes they are perfect, and other times they are down a couple of lbs. Same deal with my KLR which has tubed tires.

 
I know that you can lose a little through the aluminum itself on some wheels, but I think the bead seal is more likely the problem. I clean the bead area of my wheel very well whenever I spoon on a new tire and the only time I need to add air is when the air temperature changes with the seasons.

 
Had a problem tire once. It was losing a few pounds per day. No punctures found. Had it remounted with a new valve stem. Still leaked.

Had it remounted yet again but that time applied a liberal amount of 3M Weather Strip Adhesive around the bead. Worked great. No more leaks and was able to go back to my weekly pressure check.

https://www.amazon.com/3M-08008-Black-Weath...e/dp/B00063X38M

 
I have a leak problem on my rear tire. It is the original tire with about 6K on it. Have done a visual and tactile inspection with no obvious issues. Replaced the stem valve and still lose about 8 psi the next day. I have a set of new Pirelli Angels in the shed so it is time to upgrade my tires.

 
Some loss is normal over time. I was losing a little more than normal recently from the front tire and finally discovered that the valve in the stem was loose. I got one of those little valve removal tools (which you can also use to tighen the valve) and tightened it up--problem solved. Turns out that the plastic valve stem cap was all that was keeping air in the tire.

 
The only way that you should not be checking your tire pressure on a regular basis is if you have a tire pressure monitoring system installed, and then you're checking the pressue constantly. ;)
Seriously, tubes, no tubes, car, bike. You can't expect them to hold air forever.
+1

Also, you'll naturally lose some pressure as ambient air temps decrease. It shouldn't be more than a few pounds at a time, but colder temps will result in lower pressure. The reverse is also true, so don't check your tires after you've been driving for a few miles and the rubber has warmed up.

I check 'em before every ride. It's safer, lessens tire wear and improves the bike's handling. :thumbsup:

 
Some loss is normal over time. I was losing a little more than normal recently from the front tire and finally discovered that the valve in the stem was loose. I got one of those little valve removal tools (which you can also use to tighen the valve) and tightened it up--problem solved. Turns out that the plastic valve stem cap was all that was keeping air in the tire.
and not only does the valve core in the stem get loose, if you ride without the little cap, stuff can get inside the stem and clogs up the little valve core seal and makes it leak. Also a plastic cap just keeps the core from getting contaminated , it won't seal properly against slow leaks like the metal caps can. And all this to say that I now carry 2 extra valve cores and an extra metal cap with the remove tool in my little emergency tool pouch. DAMHIK ! We were 30 bikers and noone had a valve core removal cap/tool or a spare valve core. Luckily there was a local bicycle shop in the Green Mountains for the necessay stuff! ;)

more valve core info

 
I chewed up a front because of low pressure...taught me to be vigilant about checking pressures.

However, since I replaced the OEM tire with a PR2, it hasn't once lost any pressure. (That's about a year and 6k miles.)

I decided it must have been the mounting job on the original tire.

Mike

 
I've had the new 09 about 3 wks now & ...prone to losing pressure ...? If so, how much would be within the "acceptable" range? By acceptable I mean significant handling changes.
for me 36 psi front is a break point with

bad handling changes @ lower pressure, so suggest try to keep front >36 psi.

[SIZE=8pt] $.02[/SIZE]

 
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Try soapy water in a spray bottle. if you have a leak it will make soapy bubbles where the air is leaking. You might find a leak if not just hose of you wheel with clean water.

 
I chewed up a front because of low pressure...taught me to be vigilant about checking pressures.
However, since I replaced the OEM tire with a PR2, it hasn't once lost any pressure. (That's about a year and 6k miles.)

I decided it must have been the mounting job on the original tire.

Mike
My experience also with the factory tire. I mount my own tires and made sure the bead was clean before installing my first tire and haven't had trouble since other than normal pound or 2 loss per month. 42k miles and numerous tires now with no problem.

 
If you try the soapy water to find the leak, take your time when doing the search. A slow leak takes time to blow bubbles. Check the whole tire, not just the tread. If you don't find a leak, do the whole procedure again. If you have the wheel off the bike it is easier to check the tire/rim seal.

 
To find those really difficult to pinpoint leaks you need to take the wheel and submerge it part way in your neighbor's swimming pool. The rising air bubbles are much easier to see than the snoop bubbles.

Tip: This should be done under cloak of darkness with a flashlight,

unless you run this past said neighbor beforehand... ;)

 
To find those really difficult to pinpoint leaks you need to take the wheel and submerge it part way in your neighbor's swimming pool. The rising air bubbles are much easier to see than the snoop bubbles.
Maybe not, this worked for me, it's still on the bike in the pic.
 
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I loose a couple pounds a week most weeks. It must be the wheel, the tire, or the value core because

my skill at checking the air pressure is wondrous. I haven't let an ounce escape in years. "just saying" :lol:

 
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