Commuting - 3 flats 1 month with studs, somebody help

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akbiker
11-30-07, 02:40 PM
I bought some used nokian hakka 300 studded tires for winter riding here in Alaska. I love them, but i keep getting flats in the same place over and over, 3 times so far. After about 10 miles my front tire goes flats from a rip at the base of the valve stem. I have used three different kinds of tubes all presta valves. These are not slow leaks either. the tire is fine and BOOM total loss of air, never while riding only while it parked, usually immediately after I dismount. After the second blowout I made a meticulous inspection of the entire tire and rim for causes. I taped around the valve hole in the rim just in case, but there doesn't seem to be anything else wrong. Oh, by the way it only the front tire (the back has been great) and I run about 35-40 psi. I weigh 170 and I am not really riding aggressively or doing anything out of my normal routine of commuting. Any help would be great because it is getting really annoying and expensive. thanks


idcruiserman
11-30-07, 02:46 PM
I've gone through 3 tubes while mounting my Nokians. Always before riding them. It was mostly due to trouble mounting the stiff tires. Have you tired different tubes?

acroy
11-30-07, 02:51 PM
weird.
tube wrong size maybe?
stem hole too large?

consider converting to Tubeless and get rid of ALL flats... ;)


ItsJustMe
12-01-07, 12:41 PM
That's bizarre. I'm going into my 3rd season on this set and I've never had a flat on them (about 3800 miles so far). I don't know what causes valve stem leaks; maybe googling for it would help (try using site:bikeforums.net in the search)

markf
12-01-07, 01:26 PM
If the tubes are too small, they'll stretch too much when you inflate the tire, and be vulnerable to flats. Even though you have 26" tubes and 26" tires, tubes are meant to accommodate a certain width range. Check the label on the tire, check the size range on the tube (it should be printed on the box), and make sure your tubes are meant for tires as wide as your Nokians (26 x 2.1?).

Jeffbeerman2
12-01-07, 02:25 PM
consider converting to Tubeless and get rid of ALL flats... ;)

?

Please explain

newbojeff
12-01-07, 03:45 PM
That is weird. I have Nokians too and have not flatted (yet). I think when I do, I will just be calling my wife because a) they are very difficult to get on and off and b) it's going to be wicked cold if I'm riding with them.

The fact that you are getting these at the base of the valve stem makes me think it is a rim problem or you are doing something when you mount the tube/tires. Do you always mount, say, from the valve out or finish at the valve?

The dismount timing has me confused too. Could it have something to do with the wheel deforming slightly while you're riding then changing when you get off? (Never heard of that) Tube expanding during your ride? (Probably too cold to have much of that) How about having a slight pinch when you first mount the tire then shrinkage of the tube in cold weather causing a rip? Dunno. Anybody else?

Severian
12-01-07, 04:05 PM
Possible cause. The rims you're using are designed for Schrader valves. If you put Presta valved tubes in you've got all this extra space around the valve where your innertube can balloon out and blow. Go to your LBS and ask them if they have presta valve grommets. If they're any good they will know what they are and have them.

What they are: a rubber grommet that you slot into your valve hole on your rim to fill space between the rim and the valve stem.

akbiker
12-01-07, 07:05 PM
the hole is a little large for the presta valve, but have used presta in this rim for about 5 years no problems. The only thing I can think is maybe these tires ride different and cause more stress in that area. These are the correct tubes 1.9-2.2 width. I think this is the best suggestion so i am gonna get some schrader valve tubes.

cooker
12-01-07, 07:11 PM
I know you said you taped the valve hole but still it seems weird that it would be that same place each time. Are you sure there isn't a little roughness in the rim hole?

I_bRAD
12-01-07, 07:17 PM
Is the tire on inside-out?

Hydrated
12-01-07, 09:39 PM
Is the tire on inside-out?

I really really think that this would do it... :D

ItsJustMe
12-02-07, 04:05 PM
I just had my first flat with the Nokians. My rear tire has lost a few studs, and I picked up a small stone in one of the holes. It worked its way in and punctured the tube.

The bike stores are closed today so I cut up the old Race Lite tire that I took off to put the Nokians on (it was trashed) and made a tire liner out of it. Hopefully that will hold. The tire is heavy enough to be a gyroscope now.

acroy
12-03-07, 07:34 AM
?

Please explain

see here:
http://www.bikeforums.net/showthread.php?t=363049
http://www.bikeforums.net/showthread.php?t=299544

i converted standard tires/rims to tubelss and have been flat-free for almost 7 months now. Previous record was about 3weeks (with VERY tough tires, Armadillo and Marathons). the system won't stop ALL flats of course, but almost all!

Tubeless is the best-kept commuting secret out there.

Cheers

ngateguy
12-03-07, 08:40 AM
see here:
http://www.bikeforums.net/showthread.php?t=363049
http://www.bikeforums.net/showthread.php?t=299544

i converted standard tires/rims to tubelss and have been flat-free for almost 7 months now. Previous record was about 3weeks (with VERY tough tires, Armadillo and Marathons). the system won't stop ALL flats of course, but almost all!

Tubeless is the best-kept commuting secret out there.

Cheers

My experience with tubeless has not been the same. They were such a pain in the a** to repair when the do go flat(and they will). I ended up putting tubes in them anyway. No more tubeless for me. I just use good tires and tire liners that has stopped the flat tire problem.

akbiker
12-03-07, 07:43 PM
I have only ever had one flat before this. so I think I would only try tubeless as an experiment.

I found some sharp edges on the rim around the valve hole. I filed them off and tried switching to schrader valves. I'll let ya know how it goes.

BikingGrad80
12-03-07, 09:22 PM
Are you using the nut that holds valve straight on the rim? If so take those nut and through them as far away as you can. I went through half a dozen tubes that separated at the base of the stem before I did that and haven't had that happen once since. For some reason the nut puts a lot of tearing stress on that area when the pump is inserted and removed over and over. The nuts are not only nonessential that are harmful and a waste of weight.