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I have been using my bike for a few years now, and for the last month i am constantly getting this problem. After riding a day or two, it looks like my tube gets rotated a little inside the tire, and the valve becomes bent. If i continue riding, the tube gets torn. So i have to remove the tire, wiggle the tube a bit, and it's back to normal for a few days.

The tube seems to fit very well, and i don't notice any inconvenience when inserting it, so maybe my problem is not caused by bad tubes (or maybe it is? how can i make sure?)

Another thing that might be relevant: i started riding moderately technical terrain in the last year (going down rocky roads, riding downstairs in the city). The problems started just a month ago; maybe the additional stress, combined with the warm weather (25-30°C now), is the cause?

I also use anti-puncture tape.

So, what causes my problem? How can i fix it?

New tube: state_1

After some riding: state_2a state_2b

After a puncture: state_3

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As a stop-gap, you could switch to Presta tubes, which bolt down to the rim and might help the slipping? amazon.com/Slime-Smart-Presta-Bicycle-1-75-2-125/dp/B000ENOPOA –  Jack M. Jun 18 '12 at 1:34
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Your tire is slipping and pulling the tube along for the ride? Put talc inside the tire so the tube and tire slip and DON'T stick and cause pinches and stem rips. Also could make yourself a gasket ring for additional stem protection as well as taking a file to the rim and smoothing out the edge. Yeah, clean your tire too so the rim grips it better but you'll always get some slippage when riding under inflated so what you're looking for is a frictionless interior. –  Chef Flambe Jun 18 '12 at 21:23
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4 Answers 4

up vote 6 down vote accepted

I would bet this is caused by a tire with rubber that got "old". This tends to happen to MTB tires that are repeatedly ridden on mud, and I had some tires with this behaviour before.

The problem seems to be insuficcient friction between the rubber and the rim around the bead, specially on those tires with a material resembling fabric on that region (like it seems to be your case, judging by the first photo), and are worse on the front tire since it applies traction only while braking - the rotational force is always applied in the same direction.

One measure to take, as already mentioned, is to put a higher pressure on the tire. It might allow you to get home without damaging a spare tube, but it's not the ideal solution since the slipping tendency is still there anyway, and sooner or later the tire ends up slipping, most probably when you don't expect.

One other measure, that actually works very fine, is to "reactivate" the rubber on the groove where the rim and the tire "seat" against each other, considering that:

  • In tires with old rubber, many times the said surface is "shiny", or "glassy", or "vitrified", or "mirror-like";
  • In tires with fabric in the bead, the rubber "disappears" with use, and the slippy underlying fabric is left to make contact with the rim.

Both conditions contribute for the slipping due to reduced friction coefficient. So, to REACTIVATE the grippiness of the material, you should:

  • Take the tire from the bike and wash it with plenty of water until it is completely wet. Since the tire is off, you can wash the rim either;
  • Brush the bead groove vigorously with a properly-sized brush, applying some abrasive soap mixed with water. Mechanics soap could be great but maybe too violent. I had excelent results with toothpaste (seriously!), and even with glycerin soap without abrasives. In any case, adding water enough to get a good foam is much better than just rubbing the dry product on the rubber. Rinse repeatedly after this with pure water, aiding with the brush;
  • Optionally, at last you can apply those products to make car tires "shiny". These tend to somehow protect the rubber from getting dry and glassy again.
  • Important: assemble and inflate the tire while it is still wet.

I had tires almost unusable because of this slipping problem, and the problem disappeared like magic after performing these steps.

As an additional fact, any modifications I tried to make in the rim (cleaning, sanding, filing, grooving) had no effect.

Hope this helps!

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Actually, applying a preparation intended for rubber V-belts might be a good solution to the "old rubber" problem. Several options are available from a hardware store or auto parts place. –  Daniel R Hicks Jun 17 '12 at 22:00
    
@DanielRHicks another trick to the utility-belt! –  heltonbiker Jun 18 '12 at 1:54
    
This method works just like specified (magic)! –  anatolyg Jun 27 '12 at 6:25
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The tire slipping on the rim is generally a sign of an underinflated tire. What sort of pressure are you running in the tires?

Otherwise, it could be that that old rim is coated with some substance that makes the tire slip. Or it could be that the tire itself is old and hardened to where rubber does not grip the rim well.

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Of course, in terms of the punctures it would be wise to examine the rim in the area of the stem hole and check for sharp edges. –  Daniel R Hicks Jun 17 '12 at 20:45
    
Underinflation! There is slime in there too, and that might add to the problem, but even if you coat the whole thing in grease, a properly inflated tire/tube will not rotate on the rim. –  BillyNair Jun 18 '12 at 19:29
    
I have heard of cyclists in Alaska having trouble with the tires spinning on the rims at -10F and below. But at those temps you don't even need air in the tire. –  Daniel R Hicks Jun 18 '12 at 19:56
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These are all helpful. I just wanted to add that a bike store guy told me to bore out the hole in the rim. I just did this and although the tube slipped, I didn't break the valve this time. I'll try other suggestions to stop the spinning totally.

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I had the same problem climbing steep hills using low gears and a double wall rim. After some trial I 1) Elongated the inner rim wall 1/8" on each side of the tube filler, 2) Glued one side of the tire to the rim for 1 ft. using rubber cement, 3) Increased the air pressure to 48 psi. After the above I can climb with no problem for 2 years. I could have gone tubeless but didn't because of other concerns. DK

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