Author Topic: Original Magic Pie rips out valve stems.  (Read 118 times)

Offline e-lmer

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Original Magic Pie rips out valve stems.
« on: August 05, 2020, 03:07:24 AM »
I have tried many different tubes.
Thorn resistant, Schrader, Presta...
I replaced the rim tape, but I keep tearing the valve stem out of the tire.
Anyone else see this? Have ideas?

Offline Bikemad

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Re: Original Magic Pie rips out valve stems.
« Reply #1 on: August 05, 2020, 12:17:48 PM »
Hi Elmer,

I have never experienced this particular problem, but what width tyres are you using, and are you running them at a very low pressure?
If the inner tubes are not wide enough for the tyres, they can be stretched excessively when inflated in a wider tyre making them more prone to failure.

Do you use lubricant when fitting tyres that could allow the tyre and inner tube to gradually creep around the rim in relation to the fixed valve stem until the tension is too much for the valve joint?
Rubber inner tubes also become weaker with age, so "old stock" inner tubes will be more likely to fail, but as they don't usually have a "Best Before" date it's difficult to know how old they could be.  ::)

Have you considered using puncture proof solid tyres?



These eliminate the problem of tyres gradually losing pressure over time and more importantly, there is no chance of being inconvenienced by sudden deflation due to a bad puncture during a long ride miles from home.
I have been wanting to try one of these for some time now, but I can't find any in a 26" x 2.35" size. :(

Alan
 

Offline e-lmer

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Re: Original Magic Pie rips out valve stems.
« Reply #2 on: August 05, 2020, 10:04:11 PM »
I do not use any lube (on the tube), and I try to keep the pressure up as I am a large man.

But it seems that the tube is rotating inside the room with enough force to tease any tubes.

With single wall time this didn't happen, the stem just leaned
and you could see the issue. 

I haven't seen solid tires in years...

Offline Bikemad

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Re: Original Magic Pie rips out valve stems.
« Reply #3 on: August 06, 2020, 10:37:23 AM »
If you use a Sharpie or permanent marker to make a mark on the side of the tyre in line with the valve hole in the rim, you will be able to see if the tyre bead is slipping and moving in relation to the rim.

If it does move, I suggest that you thoroughly clean the outer edges of the tyre bead and the inner edges of the rim to allow them to grip together properly without moving.

If the tyre remains fixed in relation to the rim, the tube should also not be able to move and it should not be able to apply tension at the base of the valve.

Alan