Help - Constant splitting tubes at valve shaft !!

[albion]

Mini hand pumps - I learnt my lesson and will possibly never use them again. Its not fun when you snap your 2 valves in one day!

I have gone back to my traditional Blumen of Zefal pump with a screw on tube .
Methinks a very expensive hand pump will put less strain on the valve but I'm happy with a bit less maximum pressure on puncture day.

 

[PpPete]

I don't bloody know then.

What ?
First time for everything I suppose....

Looking at that picture I would suggest that DZ guessed right yesterday.

 

[Svendo]

I had a couple of problems with valve seat failures this summer when my D_A C24s were new on the rear. Led to an embarassing 'used both spare tubes, had to beg for another' incident 20 miles from home. No sign of a particular burr or sharp edge on valve hole, but gave it a gentle sand anyway and not had a problem since over probably 1500 miles.

 

[albion]

It is really the pump with the tiniest ones often needing a manic method to get anywhere blowing the tyre up.
The physical action of it just yanks the valve both sideways and up. An inner screw might just help but that gives other problems too.

I initially blamed cheap inner tubes until expensive Michelin tubes did same.
My turbo morph pump also has a valve saving extension tube but at 330 grams it is 200 grams heavier than my zefal..

 

[zacklaws]

I had this problem a while back and I found it was the locking nut on the valve being to tight and ripping the valve out of the tyre, but as you have tried with and without locking nuts, it rules it out.

Alternatively, when you fit the tyre, are you pushing the valve up into the tyre and looking to see that you are not trapping the inner tube with the tyre against the rim in the valve location before you pump it up. This is one reason why I like long valves as it easier to push the inner tube up into the tyre, some short ones on a slightly deepish rim are not long enough to push in far enough

 

[byegad]

Maybe a collar made from an old tyre, the exact bit you are showing in your picture dropped over the valve might stop it pushing off like that.

 

[Alien8]

I've had a couple (one front, one back) of Vittorias split at the valve over the last few weeks. They were spares that I reckon must have been at least 5-years old - I have wondered about inner tube degradation over time. Prior to that I can't remember it happening to me before.

 

[MacB]

Well I use the locking ring on all mine and have never had this problem, though would never do them up tightly, just tight enough to ensure no rattling.

If the rim is drilled for schraeder then I would expect to use a litle rubber gromit thing in the valve hole along with a presta tube. All of my rims came with this fitted and I would need to remove it to fit in a schraeder valve. Without this I can see that pressure would start to force the rubber base of the valve into the hole. The gromit provides the same sort of protection as you've been trying to make via rubber washers.

If that is the case then I'd fit a gromit and also fit new rim tape, I like Velox. It's feasible that this has only started to happen recently as the hole in the rim tape has become slightly enlarged, or off centre, over time.

If this is not the case then I have no idea.

 

[giantxtc]

Well I thought I would report back on this one as there were so many helpful suggestions to the cause of my problem. I've been riding for 5 days now without a problem, which compared to my recent puncture rate is quite a breakthrough. Fingers crossed I think the problem has been solved.

As suggested by a couple of board members, I smoothed off the hole in the rim with emery paper, so much in fact that it practically had a radius on it when I was finished. It seem's to have done the trick and I'm well and truly back in the saddle. Even though there was no burr, it seems the hole itself may have been cutting the tube away from the valve under pressure.

Thanks to anyone who lent a suggestion as I was going crazy with this one.

 

[PaulSB]

Well my son has this problem so I have a happy evening ahead studying all of these suggestions!

I suspect his problem is not seating the valve correctly.

 

[Gravity Aided]

I've never run across this problem, but I use the lock ring. Although I always filed the valve hole in the rim, and went over it with sandpaper, because I had a similar problem many years ago. It seems odd to me that a bicycle wheel works as well as it does, given all the things that could go wrong with them.

 

[PatrickPending]

think its been mentioned earlier - those pumps where you put the end of the pump on the valve - you need to be careful or you can experience the symptom you describe. I personally prefer something like a top peak road morph for this very reason. The tube between the pump and the valve eliminates or drastically reduces stresses on the valve whilst pumping.

 

[Banjo]

I had exactly the same problem with a hybrid bike a few years ago.really frustrating.I am convinced that the tyres were moving on the rim when braking ripping the valve stem.try marking the tyre and rim to see if this is happening.I dont remembr how I fixed it tbh.

 

[PaulSB]

I've found this thread a great help over the last few days as I attempt to solve the same problem on my lad's rear wheel. In common with the original poster the wheel has been fine for years and over recent months four valves have split horizontally at the base. The wheel is a DRC touring and on investigation I see it is a "double" construction, i.e. there is effectively an inner and out wheel with a gap between the two - don't know what this is correctly called. It's clear the valve has been splitting where the valve base is in contact with the inner section.

To date I've carefully cleaned and smoothed the hole in both sections and then used three layers of electrical tape, on the inner section, to cover the metal edges to protect against any remaining rough edges and help the valve seat more securely, but not rigidly, in the hole. Though I think I know how to fit a tube I've paid special attention to comments here and especially ensuring the valve is correctly seated inside the tyre after fitting. I've also talced the tube. I've educated my son in all of this to be sure he changes his tubes correctly.

The wheel has been serviced, new bearings, re-greased etc and trued. This needed doing and hopefully helps to eliminate the unlikely(?) possibility the wheel was somehow stressing the valve.

We will be testing the outcome this weekend.

The last question I have is re the "useless" locking screw. What are the arguments for and against? I've always used them when the tube is supplied with one but when not haven't. Logic says if the manufacturer supplies the screw and threads the valve the producer believes they have a value?

Would like to have opinions before deciding which way to jump on this issue.

 

[DWiggy]

A little advise from my own experience:
Get a track pump for home to inflate without stressing the valve out, as 100+ psi it hard to do with a hand pump without stressing the valve.
Co2 for repairs on the road..it's just altogether faster & easier!
Don't use the screws that you get with the inner tubes, you might be over tightening them and when inflating you could be putting the base of the tube under stress.
Use Velo rim tape and get rid of the old tape/band, this stuff is super cheap and really worth changing.

Hope this helps