Cut valves on Lafree

[prState]

I realize this is a tire problem, and not specifically electrical. I've done two replacements on the rear tire tube and the valves have gotten cut at the base, ruining the brand new tubes.

The first one was definitely crooked, and I didn't notice until too late, the second most definitely not. I rode it 3 miles and it suddenly released all the air. I can't really see what is doing this. Is it possible the edges around the valve tube hole have become sharpened. Would loose spokes cause the tire to warp as you ride thus shifting the tube and cutting the valve?

Any other ideas?

The rim is 26 x 1.5, the Tube is 26 x 1.5 -1.75, the tire is 26 x 1.75

thanks

 

[Beeping-Sleauty]

bah humbug

I realize this is a tire problem, and not specifically electrical. I've done two replacements on the rear tire tube and the valves have gotten cut at the base, ruining the brand new tubes.

The first one was definitely crooked, and I didn't notice until too late, the second most definitely not. I rode it 3 miles and it suddenly released all the air. I can't really see what is doing this. Is it possible the edges around the valve tube hole have become sharpened. Would loose spokes cause the tire to warp as you ride thus shifting the tube and cutting the valve?

Any other ideas?

The rim is 26 x 1.5, the Tube is 26 x 1.5 -1.75, the tire is 26 x 1.75

thanks

could it be the valve not centered in the valve hole ? or perhaps a ragged edge on the valve hole ? this can happen if the thread of the valve is scraped against the valve hole and burring up a sharp edge ? maybe the inner liner tape off centre ? if it's happened twice, i'd be inclined to get the tyre & tube off the wheel and have a good look at the hole with a lens, perhaps using a tube with a threaded lock ring to secure the valve in the hole might help. schwalbe do a good one.

 

[flecc]

The thin Presta valves originally intended for high pressure slim tyres on sports bikes are more inclined to do this in lower pressure applications, and as I always do, I drilled the holes on my Lafree to fit Schraeder valve inner tubes.

However, run the checks Beeps suggested, since this shouldn't be a recurring problem.
.

 

[prState]

Thanks! I think I'm going to take it into the bike shop today. I just can't see what's wrong.

I think now, it may have destroyed the original tube the same way of these two new ones. 'Cause when I took that tube out I expected to see a hole (it ruptured with the sound of loud bang). I was out on the road, and just assumed I wasn't seeing the hole in the tube, but I bet it was also around the valve.

 

[prState]

Well, I got the wheel trued (and another new tube) and have put about 6 miles on it without a problem.

So, maybe that was it? I rode 4 years without doing anything to the wheel since I bought it. Perhaps it had just curved with loosening spokes in such a manner to create a motion of the tube enabling it to be cut at the valve insertion point. Or maybe I just got faulty tubes, but I don't know for sure.

Anyway, the wheel rotates in a nice straight line now!

I should probably get the front wheel done as well!

Also, I have a new tire, a Continental Travel Contact (safety system) which I like just fine. Very smooth down the center contact patch for street riding, but some tread on the outer edges for gravel when you sink in a bit.