I was wondering if anyone has used these and if they had problems? My Wife purchased a Norco CCX this spring and she has had problems with the tubes going flat. They are Axiom 700x28/32C with presta valves. She or sometimes I inflate them to 80psi. She had left the bike in the back of the van on a hot day and they blew. When she did it again she deflated them, then reflated later and went for a ride and they blew again. She rode into work this morning, left the bike at the rack under tree's all day. We went to pick it up and the front tire blew. It was good when she left it. I was wondering if anyone had heard or had these problems. As well, if anyone had any suggestions for a better brand of tube. Thanks!
Axiom Bicycle Tubes
Posted 05 August 2011 - 05:36 PM
Tubes are simply membranes to seal air. But they can't hold any pressure.
Take a tube and inflate it outside the wheel and it will burst pretty quickly. A tube is just like a toroidal balloon. It is the tyre and the rim (and the connection between them) which must provide the strength to hold the air pressure.
Blowouts usually occur for two reasons:
- The tube was not contained properly in the tyre. Part of it may have been pinched under the tyre bead which can led to it blowing the tyre off the rim (whence the tube blows itself). This is often caused by improper installation of the tube, or use of the wrong size tube for the tyre. When fitting a tube you should be careful to squeeze the beads of the tyre in and check that the tube is completely under the tyre all the way round the wheel.
- Tyre bead issues. Some tyres have fairly loose beads and if they aren't seated correctly the bead can come loose (I had this happen to me at work - careful reseating solved it). Also, a defctive tyre may never make a proper rigid connection with the rim hook.
But it is most definitely not the fault of the tube.
- Reid2 and like this
Posted 07 August 2011 - 10:16 AM
+1 on Tafi's response for the most part tubes aren't responsible for flat tires, sure there's the occasional tube with the bad valve core or that separates where the valve meets the tube, but the kind of blowouts you're describing are almost certainly related to issues with the tire, rim or rimstrip.
Based on your post above I suspect you know that leaving a fully inflated tire inside a hot car often leads to blow outs as the hot temps force the tube pressure up above the max pressure ratings and the tube blows out as the tire blows off the rim. So letting some air out of your tires before storing them in hot places is a good idea, but don't let most or all of the air out or you greatly increase the risk of pinching some of the tube between the tire bead and the rim which will lead to a blowout during or shortly after reinflating the tire. Yes you can and should reduce this risk by carefully checking the tire all the way around as Tafi advises prior to fully reinflating the tire. But better yet, just let out some of the air and leave the tire mostly inflated so it holds its shape and isn't easily pinched when leaving the bike in hot enclosed places.
The other flats your wife is having suggest that there's something else going on. Perhaps there's a bit of debris like a small shard of glass or thin wire strand stuck in the tire that's causing repeating flats or perhaps the rim strip is damaged and not reliably covering the spoke heads which can easily cause the kind of problems she's having. Or perhaps the tire doesn't fit the rim well and is prone to either blow outs or to pinching the tube when pressure is reduced, this happens on some larger commuting and touring tires that are very easy to mount on the rims but might require some care to seat the beads well and can be prone to pinching the tube.
I'd remove the tire and carefully inspect everything starting with the rim strip and how well the spoke heads are covered as well as carefully inspecting the rim itself for sharp burrs or edges that might be causing flats, this can happen if she dinged the rim hitting a pothole or curb when the pressure was low (or during one of the blowouts). Then I'd very carefully inspect the inside of the tire with my fingers and eyes checking for anything sharp that's embedded in the tire itself, small wire strands are common culprits for repeating flats. If everything is good then remount the tire with a fresh tube but pay careful attention to how snug the tire fits, how well the bead seats when reinflating and how much or little the tire tends to trap the tube and how much you have to work to carefully avoid tube pinches. If the tire mounting is harder than usual (compare the same process to tires on your bike that presumably don't blow out regularly) then consider a new set of tires for her bike.
If all that doesn't make sense then take it to a good local bike shop and explain everything that's happened and have them take a look at the situation.
- Reid2 and like this
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