crazyal
Super Member
Good valve stems are made from Ethylene Propylene Diene Monomer rubber, or EPDM for short. It's a synthetic rubber. China is making cheap ones made from natural rubber and like cheap tires will dry rot very fast. Unlike those cheap tires stems don't have any cords inside to reinforce them. Most shops just cut them off and replace them every time they change a tire. Of course with the tire pressure sensors being mandated the future of stems is in real question.
If you bend the stem with your hand and see cracks or if you hear air leaks then replace them. I have one of those el cheapo HF tire changers, works great for this as you only need to dismount the front side of the tire. By doing so you don't mess up the balancing.
But I don't think it's all valve stems. Years ago after driving about 100 miles I watched one of those small 8" tires just explode after sitting for 10 minutes.
The metal stem come in two different styles (or maybe more). There's one style that's all metal with a rubber washer that goes on both sides of the wheel and another style where it still has the usual "pop in" style base, I think they are a TR600. The all metal ones are fine but if they get hit they have no give.
I think your tire guy is off a little though. I think the standard stems are rated for 60 psi, not 50, it's an industry standard. If he's so worried about the stems then he could easily find and buy the EPDM TR600 stems, they only cost a few cents more so it's not like he would be loosing money. Plus he could put up a sign saying "we only use high quality high pressure valve stems" and put up several articles showing why the cheap ones are bad. Who here hasn't spent a half hour in a tire shop waiting for them to swap tires?
http://en.wikipedia.org/wiki/Diene
If you bend the stem with your hand and see cracks or if you hear air leaks then replace them. I have one of those el cheapo HF tire changers, works great for this as you only need to dismount the front side of the tire. By doing so you don't mess up the balancing.
But I don't think it's all valve stems. Years ago after driving about 100 miles I watched one of those small 8" tires just explode after sitting for 10 minutes.
The metal stem come in two different styles (or maybe more). There's one style that's all metal with a rubber washer that goes on both sides of the wheel and another style where it still has the usual "pop in" style base, I think they are a TR600. The all metal ones are fine but if they get hit they have no give.
I think your tire guy is off a little though. I think the standard stems are rated for 60 psi, not 50, it's an industry standard. If he's so worried about the stems then he could easily find and buy the EPDM TR600 stems, they only cost a few cents more so it's not like he would be loosing money. Plus he could put up a sign saying "we only use high quality high pressure valve stems" and put up several articles showing why the cheap ones are bad. Who here hasn't spent a half hour in a tire shop waiting for them to swap tires?
http://en.wikipedia.org/wiki/Diene
