Dual Valves?
- Thread starter rockyash
- Start date
Yeah I saw that but no one is saying anything.
Running 2 tubes seems odd because surely it would be heavier and roll worse than say just one heavy DH tube and even a half inflated tyre is going to ruin your race run. There's also the possibility that you pinch flat through both tubes at once anyway. It's the World Champs so there's no real need to do damage control for points, is getting 30th on a half inflated tyre really that much better than 50th on a flat, especially if it is slower rolling to start with anyway.
I thought they might be running one standard tube and then the other is a UST valve, so there effectively running a UST set up with some added protection against burping the tyre and losing air that way. Although neither really looks like a Mavic UST valve.
Either way they've got everyone talking so it could just be a brilliant marketing idea
Running 2 tubes seems odd because surely it would be heavier and roll worse than say just one heavy DH tube and even a half inflated tyre is going to ruin your race run. There's also the possibility that you pinch flat through both tubes at once anyway. It's the World Champs so there's no real need to do damage control for points, is getting 30th on a half inflated tyre really that much better than 50th on a flat, especially if it is slower rolling to start with anyway.
I thought they might be running one standard tube and then the other is a UST valve, so there effectively running a UST set up with some added protection against burping the tyre and losing air that way. Although neither really looks like a Mavic UST valve.
Either way they've got everyone talking so it could just be a brilliant marketing idea
cramhobart
Likes Dirt
I'm just guessing but is it an attempt to balance the wheel?
spinner
Likes Bikes and Dirt
That sounds like it. Only thing I've heard about this is that they are running tubeless (one valve) and using an inflatable internal beadlock (the other valve).I thought they might be running one standard tube and then the other is a UST valve, so there effectively running a UST set up with some added protection against burping the tyre and losing air that way. Although neither really looks like a Mavic UST valve.
I have no other info I'm afraid , but I know that some 4WD and moto people use them.
Welshy
Likes Bikes and Dirt
The GT mechanics ran the same thing on Hannah's bike at the US champs, where it was explained within limit.
One valve is for a UST conversion kit which isn't inflated. The second valve is for a lightweight tube. The rationale is that if they are to pinch flat the air from the broken tube will inflate the sealed tyre and lead him to an unimpeded run.
One valve is for a UST conversion kit which isn't inflated. The second valve is for a lightweight tube. The rationale is that if they are to pinch flat the air from the broken tube will inflate the sealed tyre and lead him to an unimpeded run.
Pretty sure Welshy is onto it.
Running a normal tyre + tube setup - the other valve is for adding sealant, thus having the sealant inside the tyre but outside the tube - if they were to pinch flat the air would just stay inside the tyre and they'd be able to (hopefully) keep on the pace and finish in a respectable time.
The only reason I can see for them not running a complete tubeless setup is so they can keep the pressures low: too low with tubeless and the tyre will be easy 'burp' out some air if they slightly dislodge the tyre from the rim.
Running a normal tyre + tube setup - the other valve is for adding sealant, thus having the sealant inside the tyre but outside the tube - if they were to pinch flat the air would just stay inside the tyre and they'd be able to (hopefully) keep on the pace and finish in a respectable time.
The only reason I can see for them not running a complete tubeless setup is so they can keep the pressures low: too low with tubeless and the tyre will be easy 'burp' out some air if they slightly dislodge the tyre from the rim.
Josh Seksy
Likes Bikes and Dirt
I'd agree with Welshy,
I've actually done a similar thing before, just to experiment.
I used a non-ust tyre (furious fred) on a ZTR Olympic wheelset.
Basically I fitted the tyre, filled with some selant, spun it to get it spread evenly, then fitted a superlight maxxis tube.
It worked to a degree, i did loose a bit of air when I pinch'ed, but thats because i don't think it leaked with enough pressure to seat the tire.
Before you ask why...
It was a road&mtb event, so obviously you needed a fast lightweight tire, with enough tread to ride ST, me being a big bloke, I wasn't going to take any chances!
-Josh
I've actually done a similar thing before, just to experiment.
I used a non-ust tyre (furious fred) on a ZTR Olympic wheelset.
Basically I fitted the tyre, filled with some selant, spun it to get it spread evenly, then fitted a superlight maxxis tube.
It worked to a degree, i did loose a bit of air when I pinch'ed, but thats because i don't think it leaked with enough pressure to seat the tire.
Before you ask why...
It was a road&mtb event, so obviously you needed a fast lightweight tire, with enough tread to ride ST, me being a big bloke, I wasn't going to take any chances!
-Josh
Ivan
Eats Squid
What Welshy has said is certainly plausible, and this is also a possibility,
http://www.tubliss.com/
http://www.tubliss.com/
Last edited:
el~rio
Likes Dirt
That looks like a really good idea, super low pressures with no chance of burping. But how would you get the inner bladder into the right place?
If it was tight enough, wouldn't it just move into place by itself?
Ivan
Eats Squid
Thats the idea. It's a very tight fit around the rim for the inner tube.
el~rio
Likes Dirt
That sounds right, I mustn't have been thinking
Burrito_Boy
Likes Bikes and Dirt
Oldschool Le’ System by Michelin anyone? Wasn't that a similar premise?
flamshmizer
Likes Dirt
Probably not, every rim i've owned the valve has been oposite the seam, so the pin and weld probably compensate for the valve stem. I reckon those people who run no valve caps actually throw the balance of their wheel out
Also the valve stems are off centre relative to the other. Would be interesting to know the story.
