tire pressure releif valve

[eprx799]

Does anyone have any info on these? There are no markings on them. I have them in a set of panasports and want to replace them. I bought them off of this forum about a year ago and am just getting around to using the wheels.

 

[Matt Blehm]

With just a glance, they look like these guys..
http://www.longacreracing.com/products.aspx?prodid=7366

 

[Jonathan Spiegel]

Just a bit of personal experience - these may work well for some circle track guys, but I have found that if you end up pushing hard for several laps, these will bleed off excess pressure buildup, but once you get back in the groove, your tire pressures are now lower than they should be, with no way to get it back. Plus, I hate anything that may allow a leak at some point -