Presta valve material

[Rexlion]

My Presta valves (on new Yamaha ebike) are a shiny silver color. Is it at all safe to conclude that they are anodized aluminum? Or do valve mfrs produce silver-plated brass valves? I'd like to get some Presta-to-Schrader adapters and leave 'em on the valves, but I know that attaching the dissimilar metals aluminum and brass together would cause galvanic corrosion (unless a preventive coating is present). I can buy adapters made of either brass or aluminum, so I'm debating which type to get. Maybe the shiny silver I'm seeing is enough to prevent corrosion, though. What say you all?

Why this is on my radar: I run TST external tpms sensors on my vehicle's tire valves. TST uses brass. One time the tire store used aluminum valve stems instead of the usual chrome-plated steel, and the sensor welded itself onto the valve.

 

[Aushiker]

Take this with a grain of salt, but my understanding is that Presta valves are generally made of aluminium, whereas the Schrader valves are made of brass, as you found out.

 

[stompandgo]

Good quality Presta tubes have valves that are nickel plated brass. Just grease the adapters before installing them and you should be fine.

 

[Rexlion]

Sounds like I am not going to be able to tell visually. Okay then... I'll use some anti-seize stuff or something.

 

[harryS]

I've kept brass Shraeder adapters screwed on the Presta tubes on two bikes for ten years now. They're always being screwed on/off to check tire pressure. Never worried about them binding,

 

[Rexlion]

I've kept brass Shraeder adapters screwed on the Presta tubes on two bikes for ten years now. They're always being screwed on/off to check tire pressure. Never worried about them binding,

That's the thing: when they're being removed and reinstalled on a regular basis, they don't have time to weld into place from galvanic corrosion. It's when aluminum and brass are kept mated for at least a few months that they can bond to one another. I write this as a PSA for those who don't know, because it was a $$$ lesson for me on my motor vehicle; the pressure sensor I'd installed on the valve wound up being ruined along with the valve stem when it came time to R&R the sensor's battery, because it would not come off for anything. Similarly, if this happened on a Presta valve, one would have to saw the valve off in order to change the inner tube.

 

[harryS]

An after market sensor on a car has to be (a) real tight and (b) sloshes thru rain/slush 24/7. My adapters are on finger tight. The valve stem underneath is screwed down to hold the air, and they always leak, hence a check before almost every ride, Plus they don't see winter conditions when they are undisturbed for months, sometimes years, if not ridden.

You can also put one pliers on the stem of a presta valve and a second one on the brass adapter if finger torque isn't enough,