Hey all, either reassure me I'm not an idiot, or crush my delusions of competence and explain to me how this Silca pump chuck works on a Presta valve.

The brass tip threads beautifully on to a Schrader valve, but it's much too wide for a Presta, there's no seal. I bought it off eBay and the seller listed it as Presta compatible, but there's no way I can figure to make this pump fill a tube with a Presta valve. And yes, I've reversed the plastic insert and tried it both ways.

My thoughts are that this is a Schrader chuck or the seller failed to include the leather washer. Worst case scenario I'm just kind of dumb.

I can't tell for sure from looking at your pictures. As a general rule, after disassembling the chuck, you reverse both the white plastic piece and the black rubber one. Then you reassemble the chuck.

there is a separate part for presta that threads into the schrader stem thread

It is a variation on their push on bell shaped air chuck, with threads like schrader stems,

instead of barbs to push into the end of the hose..

you are missing that part of the combination. the seller shorted you that important part.




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As a temporary fix, go to the nearest bike shop and buy a presta to schrader adapter. Looks like this one Presta to Schrader Bike Valve Adapter Genuine Innovations MTB / Road Valve Stem | eBay You can buy them from overseas sellers for a buck each but you don't have time to wait for them to get here.

I have a couple of pumps that work on both valves. The little rubber piece that fits in the pump head is reversible with a large hole on one end for schrader and a smaller opening for presta on the other end. You just flip it around to change from one valve to the other.

Mine isn't exactly like yours but see if there are similarities. The middle brass section flips over. One side is schrader and the other is presta. See if yours is similar. Worse case is you buy a new head. I have had my Silca for about 30 years and I just overhauled it.