Bicycle Mechanics - Silca pump - how does air chuck lock on stem?

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oldokie
12-30-06, 06:13 PM
The Silca air pump appears to have a "press-on" style of presta connector to the tube stem. Since it does not have a thumb lever to lock it on the stem, are you required to hold it in place when adding air or is it able to stay in place on it's own?

rmfnla
12-30-06, 06:17 PM
Nope. Just jam it on and pump away.

Don't forget to unscrew the Presta thingie!
HillRider
12-30-06, 07:08 PM
Are you describing the Silca Floor pump? The Presta-Only chuck is a friction fit on the valve stem and relies on the tight rubber washer in the chuck to keep it in place. If the washer is in half decent shape, it will easily reach 120+ psi with no blow-off problems. When the washer is badly worn, it can be replaced for about $1 at nearly any bike shop.

I have an old Silca floor pump that's used 3 or 4 times a week for at least 10 years and is only on it's third chuck washer.

oldokie
12-30-06, 07:23 PM
Thanks. I don't have a Silca pump but I was looking to order one of the Silca air chucks for so I could make up a bike specific air hose for my compressor. Was not sure how it stayed attached while I was busy controlling the air pressure.
rmfnla
12-30-06, 07:23 PM
Are you describing the Silca Floor pump? The Presta-Only chuck is a friction fit on the valve stem and relies on the tight rubber washer in the chuck to keep it in place. If the washer is in half decent shape, it will easily reach 120+ psi with no blow-off problems. When the washer is badly worn, it can be replaced for about $1 at nearly any bike shop.

I have an old Silca floor pump that's used 3 or 4 times a week for at least 10 years and is only on it's third chuck washer.

Good point; I did assume it is the floor pump. What a classic!

Yours is 10 years old? It's barely broken in!
cmh
12-30-06, 09:43 PM
I just got a Silca pump for xmas! Woo hoo!

I have pumped up 6 tires so far.
Retro Grouch
12-31-06, 05:55 AM
Are you describing the Silca Floor pump? The Presta-Only chuck is a friction fit on the valve stem and relies on the tight rubber washer in the chuck to keep it in place. If the washer is in half decent shape, it will easily reach 120+ psi with no blow-off problems. When the washer is badly worn, it can be replaced for about $1 at nearly any bike shop.

There's actually a bit more to it than that.

That big brass "thingie" that holds the rubber washer in place is threaded. When the chuck is new, it's not threaded on very much. As it wears so that the chuck fits onto the valve stem too loosely you can tighten it up about 1/8 turn and make it work for a very long time.