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Dumb Question about Zipp 303's(10 posts)

Dumb Question about Zipp 303'sberni
Jan 28, 2004 9:41 AM
I recently acquired a set of Zipp 303 tubulars with Vittoria tyres already attached. The Presta valve is just visible below the rim surface (38mm deep).

I realise that to inflate the tyres I need a valve extension, but my question is this....

Once inflated does the extension come off? i.e. do you ride with it on? If not, how is it possible to screw down the Presta valve so that air will not leak from it?

If the extension is supposed to stay on, surely this is a significant weight on the rim that helps to offbalance the wheel?

I never used tubular wheels before so hence the ignorance!

re: Dumb Question about Zipp 303'streebound
Jan 28, 2004 9:53 AM
I can't reply to what others do with the extensions because my rims aren't deep enough to need them, yet.

But I will say that you should probably peel off the tires and reglue them on with fresh glue, unless you are absolutely certain that the current glue is fresh and that the previous owner of the wheels did a proper job of gluing.

YMMV, but crashing always sucks.
re: Dumb Question about Zipp 303'srogue_CT1
Jan 28, 2004 10:19 AM
Yse, you should remove the valve extension after you use it. In my experience they can loosen and fall off while you are riding.

But, a better way would be to remove the tire as the other poster recommended and get a set of Vitoria valve extenders. Then follow the directions and remove the valve core from the tire and install the extension. Then install the valve core on the end of the extension and you will have a fully functioning valve that will give you an accurate pressure reading. This is the best way to deal with deep section rims.
re: Dumb Question about Zipp 303'sMShaw
Jan 28, 2004 10:32 AM
To everyone but the OP: Lets see: you want a LIGHT rim and want to go add a chunk of metal to it? Hmmm...

I've got two pair of 404s and one 340 rear wheel. They all use valve extenders that I remove after use.

Presta valves by their design are held closed by the air pressure inside the tube. The little brass nut on the top of the valve is "just in case." Leaving the little nut undone doesn't affect the air holding at all.

The 340/303 rim is shallow enough that you should be able to screw the nut up and down far enough to make it useful as a security measure. Just get a short valve extender and keep it with you when you're out riding. I've got mine taped to my CO2 cartridges.

Make sure that you bring a spare when out riding! I normally bring a tube of Tufo tire sealant too. Always easier to try the Tufo goop first... If that don't work, THEN strip the old tire off.

That help?

re: Thanks alot, but...berni
Jan 28, 2004 12:44 PM
Hey, maybe I'm missing something here, but wouldn't it be alot easier if the tyre (or tube) manufacturers just made their valves longer?

That way, no hassle with extensions, right?

Or is it not that simple?!

(by the way, for what it's worth the wheelset is about 1750g, including the tyres, 20/28 spoke).

Anyway, thanks for the help!
leave the valve extenders onSuds
Jan 28, 2004 1:31 PM
and the presta valves open for the common extender that screws over the existing valve. The nut on the valve is just backup seal as stated above. Vittoria Corsa tubulars have a latex tube, so you are going to need to check your pressure before every ride. Just keep in mind that the only way to release pressure from the tire once the extender is there - is to push a paperclip or 2mm allen wrench into the extender.

A second option, one that I recommend, would be to purchase the Tufo valve extenders. With these, you remove your presta valve, screw the exteder into the tire(tube) and then attach the presta valve onto the extender - essentialy creating a long stemmed tubular tire.
I've seen tubes with longer stems buttreebound
Jan 28, 2004 1:46 PM
but not sure about tubular tires with a longer stem option.

Rummage around on the Tufo site some and see what you find.
This page shows an extenter:
re: Dumb Question about Zipp 303'sBob1010
Jan 28, 2004 3:59 PM
Very simple...Use the Zipp valve extensions.. as I have used many others that seem to be smaller in diameter. Use plumbers tape around the valve stem with the valve fully open..then take a needle nose and slighly open the valve a tad more which should lock the valve open. Take the valve extension (Zipps will use a allen to tighten)with the plumbers tape in place and screw the extension on and leave on..It is about 30mm in length and when you need to let air out use a small nail.. which is almost never no big deal..Problem solved.
re: Dumb Question about Zipp 303'sNo_sprint
Jan 29, 2004 7:09 AM
I use a little loc tite on my plastic extensions, leave them on.
re: Dumb Question about Zipp 303'sJohn445
Jan 29, 2004 8:07 AM
I agree with the above posts stating to leave the extension on. I have 404's and if I don't use teflon tape and screw the extension on mechanically it is impossible to get 120lbs of air pressure without leakage at the joint.