ZIPP 340 valve stem

[duff_duffy]

Just picked up these wheels...ZIPP 340s, kind of old but like the look to them. The valve stem on it looks like this but is missing something! Can anyone enlighten me on what to order to get it to pump up? Thanks in advance -
Andy

[Vientomas]

Valve core?

[AngryScientist]

take those tires off and throw them out. i can see the dryrot from here.

that looks like a pretty typical cheapo valve extender to me.

https://images.amain.com/images/large/bikes/sram/00.1915.130.090.jpg?width=950

[duff_duffy]

Tires going too trash soon...want to just ride up and down block 1x to make sure no other odd issues with wheels. Bike and tires sitting for years, will be replaced but just never had to put valve core in and not sure if Zipp did anything odd years back. Maybe best just to replace tires first after all....

[AngryScientist]

Tires going too trash soon...want to just ride up and down block 1x to make sure no other odd issues with wheels. Bike and tires sitting for years, will be replaced but just never had to put valve core in and not sure if Zipp did anything odd years back. Maybe best just to replace tires first after all....

yea, those sidewalls look so bad that i'd be surprised if you got up to road pressure without a hemorrhage and sidewall blowout.

[cmbicycles]

No valve core for that extender, it just threads on the end of the normal presta valve. Hopefully the valve under the extender was left unthreaded before they put it on. You should be able to just put a pump on it and start putting air in, but, if nothing happens you may have to poke a small Allen into the valve to pop open the core, or the valve may be threaded closed, or it just may not hold air at all. If they hold air, I doubt a short spin up the block would be eventful, but I wouldn't put full pressure in unless they look better in person.

[duff_duffy]

thanks for feedback. Relooking at tires and listens to few replies am just going to trash them before riding. Front better than back but not much. Pretty cool wheels, Zipp rims to my favorite Record hubs. Swapping some parts around to build up something special coming in about two weeks. Come on DHL, deliver fast!!!

[duff_duffy]

Thanks for the tip! Just got it to inflate, keep your fingers crossed am going for a short ride with no turning;). Then will swap tires.

No valve core for that extender, it just threads on the end of the normal presta valve. Hopefully the valve under the extender was left unthreaded before they put it on. You should be able to just put a pump on it and start putting air in, but, if nothing happens you may have to poke a small Allen into the valve to pop open the core, or the valve may be threaded closed, or it just may not hold air at all. If they hold air, I doubt a short spin up the block would be eventful, but I wouldn't put full pressure in unless they look better in person.

[cmbicycles]

Hope you are able to post again after the test ride. ;) Nice that the wheels have Record hubs... 28h?

[Gummee]

thanks for feedback. Relooking at tires and listens to few replies am just going to trash them before riding. Front better than back but not much. Pretty cool wheels, Zipp rims to my favorite Record hubs. Swapping some parts around to build up something special coming in about two weeks. Come on DHL, deliver fast!!!

I built a few pair of 440s on Superbe Pro track hubs 'back when.' Raced em at the Sandy Eggo Velodrome.

Not as aero as the Firecrest, but hey! I'll bet the price was a lot lower than Firecrest too!

M

[oldpotatoe]

Thanks for the tip! Just got it to inflate, keep your fingers crossed am going for a short ride with no turning;). Then will swap tires.

When you get new tires, get the valve extender where you can reinstall the valve guts into the new long valve extender.

[joshatsilca]

Just picked up these wheels...ZIPP 340s, kind of old but like the look to them. The valve stem on it looks like this but is missing something! Can anyone enlighten me on what to order to get it to pump up? Thanks in advance -
Andy

Woah! That's a blast from the past! The 340 rim with that decal was made 1997-1999 and discontinued in 2000 when we went to an all-unidirectional carbon construction. That is an original valve extender of the era.. the type that just goes over the top of the valve core as back then even a lot of the available tubulars didn't come with removable valve cores!

When you have the tires off, inspect the spoke nipples from the tire side with a flashlight.. if the rims were built with aluminum nipples you might be at risk of galvanic corrosion under the nipple heads which would appear as a white powder when you look in there with your flashlight. Sometimes the corrosion creeps down the nipple and is visible from the hub side of the rim as well.

Josh

[carpediemracing]

I had both the 340s and 440s. Others can confirm this but Zipp made significant running changes on the rims during production, based on my calls to them while I sold the rims. Since the shop closed end of 1997 I must have only ordered them for one year.

My experiences with the rims is that you can't put too much tension on the spokes, and in fact the earliest 440s took very, very little tension before the rims split. This might be because I built them without washers? I don't know, but typical 28H 3x tension (and I built wheels with lower spoke tensions so I virtually never had an aluminum rim crack for me even after many years of use) would split my 340/440s. We weren't a big shop but did maybe 40-50 rims, most of them built on 24H hubs (Oschner seemed to have 24H Record hubs on sale for forever at the time).

I found that building the wheels with 16 drive and 8 NDS spokes worked well, the drive side didn't need as much tension, the non-drive side wasn't so loose that you had to use Loctite or similar to keep it from loosening. Since on-sale 24H hubs were cheaper than 32H, I didn't build many like that, but a lot of rims went onto existing 32h hubs.

Having said that my 340s were my favorite wheels for a while. As light as a Campy Record Crono rim (built 28H, on Record hubs) but more aero, so they were super nimble but got 1-2 mph in a sprint. My rear 340 split but I used a front for a few years.

340 front with a TriSpoke rear in action, circa 1997:
http://1.bp.blogspot.com/_TbmplkIYLx8/SxSWxbe1swI/AAAAAAAACVM/4Xyky-CNHDI/s800/Ninigret.jpg

As far as valve extenders go, I prefer the extenders that simply screw over the valve, like the one on the OP's picture. Even now I prefer them to the type that replace the core. Less chance of leaks while riding. My steps for those valve extenders:
1. Unscrew the presta "nut" at the top of the valve as firmly as possible without unscrewing or breaking the valve. I use pliers and a low amount of force, probably similar to a stem bolt torque.
2. Screw on adapter.
3. Check to see that valve will open normally (pump air into it).
4. Carry a pin of some sort around (2mm Allen wrench?) to poke the valve.
5. If you have to "re-unscrew" the presta nut (somehow it worked loose), you can put the valve extender upside down onto the nut, press hard, and unscrew. It'll unscrew the nut.

I could see that not working on dirt roads but I've ridden extenders on roads (races) with potholes so bad that many riders' bars/stems turned, and I never lost air from such a valve set up.

[oldpotatoe]

I had both the 340s and 440s. Others can confirm this but Zipp made significant running changes on the rims during production, based on my calls to them while I sold the rims. Since the shop closed end of 1997 I must have only ordered them for one year.

My experiences with the rims is that you can't put too much tension on the spokes, and in fact the earliest 440s took very, very little tension before the rims split. This might be because I built them without washers?

No idea of when but zipp removed the aluminum strip nipple seat, that the nipple pushed against and after that, many zipp rims pulled eyelets out when building(ask me how I know)...