In a word, brilliant.
Completely overthought, over engineered and over-built…and I say all that as a compliment.
Well done, Josh.
true aeroweenies will see that rubber bit in the middle and think “PRAISE SCIENCE”
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Thanks everybody! This one was a long time coming and as with most products, seems so simple and yet nearly killed me trying to get it just right.
The very cool side effect of these extensions is that you have to size them correctly, and when you do, you only have as much valve protruding as you need…so there is a very real aero benefit for most people compared to most baseline setups, also it was seen in the tunnel (not my test, done by a company testing these for potential OEM use) over a 3 run average that the ribbed extender seemed to reduce drag and wattage to spin ever so slightly compared to a smooth extension…not selling on aero side-effects just yet, but seems likely.
As a blatant plug, please be sure to tell your local tri/bike shop how necessary this invention is!
Thanks to all, as with many ideas, this one was very much inspired by issues voiced on ST.
J
The very cool side effect of these extensions is that you have to size them correctly, and when you do, you only have as much valve protruding as you need…so there is a very real aero benefit for most people.
J
Hey Josh. What sizes would you recommend for a Flo 60 and a Flo 90, both with a 51mm RVC tube?
I’ve done the math and just figured it wouldn’t hurt to double check before completing my purchase.
Scott
I’m a fan of all things overthought, overengineered, and overbuilt… but sadly these didn’t work with my Zipp 404 and Vittoria Latex 51mm stem combo :-/
What size did you use on your 404’s?
I want to use these on my 808’s with the same 51mm vittoria latex tubes.
Josh, Any idea if I could get these to work properly in that setup and if so what size extender?
51mm tubes have really complicated things as they put the valve threads more or less at the inner edge of rims in the 55-60mm range. 32, 37 and 42mm tubes are by far the most common and we have solutions that will work with any of those on rims at this depth. On the upside, the rubber sleeves are more aero than smooth, they will damp noise even if they don’t eliminate it and they look awesome on your wheels, but as you can see in the picture, the flats and threads on the bottom of the extension are in the rim hole where you would want the gasket to be and the threads are about 2mm below that because the valve is just too long.
We are working on a cross-reference guide to help with this, but it has been incredibly difficult to get actual valve stem lengths from everybody as well as tire well depths from the wheel manufacturers…but we will get there.
I had been wondering about the possibility of cutting the Vittoria 51mm valve stem down and then using a tap to rethread the shorter stem for the RVC (This was for more clearance on my Zipp disc). When I went looking for RVC threading info I couldn’t find a clear answer on diam, thread count, etc. I’m sure you have this worked out. Are there taps available on the market for this spec or are is this something totally custom?
A second question for you Josh. I couldn’t find a contact link on your Silca page. Can you offer the Silca CO2 valve as a standalone item w/o the CO2’s for those of us that live where they can’t be easily shipped?
Thanks
Ircanuck, I used the 34mm RVC extension. As Josh said, it’s not so much a problem with the valve extender, the 51mm stem is just too long. The interface between the valve stem and the extender is almost at the rim. You shouldn’t have any issues on your 808’s. The real problem is the lack of latex tubes with shorter valve stems and a removable valve core. Perhaps SILCA could get into making latex tubes???
Here are the latex RVC tubes I know of (clue me in on any others):
Challenge - 47.5mm
Vittoria - 51mm
Bontrager - 51mm
Vredestein - 52mm
Josh, are your new extenders for removable valve core tubes?
Thanks Summit!
There is not such thing as a commercially available tap for the internal Presta thread, at least not that we’ve ever found, we have to have ours custom made.
Please email us at sales@silca.cc we for your other question, we have a solution for those outside the Continental boundaries!
Best
Josh
Hi Josh,
For latex tubes users with 404 / Enve 6 / Het Stinger or Jet 6 and so on the problem is that if you want to use latex tubes you have a choice between Michelin tubes without removable cores or Vittoria / Bontrager / Vredestein tubes which are all 51mm with removable cores. I don’t know of any option for a latex tube with a shorter valve lenght and removable core, do you ?
Not your fault at all… but just wanted to let you know you might face this situation with latex tube users on intermediate depth rims… maybe you need to offer a super high quality Silca latex tube ? 
Thanks everybody for the info…this is something we are working on but don’t have a solution for at the moment for these longer valve stem on mid depth wheels.
DamonHenry: we make both RVC and standard extensions.
Is the threading 10-40? I measured out the valve treading and it appears to be 40tpi, but I am unsure if it is size 10.
I can’t remember the diameter callout, but it’s a BSC profile thread so the major/minor diameters don’t quite line up with anything standard. There is also a critical taper in the few mm below the thread which is necessary to seal the valve core. We use a custom pre-drill followed by a custom bottoming tap so as not to risk scoring the sealing surface.
J
Is the air seal better? I think $34 is worth it just for that (even if I run 60s with latex tubes).
We use a thread-seal coating on all threads of the extensions. The RVC extensions get a clear coating that is about the viscosity of acetone, a tiny dropper drops it on and it wicks around like magic…pretty cool stuff. That in combination with the rubber seal makes the RVC version completely bullet-proof. On the tube type universal extensions, we use a high viscosity white thread-seal which is quite similar to Teflon tape, but we apply it as a liquid so that the inner thread is fully coated. We also have little custom sized O-rings that drop over the presta valve before you install the RVC…sort of a belt+suspenders approach to the problem, but between the two, they cannot leak, and they will not loosen up over time.
We use a thread-seal coating on all threads of the extensions. The RVC extensions get a clear coating that is about the viscosity of acetone, a tiny dropper drops it on and it wicks around like magic…pretty cool stuff. That in combination with the rubber seal makes the RVC version completely bullet-proof. On the tube type universal extensions, we use a high viscosity white thread-seal which is quite similar to Teflon tape, but we apply it as a liquid so that the inner thread is fully coated. We also have little custom sized O-rings that drop over the presta valve before you install the RVC…sort of a belt+suspenders approach to the problem, but between the two, they cannot leak, and they will not loosen up over time.
I asked a fellow member so it wasn’t coming from someone who profits off the product… but with that said, you fully back it money back guarantee?
I’m in the ‘tweener’ with these extensions as well. I’d gladly pay $34 for either RVC or regular extensions to cure the rattling on my Enve 45s, but I too use Victoria Latex tubes and looks like the anti-rattling material would be at the same height as the 404s pictured above.