Zipp disc valve hole - how to make it bigger??

[cycledogg1]

I currently have a 2005 Zipp 909 wheelset which is a rear disc and a 404 front, both tubular. I have struggled getting air into the rear using the "crack pipe" air chuck. But the hole for the valve is about 1/4" too short to do this correctly without losing some amount of air trying to remove the air chuck. If the hole was about 1/4" longer it would work fine. I thought about using a Dremell tool and grinding the hole larger but I am afraid it may splinter the carbon at the edge of the hole. Any experience with this problem or suggestions?
Cheers,
Rick in Tennessee

 

[CAMPYBOB]

Before taking a Dremel to a high dollar wheel, I would email or call the tech folks at Zipp. You wouldn't believe the number of very expensive firearms I've seen ruined by a Dremel tool in the hands of well-meaning owners.

Using a fine burr and following up with a sanding drum might do a nice job job on material removal. Nail polish can be used to seal any exposed carbon, but I would want to know that the material removal did not structurally affect the wheel.

 

[Pat Stowe]

I "hear" voided warranties. Would a valve extender/extension help?, I've heard Vittoria for makes them for one

 

[alienator]

I currently have a 2005 Zipp 909 wheelset which is a rear disc and a 404 front, both tubular. I have struggled getting air into the rear using the "crack pipe" air chuck. But the hole for the valve is about 1/4" too short to do this correctly without losing some amount of air trying to remove the air chuck. If the hole was about 1/4" longer it would work fine. I thought about using a Dremell tool and grinding the hole larger but I am afraid it may splinter the carbon at the edge of the hole. Any experience with this problem or suggestions? Cheers, Rick in Tennessee

Did they have a clincher 909 back than? No matter. Can you use a tubular or inner tube with a smaller valve? Vittoria might be a tire to look at since they use interchangeable valve stems on their tires, now. I would also check with Zipp to get their input. I'd holster the Dremel until you exercise at least one of those options.

 

[alfeng]

FWIW. I believe that Pat Stowe is correct about "valve extensions" being an option which should be considered ...

• IMO, "valve extensions" are probably the best option short of buying sew-ups which have longer stems BECAUSE you won't have to source a specific tire in the future

• BTW. I recall some people having problems with valve stem extensions leaking ... if that turns out to be the case, then cut a gasket from an old inner tube OR other pliable material -- punch-or-cut an appropriately small diameter hole in the over-sized piece, insert between the stem & the extension, trim the excess with scissors or a sharp blade ...

Since I am apparently no longer worthy of being on EXCEL or COLORADO CYCLIST's mailing list (Hmmm, same for PERFORMANCE, et al), the only catalogs which I receive are when they pack one in a shipment that I may receive ... but, in the past, they both used to carry the "valve extensions" which should help you to solve your problem.

 

[swampy1970]

Buy a new one of these: http://www.wheelbuilder.com/silca-presta-adapter-for-disc-wheels.html Silca make some of the best pumps and accessories, period. In almost three decades of cycling I've only come across one pump that's better than the classic Silca. I've used the Silca disk wheel crackpipe and it works well.

 

[cycledogg1]

Perhaps my question is mis-understood. The wheel set is TUBULAR. The valves on a standard tub is too long for the "crackpipe" pump head to fit in the cut out hole of the disk wheel. I am using Tufo tires which tend to have a shorter than usual valve, about 32mm as opposed to the 34mm that most tubular and clincher tubes are. So, as of now, I have to wiggle the pump head (which is by Silica specific for disc wheels) onto the valve and when finished pumping the air into the tubular, I have to wrestle the pump head off. When doing so I loose air and then not sure of the psi. It's a real hassle due to the small opening on this wheel. If the opening was longer it would allow the pump head to move up off the valve more without interfering with the release pin on the valve. I may call Zipp but since this wheel is over 6 years old, a warranty issue is out of the question. Perhaps it's an issue I will just have to live with.
Cheers,
Rick in Tennessee

 

[swampy1970]

You need to replace the tubular with one with the correct valve stem length. Hacking up a $1000 wheel because your $60 tire has a valve stem that's too long is just silly.

 

[Halfnote]

Originally Posted by swampy1970 .

You need to replace the tubular with one with the correct valve stem length.
Hacking up a $1000 wheel because your $60 tire has a valve stem that's too long is just silly.

In today's age you can't find tubulars with a long valve? Seems like everyone is running high rims now days. That's the best thing to do.

I'm a machinist, and I have done lots of work on carbon fiber racing parts for cars.

IMHO, unless you can disassemble the wheel and securely mount it in some sort of workholding device, I wouldn't touch the rim with with a carbide burr. Burr's are intended to run at very high rpm's and for what you are describing you would want to go very slowly as well. You would want to be sure you were on the center of the hole too. If it's not done properly, you could eat up your rim.

What I have done on small holes I have had to drill is to cover the area to be drilled with electrical tape. Then I run a carbide drill at a very high RPM. Depending on the diameter of the drill to be used.

If you really want to try it on your own, I would suggest looking for a small diameter grinding stone or a small diameter sanding drum for a dremel tool. Still cover the work area with a piece of electrical tape and cut out the existing hole in the tape with a X-acto knife. This may help to minimize splintering. Then you can take some nail polish to seal the edges when you are finished. A fine grinding stone and or a sanding drum will not grab material like a burr would. and if you run the dremel slow to start, then you won't remove too much by accident. You would want to make sure to use a tool smaller than the diameter you will be working. Try to hit it by hand with an on size cutter you will damage the rim.

I would not venture this unless you feel completely confident in your abilities though. I do this stuff all the time, and IMHO it would be too risky without the proper equipment and procedure to perform the work.

 

[daveryanwyoming]

Here's someone that did exactly as you're thinking. But I'm with others that a tubular with a shorter valve stem is a better option if possible.

http://forum.slowtwitch.com/gforum.cgi?do=post_view_flat;post=4058897;page=1;sb=post_latest_reply;so=ASC;mh=25;

 

[swampy1970]

In today's age you can't find tubulars with a long valve? Seems like everyone is running high rims now days. That's the best thing to do. I'm a machinist, and I have done lots of work on carbon fiber racing parts for cars. IMHO, unless you can disassemble the wheel and securely mount it in some sort of workholding device, I wouldn't touch the rim with with a carbide burr. Burr's are intended to run at very high rpm's and for what you are describing you would want to go very slowly as well. You would want to be sure you were on the center of the hole too. If it's not done properly, you could eat up your rim. What I have done on small holes I have had to drill is to cover the area to be drilled with electrical tape. Then I run a carbide drill at a very high RPM. Depending on the diameter of the drill to be used. If you really want to try it on your own, I would suggest looking for a small diameter grinding stone or a small diameter sanding drum for a dremel tool. Still cover the work area with a piece of electrical tape and cut out the existing hole in the tape with a X-acto knife. This may help to minimize splintering. Then you can take some nail polish to seal the edges when you are finished. A fine grinding stone and or a sanding drum will not grab material like a burr would. and if you run the dremel slow to start, then you won't remove too much by accident. You would want to make sure to use a tool smaller than the diameter you will be working. Try to hit it by hand with an on size cutter you will damage the rim. I would not venture this unless you feel completely confident in your abilities though. I do this stuff all the time, and IMHO it would be too risky without the proper equipment and procedure to perform the work.

In today's age? You mean in the age where all the pro peloton still runs rear disks - just like they have since 1985? Stop being a lazy f**k and make a couple of phone calls and buy the correct tubular. Randomly machining parts just because you can't find a tire with the corrrect valve stem is effing stupid. I think it'd take no more than a couple of minutes to source the correct tire... Maybe I should suggest that you first machine away 99% of each bolt holding on the faceplate of your stem. Leave a note in your back pocket that says "I'm a dolt, leave me to bleed"

 

[dhk2]

Originally Posted by daveryanwyoming .

Here's someone that did exactly as you're thinking. But I'm with others that a tubular with a shorter valve stem is a better option if possible.

http://forum.slowtwitch.com/gforum.cgi?do=post_view_flat;post=4058897;page=1;sb=post_latest_reply;so=ASC;mh=25;

Good photos, but that looks like exactly the wrong place to be removing a lot of material to me. Have no idea how the safety and life of this highly-engineered and expensive wheel has been affected, but I'd not care to experiment on my own wheel. Would be interesting to see the reaction of the Zipp technical guys to this handy little modification.

 

[CAMPYBOB]

Dremel-machining pics shamelessly stolen from Dave's slow twitch link because so many people seem to be confused as to WTF is going on in this thread.

And yes, a Dremel tool WILL work for the guy that doesn't own a Bridgeport or Gortom mill, mill vise and tooling. It DOES take a steady hand, careful layout and masking. Like I said, I've seen more $2,000 rifles and handguns turned into $500 pieces by well meaning, but totally clueless owners than I care to remember.

Before pic. Notice there is NO CLEARANCE for pump chuck. Notice also that a $1,000-$2,000 wheel should be able to fit at least 75% of the tires out there in the real world.




After pic. Wheel now accomodates tires your bike shop might actually have on the shelves.




And yes, I would STILL put a call into Zipp before removing material...whether using a Dremel tool, a Mazak, a Haas or a stick of dynamite.

 

[dhk2]

CB, believe you've posted the two "before" pics from the slow twitch link, not the "after". The first shot is a clincher rim, second is a tubular. Scroll down to see the "after" photos of the modified clincher rim with the various chucks in them. Discussion says that the removal only took out the "non-structural" lips of the bonding area, It does look like the operation was done pretty well, with nice radii, but still the effect is to put a deep notch into the inner rim sidewalls, which seems to me could weaken the wheel.

Of course, we're off-topic here, since the OP has tubular wheels, and the mod on slow twitch concerns the clincher version. Agree with your advice to contact ZIPP before proceeding.

 

[Halfnote]

Originally Posted by swampy1970 .


In today's age? You mean in the age where all the pro peloton still runs rear disks - just like they have since 1985?
Stop being a lazy f**k and make a couple of phone calls and buy the correct tubular.
Randomly machining parts just because you can't find a tire with the corrrect valve stem is effing stupid. I think it'd take no more than a couple of minutes to source the correct tire...
Maybe I should suggest that you first machine away 99% of each bolt holding on the faceplate of your stem. Leave a note in your back pocket that says "I'm a dolt, leave me to bleed"

In today's age meaning there should be a good selection of tubulars with the correct valve height. In complete agreement with your previous post sir. Probably more so than there were available is 1985. Lots of folks run Zipp wheels, I haven't heard of people having to grind, cut or mill on them.

Please note that I was not really sure of what the OP was originally speaking about, now that I have seen pics I fully understand. I agreed with you, I didn't think it a good idea to cut on the wheel at all. You can only guess at the structural integrity of the wheel once you start modifying it. Carbon fiber is pretty strong, but it's a wheel. I wouldn't want to put a wheel to the test, hit a rock on a fast downhill and suffer some kind of freak failure. Perhaps people have already done this, and that's their risk. I was in error thinking the OP was simply going to open it enough to get a valve on it. Not substantially increase a slot size by a third as it seems to appear in the photo.

Once again, my first choice would to do as swampy suggested. After I exhausted that, I would only machine on the rim after speaking to Zipp, (which incidentally they may even provide this service themselves, I don't know...) and making sure I had a solid approach on how to do it properly.

That's all not suggesting the OP actually does this.

 

[Halfnote]

Originally Posted by CAMPYBOB .

Before pic. Notice there is NO CLEARANCE for pump chuck. Notice also that a $1,000-$2,000 wheel should be able to fit at least 75% of the tires out there in the real world.

And yes, I would STILL put a call into Zipp before removing material...whether using a Dremel tool, a Mazak, a Haas or a stick of dynamite.

I wonder what Zipp's remedy for this is. This is obviously nothing new... I'm sure they would suggest a particular brand or specification for the tubular they used when they designed the wheel.

I feel pretty confident they would not want people cutting on the wheel at all.

 

[alienator]

Earlier I mentioned Vittoria tubulars because the new Vittoria's come with a stubby piece, where the stem is, to which an actual stem of the length you need is attached. Check it out:

 

[CAMPYBOB]

I feel pretty confident they would not want people cutting on the wheel at all.

You never know...Zipp may offer an alteration service for a nominal fee, of course! Always best to call the manufacturer first.

Necessity is the mother of invention...or was that Frank Zappa...or, the Russian version...Perfection is the enemy of good enough!

Back in the early 1970's drillium (look it up) was all the rage. Guys drilled hundreds of holes in their components (and even one...er...genius...that drilled rows of 1/2" holes in his gas pipe Concorde frame tubes!!!) with remarkably few structural failures. Man, I have a friend that still has a set of Universal side-pulls that look like Swiss cheese.

Triathletes and TT guys in search of seconds are as bad as the weight weenies in serch of grams. Might have to use a wider piece of 200 MPH tape to cover the new air chuck hole...

I do know that if I were using a disc with almost no room for a pump head with a 36 MM stem...I might just start scribing a few layout lines myself!

 

[Pat Stowe]

Originally Posted by cycledogg1 .

Perhaps my question is mis-understood. The wheel set is TUBULAR. The valves on a standard tub is too long for the "crackpipe" pump head to fit in the cut out hole of the disk wheel. I am using Tufo tires which tend to have a shorter than usual valve, about 32mm as opposed to the 34mm that most tubular and clincher tubes are. So, as of now, I have to wiggle the pump head (which is by Silica specific for disc wheels) onto the valve and when finished pumping the air into the tubular, I have to wrestle the pump head off. When doing so I loose air and then not sure of the psi. It's a real hassle due to the small opening on this wheel. If the opening was longer it would allow the pump head to move up off the valve more without interfering with the release pin on the valve. I may call Zipp but since this wheel is over 6 years old, a warranty issue is out of the question. Perhaps it's an issue I will just have to live with.
Cheers,
Rick in Tennessee

There are valve extenders (with gaskets?) that do not leak that would solve your problem. I can't remember where for sure, I think I can find out...

 

[alfeng]

Originally Posted by cycledogg1 .

Perhaps my question is mis-understood. The wheel set is TUBULAR. The valves on a standard tub is too long for the "crackpipe" pump head to fit in the cut out hole of the disk wheel. I am using Tufo tires which tend to have a shorter than usual valve, about 32mm as opposed to the 34mm that most tubular and clincher tubes are. So, as of now, I have to wiggle the pump head (which is by Silica specific for disc wheels) onto the valve and when finished pumping the air into the tubular, I have to wrestle the pump head off. When doing so I loose air and then not sure of the psi. It's a real hassle due to the small opening on this wheel. If the opening was longer it would allow the pump head to move up off the valve more without interfering with the release pin on the valve. I may call Zipp but since this wheel is over 6 years old, a warranty issue is out of the question.

With the understanding on your part that 'I' may still not be understanding what the problem is which may mean that this reply may be as nonsensical to you as my first one was ...
[COLOR= rgb(24, 24, 24)] [/COLOR]
I think that the [COLOR= rgb(255, 0, 0)]SILCA PISTA[/COLOR] pump head will solve your problem ...

press on ... pull off

Consequently, I recommend that you SIMPLY replace the "crackpipe" pump head with a SILCA Pista pump head ([COLOR= rgb(128, 128, 128)]it's what I opted to put[/COLOR] on my non-SILCA pump) ... they used to cost about $14+ at EXCEL & COLORADO CYCLIST but may cost a little more, now ...