Silca EOLO III Regulator and CO2 Cartridges

Silca EOLO III Regulator and CO2 Cartridges

When I learned last fall that Josh Poertner had left his position as the head of Zipp’s brain trust, I was crestfallen. Of the many industry engineers I’ve talked to about aerodynamics, Josh is as smart as they come and as clear in his explanations as a university professor. I hated the idea that I wouldn’t be talking to him anymore.

Then I learned that he had single-handedly taken on the mission of stoking the fire under the legendary Silca brand. Well, if anyone can do it, he can.

The first products I received from him are the EOLO III regulator plus Silca’s Ultra-Premium CO2 cartridges. I’ve got regulators like I’ve got socks. I can lose one for weeks on end and not miss it, only to rediscover it, use it and then remember how much I disliked it in the first place. Maybe the losing had been somewhat deliberate.

I want a couple of things in a regulator. First, I want it to function without fail. That means I want it to shoot out CO2 when I need it to. I want it to save any remainder when I want it saved. I’d prefer for it not to freeze to my hand. And I want it not to take up much room in my seat bag because I don’t use those duffels from Sackville that Grant Peterson likes.

The EOLO III has proven in just a few short weeks to be my new fave. It does get cold when I use it, but thanks to the little ring insulators, my fingers only get cold, they don’t stick to the aluminum. The kit comes with plenty of replacement insulator rings. This serves two purposes; you can customize your regulator to, say, evoke the Gulf team colors, or maybe your alma mater’s scheme. Sooner or later I expect lots of people will be using these and having them individually distinguishable will be handy if your group roars through a field of broken glass. (Hey, it’s happened.) I suppose they might wear out and break, so replaceability is handy, too.

I’ve got enough experience with CO2 to know that not all cartridges are filled equally. As Josh notes on the Silca site, a 16gm cartridge is only required to hold a minimum of 14gm of gas. That can make for a significantly different ride. And because I know no one who rides with a tire gauge, being able to rely that your tire is inflated to a safe pressure following a flat really shouldn’t be negotiable.

Here’s where CO2 use gets weird, though: the moment I try to square my preferred pressure and size tire with the volume of either 12 or 16g cartridges. I have it from several sources that a 12g cartridge should (under ideal circumstances) fill a 23mm tire to 94 psi and a 25mm tire to 90 psi. A 16g cartridge should inflate a 23mm tire to 130 psi and a 25mm tire to 120 psi. A 12g cartridge and a 23mm tire line up perfectly—or nearly so. However, any lost gas at all will result in lower than the projected pressure, and if I’m running 25mm tires I have to use 16g cartridges and then stop filling the tube at some point that seems to be most, but not all, of the gas.

Using 12g cartridges is my preferred method of inflation for 23mm tires, but it requires keeping a bulky inflator in my seat bag. I’m finding myself running 25mm tires more often these days, which makes the smaller inflator and the 16g cartridges preferable. I can carry only two cartridges, while if I’m carrying 12g cartridges I make sure I have at least three—just in case. My one issue is that while I don’t mind stopping short during inflation, I know that my thumb isn’t great at telling 80 psi from 100 psi. I figure that I may be running as little as 80 psi and as much as 110. Honestly, there are bigger problems.

The EOLO III regulator plus two Ultra-Premium CO2 cartridges go for $47.50. Most of what you’re paying for is the regulator. Another two cartridges is $12. That’s still a fair amount to pay for CO2, especially if you’re accustomed to buying a dozen 12g cartridges from the paintball place for about the same amount. Still, consistent inflation and space-saving efficiency do have their value. And when I mount up those 28s in the garage, you know I’ll want nothing but 16g cartridges in the seat bag.

, , ,


  1. Les.B.

    I have used a very similar filler for years and appreciated it’s compact size and reliable operation. I did have to be careful to keep it clean, keep dust out of the sliding parts, lest it jam. And it’s easier to use if one has threaded valves, (to hold the valve securely during inflation) however I’ve used it mostly with unthreaded with no problem. To save my fingers I usually take off a glove and use it to grasp the filler. The rubber rings on the Silca are a smart feature.

    The model that I did use is apparently out of production now.

  2. Tom in Albany

    So, I’ve used exactly two CO2 cartridges in my life. I understand the convenience. But here’s my question. What happens to all of those steel cartridges when they’re empty? Do they end up in the trash or worse, along the roadside? I enjoyed the convenience and speed to get the tire up to near full pressure. And it’s nice not to have to hold up the whole group for 5+ minutes while you’re pumping up your tire with a mini-pump (why are frame pumps so hard to find?). That said, I find the CO2 concept a bit wasteful and I didn’t like my hand freezing to the regulator – my bad there.

    Padraig, Do you know what happens to used cartridges? Are they re-usable or are they destined for the trash or better, a steel recycler?

    1. Rod

      Recyclable, with any steel fraction of waste in most jurisdictions. Still better not to use it, but you could apply the same to tubes, tires, etc.

    2. Author

      Tom: as Rod mentioned, they are recyclable. That’s where I put mine, but who knows if the people doing the final sort get it right. And as recycled materials go, I use these to a fraction of the degree that I use plastic packaging.

    3. Anonymous

      Tom, mini pumps are not intended to be used, they’re to show you are a serious cyclist.
      When a flat happens on a group ride the designated flat fixer gets a Zefal HPX from the
      guy on the steel bike, who also has a chain tool and spare shifter cable.

  3. Tom in Albany

    Thanks to you both. I hope that everyone here recycles them as well. I wonder if my LBS has a collection point. I don’t even mind if they’re selling them for their weight in scrap value…

  4. Jay

    Seems like a neat product. Now if he could re-introduce an improved Silca Impero frame pump, that would be nice as well!

    1. brent curtis

      Jay, thanks for your nod to us who still live in the old school. My Silca Impero pump with Campy metal head has filled many a flat for more than 20 years. I have filled lots of tires for folks out on the road who ran out of CO2. No recycling or refills required. It would even fend off an aggressive dog in a pinch. It is my trim color and looks good too.

  5. Hautacam

    @ Anonymous 11:56 AM: How on earth did you know about the spare shifter cable and chain tool in my seat pack? I mean, the HPX pump is hanging out there for everyone to see, but the others, not so much.

    No, but seriously, I’m glad to hear a heavy-hitting insider is taking a swing at resurrecting Silca. I loves me my 1980s floor pump (still going strong!) and Impero frame pump that is painted to match my [yes, steel] frame. If they can bring the brand up to speed and keep some of that legendary simplicity and durability, I will be a very happy middle-aged guy.

  6. bramhall

    Cosigned on Hautacam’s feelings on the return of Silca.

    CO2 cartridges are one of my biggest pet peeves about cycling. It just seems so silly to not have a frame pump unless you’re in a race.

    1. Larry T.

      +1 Park’s full-size, pretty-much-fits-all frame pump, while not the most elegant-looking thing around, is our go-to these days. What is it about guys who ride steel bikes? We’ve rescued plenty of folks who for whatever reason, found CO2 not doing the job. I would LOVE for the newly reborn Silca to revive the beautiful Impero, but I won’t be holding my breath. I wonder where the currently for retail sale Silca floor pumps are coming from…are they all new, old stock from the previous maker? I’ve got one that is easily 30+ years old that still works perfectly. While some don’t seem to understand how a simple push-on presta chuck works in the day of so-called “smart heads” the basic pump is simply bullet-proof. W Silca!

  7. armybikerider

    Register me as another fan of the venerable Silca floor pump. I bought mine in 1984 and it’s battered, chipped and scarred, but it still works perfectly. I must also be showing my age because I ride a metal frame (Ti) and always carry a pump. I’ve also rescued more than a few CO2 users when their inflation device failed them for whatever reason. I carried CO2….once. It just doesn’t fit my personality.

  8. Pat O'Brien

    Topeak Morph pumps have served me well for years. The Mini-Morph is still effective in pumping road tires. The Road Morph and Mountain Morph have built in gauges. The frame and water bottle cage mounts work well. My CO2 inflators in the drawer gathering dust.

  9. Nate

    I get the drift that the cyclist on this site are on a whole other level as far as bike performance/ descending skill etc. I suppose this is the reason for needing to get the tire pressure up to spec.

    For me, personally, I have flat tires so infrequently that I’m in limp home mode any time I get one and have to use a cartridge. Anything above 85 psi would be dandy.

    So, it’s 12g cartridges and that ‘clunky’ inflator all the way. I see on Silica’s website that the replacement premium 16g cartriges are $6 each. ouch. 12g cartridges at wal marts are about $0.45 each.

  10. FarmerJohnsCousin

    +1 for a good ol’ Zefal HPX (that locking lever gives it a little advantage over the Campag/Silca push on set up – it gets a bit difficult to wrap a thumb over the tire to hold it in place for those of us with smaller hands).

    @Larry T. The thing about frame pumps and steel bikes is not the guys that ride them but the fact that they CAN safely hold a frame pump. Those of us that were around to see the first mainstream monocoque frames and OS aluminium may have recollections of flying Silcas and Zefals at the sight of the smallest bump. Unfortunately the radii of tubes and/or junctions doesn’t allow a frame pump to sit properly in the frame. I believe that this is what helped push the popularity of mini pumps and then CO2. Neither of them as reliable as a proper frame pump, but if you’re going to carry one or the other I guess a lot of guys (and girls) will opt for the one that is quicker and requires less effort. CO2 wins.

  11. David

    Yeah, I know this is late…

    When I ride I want to ride, not stand by the road pumping for dear life trying to get my tire up to pressure. Here in Texas when its in the 90’s or over 100 degrees the sooner I can get going the happier I am. After years and spending stupid amounts on various frame pumps frame mounted and compact I am willing to admit defeat. I got a CO2 inflator that came with a used bike I bought and I love it. It gets me back riding faster which is what its all about…. I carry two tubes and two cartridges and a boot, if anything else goes wrong its probably time to call for help…

  12. yno

    does this regulator fit securely to valve stems that are smooth (non threaded) like michelin airstop? How does it achieve that and how secure is it? e.g. does it thread to the dust cap thread? or does it just rely on pressure (which seems it would be very much not secure if that was the case).

  13. Zoom zoom

    It, on the Silca site, says it ‘threads on both presta and Schrader valves’. How? Does it thread in to the tire valve to fill? Does it actually ‘thread on’ to the valve? Both types? Sounds like magic…

    Looks nice though. So many are so ‘cheap’, and easily lost. Someone should make one with a ring on it to help retrain it. Great idea, huh…

Leave a Reply

Your email address will not be published. Required fields are marked *