Tufo Tire Sealant
While we are happy riding clinchers on a daily basis, the advantages of Zipp 808 tubulars have been tempting us since we tested them. We nearly pulled the trigger on buying a set for our all-purpose race wheels. This would be the set that we’d use in the flat and rolling races, the set we'd use when riding to races, the set for local races, and so on.
What stopped us was the thought of flatting at 5:30am as we're pedaling to a local race. Running late and in the dark and cold is never a great time for flat changing. The second issue was the thought of having to race on a tire that wasn't firmly glued to the rim. Yes, tape works, but we have yet to pull off a tubular quickly, so we see the tape as one step too many when we're under a severe time constraint.
With our fears firmly in mind, we looked to Tufo's Tire Sealant as a possible solution. It's essentially liquid latex; we wish we could tell you more but the importer didn't have more information. Tufo claims it can seal any hole up to 2mm in diameter. 2mm is pretty big in our estimation; we've been known to trash clincher tires with a hole near that size. The sealant works fairly similar to the way fix-a-flat stuff works in car tires. The sealant remains in liquid form inside your tire, constantly coating the outside walls of the tube or inside wall of the tire as your wheel spins. When air starts rushing in from a cut, the liquid is forced out. As it exits, it dries, sealing the hole. Unlike the stuff for your car tires, there are no solid particles in the sealant and the action of inserting the stuff into your tire does not inflate the tire. Slime sealant, by the way, has fibers in it. Vittoria's Pit Stop, another similar product, comes in an aerosol can and can inflate your tire. But neither comes in containers suitable for riding with.
One of the nice things about the Tufo sealant is that it is sized to fit in a tubular bag. Our 50ml container measures 10.5cm tall by 5cm wide. It also comes with both a Presta valve core removal tool and a sleeve for inserting the sealant in tires that don't have removable valve cores. The one trick of carrying the sealant on the road is that the dropper at the top of the bottle comes sealed, so you'll either need to have some kind of cutting implement with you on the road or snip the top before venturing with the stuff on the road.
A drawback to opening the container earlier than you need it is that the liquid could dry out before it is needed. Once inserted into bike tires, the Tufo rep tells us that the sealant should last inside their tires two to three months, possibly less in warm weather. Actually, they are loath to recommend the sealant for any tires other than their own tubulars.
We checked with two other tire manufacturers about using Tufo sealant in their tires. Representatives from both Continental and Vittoria indicated that Tufo's product doesn't have any issues with their tires. Vittoria, naturally, recommends their product, Pit-Stop. Conti' also mentioned that Stan's should work as well. We tried contacting Hutchinson but their representative didn't return our calls.
While the weight weenie inside us says save the sealant for when it is needed, going out and looking for flats would add an element of uncertainty that would make testing the sealant pretty hard. We decided our best course of action would be to take an old set of tires sitting on a pair of underutilized wheels, insert the sealant and over the course of time try to flat the tires. The wheels have a Hutchinson Carbon Comp and Vittoria Corsa CX. Both are pretty used, the Corsa feels a bit more so.
These old wheels aren't deep-dish, but are deep enough to require valve extenders. For simplicity, the extenders are Zipp's. We like these extenders for both security and simplicity. But the Zipp people do not recommend inserting Tufo sealant through their extenders. They believe Tufo sealant is, “way too thick to penetrate through a Presta valve, and will clog up/ruin it (and probably the valve extender too).” Further, they don't recommend it for their tires, though they do think Stan's or Vittoria will work fine.
Before applying, we read the paper instructions that came in the box and watched the video on the Tufo North America site. The video is most valuable for watching valve stem removal. The paper instructions are more up to date.
Tufo has some contradictory info on how much sealant should go into each tire. At one place, they recommend 25ml, or half a bottle, per tire. In another they recommend a third of a bottle, or 16.67ml. We decided to go lean, shoot for 16.67ml per tire. We marked the bottle on one side with 1/3 hash marks, two marks, each indicating 1/3 of a container, so we knew how much to squeeze out. And the other we did a middle mark, just so we could see what the difference is.
With the Vittoria, we pumped the tire up, took a safety pin, pushed it through the tire, and removed it. Once deflated, we removed the Zipp valve extender, removed the valve core and inserted approximately 1/3 of contents in the container (16.67ml). We reinserted the core, the extender, spun the tire and inflated. Spun the tire some more. Heard hissing for a few seconds. Then it stopped. And held. With the Hutchinson, we tried adding the sealant via the tube and the valve extender. Didn't seem to work, so we removed the Zipp extender, and used the tube to insert through the valve. We then pumped and spun for a minute. We next took the pin and pushed it through. Spun the wheel a bit with the pin in, then pulled it out. A little sealant came out, the pressure went down a bit, but then it held.
We let the tires sit for a week. With latex tubes, they were bound to be pretty soft when we returned to them. We then pumped up the tires again. We pushed a safety pin through the tread of each tire, pulled it out and spun the wheels. The tires held.
A week later, we went for the third round. Same procedure. This time, the rear tire, the Hutchinson, didn't hold. We went back to the sealant bottle. Looking at the bottle, we concluded we probably didn't put in enough sealant. Possibly because using the tube was slower, and trickier, than inserting the sealant directly via removing the valve core. So we removed the valve core and inserted more fluid. With the extra sealant, it held.
A week later, we did a fourth round. The front, the Vittoria, held. The rear, we decided to up the ante a bit and push in two safety pins right next to each other, and then, after several spins, removed the pins. The tire slowly went flat as it spun. Once flat, we spun the wheel a bit more and then pumped it up. It held.
We like what we've seen with the Tufo sealant. If you're going to use the stuff with deep-dish wheels, you either need to insert the stuff before you install the tire, or you'll need both a tire with a removable valve core and the kind of valve extender that has a Presta valve on the top. We'd probably wait for a flat before putting the stuff in to minimize rolling resistance and to keep the sealant liquid as long as possible. But, having the stuff in does seem like easy insurance, and at 16ml, it's hard to imagine that rolling resistance would be changed much, if any -- probably keeping the tire at the proper pressure makes a bigger difference.