Sealant Test - Part 2
Written by: Greg Kopecky
Added: Wed Jan 29 2014
Today weíll reveal what youíve all been waiting for Ė the results.
Before we get to the meat of it, we must mention a few things.
Finally, I think another key limitation is the size of the sample. As much as Iíd love to test 500 punctures to make my data more robust, I also need to make a living (and Iím not paid hourly). Inner tube and tire thickness influence how well a sealant does its job, and we all know that product variation is a part of life. Put simply, tires and tubes do not have perfectly uniform wall thickness. Itís entirely possible that a sealant that looks poor on-paper happened to be caused by a circumstantial puncture in a particularly thin part of the tube or tire. We canít know for sure, and would need to replicate this test many times over in order to validate it.
Remember, here is the protocol:
-700x23mm Schwalbe Durano S on an Ultegra 6800 front wheel
-Three puncture sizes: 1.2mm thumb tack, 1.7mm nail, and 2.2mm nail
-Latex and butyl tubes tested
-Punctures through the tread and sidewall
-2.2mm sidewall puncture was the Ďtorture testí Ė the nail went completely through both sides of the tire
-Wheel and tire cleaned between each sealant type to avoid cross contamination
-Standardized amount of 2 oz sealant per tube (50-60ml), except for Pit Stop (one canister per tube)
-Test stopped at first failure
Stanís NoTubes / Schwalbe Doc Blue
First up for our results is the well-established Stanís NoTubes sealant. This is also repackaged and sold by Schwalbe under the name Doc Blue. Stanís has been around for a long time, and is very common in the mountain bike scene. Iíve always wondered why they donít market more towards the flat-phobic triathlon market.
The best part about Stanís, in my opinion, is the super easy two-ounce bottles that you can buy; itís the perfect amount for a road tube.
Was the puncture too large? Was I unlucky? Iíve heard many stories of mountain bikers finding giant nails in their tires after bike rides, which sealed thanks to Stanís sealant.
Here are our test results:
Vittoria Pit Stop
Pit Stop took the world by storm when it hit the market. With sealant and a CO2 inflator combined into one device, it seemed like a fantastic solution. Now we see many similar devices from the likes of Effetto Mariposa and Hutchinson.
It is worth noting that during this test, I found that each Pit Stop canister would give me about 45 psi when starting from a completely flat tire. You must carry an additional CO2 if you want to use this as an on-the-road fix.
Finally, I only had three canisters of Pit Stop, so I was unable to do a sidewall puncture test with latex inner tubes.
Effetto Mariposa Caffťlatex
Of all the sealants listed today, this is the only one that I know has worked for me in the past (it is entirely possible that Iíve suffered other puncture with other sealants and not noticed it). While riding in Colorado, I successfully repaired punctures from small goathead thorns into a WTB mountain bike tire with standard butyl inner tube using the Espresso inflator cartridge. Espresso uses the same formula as the bulk Caffťlatex, packaged in a CO2 inflator. I was ecstatic to finally have something work in a real-world situation.
I contacted the founder of Effetto Mariposa, Alberto De Gioannini, to find out more. According to him, you actually do not need to shake Caffťlatex vigorously due to its composition and particulate size. All you must do is turn the bottle upside down a couple times; thatís it. In an effort to ensure a level playing field for this test, I measured to what appeared like 50ml of liquid, while the foam rose to about the 80ml mark on my sealant injector.
Letís look at how it fared:
Flat Attack is one of two glycol-based sealants in our test. The beauty of this type of sealant is that it doesnít dry out and effectively last the life of your inner tube. Glycol sealants are also tube-specific and do not work with tubeless applications, outside of the mountain UST standard. Given the ease-of-use, I have used Flat Attack in several wheel sets over the past two years. Fortunately or unfortunately, I never suffered a noticeable puncture on any of those wheels while riding, so I havenít had a good chance to see whether or not it is effective.
Letís see how we did:
This is the other glycol sealant in our test. Unlike Flat Attackís visible goop-plus-fiber mixture, Airlock is entirely homogenous. Call itÖ snotty-mustard?
Letís see the results:
Orange Seal is a relative newcomer to the sealant game. Donít let that fool you; it has gained a very good reputation in a short period of time. Multiple people have told me that I Ďjust have to try it... it really works!í I decided to see what this orange goop was all about, and they were kind enough to send a box of samples for this test.
Orange Seal provides an easy-to-use injector tube that comes with each bottle, seen here:
Given all the hype, I was eager to see how it stacked up in our Pepsi Challenge.
Weíre left with Bontragerís TLR sealant. As mentioned previously, this sealant is advertised as being for tubeless applications; tube customers are instructed to buy their SealSafe product. On paper, I doní t see why this shouldnít be used for tubes. It has a synthetic latex base and is ammonia-free. They say that it does not degrade tire rubber, too. They only recommend 0.8 oz (25ml) for a road size tire, making our 2 ounces more than enough.
Similar to Stanís, TLR is sold in bulk-size bottles, and also in super convenient two ounce Ďsingle serveí bottles.
Notes on all sealants
With any latex-based sealant, its performance is going to degrade as it evaporates over time. In very dry climates, this can mean injecting more sealant as often as every couple months. In humid climates, Iíve gone as long as a year in higher volume applications. Especially for training applications where weight is less important, I think it makes a lot of sense to over-apply at the beginning, so you have to maintain it less frequently down the road.
How much do sealants weigh? Just for kicks, I weighed a two ounce bottle of Stanís. It came in at 72.5 grams full, 13.9 grams empty, for a liquid weight of 58.6 grams. Weight will vary by sealant type and volume, but figure in the ballpark of 100 grams per bike.
Finally, in my experience, all of the latex sealants will eventually clog up your presta valve cores. While I love sealant, it isnít very smart (it canít tell the difference between a hole in your tire and the hole in your valve - so it clogs both). Valve cores can be purchased as spares, and I always keep a few handy. With most sealants, I replace the cores every six months or so Ė very easy to do while you are topping off the sealant level.
What did we learn from all this? For one, I learned how to install tubes really well. My thumbs hurt...
I think itís safe to say that we learned some cool stuff about latex vs butyl; the performance was undeniably different between the two. Latex tubes are definitely trickier to install, however. They are so soft that they donít want to hold any shape. If you use them, you must double-triple check for pinch flats before inflating. For that reason, I would not suggest carring them as spares for on-the-road changes Ė even for a big race. Butyl tubes can be installed much quicker on average.
That said, if you do use latex tubes, does it really matter which sealant you pick? I really donít know. Most of them performed very similarly in our test. To me, thatís a big area of opportunity for future test refinement. Also note that with the 2.2mm double sidewall puncture, some of the sealants successfully repaired the entry wound, but not the exit wound (latex tubes only). I didnít catalog this for each sealant because I didnít notice it until half of the testing was done. With Caffťlatex and Airlock, the entry puncture seemed to be 100% sealed.
The best medicine, in my opinion, is to develop bigger and better lab tests, along with cataloging real-world results.
All charts © Greg Kopecky / slowtwitch.com
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