FlatOut Sportsman formula is not expressly labeled as being usable in bicycle wheels, so I called them up and ended up speaking to their product manager who specializes in the bicycle segment. This Sportsman formula was tested extensively with a fat hunting ebike manufacturer. The test environment was heavy bikes traveling over remote trails and overland. The Sportsman Formula IS recommended for bicycles.
For fat bikes, the dose for a fat tire (26" x 4.0" and above) is half of a bottle. For Plus sized (roughly) 3.0" tires, its 12 ounces. Scale down from there for smaller tires.
On the pictured cargo bike, with 26"x4.3" factory tires and different wheels, I had a jagged piece of metal insert itself into the tire. I was able to pull it out and roll the tire and FlatOut sealed the breach. It was a big enough tear that it very much lends credence to their 1/2" hole capability claim. Given its performance on that and a couple of other pinhole (goathead) punctures, it has totally replaced my use of the other leading green-colored brand. I am running it, so far, on 3 separate bicycles.
The fact that this sealant never dries out and lasts for the life of the tire is a major benefit. The fact it claims the ability to seal holes double the size of competing bicycle tire/tube sealants is a bonus on top.
TUBELESS BICYCLE SETUPS
When I spoke to FlatOut, the sealant had never been tested as a tubeless sealant. Its life-of-the-tire durability, plus its ability to seal larger holes attracted me to it as on my large cargo/bikepacking bike flats are a disaster and often on the street are past the capability of the water thin sealants in common use. This stuff is thick and better suited to holes both big and small. The FlatOut product specialist I talked to recommended - to be sure of a bead seal to the rim - that I paint the tire bead with FlatOut on the outside where it contacts the rim to ensure bead and rim form an airtight seal... and give it a try. Well, I wasn't able to do the bead-painting, and instead treated the installation like a standard tubeless install, adding the sealant after using air to seat the tire bead. It has worked PERFECTLY. I couldn't ask for better. No air loss whatsoever in the tire over time (the pictured bicycle wheels tubeless and are the ones I put FlatOut into).
In the picture attached to this review, I changed from 80mm rims and 26x4.3" tubed tires, which were my first FlatOut test - to what you see in the pic now: 90mm rims, set up tubeless, and 26x4.8" tires with 16 oz of FlatOut inside each tire.
NOTE:
FlatOut seems to spread itself evenly around the interior of the tire and stay that way even after sitting for a bit, as even though there is considerable sealant inside the tire, there is no sloshing or unbalanced rotation.
PRO TIP: Flatout has a resealable application hose built directly into its lid. If you have presta valves, just take a common, cheap presta-to-schrader adapter and put it over the applicator hose. Then when you remove your valve core to inject the sealant, simply press-fit the adapter to the un-cored valve. The o ring already inside the adapter will provide a seal and you can easily inject FlatOut into the tire.
| Manufacturer | MULTI SEAL |
|---|---|
| Brand | FlatOut |
| Model | Sportsman Formula |
| Item Weight | 9 pounds |
| Product Dimensions | 9 x 5 x 10 inches |
| Country of Origin | USA |
| Item model number | 25130 |
| Manufacturer Part Number | 25130 |
