After returning from the Sea Otter Classic, I compared Slime’s new tubeless tire sealant against the Finish Line tire sealant. I knew my Stan's tire sealant was already dried in my mountain bike tires, so on Sunday morning, I took the tire off and cleaned out the dried tire sealant. I put about 4 oz. of Slime tire sealant in the front wheel and 4 oz. of Finish Line in the back wheel.
I usually ride three times a week (Tuesday, Thursday and Saturday or Sunday morning). I have three different bikes, so I don't always ride the same bike. The one I ride the most often is my Santa Cruz Tallboy C, which is the one that I tested the tire sealant on. The test bed was for 29er wheels with tubeless-ready Mavic wheels and Continental X-King tires (2.3 in the front and 2.2 in the rear).
The tire setting was quick and easy. The beads went into place easily for both the front and rear tire since both tires and wheels are tubeless ready. There weren’t any major leaks that I could hear, so I went through the motions of making sure the tire sealant covered the entire tire.
Sunday: I checked on the tires and the front tire (Slime) was set and it did not lose any air, but the rear tire pressure was low (Finish Line) so I added some air and shook the tire again, in hopes that any leaks that may have been letting air escape would get sealed up with Finish Line tire sealant.
Monday: I checked on the wheels in the morning and the tire pressure was down on the rear tire again, so I added more air. On Monday evening after work, I checked on the tires again and the rear tire had lost about 10 psi, so I added more air and shook the Finish Line tire sealant again.
Tuesday: I checked on the tires again and the front tire was fine, but the rear had lost a little more air (less then what was lost on Monday). I figured I needed to shake the wheel again to let the sealant splash around to seal any leaks. After that, I went on a two-hour ride and everything held up without any issues on the ride.
Wednesday: In the morning, I checked on the bike wheels and rear tire was low again. This time, I washed the rear wheel and tire and I placed it in water to see if it was leaking air, and it was leaking air very slowly in several areas on the tire bead. The Finish Line tire sealant did not seal the small air leaks between the tire and the wheel.
I took the tire off to make sure the tire bead was clean and it was. I cleaned the tire bead and the rim again to make sure nothing was in the way of the tire setting on the wheel. I went ahead and set the tire and went through the same steps as I did to set the front tire. I shook the tire to make sure the tire sealant would splash all around and this time, I set the wheel on its side to make sure the tire bead had enough tire sealant to seal any air leaks. Wednesday night, I added more some air and I placed the wheel on the other side to make sure the bead would seal on the other side.
Thursday: It looked like it was better as I just lost about 5 psi in the rear tire. I added some air and shook the tire to make sure everything was sealed. Thursday evening, I checked on the tire and it was low, so I added some air and I went for a two-hour ride. During the ride the tire held up.
Friday: I checked on the rear tire and it was low on air again, so I shook the tire to get the sealant all around the tire and wheel. Friday night, the tire was low again, so I added more Finish Line to the tire sealant and pumped the tire, then shook it all around to make it would be able to seal the bead properly.
Saturday: On Saturday morning, the tire was low but I added some air and I went on a ride. My ride was for about four hours. Toward the end of the ride, I could feel the rear tire pressure was low so I stopped on the trail and I added air. The tire held up to finish the ride. I once again shook the rear tire to give the sealant a chance to seal the tire the wheel so it would stop losing air.
Sunday: I checked on rear wheel and again the tire was low. I added more air and placed the tire in water to find that it was leaking from several spots coming out from the tire bead.
Monday: At this point, I had given the rear tire several attempts to seal the air leak. Getting frustrated with this, I took the rear tire off the wheel and removed the Finish Line tire sealant from the wheel and tire and added Slime sealant. I checked on the rear tire to see if there is any air was leaking from the wheel and it was from the side tire bead. I shook the wheel around to get the tire sealant to cover the air leak and placed the wheel on its side.
Tuesday: I checked on the tire and it looked like it lost a little air, but I added some more air and left it on its side to make sure the sealant would cover the air leak. Tuesday evening, I came home and checked on the rear and the air pressure did not go down. I went on my ride and came home with no issues. Thursday morning, I checked on the rear tire and air pressure had stayed the same as Tuesday and it did not drop.
Looks like I won't be able to do a comparison of Slime and Finish Line tire sealant to see which will last longer and seal the air leaks. Or you can already say Slime tire sealant won, since Finish Line was not able to seal the small at leaks between the tire and wheel.
The real view from the field.