Tyre sealants are like toothpaste. Not for the consistency, but because once you choose one you’re unlikely to change. I have used a few in the past 10 years, but mostly settled on Stan’s NoTubes sealant. It works well, but it does separate and make big latex monsters, and struggles with sidewall punctures a little.
FRM are known for the lightweight Italian mountain bike bling. They do some positively gorgeous parts out of carbon and scandium, and an interesting range of frames, suspension forks and wheels that are rare sightings on trails or at races.
FRM Sealant – not uncommon on many workbenches.
They also do some nice tubeless conversion parts, and an accompanying sealant.
The sealant is a little different in how it works to the NoTubes variety. Without knowing a measure for viscosity, it does feel a bit thicker. But that’s because it works in a different way. As it’s designed to be used as part of a conversion, it coats the inside of the tyre. A UST tubeless tyre will have a pretty thick sidewall to help guard against punctures. What the FRM Sealant does is leave a coating on the inside of the tyre, so there is already sealant there if you do run into something too sharp. There is still liquid sloshing around that will seal holes, but it has already set a coating, from bead to bead.
It looks the same when you put it in a new wheel.
This is very evident when you remove the tyre after a a few months. Instead of finding some latex monster and some watery latex, you have a coated tyre with some stringy latex around the bead and rim. Still messy, but in a sense it’s still functioning a bit better than the former messy option. One strange occurrence was using CO2 to inflate tyres. The sealant looked like… cottage cheese. This only happened once, so maybe it was something to do with a coating inside the new tyres, but it was odd. I removed the tyres, put new sealant in and used a track pump, and had no issues. The cottage cheese variety hadn’t been sealing.
Apart from this one instance I’ve had no issues with FRM Sealant. It has sealed up tyres well, I haven’t had any punctures that have stopped me riding, and best of all when I’ve changed tyres there has still been sealant in there – not latex monsters.
The sealant comes in 500mL and 1L containers, that are about $AUD30 and $AUD55 respectively, but prices might vary at your shops.