Credit: Seth’s Bike Hacks

I’ve had a slow leak in the rear tire of my hardtail for months now, and I keep just pumping it up and riding it. I think we’ve all been guilty of this type of laziness, but this leak is coming from my sidewall, which means the tire really needs to be replaced.

When I pump it up you can see air coming out here, but shaking the sealant around plugs the hole for a while. Later today, the pressure will be down to around 10psi if I’m lucky.

So, while this tire is getting replaced no matter what, I’m going to use this slow leak for an experiment. Many riders have mentioned that mixing glitter into both homebrew sealants, and off the shelf brands like Stan’s can improve their ability to seal punctures.

It does sound plausible that the little grains of glitter would get lodged in punctures and make it easier for the sealant to do its job. Let’s see if glitter can give my Stan’s sealant an edge on stopping this slow leak.

Glitter-Tire-Sealant -1

I’m going to mix some glitter in with the sealant that’s already in my tire. This way we can’t attribute a successful outcome to new sealant. My assumption would be that really fine dusty glitter works best, so I’ll use this stuff. I’ll put some of these little stars in too for style points.

I’ll go for a ride to get the sealant in every little crack, and then let the bike sit for about 6 hours.

By now, the tire would have usually lost a lot of pressure, so it’s time to check.

No way, did this work? I’m going to go for another ride and then leave it until tomorrow morning, just to be extra sure.

I must say I’m surprised. This tire is most definitely holding air.

In the 3 months since this leak occurred, I have not seen this tire hold air for more than a half a day, so there’s a good chance that it was the glitter that stopped this leak.

I’m still not sold on adding glitter to sealant as a standard procedure though. I’m guessing that it also has side effects. For the same reasons it helps plug holes, the glitter may accumulate around other crevices inside the tire, and cause the sealant to clump where it shouldn’t. Sealant is designed to provide a balance of puncture resistance, longevity, and non interference with other components like valve stems, so there’s probably a good reason that Stan’s doesn’t come premixed with glitter. I simply don’t have the answer to this.

If it does provide better flat protection, it might be worth the payoff during a race, or a long distance trip where getting a flat could have huge consequences.

These theories are all just speculation though, so take them for what they’re worth. In any case, it was a fun experiment which showed that this trick just might work. Now I need to wash this glitter off myself so my wife doesn’t get suspicious. Thanks for riding with me today and I’ll see you next time.

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