Little rubber beads inside tire

[Quickstep192]

I recently had a tire dismounted and discovered a bunch of little (approx .1” dia) rubber balls inside.

Any idea what this is from?

They’re Michelins if that matters.

[Bucketlist]

Been previously patched inside and not cleaned up after.

[stownsen914]

Sometimes people use those to help balance a tire. Never tried it personally.

[TeeJayHoward]

When a tire is made, the rubber doesn't always fill the mold perfectly even. Some areas are denser than others. Because of this, the tire and wheel need to be balanced. For most street vehicles, it's only off by a few grams. In the 80s, you'd see weights clipped on to the rim of the wheel to balance things out. In the 90s, weights with adhesive on the rear became more common. That style is still used today.

However, what if your wheel and tire isn't off by a few grams but by a LOT? For example, if you have a tire that's huge and chunky like an off-road tire, the weight could be massively imbalanced. This was fairly common with early off-road tires, and it just wasn't possible to stick enough weights on the rim to counteract it. So the early off-roaders started adding a bunch of BBs inside the tire before mounting them. Via centerfugal force, the BBs would kinda-sorta balance out the tire. They were unfortunately loud, though - so alternatives were sought. Some folks played around with silica gel rounds, some with rubber balls... In the end, most settled on airsoft pellets.

Fast forward a few decades, and tire tech has grown by leaps and bounds. An off-road tire still requires more wheel weights than an all-season, but not nearly as much as they used to. However, the old knowledge of "You can balance your tire with BBs/airsoft pellets/etc" has been passed on to a generation who doesn't know (or care) about the history.

All of that just to say, if it's a handful of little rubber balls, it might be an old-skool tire balance technique. If it's a dozen or less, it's probably something else.

[john walker's workshop]

I've seen those since way back in time. Pretty sure it's just dust from the inside dry slippery coating that forms into balls. Pretty light weight for any balancing effect.

[AlBackus36]

I used to do tire repairs. I'd agree with bucketlist. You'd see more of them in a tire that had been repaired or driven on with low air pressure. I believe they are rubber remnants slowly made round by the tumbling process that is driving.

If you've never had this tire repaired or had a low pressure condition, I would ignore.

[famoroso]

Per the responses, could be a lot of things. My first guess woulda been balancing beads. Got pics?

Don't confuse it with the "crumb rubber" from a failing tire tho. Say one that may have "ran too hot as a result of under inflation," which was a Bridgestone engineer's professional opinion about this tire...

[KNS]

Originally Posted by AlBackus36

I used to do tire repairs. I'd agree with bucketlist. You'd see more of them in a tire that had been repaired or driven on with low air pressure. I believe they are rubber remnants slowly made round by the tumbling process that is driving.

If you've never had this tire repaired or had a low pressure condition, I would ignore.

I was getting new tires one time and had not noticed that one of old tires had gone low just before the old ones were removed. When the tire that had gone low was taken off a bunch debris that looked like little rubber balls were found in the tire.

The installer commented that that was a sure sign that the tire was run low and compromised and should not stay on the car.