Tire Debris - Michelin with Tubliss

[Neil E.]

This is a strange one. I recently did a complete replacement of my tires and Tubliss setup. The Tubliss is the newer Gen 2 with thicker tubes (although they don't look any thicker). Tires are Michelin Starcross 5 medium, 90/100-21 front and 120/90-18 rear. Popular with local guys, although they will usually have a 110/100-18 on the rear. I run 12 psi front and 8 psi rear.

My riding is mostly single track dirt/mud/sand with a lot of hammering over exposed tree roots. I've got 5 rides on the tires with no issues (about 400 km of use). No loss of low pressure air and only a slight bleed down of the high pressure air (over a few weeks they'll go from 100 psi to 95 psi).

Normal tire install, clean the rim, tape it well, lube the inner tube, lube the kevlar, mount the Tubliss. Insert the rim into the tire, lube the inside and outside of the bead, work around with 3 spoons (I use slime for the lube). Flip it over and do the other side.

Here's the strange part: bike on the stand, rotate the rear tire by hand and there's the sound of pieces tumbling inside the tire. WTF? Rotate the wheel about a quarter turn either way and the tumbling happens. It sounds almost like pouring charcoal briquettes out of a bag. I can only assume that somehow the inside of the tire carcass is coming apart. I've had tires with a handfull of rubber bits in them before when changing a tube or tire. Never really looked that close because it's rubber dust and small bits. Could be from the tube or tire.

I have no idea what's inside this Michelin tire. I only used enough slime to be a lube, so there's not enough in there to coat the insides. The outside of the tire looks fine and it runs reasonably true. I know there were some big quality issues with Michelin tires when they first moved the production from Europe to Thailand years ago. That should be all worked out now.

My initial thought is to add a bunch of slime and just see how long the tire lasts. As a casual trail rider I'm not in a hurry to pull it off the bike. Anyone else run into a weird tire situation like this?

[Radbuster]

In regards to the slime as a mounting lube: I friend tried that on a regular tube and the tire spun alot on the rim, since the slime appears to be a type of vaseline that doesn't dry, like soap-based lubes do.

He thought his clutch was slipping, but removed and cleaned everything and it all worked well again.

A head-scratcher indeed. Sorry, no ideas.

[Biff]

Slime will congeal over a period time into lumps, could be that.
Take it wheel bearings are ok?

[hamilton]

No experience with tubliss, but I've had more than a few heavy duty tubes with debris rolling around inside the tube after some use. Bet your noise is in the tube also.

[Moto7man]

I run tubliss on both bikes and I have never had that problem. Sounds bizarre.

[Neil E.]

It sounds strange alright. I figure that the small amount of slime dried out and formed into balls that rolled around in the tire. The carcass is light so the sound must transmit easily. I recently added a normal amount of slime to the tire and the noise is gone. The chunks may have disolved back into the liquid or are just being dampened by the liquid.

The tire is performing well so I'm not going to be concerned about it. Since my goal is to ride with minimal wheelspin, I usually get two seasons out of a set of tires so it will be a while before I update this topic.