Valve stems
 

I have trek navigator 3.0. Seems like a lot of owners are having trouble with the valve stem to start leaking due to rubbing and grinding from the hole in the rim where the valve stem goes through. Trek says there is no issue. Any suggestions?

Remove the tire and tube and smooth down any burrs in the rim at the valve seat. Also, good rim tape like Velox goes over the hole and protects the edge. Finally, cut a small disk from a bad tube, punch a small hole in the center and thread it over the valve stem to it's base. That will give a second rubber layer to protect the valve base.

de burr the edge of the hole if you wish , & don't let the PSI drop too low.
Tire creep carries the tube with it, shearing the stem from the tube.
( user error )


Trek dealer back up here is OK, can't say anything about yours in Florida.

service after the sale is a Management choice of the Shop owner , Often.

manufacturing of frame is Trek's warrantee support. [thru the dealer]

Seems like a lot of owners are having trouble with the valve stem to start leaking
due to rubbing and grinding from the hole in the rim where the valve stem goes through.

Have not heard this , Out here.. maybe a Florida Thing
No Lots of owners queued up with stem problems , Here.

Depends on a few factors. Valves don't move or wiggle on their own, so step one is to see what's going on. Be sure to mount tires with the valve straight, and keep them fully inflated so the tire doesn't creep. If you notice your valves are crooked after a while remount.

The greatest stress on a valve happens during pumping with a hand held thumblock pump. It's easy to stress or wiggle the valve with every stroke, and this is the single biggest cause of valve breakage. When pumping grip the pump in a "hitch hiker's" grip with your thumb braced against the rim or tire, and your index finger around the end of the pump. This will keep the pump stead with respect to the valve and rim.

Also, do not pump a tire with the wheel braced because, if the pump slips or shifts in your grip the entire pumping force will go against the valve. Instead pull the wheel away from what it's leaning and let the bike rock with your pumping action.

Lastly, not to let Trek off the hook, there is a problem, but it's not just them. In an effort to cut costs, some tube makers are using valves where the brass tube is shorter than before, and now no longer goes all the way to the tube. Instead it ends outside the rim, with an un-reinforced rubber tube below. This is perfectly made so that it's very easy to snap the valve off at the rim.

Trek doesn't make the tubes, but they pick their suppliers, and are only too happy to use the lowest bidder and save one cent per bike and let their customer live with the problem.

These "short valve" tubes are also sold in the after market, so when you buy a tube, open the box and feel whether the brass valve stem continues all the way to the bottom, or comes up short.

My wife and I have had 4 TREK bikes and a Raleigh. On every one of them I have routinely taken a small round stone to the valve stem holes in the rims. I have had to fix flats where the rubber around the valve stem was cut through by the edge of the stem hole in the rim. A few had burrs left from the drilling of the hole while they all had sharp edges around the holes. The round stone was used, by hand, to remove the sharp 90 degree edge of the holes. This is just a fact of life with the budget priced rims found on most of the lower priced bikes. Once the edges are rounded it should be the end of the stem rubber cutting.

I put the valve nut on the inside of the rim and have very few valve flats.

Davidad, this is plainly a schrader thing; very few such valves are threaded.

Once again I tip my hat to FB. Encyclopaedic.

...Hey, that'd be a great user name.