SuperLJ

Looks like these comes in two styles. One is just a rubber grommet that fits in the Schrader hole, the other replaces the nut on a Presta valve and has a shoulder that fits in the hole in the rim. Anyone have any experience or opinions about these?

Which do you like better and why?

tyler_fred

I have both. The only noticeable difference from my perspective is the the grommet allows the valve to flex when airing the tire. I prefer the nut.

dddd

Keep in mind that the only way to stabilize the valve stem in the rim without having all the stress concentrated at the rubber-to-metal bonding is if the double-walled rim is deep enough in section for the two walls to prevent the valve's tilting.

Nuts shouldn't be tightened any more than to prevent the nut coming loose and rattling while riding. Even this can be bad enough, as all nut tension is being resisted only by the fragile bond between the stem and the tube.

For the sake of facilitating inflation with a pocket or frame pump without damaging the tube, the wheel should be allowed to move freely as the pump head jolts back and forth.
Better yet, resting the head of the pump against a curb, a rock or against the corner of a bike's saddle (where the other corner is on the ground) physically prevents the pump head from jolting and thus from transmitting said jolting to the valve stem. This is also a good bit easier on the arms while achieving sufficient pressure with a smaller pump that might require lots of strokes.

The stepped nuts are good for centering the valve and also for minimizing the contact area on the rim's surface (since one might later wish to ditch the nuts altogether).
A sleeve of shrink-wrap on the stem can prevent rattle but still allow removal of the stem (and transfer of the sleeve to a new tube).
I generally throw out the nuts and caps, but I always keep Schrader valves capped to exclude dirt settling in the opening (which doesn't happen to Presta valves).

52telecaster

I use the plastic grommet on the inside of the rim and use the nut that came with the tube on the outside.

nlerner

I prefer the metal threaded one. I find the rubber grommet has a tendency to push out of the valve hole when you push the valve through it.

oneclick 

Frame pump presta technique: forefinger goes around the spoke beside the valve, and curls around to hold the end of the pump. Thumb goes over the tyre, last three fingers go under the pump end. When you squeeze that hand the pump head is pushed onto the valve, and the end of the pump is held steady.

You pump against your hand holding the pump end, and your fingers just make sure it stays in place - each way. It's not usually extreme pumping force that breaks stems, it's twisting. No need for a wall or anything to rest the wheel against; probably better you don't if using this technique - if you did, it's easier to pump too hard and/or twist the pump head - and break the stem.

dabac

+1

Outside valve adapters are only useful for keeping stuff out of the rim cavity and do nothing for stem survival.

IME, YMMV.

SuperLJ

Thanks for all the responses. So far it looks like it’s running 50/50. I can see advantages to both I guess.

unworthy1

there's another option the smooth unthreaded alloy collar made by Wheels Manufacturing (they call it a Presta Stem Saver, part no. PSS-1). installs from tube side, simple, effective but pricey for what this is!

SuperLJ

Cool - I have never seen those. Normally looks like the smartest option, except the rims in question are single wall, so maybe not. Actually no more expensive than the other two. Thank you!

Kabuki12

I use the smooth ones and never had any problem. I trim them down so they don't stand up too far above the rim. They are a lot longer than they need to be even on double wall rims like my early Rigida's.

DiabloScott

I use neither, with no problems.

katsup

I have all 3, but haven't used the nut as it's on a spare tube somewhere. The only one currently in use is the rubber grommet as the smooth collar sticks out the rim. The smooth collar is the nicest one though.

Cycle Tourist

One other option is a small washer with the sides filed off for narrow rims. The plastic ones don't stay in place all that well for me and the nut on the inside seems counterintuitive.

Oldbill

Back in the day wrenching (80s) we would take a Schrader plastic valve cap, cut off the closed end (so it is a spacer), slide it over the Presta valve and run the Presta nut against it. It is free, works well and it even looks pretty good.