aggiegrads

Does anybody have a low-cost but safe alternative to presta rim grommets? Something that they have used successfully like a washer, o-ring, or something else that doesn’t cost a buck and a half per tube?


I’m looking for a replacement for these to use a presta tube when I have a rim drilled for schrader.

Andrew R Stewart 

Try a "rubber" insulating grommet. grommets | McMaster-Carr They have been used for decades for this bike application. However you'll find then a sorry sub for the Wheels Al version. Andy

Bill Kapaun

$3/bike until you install Schraeder tubes.

Juan el Boricua

I made my set of "wheel savers" because I had the materials and basic tooling BITD; a buck and a half is pretty inexpensive for something reusable, specialized (as it's only purpose), and seldom needed in this time and age, and If I were to need them again, I'd bite the bullet and buy them. Just like Andrew said, anything else will not last as long, or work as good; just my $0.02.

aggiegrads

Thanks all. It looks like the best options are not significantly cheaper. This is for refurb bikes where the bike already has presta tubes that are good, but are on 26 rims drilled for Schrader. I burned through my stock of 3 pairs last week refurbing bikes for the local non-profit.

I'll buy a handful of the grommets or pay more attention to the compatibility of what I pick up in the future from the co-op.

mack_turtle

How cheap is cheap enough for you? Those adapters can be found at any be shop for pocket change.

travbikeman

Wal Mart even has these for only 89 cents:

https://www.walmart.com/ip/Schrader-Presta-Rubber-Rim-Hole-and-Adaptor/

(never mind the $6 delivery fee) ​​​​​​​

aggiegrads

Well, I am refurbing bikes out of my own pocket, so I was hoping that I could get them for "shop supplies" prices rather than "spare parts" prices.

I have purchased lube, grease, 50m rolls of 4mm and 5mm housing, bottles of loose balls, cable tips, and ferrules. I don't mind donating the shop supplies, but replacement parts start to get expensive when you start adding cable inner wires, tubes, grips, bar tape, chains, etc. Grommets are cheaper than tubes, but more expensive than cable end caps.

DiabloScott

Cheapest option of all... don't bother.


Works fine, lasts long time.

Bimmer69

You could try just wrapping some tape around the lower part of the stem.
Or get a pack of rubber grommets (I’m not sure of the exact size).

andrewclaus

I also vote for the don't bother approach. Or use the Continental tubes that have a threaded stem and the reversible nut with the adapter built in, but that's more expensive unless you need the tubes anyway.

Crankycrank

+1 or 2? Check the tubes that you have as they may already have the reducer stem nut included. I'm pretty sure even Panaracer tubes include them and their tubes are on the less expensive side.

aggiegrads

I have plenty of "reducer" presta nuts. They help center the stem, but do not prevent tube herniation, which is the problem that I am trying to prevent. I worry that the recipients of these bikes will simply inflate to recommended sidewall pressures (~70 PSI for the commuter tires that we install).

If I choose the "Do nothing" option, at what pressures do I need to worry about herniation? I'm looking for someone who already has data points, I prefer to not do my own experiments here.

cyccommute 

If you are worried about tube herniation, use two nuts. One on the under the rim and one on top. If you use two stepped ones, the stem should be locked in place even better.

aggiegrads

Ah. Now this is a low cost solution. If a presta nut under the rim isn't a risk, then I will use that. I may also pick up a few 010 and 108 o-rings to see if either of those work.

Would small tube movements in the tube rub a hole on the knurled edge of the presta nut? Am I overthinking it?

Bimmer69

Or a flat nylon washer on the rim side.
the nylon will have less of a chance of cutting the tube.

Crankycrank

Another suggestion for this along with the others above is to use the stem nut on the outer rim side and make a washer from an old inner tube and put it on the stem on the inside of the rim. I've done this a couple of times for your same situation with 100 psi pressures and no issues. Just snug the stem nut lightly, super tight is not necessary.

DiabloScott

Well my data point is 90psi is no problem in the last 6 years.

andrewclaus

My wife has had Presta stems in Shrader rims with 90+ psi inflation for almost two decades. Never an issue.

cyccommute 

Probably overthinking. Tubes don’t really move around that much.

Iride01 

Is there a community college or vo-tech that teaches CNC machining? Check and see if they have a CNC lathe and will let a student run you some of those you pictured in the OP. Those are simple to make, will be good experience for the student. Material cost is very low. The big cost comes in tooling setup which is essentially time.

Back in the days of CRT displays, I used to take bad CRT's to the local community college that had an electronics repair course and got them fixed for just the cost of the transistor or capacitor they needed.

Geepig

I try to plan the bikes I purchase for resale along with the ones I accept in part exchange etc to minimise any outlays.

I am not sure how you arrange to get the bikes you work on, but for example I picked up three bikes recently where one was mostly good, one was so-so and the other rough, but by the time I had broken the rough one down to components I had most of what I needed for the good and so-so bikes. Anything left over that I don't think I will need gets sold on as parts. As you know, tires, tubes and cables soon get expensive, so I really look hard at the rough ones for good hubs and things to sell. Often they are rough only because they have been left to rust in a basement, while under that surface they are still a low mileage bike.

BikeLite

The Panaracer Schrader-presta Valve Nut is sold in at least bags of 10 on ebay. It may be cheapest production thingy, but more practical may be nothing or wrap tape as others stated.
https://www.ebay.com/p/2255925853