After building a wheel with the Stealth2 rim I tried to install the tube from my Coker wheel (current version). When I couldn’t I noticed that the valve stem is tapered and the base larger than the normal bicycle schrader type. The Coker’s valve hole was also larger to accommodate this. Thinking that Coker used their own tubes I ordered a replacement from UDC which was stated to work with all 36er’s. However that tube appears to have the same valve sizing and also doesn’t fit in the Stealth2’s valve hole. So what is the deal? Is the Stealth2’s valve hole sizing different from the other UDC brand 36" rims? Was it designed for 29er and Foss tubes only or something? None of the UDC sites seem to mention it.
I guess I’ll have to drill it out?
Thanks for any info you have…
Drilling wouldn’t be a big deal, as you already a spare in the larger size. It would just mean the need to shim if you ever went to a tube with a smaller valve.
I have a different problem but related to valve stem size. I got two Vee Rubber 36 inch tubes and the schrader valve stem is smaller than the rim hole on both my Coker and my Titan. The valve stem is 5/16ths and the rim hole is 7/16ths (on the Titan). I had a flat on my Titan this week and when I removed the tube it had two small holes right next to each other below the valve stem (about halfway down the sidewall - not at the base of the valve). I can also see what appear to be scuff marks on the tube. It appears that the tube is shifting back and forth slightly while I ride and it wore two small holes in the side of the tube. I checked the sidewall of the tire very carefully for any foreign material but there is nothing. The valve stem on the Vee Rubber tube looks standard size to me but there is no taper at the base. Does anyone have any suggestions or have any of you had a similar problem?
Here is a picture to show the pattern of scuffing (some diagonal and some criss-crossed).
I faced the situation a few times in the past where the stem was smaller than the rim’s hole. The best way to address it is having a tube with a threaded stem because the ring can ensure that the stem remains in place and does not torque the tube during inflation (but it is not as common as regular tubes and is not available in all sizes).
My plan B is to use some electrical tape to wrap around the stem starting at the base and make sure it goes in straight and tight.
But my concern is that usually, the stem fit is related to stem premature failure either while riding or inflating. What you describe would sound like more a tire fitting a bit too loosely on the rim and shifting under load and sanding its was on the tube’s surface. You could try to add something to smooth this contact area but the usual puncture protection liners are for the top under the rolling area not the side.
Maybe beibg creative will be required (talcum powder? Grease ? Piece of gorilla tape in the area ?).
Were you able to patch the holes where you found them?
I haven’t tried to patch the holes yet. It’s not valve stem failure but thanks for sharing. I called UDC and they said since my wheel is kind of old (2011) the hole for the old UDC tube/valve stem was bigger back then. The guy described the tube as a “truck” tube. He said they have not heard of an abrasion problem like what I described but that anything is possible. I have some plastic tubing on order that I will try to slide over the valve stem and that should tighten things up. I may also make a reinforcement from an old tube to fit around the problem area.
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I have an old Niterider uni from about that era, with an oversized valve hole, never knew why. I assumed the original owner had drilled it out for some reason, but I guess not!
I slide a thin washer onto the valve stem of the tube, so there isn’t any unsupported area on the tube around the valve, but I don’t use a sleeve or anything to make the stem actually fit better.
I haven’t had any problems with abrasion on that wheel, but I saw it all the time on my MTB tubes. I assume it was from the combination of low air pressure and lots of tire flex on rough trails causing the tube and tire move against each other. Do you ride 36" muni?
Thanks for the tip.
I do ride a 36 (but not muni) and use low pressure (20-25 pounds). The sidewall on the Niterider is really flimsy/thin too so I think it moves. There are diagonal stress marks in the picture I posted if you zoom in a bit and I can also see them on the tire’s sidewall.
