TOPIC:

A discussion on another forum prompted us to pose this question to our members: What is the correct configuration of the valve stem nuts on an inner tube? We know how the valve stem nuts were placed on OEM spoke rims in the day, and even on factory-new, modern OEM rims As seen below, responses from Michelin and Continental call that into question. We can see value in both arguments. Not taking sides either way, as there seems to be no consensus. We present this only to stimulate discussion.

The following is cross-posted from st-owners.com with the OP's permission.

"I was asked what both the nuts were for on the tube's valve stem by a guy watching me swap tires today.
I explained that tube companies provide 2 on each tube so they can be used as lock nuts. He argued that every bike he's ever seen sold only had one nut on the wheel, and it was tightened to the rim.
He went on to say the 2nd nut belongs inside the rim etc.
The research begins. Every forum we could find was all over the place with one nut in, one nut out, leave the nuts off, tighten them really tight to the rim so the tube won't slip, don't do that or you'll rip your valve stem off etc.
All the "experts" said they do it the way they found them from the factory, which in most cases, if not all, is one nut inside and one nut outside, tightened down on the rim.
Which is what at least 2 Tube companies warn is incorrect, and strongly suggests against it.
The research started narrowing down as I was contacting Tire/Tube companies.
Michelin responded with this comment:

....The conical washer sits over the inner tube valve stem and should follow the contour of the valve so that the convex side sits against the wheel rim when fitting.
Once fitted to the wheel the two lock nuts sit on the valve cap side of the wheel rim. After fitment and inflation to the correct pressure, the two nuts should be backed up towards the valve cap, and locked against each other...

Continental also stated something similar, that the nuts were just used for installation, and were to be backed up to the cap and used as lock nuts.
Several youtube video's by Dunlop show their tire whiz using one nut as a lock nut against the cap (however it shows the 2nd nut on the tube before he puts it in the tire).
Neither company suggested that one of the nuts be placed inside the rim between the rim and the tube.

So what's the answer? Follow the mfgr's advice, or your neighbor's brother in law who's been doing it for 50 years and because he does it that way it must be right?
I do find it amusing that ALL the Honda's on the showroom floor only have 1 nut showing, and its always so tight is gouges the crap out of the new rims :rofl1:
How can all the motorcycle companies be assembling things wrong?
Who do you believe? The company that makes the tubes? or the company that puts tires on their bikes?"




Good Ridin'
slmjim & Z1BEBE

I recently replaced the worn Pirelli tires on my KZ650-C1 with new Pirelli tires. I thought (for once) that I would ask the folks at Pirelli about those two valve stem nuts in case I had been using them wrong for the past 54 years. Here's the reply from the expert at Pirelli. Fortunately, I had been doing it correctly over the years, but it was good to get an answer from an expert. Ed

I don't like Pirelli's answer >> they don't give a reason why & didn't mention what to do with the other nut.


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Golly Gosh, land-a-sakes where do you guys come up with this stuff?? I have been riding motorcycles since 1970 or so and I have never heard anyone mention a word about nuts on the valve stem. Now granted many of my more recent bikes have cast wheels and not spokes, but I never would have guessed there was a controversy on valve stems nuts and what to do with them. I just looked at my KZ-1000 and it only has one nut on each valve stem and they are tight to the rim. Is this right? Is this wrong? Is there a nut hidden from view under the rim? I simply don't know! Between getting needles for my carbs and now questioning my dang valve stem nuts I will go "nuts"...pun intended. I really don't have a clue on what's right or wrong, but my internal logic tells me one nut should be tight to the rim on the cap side. I don't think you would want any movement of the valve stem for fear of damaging it. I will wait with baited breath for the experts opinions on this one...…now where's my popcorn?

Rick H.

martin_csr wrote: I don't like Pirelli's answer >> they don't give a reason why & didn't mention what to do with the other nut.


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I think they actually did address both nuts. One is still against the wheel and the other (top nut) is to be tightened against the cap. Ed

I've always had one snug against the tube and one tight on the rim. Most tubes come with plastic caps so it makes no sense to lock the cap.
Steve

By 650ed: I think they actually did address both nuts. One is still against the wheel and the other (top nut) is to be tightened against the cap.

No, he didn't actually specify. And why tighten the nut against the cap?

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SWest wrote: I've always had one snug against the tube and one tight on the rim. Most tubes come with plastic caps so it makes no sense to lock the cap.
Steve

This. I used to work as a tyre fitter in college holidays and weekends back in the 70's. Most of the bikes that came in were for their first new rear. As far as I can recall thats how they were fitted from the factory and as I still do my own fitting thats how I still fit them now.