Tire tube stem nuts

[Capt_Curmudgeon]

This is about as persnickety as it gets. When installing a new tube, do you tighten down on the tube stem nut, or leave it loose? I have heard it both ways.

Another, my replacement tube came with two nuts. The box instuctions say tighten down on the first nut all the way down to the stem base, then install the tube. Intall and tighten down the second lock nut when the stem passes through the wheel. This appears to me will create a gap between the tube and the wheel. Am I missing something??

:dunno

[manicmechanic]

At our shop, we snug the first nut down to the tube, then the second nut is left loose while mounting the tire. After beading up the tire we take it to pressure, leak test, then snug up the stem nut.

[lkchris]

The stem nut exists SOLELY for convenience when installing and inflating the tube.

After that, take it off and throw it away, or at least screw it UP till it meets the cap.

Installing it at the bottom of the threads is a sure-fire way to find your inflation valve torn off.

[dlearl476]

>Installing it at the bottom of the threads is a sure-fire way to find your inflation valve torn off.

Kent, please elaborate. I've put ~ 60K on bikes in the last 5 years, on and off road, with nuts tightened down to the rim with absolutely no problems,

I have been told:

a) leave the nut loose when installing a tire, to keep from losing it inside the tire while mounting it, fill the tube to straighten it out, empty it and pump it up to 45 psi to seat the bead, then tighten down the nut after deflating to the proper psi.

b) The nut tight to the rim keeps the tube/tire from spinning in off-road conditions when lower inflation pressures are optimum. (To a point, then bead locks are required).

Like I said, following these guidelines has gotten me home safe countless times. Actually, I've only had one flat in my entire MC career, on a tubeless tire.

[flash412]

Installing it at the bottom of the threads is a sure-fire way to find your inflation valve torn off.ROtFLMAO! I've got more than a quarter million miles in the "sure-fire tear your valve off" position. 1067 of those miles were in one day, offroad, with the front tire at 20 psi and the rear at 24 psi in the Dusty Butt 1000 (http://www.deathstar.org/~flash/dustybutt.htm).

The source of that legend is with dirt bikes running less than 15 (or so) psi on AGGRESSIVE KNOBBIES WITHOUT RIMLOCKS.

Total crap for streetbikes.

[lkchris]

Total crap for streetbikes.


http://two-wheels.michelin.com/2w/front/affich.jsp?codeRubrique=8092004155119&codePage=8092004155119_23092004181009&lang=EN

http://home.jps.net/~snowbum/section5.htm
(scroll to #6)

http://w6rec.com/duane/bmw/air/index.htm
(scroll down to "valve stem.")

[flash412]

http://two-wheels.michelin.com/2w/front/affich.jsp?codeRubrique=8092004155119&codePage=8092004155119_23092004181009&lang=EN

http://home.jps.net/~snowbum/section5.htm
(scroll to #6)

http://w6rec.com/duane/bmw/air/index.htm
(scroll down to "valve stem.")I'm not going to attend the National this year. But if I was, Kent, I would make this offer to you... I would offer to walk the grounds for 8 hours, looking at valve stem nuts. I would give you $1 for every one that is NOT at the rim if you give me twenty-five cents for every one that IS at the rim. Basically, I would bet that there is OVER a 4:1 majority of folks running their valve stem nuts in the position that is "sure-fire" to rip out the valve stem.

Question #1: How many people have EVER had a first hand experience ripping out a valve stem because the nut was down instead of up or missing?

Question #2: If it is a "sure-fire" way to rip it loose, why does the vast majority snug them to the rim? (Even if you don't believe it is the vast majority, why are umpteen thousands of long-time bikers oblivious to this "sure-fire" way to destroy the tube?)

Comment: When I install a tire, I always put talcum powder on the tube, inflate the thing til the bead seats, run the nut down and then pull the valve core out. I let all the air out of the tube and then re-insert the core and reinflate it. This allows the tube to straighten itself out inside the seated tire. There is no strain. There is no problem.

[James.A]

My tube install mirrors flash412's except that I use corn starch. I do run a nut down to the rim, not sure if it matters. The only tube failure I ever had was a 12d nail.

[lkchris]

Basically, I would bet that there is OVER a 4:1 majority of folks running their valve stem nuts in the position that is "sure-fire" to rip out the valve stem.


Probably the majority of Airheads '77-on will have the paper gasket under the oil filter cover, too. It's not recommended by BMW.

Probably a significant portion of bikes at the National will have excessive tire wear. Doesn't make it correct or safe.

The fact folks are "out of the loop" as regards knowledge doesn't mean that what they do is correct via majority rule. That's not "new math" and it's a pretty poor understanding of statistics.

[flash412]

The fact folks are "out of the loop" as regards knowledge doesn't mean that what they do is correct via majority rule. That's not "new math" and it's a pretty poor understanding of statistics.Kent, earlier you said, "Installing it at the bottom of the threads is a sure-fire way to find your inflation valve torn off." I'm throwing the bull**** card on that statement. My point is that there are multiple THOUSANDS of motorcyclists out there who have been doing it wrong (according to you and your sources) for multiple decades and probably billions of miles WITHOUT HAVING THE INFLATION VALVE TORN OFF.

Maybe the bill of a baseball cap is supposed to point toward the back and maybe it is supposed to point toward the front. Somebody somewhere is DANGED sure that one way is RIGHT and the other will lead to unplanned pregnancy.

You seem invested in the idea of some form of catastrophic failure caused by the valve stem nut that a majority of riders simply have never encountered personally or even second hand. Take a statistics class. Pay close attention when they cover the notion of "confidence levels." Your "sure-fire" statement indicates a high level of confidence (shall we say >90%?) that the data just do not support. If tightening the nut to the rim was a sure-fire way to tear out the valve, then nine out of ten riders who run them that way would likely have encountered the phenomenon. That just is not so. It ain't happened. And the collective history of legions of motorcyclists (also known as statistics) suggests that it isn't GOING to happen either.

I repeat my question: have you or anyone you know ever had this happen to them or witnessed it directly, while running more than 20 psi on tires that were not aggessive knobbies? Where are your statistics supporting the fact that running the nut "the wrong way" leads to failure? Is there ANYBODY, even just one person, who has ever had this experience?

Probably the majority of Airheads '77-on will have the paper gasket under the oil filter cover, too. It's not recommended by BMW.

I'm not sure what your point is. BMW recommends NEVER changing the gear oil in their differentials. Note that lately BMW rear ends have taken to failing pretty spectacularly. BMW also says that steering head bearings now come from the factory "lifetime lubricated." Unfortunately, that lifetime will be REALLY short if you don't ever re-pack them. They can last for the lifetime of the vehicle if you DO lube them every 12000 miles or so.

Just because somebody comes up with a new theory on "the right way" to do something doesn't instantly negate an entire history of collective experience. That, my friend, is what statistics is about. That goes for lubing steering head bearings and running the valve stem nuts down to the rim.

I am happy to accept that in your mind what I do is "wrong." (It probably bothers you just as much as when you see kids with a foot of underwear showing above their belt.) In total violation of BMW factory knowledge and suggestions, I pack my steering head bearings every 12000 miles. They have NEVER failed me. Similarly, in violation of the websites you cited, I run the valve stem nuts right down to the rim. And THEY have never failed me either. I, along with countless thousands of others, will continue doing things "the wrong way," foolish twits that we are. We do it because, statistically, we have never encountered any of your "sure-fire" failures. If we HAD encountered failures, we would have learned that it was wrong, and changed to the right way. But we haven't. If we had, then the statistics would be on your side. And we would not be having this discussion, because I would be doing it "your way," too.

[dlearl476]

He's so cute when he's fired up! :D

And now, back to our regularly scheduled "Which oil is best?" thread.

[Fritzc]

The fact folks are "out of the loop" as regards knowledge doesn't mean that what they do is correct via majority rule. That's not "new math" and it's a pretty poor understanding of statistics.

I remember in 1980, when I returned to motorcycling, seeing a survey in the MOA that said most bikers ride on Continentals. Well, guess what tire brand I bought thereby raising that statistic one more notch? :doh

[flash412]

He's so cute when he's fired up! Hey... you don't want your girlfriend to find out that you said that, do ya? :drink

[Capt_Curmudgeon]

Well, that was certainly a spirited discussion and I considered each reply and piece of advice. The Michelin web site (nut off the rim) obviously carried some moral authority, but I took the litigious solution and elected to follow the tube's packaging directions exactly and snugged the nuts down (not too tight) below and above the rim. I visulized maneuvering to avoid some dumb squirrel and plowing into the proverbial busload of school kids, and then an injury lawyer finding out I didn't follow manufacture's directions on something entirely unrelated. Wimpy? Perhaps, but my personal fortune is very small and I am its preservation.

Thanks again.