Valve Stems Keep Failing

Vonripper450
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Vonripper450
Edited Date/Time 11/17/2015 12:56pm
I just bought a 2015 KTM 300xc and have torn the valve stems off both the front and back tubes twice in 4 rides. I have never had these troubles before and I am installing the tubes the same as I always have. Does anybody have any ideas what could be causing this? I am running AT81 Dunlops and the rim lock is stock.
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DuroTools
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DuroTools 11/13/2015 12:54pm
11/13/2015 12:54pm Edited Date/Time 11/13/2015 12:54pm
When you changed your tubes did you use some type of lube to get the tire off? If you did than maybe the lube you used is slippery and got on the bead lock so it is not holding. It has to be something with the beadlock, I can't see any other reason.
CarlinoJoeVideo
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CarlinoJoeVideo 11/13/2015 1:03pm
11/13/2015 1:03pm
Maybe your rim lock is not tight enough so your tire is spinning and rotating the tube?
Vonripper450
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Vonripper450 11/13/2015 1:03pm
11/13/2015 1:03pm
DuroTools wrote:
When you changed your tubes did you use some type of lube to get the tire off? If you did than maybe the lube you used...
When you changed your tubes did you use some type of lube to get the tire off? If you did than maybe the lube you used is slippery and got on the bead lock so it is not holding. It has to be something with the beadlock, I can't see any other reason.
Soap and Water. I took the tire all the way off last time and didn't see anything on the bead lock. The first 2 tubes this happened with came with the bike new.
Vonripper450
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Vonripper450 11/13/2015 1:06pm
11/13/2015 1:06pm
CarlinoJoeVideo wrote:
Maybe your rim lock is not tight enough so your tire is spinning and rotating the tube?
I tightened it down pretty good but will double check it again. Could it be crappy locks?

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DuroTools
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DuroTools 11/13/2015 1:26pm
11/13/2015 1:26pm
Try cranking them down tighter and make sure the dealership didn't Arm-all the tires or anything. If the beads have any shine shit or any slippery lube that would make it hold less obviously. If that doesn't work maybe grab a set from a older year bike, maybe they did a design change in 2015 that is flawed. It's a pretty simple part so not sure why they would change it but who knows, maybe they used a new material that isn't holding as good or made it smaller to save weight?
Vonripper450
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Vonripper450 11/13/2015 1:42pm
11/13/2015 1:42pm
DuroTools wrote:
Try cranking them down tighter and make sure the dealership didn't Arm-all the tires or anything. If the beads have any shine shit or any slippery...
Try cranking them down tighter and make sure the dealership didn't Arm-all the tires or anything. If the beads have any shine shit or any slippery lube that would make it hold less obviously. If that doesn't work maybe grab a set from a older year bike, maybe they did a design change in 2015 that is flawed. It's a pretty simple part so not sure why they would change it but who knows, maybe they used a new material that isn't holding as good or made it smaller to save weight?
That makes sense. Thanks for the help.
Falcon
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Falcon 11/13/2015 4:01pm
11/13/2015 4:01pm
Or, your tires are more flexible than you think and you have the 12mm nut on the tire valve cranked down. Are the valves failing at the base, underneath the rim? This is probably your culprit. Don't try to use that nut like a rim lock - leave it loose. I use mine to cinch the tire valve caps so they don't fall off (back them out until they meet the cap.)
You need surprisingly little force on the rimlock to lock the tire in place. Also make sure your tire pressure is sufficient to keep the sidewall supported.
colintrax
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colintrax 11/13/2015 4:06pm
11/13/2015 4:06pm
Just take the nut off the tubes. It's only purpose is to hold the stem for the first air up.
Vonripper450
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Vonripper450 11/13/2015 4:47pm
11/13/2015 4:47pm
Falcon wrote:
Or, your tires are more flexible than you think and you have the 12mm nut on the tire valve cranked down. Are the valves failing at...
Or, your tires are more flexible than you think and you have the 12mm nut on the tire valve cranked down. Are the valves failing at the base, underneath the rim? This is probably your culprit. Don't try to use that nut like a rim lock - leave it loose. I use mine to cinch the tire valve caps so they don't fall off (back them out until they meet the cap.)
You need surprisingly little force on the rimlock to lock the tire in place. Also make sure your tire pressure is sufficient to keep the sidewall supported.
It is tearing off at the base but I do have the valve stem nut as loose as possible. I put the valve cap on then back the nut to the valve cap.
Vonripper450
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Vonripper450 11/13/2015 4:49pm
11/13/2015 4:49pm
Thank you guys for all your help. It is awesome being able to use this forum as a resource.
Vonripper450
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Vonripper450 11/13/2015 4:50pm
11/13/2015 4:50pm
Falcon wrote:
Or, your tires are more flexible than you think and you have the 12mm nut on the tire valve cranked down. Are the valves failing at...
Or, your tires are more flexible than you think and you have the 12mm nut on the tire valve cranked down. Are the valves failing at the base, underneath the rim? This is probably your culprit. Don't try to use that nut like a rim lock - leave it loose. I use mine to cinch the tire valve caps so they don't fall off (back them out until they meet the cap.)
You need surprisingly little force on the rimlock to lock the tire in place. Also make sure your tire pressure is sufficient to keep the sidewall supported.
I am running 13psi. That should be in the ballpark right?
MR. X
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MR. X 11/13/2015 8:08pm
11/13/2015 8:08pm
Interesting thread , i was just talking to my buddy who rides his 450 exc on the street and he has been pulling the valve stem off the tubes also .
moto455va
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moto455va 11/13/2015 8:20pm
11/13/2015 8:20pm
Youre not supposed to leave the nut on the valve stem
Vonripper450
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Vonripper450 11/13/2015 8:27pm
11/13/2015 8:27pm
MR. X wrote:
Interesting thread , i was just talking to my buddy who rides his 450 exc on the street and he has been pulling the valve stem...
Interesting thread , i was just talking to my buddy who rides his 450 exc on the street and he has been pulling the valve stem off the tubes also .
What is getting me is I have a CRF450r and a KX250f and I have never had this trouble with them.
Vonripper450
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Vonripper450 11/13/2015 8:31pm
11/13/2015 8:31pm
moto455va wrote:
Youre not supposed to leave the nut on the valve stem
Interesting. I have never heard that before. Most of the mechanics I have had install a tube leave the nut on. I always left the nut on my 4-strokes and have never had this trouble.
tmauto769
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tmauto769 11/15/2015 6:23am
11/15/2015 6:23am
moto455va wrote:
Youre not supposed to leave the nut on the valve stem
So, I gotta ask, where did you hear this from? Whoever told you may want to let the manufacturers know this as all of them besides honda stick a nut on there and leave it there. It is tightened down to by the way. I have a buddy that I ride with that uses the stock honda rubber, I tighten mine down and neither of us has ripped a valve stem out.
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colintrax 11/15/2015 12:09pm
11/15/2015 12:09pm
moto455va wrote:
Youre not supposed to leave the nut on the valve stem
tmauto769 wrote:
So, I gotta ask, where did you hear this from? Whoever told you may want to let the manufacturers know this as all of them besides...
So, I gotta ask, where did you hear this from? Whoever told you may want to let the manufacturers know this as all of them besides honda stick a nut on there and leave it there. It is tightened down to by the way. I have a buddy that I ride with that uses the stock honda rubber, I tighten mine down and neither of us has ripped a valve stem out.
Let me ask you this, what purpose do you think it serves? Just because it gets left on doesn't make it right
moto455va
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moto455va 11/15/2015 5:13pm
11/15/2015 5:13pm
tmauto769 wrote:
So, I gotta ask, where did you hear this from? Whoever told you may want to let the manufacturers know this as all of them besides...
So, I gotta ask, where did you hear this from? Whoever told you may want to let the manufacturers know this as all of them besides honda stick a nut on there and leave it there. It is tightened down to by the way. I have a buddy that I ride with that uses the stock honda rubber, I tighten mine down and neither of us has ripped a valve stem out.
Ive heard it from a few places. But just because the manufacturers put it there doesnt make it right.

Basically, the tire is going to spin on the rim regardless of a rim lock. It might not be much, but it happens over time. The valve stem has to be able to tilt a little to compensate for that without tearing, and it cant do that with the nut on there.

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tmauto769
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tmauto769 11/15/2015 5:59pm
11/15/2015 5:59pm
hmm, mine don't. check your pressures much?
ML512
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ML512 11/15/2015 6:05pm
11/15/2015 6:05pm
Dunlop and Pirelli techs at the races run valve stem nuts but back them off to meet the cap so the valve stem has a bit of float (so it won't tear the base of the stem under flex). Considering how many tires these guys knock out, I'll go with them. Laughing
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ianhendry46 11/16/2015 10:06am
11/16/2015 10:06am Edited Date/Time 11/16/2015 10:07am
I've dealt with this issue a few times, replace your Beadlock with the motion pro Beadlock and that usually fixes this issue. In extreme cases, I have actually drilled a second Beadlock hole and used two bead locks. It is a pain in the ass but it does work. Also, drilling the rim does not affect the integrity of the rim( I was worried about this.) Since you're riding in the woods, the extra weight isn't really a concern.
Andrew337
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Andrew337 11/16/2015 11:07am
11/16/2015 11:07am
I would try new rim locks. Also, double check that the rim lock is still tight after your first ride with a freshly mounted tire, as the bead may not have been fully seated and will settle into the rim a little better in the first few laps. This happened to me a few weeks ago. I found the rim lock was barely snug after my first moto on a new tire, and the tire had spun on the rim and nearly tore the valve stem. And if you use anything to lube the tire to help with mounting make sure it is something that will dry completely and not leave any slick residue between the tire and rim. Windex works well for me, along with baby powder inside the tire to keep the tube from chaffing.
Vonripper450
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Vonripper450 11/16/2015 7:20pm
11/16/2015 7:20pm
Thanks for all of your responses. I rode the bike yesterday and everything went well. I made sure the stem nut was backed out and I cleaned up the tire bead with soap and water to ensure I wasn't getting Armorall slip. The sidewalls were pretty shiny when I got the bike. The only problem with my test ride was we ended up riding in 3 inches of snow.
tmauto769
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tmauto769 11/16/2015 7:32pm
11/16/2015 7:32pm
ML512 wrote:
Dunlop and Pirelli techs at the races run valve stem nuts but back them off to meet the cap so the valve stem has a bit...
Dunlop and Pirelli techs at the races run valve stem nuts but back them off to meet the cap so the valve stem has a bit of float (so it won't tear the base of the stem under flex). Considering how many tires these guys knock out, I'll go with them. Laughing
I thought they used the mousse insert deal. Well I thought I heard Emig babbling about it during a race one time anyway.
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Matt Fisher 11/17/2015 11:13am
11/17/2015 11:13am
Make sure the inside of the rim where it mates to the tire isn't "polished". There should be lines/groves perpendicular to the edge of the rim that help keep the tire in place. I've seen rims that had really small grooves and grooves filled in with bits of dirt. You might even consider taking a sharp file to the grooves and carefully make sure they can "bite" the tire.
mattyhamz2
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mattyhamz2 11/17/2015 11:42am
11/17/2015 11:42am
moto455va wrote:
Youre not supposed to leave the nut on the valve stem
Vonripper450 wrote:
Interesting. I have never heard that before. Most of the mechanics I have had install a tube leave the nut on. I always left the nut...
Interesting. I have never heard that before. Most of the mechanics I have had install a tube leave the nut on. I always left the nut on my 4-strokes and have never had this trouble.
I leave the nut on my tubes but I have them up right against the valve cap. If you have it tightened down to the rim or close to the rim that's your issue
lumpy790
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lumpy790 11/17/2015 12:56pm
11/17/2015 12:56pm
ML512 wrote:
Dunlop and Pirelli techs at the races run valve stem nuts but back them off to meet the cap so the valve stem has a bit...
Dunlop and Pirelli techs at the races run valve stem nuts but back them off to meet the cap so the valve stem has a bit of float (so it won't tear the base of the stem under flex). Considering how many tires these guys knock out, I'll go with them. Laughing
this

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