Jump to content
Sign in to follow this  

Ripped valve stem AGAIN!!!

Recommended Posts

Any special tip to stop this from happening?

Perfect super heavy duty tube running about 18 psi in a Maxxis IT 18" rear tire.

PPlants2005_0208_103818AA.JPG

Share this post


Link to post
Share on other sites

I only use 1 rimlock BUT !!! after i get my wheels back from the shop with new tires , i always give the nut a few more turns to be safe. I realy give a good yank on the wrench= no problems. :cry: I am usually never running more than 15 PSI .

Share this post


Link to post
Share on other sites

...some rimlocks are really cheap junk that don't work too well. Keep that in mind.

Share this post


Link to post
Share on other sites

The reason that this happens is because the tube slips inside the tire under hard acceleration. The nuts around the stem prevent the stem from flexing with the tube. That causes the tube around the stem to rip. When you install the new tube, don't put the outside nut on the stem. You'll be able to see when the tube has spun because the stem will be on an angle. Take off the tire and straighten the tube. Its a little bit of work but it beats buying new tubes all the time.

When I'm installing a new tube, I try to install it so that the tube is spun a little in the opposite direction that the acceleration makes it spin. That way it has even more room to spin in the tire. I also think that a tube spins a little and then settles into one spot. Installing the tube a little "crooked"(for lack of a better word) will allow the tube to spin and then settle in the correct, or close to correct position. I don't have any evidence to back this up, but it makes sense in my head. Did I spell sesne right?

Share this post


Link to post
Share on other sites

Get yourself a really sharp chizzle and a hammer. Remove the tire from the rim and notch the rim all the way around on both sides (every half inch or so) where the tire seats to the rim. Angle the chizzle so the displaced metal grabs the tire under accelleration. It'll never move again.

Share this post


Link to post
Share on other sites
The reason that this happens is because the tube slips inside the tire under hard acceleration. ?

I think a better way to describe might be that the tube doesn't slip inside the tire when the tire slips on the rim under hard acceleration. The tire slips on the rim and pulls the tube with it. The valve stem stays bolted in place to the rim and the stretching tube eventually tears.

I put the nut on the tube but spin it up against the valve cap, for the same reason, so you can see if the tube has moved. I also pour baby powder inside my tire to help the tube slip inside the tire. I run 2 and 3 old tubes over the tube that is holding air to protect it from stud damage and use baby powder between each layer. Before using it there would be lots of rubber schrapnel inside the tire when I took it apart. Someone mentioned the baby powder trick and I've been using it ever since and there seems to be a lot less chafing of the tubes. Maybe some silicone spray lubes would work too but I'm gonna finish off my bottle of powder first.

I also have 35's on my truck with tubes in them 'cause they're full of holes but still have lots of tread. I keep an eye on the stems and when they start to lean I jack up the corner, let some air out of the tube until it gets loose inside the tire and straightens out, and then fill it up again. You can do the same with the bike. if you see the stem leaning just letting the air out of the tire and shaking it around a bit will center the tube up, no need to dissassemble.

Share this post


Link to post
Share on other sites

That sucks. What brand of tube and what brand of rim lock are u using?

Share this post


Link to post
Share on other sites

I've had that problem too. I think when rimlocks get old they start to bend in on themselves and not clamp as well regardless of how tight you make it. The weird thing is I just got a new KTM and it is doing the same thing. I might try to mark my rim and tire to make sure that the tire is in fact slipping because I tighten my rimlocks pretty tight. I use a tire mounting compound to lube the tubes because I have chaffed through tubes before, and maybe this lube is getting between where the tire and rim touch. I guess the best solution would be to get bib mousses!!

Share this post


Link to post
Share on other sites
That sucks. What brand of tube and what brand of rim lock are u using?

The tube is a FLY Racing SUPER IV Heavy Duty 4.00mm.

The rimlock is a ???????? :cry: Who knows??? It came with the bike.

I don't think the tube is the problem.

I might try two new rimlocks.

I don't want to groove or notch the inside lip of the crappy bent rims.

Share this post


Link to post
Share on other sites

Do what Tubo said and notch the rim. Get a new rimlock also. Sounds like yours is toasted.

Share this post


Link to post
Share on other sites

i have popped a hole in my tire out around china wall and rode all the way back to camp at vendor flats on a flat tire... when i pulled the tire off the the tube never moved... somehow enough sand got inside my tire that rubbed a hole into my tube... kinda wierd but i replaced it and never had any probs since...

Share this post


Link to post
Share on other sites

The other reason to consider dual rim locks is the bike can be ridden back gently when flat and still does OK on hill climbs! :cry: I wonder why Yamaha puts 2 rim locks on as standard now? :cry:

Share this post


Link to post
Share on other sites

go with 2 rim locks :cry::cry::cry:

i know a lot of guys with xr 650s that run 2 :cry:

Share this post


Link to post
Share on other sites
...................When you install the new tube, don't put the outside nut on the stem. You'll be able to see when the tube has spun because the stem will be on an angle. ............................................................................ but it makes sense in my head. Did I spell sesne right?

:cry::cry: The *FIRST* time, you spelled it correctly.. :devil: But YES, What MajorDanage said, do not put the valve stem locking nut on or at least back it off to allow the stem to tip over if it slips again. This is standard proceedure for all of my bikes and all of the other guys that ride similar bikes.

If you really want to use the locking nut, wait until you have your slipping problem solved.

Oh, and you don't need to remove the tire to spin the tube stem back to straight. Loosen the rim lock(s), let ALL of the air out, break the tire bead from the rim. With the bike on a stand and in gear, yank on the tire (use tire lube to help) until the stem is straight again. With the tire lube already on, you should be ready to just pump the tire back up. The tube should be ok, but double check anyway to make sure the tube is not pinched between the tire and rim as you reinflate.. Did I cover everything? Whew!!

However, when I used to run rear tires with tubes, I found the tube was NOT slipping in the acceleration direction... it was the braking action that was doing it... Turned out that it was happening on hard stops, when dropping off of steep cliffs or rock steps. It was when the weight comes off the rear and then the rear tire hooks up and releases in a chatter affect. The jerking action while there was no weight on the tire was able to kick the tire around. With the weight or power back on, the increased pressure helps the tire grip the rim.. This still happens with the front tire, but not from hard forward braking.. it happens when grabbing the front brake in a panic as the bike is headed back down the hill from a failed attempt... rear tire first! Again, no weight on the tire and brake locked.

Some people claim that the tube can creep around inside like a caterpillar, but I thought that would only happen under low pressures. Marking your rim and tire would be a good way to decide what is moving and in what direction... tire or tube... then come back and let us know. :cry: Oh yes, what are you using for tire lube? :cry::cry:

Share this post


Link to post
Share on other sites
I put the nut on the tube but spin it up against the valve cap, for the same reason, so you can see if the tube has moved.

This is the key. This is the sure fire method to stop your flats.

Nobody spins tubes more than me. I run less than 5 pounds and 1 rim lock. NEVER tighten the nut to the rim. My tubes spin and my valve is always at an angle but no flat tire. After a few rides I straighten it out. Tighten the nut to the rim and you are just asking for a valve rip flat...

Share this post


Link to post
Share on other sites

That's right, Frostbite had a good write up on it too.. I didn't see that.. Here in Washington State, the baby powder doesn't last very long.. too much water here and the low pressures I run allow water to get in by the spoke nipples, front rim lock bolt and front valve stem.. Oh yes, rear tire is tubeless.. no tube no cry... :cry:

Share this post


Link to post
Share on other sites

Instead of installing the nut on the stem you can go to your local Honda dealer and purchase the rubber covers that slide onto the stem and are held in place by the valve stem cap. It seals the hole and allows the stem to move.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×