What Is A Rim Lock & What Does It Do?
That bolt that is sticking out of your rim is the rim lock. In case you had that “why do I have two valve stems, wait, why is there a bolt coming out of my rim?” moment.
Your rim lock is merely a clamp that holds your tire in place on the rim and is found on every dirt bike.
It is designed to fit between the tire and the tube, with metal cleats on the bottom to grip the inside of the tire bead.
When your rim lock is in good shape and seated correctly on the rim, your tire WILL NOT MOVE.
How Your Rim Lock Works
If your rim lock is not seated, your tire correctly is going to spin on the rim. This will cause your tube to tear at the valve stem, resulting in an instant flat tire and a ruined day of riding.
To demonstrate just how secure a rim lock is, I cut out a section of an old tire. I’m then going to try and rip it off the wheel with a pry bar.
On my first try, I secured the rim lock hand tight, and I had to pry the tire sideways to get it off the rim.
The second time, I secured the lock like I normally would. I hurt my shoulder, trying to rip it off.
I’m well aware I can’t put the same amount of force on this tire that it would see in use, but you get the idea.
You can see how well a properly seated rim lock works, so let’s talk about what makes it NOT work.
How Does Your Rim Lock Fail?
Pinching The Tube – if your tube is hung up on the rim lock, it will pinch, and probably tear. That defeats the whole purpose!
The solution is to simply double-check your tube during install.
Alignment – If your rim lock is not straight with the tube, it will not get a full bite.
To avoid misalignment, simply give your lock bolt a few good pushes against the tube before you tighten it. The rim lock is contoured enough that the tube will straighten it out for you.
Mounting Hole Is Too Big – This is caused by tightening the nut too tight too many times, and the hole is worn out.
You can fix this with a washer.
And the number one cause of a failed rim lock – It’s too loose!
I’ll let you figure that one out on your own.
A high-quality tire will have a steel band inside the tire bead called a bead wire.
When the metal cleats clamp down to the inside of the tire bead, they need something to clamp too.
Some low-quality tires don’t have a bead wire, so the cleats are just gripping rubber, and won’t be as effective.
Not sure if your tire has a bead wire? The best way to tell is to cut your tire in half. (Joke)
Rim locks are used for tires with inner tubes. Even if you run a mousse tube, you should still make sure your lock is installed correctly.
If you run a Tubliss system, I just made you read this whole thing for nothing.
If you have any questions or anything to add, please leave them in the comments or on our FaceBook page!