Pitlock Hex Bolt Security

Protect Your Hex Bolts With Pitlock Pitstoppers

Pitstoppers are Pitlock’s solution for protecting the components on your bicycle secured by Hex bolts (Allen bolts.) Although Pitstoppers are not uniquely keyed, they’re extremely easy to install and uninstall with the right tool, extremely difficult to tamper with, and prevent all but the most determined thieves from making off with your valuable parts.

Pitstoppers come in four sizes to accommodate nearly every bicycle component, from bells to racks to saddles. Although they may look perfectly cylindrical at first glance, they’re actually slightly conical, which prevents them from working their way loose after being pressed into place. See below for sizing details, instructions on how to install / uninstall, and our list of FAQs.

If you have any questions, please contact us.

To purchase, please visit our Pitstopper page.

Sizing Details: How To Determine What Pitstopper You Need

Pitstopper sizes refer to the thread diameter of the bolts they secure. This is not the same as the size of the hex wrench (Allen wrench) used to remove the bolt. For example, an M8 Pitstopper will fit a hex bolt with an 8mm thread diameter; a bolt this size will be removed with a 6mm Allen wrench. You can easily measure your hex bolts with an Allen wrench, and use the sizes listed here to determine the correct Pitstopper required. Here are the available Pitstopper sizes, and their corresponding hex wrench sizes:

  • M5 = 5mm thread diameter, which requires a 4mm wrench
  • M6 = 6mm thread diameter, which requires a 5mm wrench
  • M8 = 8mm thread diameter, which requires a 6mm wrench
  • M10 = 10mm thread diameter, which requires an 8mm wrench

image demonstrating how to determine which pitstopper size you need

Installation Tips!

  • To remove Pitstoppers, there must be a backstop for the screw to push against. If the socket is too deep, add a small spacer (such as a ball bearing padded with material to prevent rattling.) 
  • Tap the Pitstoppers into place very lightly to prevent damaging your bicycle. There isn’t much force required, you only need to wedge them in place!

Installation Instructions

To install Pitstoppers, follow these steps:

  1. Clean the hex socket by removing any dirt or debris that has accumulated there, and prep it for installation by greasing the inner surface. This will prevent corrosion, which may make removal of the Pitstopper more difficult.
  2. Insert the Pitstopper into the hexagonal socket of the Allen bolt. If the Pitstopper does not easily fit, turn it upside down. Pitstoppers are slightly conical, and therefore can only be installed from one direction.
  3. Press the Pitstopper in by hand, and then gently hammer the protruding area into place until it is nearly flush with the bolt’s head. You should be unable to use pliers to grip the Pitstopper.
To uninstall your Pitstopper, follow these steps:

  1. Insert the screw that came with your Pitstopper set by hand, being careful not to cross-thread it.
  2. Once you’ve fully inserted the screw by hand, use a Phillips-head screwdriver to drive the screw against the base of the hex socket. As you drive the screw in, the Pitstopper will pop out because it is only held in place with an interference fit.

Frequently Asked Questions

How many Pitstoppers come in each package?

Each set of Pitstoppers comes complete with two Pitstoppers, and one screw.

How do I install Pitstoppers?

Please see our instructions above, or watch our installation video.

Can I use Pitstoppers to protect my saddle?

Yes! The most commonly sized seat bolt will require an M8 Pitstopper.

Are Pitstoppers Unique?

No, the Pitstopper screw isn’t uniquely keyed, unlike the rest of Pitlock’s products. However, the screw that comes with your Pitstoppers have a non-standard thread and pitch, which means that they can only be easily removed with the screw that came with your set. Do not lose this screw! Keychain containers are available to help make keeping track of these tiny screws easier.

Will Pitstoppers fall out?

Pitstoppers rely on an interference fit (also known as a press fit) to hold them securely in place. They are slightly conical in shape, and gently hammering them into place during installation will keep them from falling out (even while commuting over the most horrendous potholes in your city!)

Can I use a magnet to remove a Pitstopper? What about a pick? Can other screws be used?

Without the proper tool, Pitstoppers are extremely difficult to remove. Pitstoppers are non-magnetic, and will not be removed with a magnet (even a rare earth magnet!) We can’t say it’s impossible to remove them without the screw included in the set (even Pitlock skewers can be defeated by a dedicated individual with an angle grinder…), but they’re highly tamper-resistant. Pitstopper screws have a non-standard thread and pitch (which makes them hard to purchase, and is why we don’t publish it.)

Can I only install Pitstoppers once?

Pitstoppers are intended to be reused over and over again. Each installation and uninstallation should not reduce their longevity.

What size do I need?

Pitstoppers sizes correspond to the thread size of the bolts they fit. This is not the same size as the hex wrench / Allen wrench used to remove the bolt. Please see our measurement guide for further clarification. Here are the available sizes of Pitstoppers, and the hex wrench sizes they correspond to:

  • M5 = 5mm thread diameter, which requires a 4mm Allen wrench
  • M6 = 6mm thread diameter, which requires a 5mm Allen wrench
  • M8 = 8mm thread diameter, which requires a 6mm Allen wrench
  • M10 = 10mm thread diameter, which requires an 8mm Allen wrench