We’ve all done it.

You’re maintaining your pride and joy and you round out a bolt as you tighten or loosen it. You’ve turned the hexagonal shape of the Allen / Hex bolt into a circle, and there’s now no way to work on it.

If you’re lucky, the bolt isn’t tightened into a hole in your bike and you can use your fingers to remove it. If you’re less lucky, the bolt is stuck in place until you figure out a clever way to remove it.

Rounding or ‘stripping’ a bolt is normally the result of one or more common errors. Here’s PRO BIKE TOOL’s guide to how to avoid making those mistakes and save you causing your bolts some bother!




One reason bolt heads get rounded out is because the tools used to work on them are low quality. Lower quality tool bits are made from ‘soft’ materials that are liable to degradation over time, meaning the hard corners of an Allen key can become round with lots of use.

Working on a bolt with a rounded tool that does not fit flush into the bolt head increases the risk of the tool bit slipping inside the bolt – thus rounding out the bolt as well! This slipping is the result of a lack of adequate friction between the two surfaces.

So, one of the first steps to avoiding rounded bolts is ensuring that the tool bits you use to work on your bike are top quality stainless steel. Materials as hard as this do not degrade over time.

Guess what?! All the tool bits provided in our wrenches and multi tools are made from top-quality heat-treated steels and are almost impossible to deform, thus helping you avoid the dreaded rounded bolt!


Ensuring you keep your bolt heads clean during your regular bike-cleaning routine is a great way to avoid rounding them out. Debris or grease in the bolt head will reduce friction between the bolt head and the tool bit when you tighten or loosen the bolt. This makes it more likely that the tool slips inside the bolt as you work, opening up the possibility of rounding the bolt. Similarly, a rusty bolt head can deform and become misshapen over time, again compromising the connection between the tool and the bolt. To keep your bolts clean, spray them with a water-repellent such as GT85 and wipe it clean with a thin cloth (kitchen cloths work very well for this). Quickly doing this every time you clean your bike only takes a few minutes and can save you a lot of hassle!


No, that’s not supposed to be an innuendo. One of the main reasons people round out their bolts is because they fail to take the time to fully insert the tool into the bolt head when performing their maintenance. When in a rush, it’s easy to either half-insert a tool bit into a bolt head, or do so at an angle.

Either of these situations increase the risk of the tool slipping as you work, rounding out the bolt.

When we work on our bikes here at PRO BIKE TOOL HQ, we find that actually pushing the tool bit into the bolt as we unscrew it helps lower the possibility of the tool slipping in the bolt. It may sound counterintuitive to push the bolt as you unscrew it, but doing this ensures a safe and secure contact between bolt and tool. Make sure to only push gently though or you’ll never loosen it!


A common way to round out a bolt is by applying too much force to it when tightening. There’s only so much strain the hexagonal bolt head shape can take, and if this becomes too much, the metal will simply give way and leave a round shape.

To ensure you’re always applying the correct amount of force to a bolt, you should use a torque wrench to finish tightening a component, only applying the recommended torque for that part. This is primarily to prevent you damaging valuable components, but it will also stop you destroying your bolts.

We stock three types of torque wrench – a 3/8 inch set, a ¼ inch set, and a portable adjustable wrench. One for all needs and situations!