Sport And Biking Talk: How to: Proper bolt tightening patterns

Wednesday, November 30, 2016

How to: Proper bolt tightening patterns

Properly tightening your bolts in a specific pattern ensures that there is a uniform distribution of load across the part’s surface. Photo courtesy of Art’s Cyclery

Editor’s Note: This article is courtesy of the team at Art’s Cyclery. The original post can be found here.

So you’re installing a new chainring (or other critical component) and are wondering if there’s a specific pattern or way that you should tighten the bolts? Well, although this process may seem entirely simple, there’s more to it than simply tightening your bolts one-by-one. This holds especially true for those folks utilizing carbon parts. Press play to learn more.

//www.youtube.com/watch?v=qDN0SXEaj94

As a recap, there are three separate components that will utilize a specific bolt tightening pattern:

Chainrings (road and mountain) and cranks (road and mountain)
Disc brake rotors
Stem faceplates (road and mountain)

Properly tightening your bolts in a specific pattern ensures that there is a uniform distribution of load across the part’s surface. If you were to simply go one-by-one and tighten the bolts, the part may seat incorrectly and will end up with uneven pressure across its surface. Depending on whether you’re working on a 4-bolt, 5-bolt, or 6-bolt part, the process for tightening the part will differ.

Many different cranks and most stems utilize a 4-bolt pattern. Start by installing any bolts you’ll be using hand-tight. Start with the bolt in the upper left corner and tighten it down until it’s just begun to tighten. From there, you’ll repeat the same process on the bottom right bolt, then the bottom left bolt, and finally the upper right bolt, creating an “X” across either your stem or chainring.

Once all bolts are semi-tight, follow the same “X” pattern as before and go through one-by-one and tighten the bolts to their final torque specs.

Many cranks and chainrings utilize a 5-bolt pattern. Once again, install all bolts hand-tight in any particular order you like.

For all 5-bolt parts, you’ll want to tighten them down using a “star” pattern. Starting at top-dead-center, tighten the first bolt until it’s just begun to tighten. Going clockwise or counterclockwise, skip the next bolt, and repeat the process. Keep tightening every-other bolt until all five are slightly tight. From here, follow the same “star pattern” and tighten each bolt to its final recommended torque spec.

All disc brake rotors have a 6-bolt pattern. After tightening all 6 bolts by hand, start at top-dead-center and tighten your bolt. From there, you’ll want to go straight down, upper right, lower left, lower right, and finally upper left. Repeat the same process and tighten each bolt to the manufacturer’s recommended torque spec.

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