Threadlocker
Threadlocker is a liquid that keeps bolts from shaking loose. Use medium strength blue where a part must come apart again; Park Tool's 10 ml bottle lists at $19.95.
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Threadlocker is a liquid you put on bolt threads that sets once the bolt is tight, so it won't shake loose. Medium strength can still be undone with hand tools, which is what most bike bolts need.
What it's used for
- Chainring bolts and some direct mount chainring lockrings. Park Tool suggests mild threadlocker or grease on chainring bolts (Park Tool). See check cranks and the bottom bracket.
- Small bolts that keep backing out, such as bottle cage bolts. The Competitive Cyclist listing gives these as an example use for the blue strength (Competitive Cyclist, Park Tool Threadlocker).
- Any bolt your bike or part maker says to secure with threadlocker. Check during a bolt check.
What to look for
- Medium strength (blue) for most jobs. The listing says Park Tool's blue is comparable to Loctite 242 and 243 and is for bolts that need to come off easily (Competitive Cyclist).
- High strength (red) only where the maker calls for it. The same listing says red is comparable to Loctite 262 and 263 and is for high load bolts that are rarely taken apart, such as suspension pivots (Competitive Cyclist).
- Not for titanium. Park Tool recommends anti-seize instead on titanium (Competitive Cyclist).
- Prime as directed. Park Tool recommends its primer on parts and carbon surfaces first, and warns that skipping it can leave parts permanently bonded (Competitive Cyclist).
Never put threadlocker on electrical connectors, battery contacts or motor axle nuts unless your bike maker says to.
Best price we found
- Park Tool Threadlocker, 10 ml at Competitive Cyclist: $19.95, checked Nov 9, 2026
- Park Tool TLR-1 Medium Strength Thread Locker, 10 ml at Excel Sports: $19.95, checked Nov 9, 2026
Prices change often, and a local shop may match them.
Where to buy
- A large bike retailer, as above.
- A local shop, through find a shop.
Guides that use it
Sources
- Competitive Cyclist, Park Tool Threadlocker, competitivecyclist.com
- Park Tool TLR-1 Medium Strength Thread Locker, 10 ml at Excel Sports, excelsports.com
- Park Tool, parktool.com
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