Chains
Used MTB chains from UK sellers, matched to your drivetrain's speed count — Shimano, SRAM, KMC and YBN. Chains are consumables and the most important wear item in your drivetrain, so check elongation before you commit to one.
Why replace the chain before the cassette?
The chain is the most frequently replaced drivetrain component and the one that dictates the lifespan of everything else. A worn chain accelerates wear on your cassette and chainring, so replacing the chain on time is cheaper than replacing the entire drivetrain. Unlike a set of pedals, a chain is bought expecting it to wear out.
Which chain matches my drivetrain?
Chains are specific to your drivetrain's speed count — a 12-speed chain is narrower than an 11-speed chain, which is narrower than a 10-speed. Using the wrong chain width causes poor shifting, excessive wear and potential chain drop, however well the rest of your MTB components are set up. Shimano and SRAM 12-speed chains are cross-compatible in practice, though both brands recommend their own, and KMC and YBN make quality third-party options in all speed counts.
How do I check a chain for wear?
A chain wear tool (Park Tool CC-3.2 or similar) is the definitive way to check. Replace at 0.5% elongation for 11 and 12-speed drivetrains, as the narrower chains and cassettes are less tolerant of wear than older 10-speed systems; at 0.75% elongation, you have likely damaged the cassette too. Checking every 300-500km saves money in the long run. Some riders get 1,500km+ from a 12-speed chain in dry conditions; in UK winter mud, 500-800km is more realistic.
Quick link or connecting pin?
Most modern chains use a reusable quick link (master link) for installation and removal. SRAM chains come with a PowerLock that is technically single-use, though many riders reuse them without issue, and Shimano chains can use either a connecting pin or a quick link (SM-CN910 for 12-speed). KMC's Missing Link is the most robust reusable quick link design. Carry a spare quick link on every ride — a snapped chain is the most common trail-side mechanical.
Which chain lube should I use?
Clean and lube your chain after every muddy ride, or every 100-150km in dry conditions. Wet lube lasts longer in rain but attracts more grit; dry lube stays cleaner but washes off in wet weather. Wax-based lubes (Squirt, Silca Synergetic) offer the best of both worlds but need the chain stripped completely before first application. A clean, well-lubed chain shifts better, runs quieter and lasts longer.