Chain Tools

What does a chain tool do, and which type should I buy?

A chain tool drives the rivet part-way or fully out of a chain link so the chain can be shortened, removed or rejoined. Bench tools such as the Park Tool CT-3.3 use a long handle and a hardened driving pin, with a second cradle position for easing a stiff link back into line; folding versions like the Park Tool CT-5 do the same job with far less leverage and are built for roadside repairs rather than repeated workshop use. Listings often bundle related chain tools, so expect to see master link pliers such as the Park Tool MLP-1.2 and wear gauges like the Park Tool CC-3.2 in the same sale.

Will an older chain tool work with 11- and 12-speed chains?

Modern chains are narrower across the outer plates, around 5.2 to 5.3mm on 12-speed against roughly 7mm on a 1/8in single-speed chain, so a tool cut for 5- to 8-speed leaves the plate unsupported and can dish or crack it as the pin goes through. Sellers usually quote the speed range stamped on the tool or printed in its instructions, and it is worth asking for a photo of the cradle. Chain systems also differ at the joining stage: Shimano road chains have used a one-use joining pin driven with a tool such as the TL-CN28, SRAM uses the PowerLock quick link, and Campagnolo 11- and 12-speed chains need the brand's own peening tool rather than a general breaker.

Do I still need a chain tool if my chain uses a quick link?

A KMC MissingLink or similar quick link lets you split the chain with master link pliers alone, which covers cleaning and most trailside fixes. Fitting a new chain still means removing surplus links to set the length, and that needs a breaker. Riders who only ever open an existing chain can get by with pliers, but anyone buying chains by the box will want both.

How is a chain tool different from the rest of a hand tool kit?

Chain tools are single-purpose: the driving pin, the cradle and the thread pitch of the handle all exist to sit a chain rivet squarely under a punch, and nothing else in a hand tool kit will do it. General pliers will not open a quick link cleanly, and the allen keys and wrenches that handle the rest of a drivetrain stop at the chainset bolts. Most people buy a chain tool as an addition to a kit rather than as part of one.

What wears out on a used chain tool?

The driving pin is the part that fails: look for a tip that is bent, blunted or mushroomed, since a pin off-centre by even a fraction will push a rivet out at an angle and ruin the plate. Wind the handle in and out and feel for slack or grit in the thread, then check the cradle where the chain sits for peening or a cracked shoulder, which stops the roller sitting square. On folding mini tools, check the alloy body for flex and hairline cracks at the pivot, and on master link pliers check the jaw tips have not splayed. Tools stored in a damp shed often have surface rust on the pin and stiff threads, which is worth pricing in.

What is a fair price for a used chain tool, and when should I buy new?

Steel bench tools last for decades of light home use, so a well-kept older workshop model in full working order is usually a better buy than a new budget one at the same money. Check first whether replacement driving pins are still sold for that model, because a tool with a broken pin and no spares available is worth little more than scrap. Buy new if you need documented support for a specific 12-speed chain, or if the tool is going into a saddle bag where a cracked body would leave you walking.