MTB chain guides and bash guards

How to choose an MTB chain guide

In enduro and downhill riding, a narrow-wide chainring and derailleur clutch are not always enough: the chain guide keeps the chain secure, while the bash guard protects the chainring from impacts. OneUp, e*thirteen and Shimano cover common setups, including e-MTBs.

Which mounting does my frame have?

• ISCG05 : three tabs around the bottom bracket, the most widespread standard.
• ISCG (older, known as ISCG03) : same principle, different bolt spacing, on older frames.
• BSA bottom bracket mount : a plate clamped between the frame and bottom bracket, for frames without mounting tabs.
• Motor mount : Bosch, Shimano and Brose e-MTBs have their own interfaces.

Chain guide only, bash guard only, or both?

• Chain guide only : sufficient for enduro riding to retain the chain, with minimal weight.
• Bash guard only : protects the chainring on rocky sections without retaining the chain.
• Complete set : the choice for downhill and bike parks.
• A top guide only, being lighter, already covers most of the risk of chain derailment.

What chainring size?

Each guide specifies a compatible tooth range, generally from 28 to 38. The slider must follow the chainring radius: if it is too large, it lets the chain pass through; if it is too small, it rubs constantly.

Wear parts

Upper and lower sliders are consumable parts, available individually. Replacing them costs far less than a complete guide and can be done without removing the crankset on most models.

See also: MTB chainrings · MTB chains and quick links · MTB cranksets and crank arms