MTB Shock Spacers & Hardware

How to choose your MTB shock mounting hardware

Spacers connect the shock eyelets to the frame mounting points. They determine the mounting width and bolt diameter, and must match each end exactly — as both sides do not always share the same dimensions.

The two dimensions to measure

• Width between the frame mounts: 21.8, 22.2, 25 or 30 mm depending on the model. Measure with callipers rather than relying on the frame spec sheet.
• Bolt diameter mounting bolt: 6, 8 or 10 mm.
• Both ends separately : it is common for a shock to require different hardware at the top and bottom, especially on linkage frames.

Metric or imperial

Recent frames are all metric, while older ones are imperial. RockShox kits often bundle both formats in the same box, which prevents mistakes if you are unsure of your frame's generation.

With or without bearings

• Bushing mount kits : the original standard, simple and durable.
• Bearing mount kits : they eliminate rotational friction in the shock eyelet, which is noticeably felt at the beginning of the stroke on small bumps. However, they require more frequent checks, especially in muddy conditions.

Inspect along with the bushings

Spacers and bushings work together and wear out together. A scored or ovalised spacer will destroy a new bushing in just a few rides: when you replace one, always inspect the other. This is the most common cause of a knock returning shortly after a repair.

To find out more: How to choose your MTB shock mounting hardware and bushings

See also: Shock seals and bushings · MTB rear shocks · MTB frame bearings