Grease is the word

Does unused grease and oil deteriorate or degrade over the years, and is it advisable to renew ball bearings when servicing a wheel?

Tony Broadberry

Unused oil and grease can degrade over time – the former usually through contamination with moisture, and the latter by hardening and separation of the base fluid and thickener. Storage life as stated by the manufacturer might be five years for motor oil and two years for specialist greases. In practice, either oil or grease kept under suitable conditions will remain usable for decades provided it is not to be subjected to extreme service conditions.

If there’s no sign of wear or damage in bearings, there’s no point in replacing them. Cartridge bearings should be checked for roughness, free play and any visual sign of damage such as rusty seepage past the seals or shields. Any of these means they should be replaced with new bearings having the same numerical code, e.g. 6805. The balls in cup-and-cone bearings should be visually inspected for pitting and rust. If either is found, the races and cones may need replacing at the same time (if available).

Richard Hallett

Cycle Technical Editor

​This was first published in the August/September 2015 edition of CTC's Cycle magazine.

This Q&A was published in 'Cycle' the magazine for members of Cycling UK. To contact the experts, email your technical, health, legal or policy questions to or write to Cycle Q&A, PO Box 313, Scarborough, YO12 6WZ