Bearings
 

I need to replace my head bearings but I'm not sure what to get. I have a 29 inch Genesis mountain bike GS29. Not sure what to get can anyone help?

What's in there now? The bearing covers should have a maker's name and model number. Just get the same bearings.

If unable to ID the spec from brand's website or other reference then falling back on the time tested method will have to do, take things apart and look/measure what's actually in hand (and not claimed to be, as on a spec sheet). Andy.

If you need to replace the balls in the headset just get the same diameter, usually 5/32".

If the headset is old school loose or caged bearings, disassemble, clean and reassemble with new grease. If the bearings are sealed cartridge type, remove the cartridge, carefully pry up the seal, clean and regrease. Headset bearings are for low speed support rather than high speed so a degree of wear is acceptable. If in doubt just replace loose balls or an entire cartridge. Cartridge ID is usually on the side or take to a shop for measuring. For grease use Phil’s, marine grease or my choice (just for headsets) - heavier moly. Likely plenty of DIY’s on youtube if needed. For loose bearings, a magnet is your best friend.