Work out Headset bearing size?

[livpoksoc]

Headset needs to be replaced (or at least serviced). I have done this job myself in the past, but can't remember how to work out the right bearing size. GCN always refer to Cane Creek, but they suggest you measure the bearings in the bike. All well and good but I'm tight on time and would prefer to do the disassembly once, pop the new bearings in and reassamble rather than do the job twice to measure up.

Any hints greatly appreciated. The bike is here:

https://www.sigmasports.com/item/Trek/Madone-31-C-H2-Road-Bike-2014/1KP7

 

[fossyant]

You've either got to get googling, or, and you won't like it, take the stem off and pop the bearings out and read the numbers on the side. It's not straight forward with headset bearings as you also need to come the angle of the inside and outside 'face' - the bearings usually come in 45/45 or 45/36 or 36/36, then of course there are many sizes.

 

[fossyant]

https://www.edgesportsuk.com/store/...kit-2011-and-later-acb3645-and-acb6808ss.html

 

[fossyant]

Personally, unless it's really gritty, bite the bullet and service them. Pop the seals off, blast them with brake cleaner (it's great for stripping dirty oil out), dry, then re-grease. Whilst at it, try and carefully read the numbers on the sides of the bearings. There is a good chance they may be worn off, but you might just be able to read them if you clean the sides.

 

[livpoksoc]

Personally, unless it's really gritty, bite the bullet and service them. Pop the seals off, blast them with brake cleaner (it's great for stripping dirty oil out), dry, then re-grease. Whilst at it, try and carefully read the numbers on the sides of the bearings. There is a good chance they may be worn off, but you might just be able to read them if you clean the sides.

True. Sod it, will do just that.

 

[livpoksoc]

Serviced the headset last night. Bottom bearing had markings on it 'acb680855', the top didn't have a serial, but did have 'cane creek 41mm'. Weird to have different markings. Is there a way to tell what size the bottom one is, as I can only find one stockist of the pair.

 

[OldShep]

Is there a way to tell what size the bottom one is

Simplest way I know is by using a vernier calliper.