After discovering that my bottom headset bearing is shot, I've been looking for a replacement. When I bought my RAG+, the headset specified is just IS42/IS52, while NS Bikes sell one, the Brand X one looked similar (ish), and was much cheaper, so I went with that.

So it turns out that replacement bearings come in different thicknesses, and with different angles to the taper, who knew? So while I can find bearings, I've got no idea what I should be putting in the frame. 45°/45°, or 45°/36° taper, 7mm, 8mm 9mm for the thickness.

Evidently the Brand X one is 9.7 ± 0.5mm, no idea what the NS Bikes one is, or this Cane Creek one. These headset bearings on the Wych Bearings website seem to come in all sorts of thicknesses...

So which bit of my bike do I need to measure to figure out what bearing I need...?

Far as I know. The angle is mainly for the bottom bearing. 45 or 36 will be dependent on the angle it marries to the crown race. If it looks shallow (the crown race angle) then it'll be 36 degrees. If its looks perfectly angled at 45 degrees, then, erm, it'll be 45

Hope that helps...

If you look up S.H.I.S in the ParkTools site it explains the various current stabdards of headsets

It's more the thickness of the bearing that I need to calculate. I have no idea how much of a gap there should be between the headtube and the fork. If I measure up into the headtube, to where the bearing sits, how much do I need to subtract to compensate for the race etc.

Are you replacing an existing bearing that's worn out? If so measure the bearing you have.

sean_iow wrote: ↑Sat May 23, 2020 5:33 pm Are you replacing an existing bearing that's worn out? If so measure the bearing you have.

I bought the headset separately to the frame and fork, I didn't know they came in different thicknesses, I just assumed IS42/IS52 was a "standard"... My existing one, which I have issues with, is 9mm, just don't know if I should get an 8mm or 7mm or try and find another 9mm.

Is it possible to email frame manufacturer and ask for more precise bearing type and sizes required?
Unfortunately, steering bearing combinations are numerous.

Cyclepeasant wrote: ↑Sat May 23, 2020 10:14 pm Is it possible to email frame manufacturer and ask for more precise bearing type and sizes required?
Unfortunately, steering bearing combinations are numerous.

I sent them a message yesterday, not hopeful of a speedy response...

The plot thickens, found this comment in a review of my headset:

I didn't realise when I bought this that there are at least two standard sizes for the top race: 31 and 31.8mm. my frame (on one carbon 456) takes 31, this is 31.8 which is apparently a Campagnolo standard. I feel this should have been made clear in the description.

I have no idea how true this is, as I don't have calipers to measure with. It would, however, explain the tiny bit of play that I get. At this point, I may as well just buy a whole new headset and be done with it. So...

Are headsets something that you get your moneys worth from? I.e. is it worth spending a bit more, on say a Cane Creek Hellbender 70, rather than another cheapo one...?

K1100T wrote: ↑Sun May 24, 2020 11:46 pm The plot thickens, found this comment in a review of my headset:

I didn't realise when I bought this that there are at least two standard sizes for the top race: 31 and 31.8mm. my frame (on one carbon 456) takes 31, this is 31.8 which is apparently a Campagnolo standard. I feel this should have been made clear in the description.

I have no idea how true this is, as I don't have calipers to measure with. It would, however, explain the tiny bit of play that I get. At this point, I may as well just buy a whole new headset and be done with it. So...

Are headsets something that you get your moneys worth from? I.e. is it worth spending a bit more, on say a Cane Creek Hellbender 70, rather than another cheapo one...?

I used to take the top end headsets (thats where the cheaper bikes/builds save their money) from the top end bikes I used to strip down for parts then fleabay owt worth selling. Meant I had some decent headsets to use.

I wouldn't go cheap (only got the Brand X to make do as the bike was costing me a fair bit to get up and running) and yes you do get what you pay for IMO. But there's obviously a limit. I reckon about £40 budget for a headset would get you a nice and decent one... Anything more than about £50 is probably getting into the extravagant extreme but many do and are happy with their decision

Oh FFS!!! How hard can it be to find a headset that fits!



I give up...