I bought a NOS Ridley supercross earlier in the year, just building it now to find they don’t make headsets for them any more.
I need an FSA Z-41CX with press cups for frames with a headtube with 48mm OD and 43mm ID
All the new ones are for 50mm OD and 44 ID frames
Once I have the cups it takes standard sealed bearings.

So ream? reduce? or have a set made?

If anyone has the right headset!

Ream it out? Won’t be cheap though.

Not sure about going down to a 2mm thick headtube myself.

how much meat is there on a normal headset cup? Could you get 0.5mm taken off?

Found them on ebay searching for FSA Z41, without the CX.

Sellers – random.bike.parts and crosslakesales, both in America, if you know someone who can buy it and send it for you.

how much meat is there on a normal headset cup? Could you get 0.5mm taken off?

Should be enough material there, will be a bit of a pig to machine though.

I wouldn’t ream the head tube down – strong chance of it cracking in use if you do that.

What’s the headset material like? I’ve modified cups and races before, if they’re aluminium or normal steel they’re machinable, if it’s a hardened bearing race then trickier.

FSA tech docs list the OD of the cups I need as 43.5mm. The OD of the cups on current Z headsets are 44mm that 0.5mm overall but too much to force in. Perhaps reduce the press fit cups which are aluminium?

Once I get the cups in it just takes regular bearings. In fact the old and new headsets take the same, It’s just that headtubes went from 48mm OD to 50mm OD
The old Canondale Supersix were the same.

Well if it’s aluminium then easy to turn down. Happy to do it for you if you can’t find anyone local.

Thanks everyone at least I have options, those Ebay US ones look right, found some listed here but they turned out to be later larger ones.
bencooper thanks, I’ve got a local chap. The cups are straight and 10mm deep (into frame) sounds quite easy? though I’ve no idea.

Cutting it fine no built bike and racing in three weeks.

Should be easy for anyone with a lathe then 😉

🙂