Has anyone tried this? My headset bearing is an odd size and impossible to get hold of.

The bearings are definitely rusty but not sure if race will be knackered too??

It’ll be knackered.

Just get a new headset with common bearings?

What headset is it/what frame?

Planet X nanolight

Lower bearing is 51.5mm diameter, an odd size. I have been searching for ages.

Only “in stock” option I can find is planet X headset for £50 which is different but has common lower bearing. Ribble has another headset that will work…due back in stock March. Nothing elsewhere.

£50 is a lot of money for a cheap bearing!

I assume you mean replacing the cartridge in a lower headset cup? Have you removed the old one? There should be a number on it.

My question is about replacing the loose bearings within the cartridge bearing itself.

I know the dimensions 51.5x40x7 45o.

Bit of a warning really against buying Chinese catalogue frames with random headsets!

Are you sure it’s not a 52mm OD?

Otherwise, I’d pop of the seals with a sharp blade, flush the bearings and then repack with grease.

Replacing the balls? That’s impressive, good luck!

Surely it’ll be 52x40x7?? – Superstar components Type 2 for example.

Surely it’ll be 52x40x7??

It’s a planet x. It’ll be whatever they’d have got cheapest.

I don’t think it’s going to work.

New headset time.

Bit of a warning really against buying Chinese catalogue frames with random headsets!

Catalogue frames tend to use common sizes everywhere they can – hence the cheapness. Definitely worth getting the bearing completely out and checking for a number.

To answer the original question – can’t be done

These guys have a 51.8x40x8 45 degree:

here

Could be made to work if the bore is a bit over. I take it it’s going into a carbon bore on the frame, rather than an alu cup? If so then some very careful sanding would get you there.

They also have a 51x40x7. If you put a *very* slightly greasy (as in wiped off) bearing in to the bore with some toughened epoxy at the sides, and assemble the headset before it dries (and rotate the bars a bit to ensure it’s squared) then it’ll sit where it wants to be and should still be fairly easy to remove when you need to. Degrease the frame a lot first, and the epoxy should stay put permanently

Neither of these are good for your frame warranty (but this is PX, so meh), and the first is obviously a bit more drastic… Up to you if you think the material is thick enough.

Definitely not 52 (tried it and 0.5mm surprising difference). There are basically 3 frames that use this as far as I can find. Nanolight, Ribble R872 and a De Rosa one.

From scouring various forums can definitely confirm lots of cheap Chinese frames use random headsets!

It’s an alu cup, would the epoxy trick work with that? I like the idea of sanding too. Thanks for this.

Have a friendly turner take a skim off the bore then use 51.8 or 52?
Or if using a 51, Loctite do some stuff that fills loose tolerances.
Bodgers R Us

No worries! Epoxy would work in an alu cup. Sanding would work on an alu cup, but only if it’s much thicker than what you’re removing.. I’d tend towards filling in that case.

Bearing seating compound would also work, but not be quite as impact resistant as epoxy.. Loctite 6xx or similar is meant for gaps up to 0.1mm, but if you use it with an activatior spray it’ll go a bit bigger. The problem with that is that it’ll set hard with the activator before you have time to get the headset together. It may also be harder to remove the bearing later as it bonds to the metal. Hence why using the very thin coat of grease on the bearing with epoxy. It’ll form the shape, but hopefully prevent bonding.

Bodgers R us indeed! 🙂

I have an old Ribble carbon frame in the shed. I’ll see if the headset is salvageable tonight.

Bit of a warning really against buying Chinese catalogue frames with random headsets!

My On-One (Planet X) tapered headset uses the same bearing sizes as a standard tapered Hope headset. Which is handy as all my bikes use the same headset bearings basically, some of which have Hope headsets. I get the same spec bearings from simplybearings.co.uk.

Anyway, Nanolight headset / bearings…

http://www.bikeradar.com/forums/viewtopic.php?t=12796015

there is one listed here, but it’s not obvious if you can buy one

https://www.euroasiaimports.com/ProductCart/pc/Cobra-Integrated-Road-1-1-8-inch-x-1-1-2-inch-Headset-for-Tapered-Forks-2455p18753.htm

It’s a tapered bearing, the 51 should fit perfectly well once the taper comes into play. It’ll just self centre and pretty much wedge itself into place. Might seat fractionally lower (?), but the change between 51.5 and 51 will be miniscule. If there is any difference at all.

Weren’t these three actually the same frame?

Nanolight, Ribble R872 and a De Rosa

Can vaguely remember reading something about it somewhere, and maybe the Orange road bike being another identical/near identical frame.

I’ve recently opened, fully disassembled, cleaned, greased and reassembled a sealed cartridge headset bearing on my bike – easy job! Just make sure you are always ready to catch the bearing balls, as they tend to jump out in the most unpredictable moments… 8)

I’ve done an old STX cartridge headset on my classic MTB, but if bearings are rusted, it often means the races are pitted.

Have you visited your local bike shop or bearing company?

I’m always amazed just what a good bike shop can find for you.

Where are you based?

For the time and effort involved in replacing the teeny tiny balls in a cheap and now knackered headset, I’d just fit a new one.

Replace the cartridge yes. Replacing the whole headset is pointless/faff, unless it’s knackered, or like the OP you can’t find the cartridges.

Except cage bearing headsets. Knackered balls probably means knackered races in the headset, thus new headset.

Ditto replacing the balls in a cartridge. Just get a new cartridge really. If they’re not too bad you can just clean them up and regrease, but it’s really a lot of hassle. I’ve tried before and only way to avoid grinding is to pull the cartridge apart and then I find it doesn’t go back together so well, and still there’s some grittyness in it.

p.s. Asked Planet X what bearings they used?

Now stocked by Kinetic Bike Bearings (very rare bearing):

https://www.kineticbikebearings.com/acb515h7.html