Dura-ace C50 hub service

Changing the cassette on my C50's - I thought I would have a look at the bearings - they are a year old now give or take.

A quick read up online - and I was amazed. What an evolution.

I switched from cup and cone as quickly as there was an option.

I used to use Shimano, and Miche hubs back then. I was me. I took them to bits, I ensured they were greased - hell for winter hubs I put bits of old inner tube packed with grease over the exposed cones to help with sealing.... but whatever I did - I ended up with pitted and scored cups and cones.

My first pair of handmade wheels where from the local guy for Thanet RC the legendary Harry Rowland Wheelsmith. They had wide bladed spokes (wider than modern ones), hand filed hubs, and the key here - Mavic 501 hubs - with pressed bearings.

They lasted, and lasted and lasted. No ticking, no rumbling just smoothness. In fact - I got them as a teenager, and they are still in the shed now. Along with about three other pairs of Mavic 501 hubs (screw on blocks - Sachs Mailard as it happens - pre-dating freehubs and cassettes).

Anyway - as such I have a bet of a reservation on cup and cone angular bearings.

Sure you don’t need a bearing press.

Sure you have bearings being efficient when cornering.

Sure you can adjust them.

I just feel a bit like they are going to fall to bits under me.

So here I was taking a pair of modern Dura-Ace hubs to bits. Nerves much?

Opening them up they are clean, mirror finished, with the familiar fluo yellow Shimano grease throughout.

The opening involves skewer out, and then two 5mm allen keys on each side to remove a locking nut from one side.

Then a dust cover slides off. The dust cover is keyed to the flat sided axle.

Inside the dust cover is a splined recess which engages with the splined outer of the cone on that side.

Removing that means the axle can be removed.

However - here is the key - you can adjust the cone WITH YOUR FINGER TIPS.

Oh My [Deity Of Choice].

... then replace the dust cap with the flat edged retainer that engages with the splines , and you lock in and pre load with the outer lock with the 5mm keys again.

What a truly inspired system.

This being said - the washer / seals had me stumped. YES I kept them separate, yes they only go in on one side, however the one for the drive side  (now shown in this picture) - goes unfinished side out.

I know this as a spent an afternoon scratching my head when assembling nice side out to find the wheel would barely turn. Arse. Trashing a pair of top of the line hubs was not something I had scheduled for the weekend strangely enough.

Re assemble no seals - and moves freely - proving the point.

Re assemble unfinished side out - turns freely again. Great success.

What a genius design. Thank you Shimano bods.


The front differs in that the two side seals are the same, and the bearings are the same on both side. However the axle and adjust / lock are the same. The bearings are caged which is convenient.

The rear differs in that the drive side has large bearings - 13 of them, and a different seal for that side.

Remove, clean, and pack with ceramic grease before re-assembling.

Vaguest of ticks in front, gone, and play in rear, gone. Result.


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