I just replaced the bearings in this hub. They're seated properly and in as far as they go; I used a large deep socket and a mallet to carefully tap in the outer races. But the axle has about 1mm of side-to-side play, as if the shoulders on the axle weren't spaced quite wide enough. If I tighten the lock nuts against the inner races, I can stop the bearings from moving. That shouldn't be possible; those races should lock up against the shoulders on the axle without loading the bearing.

It's as if the axle never was right in the first place, which is possible (I bought these wheels used). These are Suzue hubs. The shoulder-to-shoulder measurement on the axle is 70mm, which I thought was standard, and looks correct. There were no washers on the axle 'inside', between the bearings and the shoulders; but maybe there should have been. I don't know what else to think.

The most obvious answer is one or both the bearings have not been seated far enough. Make sure the socket you are using is not too large so it's diameter is not larger than the bearing.

Logically I'd have to agree, but both the bearings were solidly driven in. I conclude that the axle is not the original, and the shoulder-to-shoulder distance is wrong for this hub, and is really supposed to be 71.

I removed a bearing and added a 1mm spacer between the axle shoulder and the bearing race, on the non-drive side; drove the bearing in again, tightened the locknuts and it feels perfect. I'm going with this slightly dodgy fix. And next time I won't buy used wheels with unknown history.

I just checked the rebuild kit and it looks like it comes with a couple of spacers ; if they are .5mm@ it would explain you problem and solution..

Thanks for that info. What rebuild kit were you looking at?

When I got these wheels I was told they were from a tandem. I've since found out that Suzue in fact made "tandem" hubs. I don't know what's different about a "tandem" hub, but I found out there's a Suzue tandem axle available - with a shoulder-to-shoulder of 71mm. So one possible explanation is that someone replaced that axle with one having 70mm spacing.

Another possible explanation is the one you found, which is why I'm wondering what that kit was.

This is what I found; I don't know if the axle would fit your hubs..
https://www.amazon.com/dp/B001CC9GE6/...SIN=B001CC9GE6

I also found the tandem axles you were looking at.https://www.sjscycles.co.uk/suzue-tan...s&currency=usd Apparently the old Suzue tandem axle had a habit of bending but these new ones are better. The old axle could very well have bent was replaced with the wrong axle.

$81 for one axle. It had better not bend, for that price. :-)

I've taken apart a Suzue hub that had cartridge bearings. It had a small spacer on the axle, presumably it was there to give the proper spacing. Looked like a washer. I'm pretty sure I was the first to disassemble it since it left the factory. Maybe yours have been rebuild and the spacer dropped and lost?

Axles always break on the inside of the cone on regular axles. https://share.ovi.com/media/currentre...resident.10052 On sealed bearing hubs they will break where the axle meets the bearing seat I have one around here somewhere meanwhile here is somebody else's https://www.flickr.com/photos/loosenu...ls/4535130882/ This is not all bad it moves the stress point out 10mm making the axle effectively 40/30 or 1.33 times as strong not indestructible but better.