Angular contact bearings – fitting and which way around.

My bike’s main pivot runs on EnduroMax 7902 angular contact bearings.

Most of the instructions seem to assume these come with one blue seal and one black seal but it seems they’re not actually made like that any more (blue on both sides).

From Wych bearings – When fitting these angular contact bearings ensure the load is applied to the inner ring on the black seal side of the bearing. Usually this means the black seal should be facing out

That seems odd for a start as usually you fit with pressure on the outside edge to avoid landing the bearings and you press them in…

Nicolai’s instructions are that The bearing Enduro MAX 7902 2RS must be mounted with the blue face towards the middleaxis of the swingarm.

The bearings I’ve got have two blue faces but the inner ring on one side is thicker. Does the wide inner rim go facing the frame or facing out?
What surfaces do you press it in on (assuming that you don’t have a specific tool to do it and are planning to bodge something out of washers and sockets)

(also, when it says ‘load’ is that load when in use, or what you can press on to fit them)

I don’t know about Nicolai specifically, but angular contact bearings have a bigger lip on whichever face of the inner ring is supposed to be loaded (I.e. supposed to contact the other surface). This usually faces outwards from wherever you’re trying to press it in.

From memory, I thought it was usually the blue side facing out although I’m not 100% sure on that fact and it doesn’t apply in your case anyway (and of course, manufacturers could change the colour). It looks like the instructions from Wyche and Nicolai are at odds with each other. I think I agree with Nicolai.

In theory I suppose you should press it in only around the outer ring.
I’ve never bothered to be that fussy.

‘Loaded’ will mean loaded when in use.

I’m pretty sure it means load when i use, not the load when pressing them in. Always press on the outside in my opinion.

Nicolai’s instructions are that The bearing Enduro MAX 7902 2RS must be mounted with the blue face towards the middleaxis of the swingarm.

The bearings I’ve got have two blue faces but the inner ring on one side is thicker. Does the wide inner rim go facing the frame or facing out?

Does looking at the old bearing you are replacing give any clues?

@Rubber_Buccaneer

Does looking at the old bearing you are replacing give any clues?

I replaced the bearings a while back. The replacement set seem to have failed much quicker than the original set so I’m not confidant I fitted them the correct way around last time….

It looks like the instructions from Wyche and Nicolai are at odds with each other. I think I agree with Nicolai.

Not necessarily – I found an old thread about Canyon bearings that was asking a similar question. The bearings are fitted into the swingarm and I *think* the loaded lip should face inwards (ie towards the middle of the bike) as the swingarm is then clamped top the mainframe so the load is on the inside face of the swingarm.

Not necessarily…

I was referring to the blue vs black argument. But yes it’s possible to install bearings facing inwards.

But essentially unless you’re installing the bearings into a very atypical frame design*, then the large inner ring should always face towards you as you’re hammering** it in. Or to put it another pay, away from the direction you’re installing it into.

* I’m thinking if hypothetically the pivot could be ‘behind’ the plane in which you’re pressing the bearings – but I’ve never seen it on a mountain bike.

** Other tools are available. Allegedly.

@b33k34 it so happens I have a bearing kit for a 2016 Ion GPI (fits others too) in the shed so I just went to take a look.

The instructions I received from Nicolai say for the main swingarm pivot

Attention!!! The bearing Enduro Max 7902 RS must be mounted with the blue face on the inner direction (bearing seat direction).

And my bearings have the blue and black seals.  The blue seal is on the side with the thinner inner race.  I will try to link to a photo

One of the pivots on my (Canyon) bike is like the ‘hypothetical’ – the bearing is specced so the inner seat is also wider than the outer (to fit through a hole in the seatstay). But that’s the only one I’ve seen like that. I don’t know how common it is.

View post on imgur.com

So I think that means the correct way is as Superficial says, the thin race is on the side facing in while the fat race is on the side you are pushing against

The thick lip trumps the colour. The black side (in your case) is the side for the inner to be loaded.

I think it all agrees with what you are saying, as per your ‘Normal’ diagram the blue seal goes in first and the black with the fat race faces out.  You, Nicolai instructions and the colours all agree…..don’t they?

From an engineering point, as long as you don’t need to allow for things heating up and expanding, it doesn’t really matter if bearings are mounted face to face, or back to back, as long as they mirror each other.

The big catch is if you’re relying on the inner/outer to hold the outer/inner in place.
I.e. if you’re relying on the outer races being held in to their bore/seat by the inner races being clamped together, putting them in the wrong way will mean the outers don’t get clamped in place and everything will just fall apart.

You, Nicolai instructions and the colours all agree…..don’t they?

Sorry. Yes – having re-read the OP I now realise I was imagining the Nicolai swingarm in a way that might be wrong (I’ve never looked at one closely).

One last thought OP, you could seek advice from Geometron Bikes.  They will have replaced a few Nicolai swingarm bearings