Rear wheel bearings shot warranty ???

[davebike 943]

I have probably said it before but  MY view is

The common cause of early wheel bearing fail is two-fold

Lack of grease when you have a wheel out grease the bearing and spindle  tyre places never do  and I wonder about dealers

Tyre fitters and mechanic doing wheel spindles up with power tools  !!

 

I try if I buy a bike to have the wheels out and grease fairly quickly !  OK OK I have a workshop so it is easy !

[jeremyr62 2,541]

But the bearings are sealed bearings?

Do you just slather grease in the general area and hope it finds its way in there?

[Andy m 23,502]

The seals are dynamic, so by definition not complete (there is no such thing, why do kids balloons go down) . No gap means no rotation. Even if that gap in theory is microns it still breathes. If the outside consists of grease the only thing that can go in or come out is grease. 

 

The tyre fitters air gun is totally capable of squashing a bearing to the point it distorts. If you ever see one set to tighten beyond running a nut down a long thread it is entirely acceptable behaviour to insert the gun, pull the trigger and watch the formerly employed "technician" rotate like the kebab shops Friday night special. Good luck enforcing this unless you are prepared to fill the guns reverse lever with epoxy so it only un-does. 

 

No factory assembly uses grease without either automatic application or a huge fight with production/elven safety . You just can't stop people making a huge mess, falling over on it, eating it, using it to hold swarf and filth in joints etc. 

 

Andy

 

 

[MikeBike 5,005]

On 18/05/2021 at 19:08, Mrkitty2 said:

Greetings all, I know this has been mentioned elsewhere, but having suffered 4 sets of rear wheel bearings over 57k miles, I discovered that my rear axle spacer collar was too short, allowing lateral load on the bearings… I replaced it and have had no  problems since. Worth checking. I’m on a ‘16 750XA and using it for courier work. Check that when the bearings are seated there’s no gap between the spacer and the inner races. I’ve also got a CBF600SA that I did 194,000 miles on… Only one set of rear bearings required in all that time.

Which collar was it? Which item from following linked image/list. (Can't post image)

https://www.fowlersparts.co.uk/parts/5840751/nc750x-abs-dual-clutch/rear-wheel

 

I don't understand how it can be too short. Was it somehow worn or were the bearings fitted too narrow then?

 

 

 

 

Edited May 20, 2021 by MikeBike

[listener 11,178]

I had my previous 750X for just short of four years (just over 30k miles on it) and I had no issue with either wheel bearing.

 

 

28 minutes ago, Andy m said:

The tyre fitters air gun is totally capable of squashing a bearing to the point it distorts.

 

Thankfully my fitter used good old fashioned 'brute force and ignorance' rather than an air gun! 

And he knew how to properly balance the 'brute force' against the 'ignorance' ... 

[Slowboy 20,408]

1 hour ago, MikeBike said:

........I don't understand how it can be too short. Was it somehow worn or were the bearings fitted too narrow then?

Someone programmed the CNC machine wrong and it churfed (technical term😁) out loads of them before anyone noticed? 0.2mm still overloads the bearing.
Maybe they did notice but didn’t get every vehicle through rectification in time......

Human error still creeps into a machine world.

Edited May 20, 2021 by slowboy

[Steve Case 949]

I have a cunning theory... the spacer is the same length as the space between the surfaces the bearing sit against and with a lick of paint this would be fine.

 

However the wheels appear to be plastic coated or something similar and the coating is easily a mm thick, same on both sides 2mm gap between the spacer and the bearing inners. Distort the bearings by 1 or 2mm and they will fail in the end.

Mind you this doesn't explain why the spacer is not dropping?

[Grumpy old man 4,673]

On 20/05/2021 at 09:07, MikeBike said:

Which collar was it? Which item from following linked image/list. (Can't post image)

https://www.fowlersparts.co.uk/parts/5840751/nc750x-abs-dual-clutch/rear-wheel

 

I don't understand how it can be too short. Was it somehow worn or were the bearings fitted too narrow then?

 

 

 

 

'Yeah  I'm with you on this. If you put the brake side bearing in 1st tap it all the way in to the stop, put the spacer in from the other side and tap the bearing in all the way to the spacer. I don't think there's a lip on that side so in theory it'll go in all the way. 🤔

[jeremyr62 2,541]

53 minutes ago, Grumpy old man said:

'Yeah  I'm with you on this. If you put the brake side bearing in 1st tap it all the way in to the stop, put the spacer in from the other side and tap the bearing in all the way to the spacer. I don't think there's a lip on that side so in theory it'll go in all the way. 🤔

I will be doing this very job in the not too distant future. I will report back. I'd be surprised if there wasn't a shoulder on both sides to seat the bearings. There normally is afaik to ensure they are square.

[Grumpy old man 4,673]

4 hours ago, jeremyr62 said:

I will be doing this very job in the not too distant future. I will report back. I'd be surprised if there wasn't a shoulder on both sides to seat the bearings. There normally is afaik to ensure they are square.

Make of it what you will😊

 

[Steve Case 949]

my suspicion is that explains it so that some technician doesn't forget the collar.

 

I would expect a step the full length of the collar that stops it from dropping too far and preventing the wheel spindle fitting thru. Mind you what I expect and reality may be miles apart!