Bearing

[martin007]

Hello.


Soon I'll have to be a mechanic in my powerchair.
Some bearings need replacement.
The first step is to identify the technical name of the bearings.

They are bearings similar to this one.

[Burgerman]

I dont know. That is not a standard bearing.

[martin007]

You hit the nail.
It is not a common bearing.
That's the problem.

[ICEUK]

Something like this?

https://www.onlinebearings.co.uk/Bearing-Inserts-c-716/

[martin007]

Something like this?

https://www.onlinebearings.co.uk/Bearing-Inserts-c-716/

No.
The length of the cylinder (added) is approximately twice that of the bearing.

[Burgerman]

Where is it used? Any drawing?

[martin007]

Front wheel fork attachment.

[martin007]

> https://www.mobinova.nl/en/ball-bearing ... heels.html

With the longest (marked) cylinder.

[Burgerman]

Well you will either have to pay it or use a spacer.

[martin007]

"Longboard Bearing"


> https://www.slickwillies.co.uk/biltin-l ... rings.html
> https://www.skatewarehouse.co.uk/mindle ... rings.html

[Burgerman]

No thats a bearing of some type used on a longboard in this case. You need to know the size too. Yours are bigger. Measure to closest mm ID, OD and width.

[martin007]

Now I have an idea of how to look for the bearing.
I'll keep you informed.

[ex-Gooserider]

There should be a number or set of numbers on the bearing, you may need to clean it thoroughly and / or use a magnifying glass or play with lighting in order to read them. Put those numbers into a search engine, and you will probably get links to bearing supply houses...

Those numbers will describe the bearing if it is an industrial standard one (most are). Worst case, pull one out and take it to a bearing supplier (most decent sized cities will have at least one)...

Most bearings don't have an extension like the one you have in the picture, if you can't find one that does have the extension, you may need to get a spacer or have one made to account for the difference. Aside from possibly being more of a pain to put together, this won't hurt anything, and bearings w/o the extension are likely to be less expensive.

ex-Gooserider

[martin007]

I think an alternative would be to place 2 normal bearings instead of the current one.

What do you think?

[woodygb]

Use a Standard bearing plus a suitable spacer to make up the difference.... using another bearing as a spacer could work but ...YUCK!

[martin007]

using another bearing as a spacer could work but ...YUCK!

Can you extend it a little more?
What problems can there be?

[Burgerman]

None if that will fit.

[martin007]

In theory (it seems) that there are 2 long bearings on top of each other.
I wonder.

Why?
Do engineers like to complicate life?

[Burgerman]

Who knows. They may well use 2 on top, so the spacers allow you to tighten the bolt/nut and not load the mearings. You can do the same thing with 2 spacers.
You ca make two spacers by taking apart a nomal bearing and using just the centre part. Add grease so it all comes apart later without rust...

[martin007]

imagen_2020-12-22_202749.png (4.26 KiB) Viewed 2493 times

I think (I will confirm later) that the long bearings are placed like this.
The black part is a screw that holds the wheel.

imagen_2020-12-22_203436.png (44.84 KiB) Viewed 2493 times

[martin007]

[woodygb]

That part of the caster is called a stem.

[martin007]

Any idea why 2 bearings?

[biscuit]

@Martin: are you looking for bearings for the castor stem or for the middle of the wheel? Or both places?

[martin007]

for the castor

[woodygb]

for the castor

That statement still doesn't make things clear Martin...

The word "Castor" usually applies to the assembly including the wheel...

cas·tor (kăs′tər) A small wheel on a swivel, attached under a piece of furniture or other heavy object to make it easier to move.

So ... Bearings are for ?....Going ON the STEM or going IN the WHEEL or for BOTH ?

[martin007]

Sorry.

The bearings are for the STEM.

[biscuit]

https://www.bilcastors.co.uk/product-ca ... ng-spacer/
This company might have a part you need? Or eBay might have entire wheelchair castors that fit?
I don't seem to have swivel bearings on my castor stems. But I suppose I must have.
I have just put a pair of castors from my old chair in the tip. You might be lucky if you look for complete replacement castors in eBay.

[martin007]

The wheels are in perfect condition.
I'll get to work next week.

[iainsherriff]

do you KNOW the correct bearing is 608ZZ ?
22 x 7 x 8 maybe the right physical size but a bearing on the stem in that position should be a taper roller not a ball bearing, unless there is a thrust bearing as well ?