Shimano Deore M592 derailleur hanger
 

I have Shimano Deore M592, long cage on my bike (Radar Breezer Expert 2021). I am wondering is there a derailleur hanger spare for this part? Looking at the Shimano pdf it looks like this is all just a single unit?

https://si.shimano.com/de/pdfs/ev/RD...-M592-2909.pdf

I don't know if I'm understanding you correctly, but that diagram doesn't show the derailleur hanger. On your bike, the hanger is built into the frame. On aluminum or carbon bikes, the hanger is a separate piece that attaches to the frame. In either case, the derailleur attaches with Part 1 on the diagram, labeled "B-Axle Assembly", and the large bolt screws into the hanger.

Are you asking whether that bolt is available separately? What's actually going on with your bike?

That's not the hanger, that's the cage.

sounds like you're looking to replace a part that isn't available separately... the link between the derailleur hanger and the knuckle of the derailleur body... the part labelled "#1" mounts it to the bike's Der. hanger, right?
You'll need to Replace the Entire Derailleur.. that link moves the derailleur pivot point rearward which improves other geometry for the derailleur.
the ones i've seen are Swedged (similar to Riveted) in place and are not removable/replaceable.

The silver part is the hangar-

https://cimg3.ibsrv.net/gimg/bikefor...dc0f578d29.png

You didn't reference a part number. Are you referring to the entire derailleur body, which doesn't have a part number?

Nothing is going on. I am aware that the hanger is a separate piece in the system. I thought its this part on the picture, but by looking at the diagram again, it seems this is just part of cage and cannot be replaced. I wanted to have a spare hanger. Is this system does not have a hanger, why is it built as such? And what happens if you hit the cage and it bends? (can you fix this ?)

https://cimg4.ibsrv.net/gimg/bikefor...4a52bb421c.jpg

Highly unlikely that part of the derailleur will bend, it’s a pretty beefy piece. The derailleur hanger, the part of the bike that the derailleur mounts to, will bend first.

I think we're still struggling with the terminology. In your case, the hanger doesn't appear replaceable, and is part of the bike frame. It's the part of the frame that the derailleur attaches to. It's the purple portion of your frame below the axle. What you're pointing to in your photos appears to be part of the derailleur body.

The "cage" is made up of the two pieces that contain the pulleys (# 7 and #10 in the diagram).

That part you're pointing to (don't know what it's called) seems one of the least likely parts to break in a collision or crash. There are other parts of the derailleur that will get torn up before that metal plate bends.

I'm guessing that metal plate exists to locate the pivot point at the correct place for that derailleur design. Narrower range RDs have the pivot point right where the RD screws into the hanger, but wider range RDs have the pivot point stood off from that point.

+1. Personally I wouldn't worry about keeping a spare but this MAY work if you ever needed one. Wolf Tooth RoadLink Derailleur Hanger Extension – Wolf Tooth Components

Agreed. If that part of the derailleur ever got bent, you're probably going to need a new derailleur--at the very least.

The part the OP is looking for is called the "B-Axle Unit".
Here is an eBay posting for the equivalent part for an RD-M772:

https://www.ebay.com/itm/35464569849...item529287e7c2

Now whether they use the same part, I do not know.

Since it's not specified as being replaceable on the Shimano parts diagram, I'm thinking it isn't.

$67 for that one little part?!? You can a whole new Deore 592 RD for $60.

Yes, I understand now, hanger is part of the frame on this bicycle. You learn something new every day.

Still, I would rather have replacable hanger than this design. If it gets bent you can replace it in the field, while for this design you do need to find a capable mechanic, or use whatever you have left of rear gears.

But also, no point of thinking about this too much ,anything can break on a bicycle.

I get the sense that you read something about having spare derailleur hangers, and assumed that applied to all bikes.

Look at post #5 above. Bill has posted a picture of a bike with a replaceable derailleur hanger. They put those on aluminum and carbon bikes so that in the event the derailleur gets bashed, that part gets bent instead of bending or breaking the aluminum or carbon frame. It may or not save the derailleur but it is meant to save the frame. If you have a bike that uses one of those, it is best to have spares because they're not universal. Years from now the one for your bike might be hard to find.

Because your bike is steel, it has what's called an integrated derailleur hanger. Being steel, it is very unlikely to bend in a minor accident. That means the derailleur will bend or break instead. You could make a case for having an entire spare derailleur, if you're paranoid about it. The actual best course of action is to avoid accidents and treat your bike with care - don't bash the rear derailleur.

If I recall the aluminum XT B-unit thingy is thicker and not interchangeable with the thinner steel one found on the Deore 592.

And if it does get bent--you can bend it back.

I can assure you that part is steel in the XT unit.
2 of my bikes have them.

What if you cant get a spare hanger for some bike, you are screwed?

If it bends badly or breaks off, then yeah, pretty much. A frame builder should be able to weld a new one on...