I'm finally getting around to building a hardtail for Mrs MTQG out of all my spare old bits.
The Chameleon frame I am using had derailleur gears before I converted it to Rohloff, but there's a couple of things that don't look quite right now that I am trying to refit them.

First of all, the cable on the rear derailleur.

Looking at the position of the ferrule and the cable clamp with it in lowest gear, that's a hell of an angle. That can't be right can it ?

Next, the cable guide and front derailleur.

That guide obviously routes the cable in from the top, yet the derailleur looks like the cable should come in from the bottom.
It's a couple of years since I took it off so I can't remember how it was, but that doesn't look right.
Will that derailleur fit that frame ? If so, how ?

Both are fine – chain tension will pull the rear mech forward, and the front is OK – try it!

It's not the chain tension I'm bothered about on the rear,it's the angle of the cable. Maybe I should have fitted it before taking the picture.
Imagine the outer cable coming in from the left in that picture above.
As the inner exits on the right, it then bends immediately down by 45 degrees to the clamp.
Surely that will wear a groove in the ferrule and then the aluminium derailleur body, as well as making it stiff to operate as it gets dragged over a sharp edge.

I can run the front cable directly from the guide on the frame to the clamp on the front derailleur from the top. Again,it will exit at an angle, but not as sharp as the rear one, so I guess it will work OK.

when you fit the chain the cable angle will be fine.

have a look at the derraileur section on parktool.om for some examples.

Cable angle is a bit guff on seatstay routed bikes (unless you have sram or a rollamajig) but it works.

Fitting a chain won't make any difference.
It's not the angle between the cage and the derailleur body I'm worried about. I can see that will get pulled round when the chain is fitted.
It's the bend in the cable as it leaves the adjuster that looks wrong.

When the parallelogram is swung fully out on to the smallest sprocket, the cable clamp is in line with the cable adjuster.
When it is swung fully in to the largest sprocket it puts a sharp bend in the cable.
This happens regardless of the cage position so fitting a chain will make no difference.

This one on the park site does the same, but not as badly.

it just looks like there should be some sort of plastic guide there to line the cable up better.

Al, Mrs MTQG's bike has got SRAM on the rear and the cable rolls nicely round a curved plastic doo-dah.
I thought there must be something missing off my Shimano derailleur, but is that normal then ?

Shadow rear mechs have better cable exit angle for this reason, but it is a bit poo that the cable had to a 270 degree loop to get to the chainstay.