no, not rust, a tiny bubble, only superficial,...

[deQuincey]

A common conversation among classic car owners is rust;
If the conversation doesn't break out, then rust is the elephant in the room.
mischievous looks searching for that little bubble below the rocker panels
Sad faces and happy eyes depending on the circumstances, his car your car
a world of sensations, but what happens when it happens?
It can be repaired one way or another, I was shown this recently
to my untrained eye doesn´t look too badly done

this car lived in Madrid for many years, supposedly dry weather, no salt during winters,...well

 

[bavbob]

I recall buying my first BMW in 1986, it was a 320i. The person who sold it to me said "electrons love BMW's, especially the shock towers".

 

[eriknetherlands]

@deQuincey , although the pictures are a bit small, the fix of the front the part of the sill(rocker) seems to be done to an acceptable standard. Rust will be dormant for a long time if the car is well loved from now on.

One could have made the choice to replace the full inner sill and
not only the front 40cm.
This would make it a very, very decent repair, and double as expensive.

Rust of this size in the front sills usually also means bad rear sills and bad front shock towers: both are difficult jobs like the front sill.

 

[deQuincey]

@deQuincey , although the pictures are a bit small, the fix of the front the part of the sill(rocker) seems to be done to an acceptable standard. Rust will be dormant for a long time if the car is well loved from now on.

One could have made the choice to replace the full inner sill and
not only the front 40cm.
This would make it a very, very decent repair, and double as expensive.

Rust of this size in the front sills usually also means bad rear sills and bad front shock towers: both are difficult jobs like the front sill.

Rear sills and front shock towers were also repaired, I have seen the pics, but too much carnage for dinner time me think