I replaced the garage door extension spring with the same (I thought)
strength springs now the opener struggles a little. The existing springs
were "orange" so they were probably (maybe) 170# springs. I could only find
brown 160# replacements so I used them. Would 20# total difference cause
the opener to struggle?

OR....
The old springs were double..one INSIDE the other...not next to each other.
The springs were quite old and I'm guessing, again, that they needed 2
spring to get that much strength. Looking at the pattern of the orange
paint they used it looks like they were painted AFTER one was inserted in
the other. Based on this I'm _guessing_ that the two spring together make
one 170# spring. Or am I wrong on this and the old springs were actual two
170# springs!?

thanks