Simonton window coil balance
Hello! Simonton actually no longer makes this balance. We have a modern Certainteed brand pivot shoe that is a very similar design, but in most cases it's not an exact fit and actually struggles to operate in the track.
Fortunately we have another balance system that works even better than either the Simonton or Certainteed brand, but it takes a little extra handy work to install. I recommend watching the video below, which will tell you exactly what parts you need to buy and how to install them. Just note that you will need to know the exact weight of your sash to determine the appropriate spring strength, so make sure to have that on hand.
Your best bet is to just weigh the sash yourself. The new Series 159 springs use a different rating system than your originals so you can ignore what's printed on them.
The rule of thumb is to weigh your sash on a scale and divide that by how many springs support it altogether. So, for example, if your sash weighs 15 pounds and you only have one spring per side, then you would want to use the 7.5 pound rating.
Note that your sash weight may be an even number, which will make it a little awkward matching up these .5 pound increments. In my experience you're usually safe rounding to the next pound. For example, if your sash was 10 pounds and you only had one per side, then you would be fine using the 5.5 spring. That would add up to 11 pounds of total support. That extra pound won't be the end of the world and you likely won't notice a difference.