Sash spring hardware

Thanks for posting. This shoe most closely resembles the Certainteed 15-192, which uses Series 170 and Series 172 Coil Balances. However, we've found this assembly does not fit well in Simonton windows, in spite of the aesthetic similarity. One has to rub down the alignment bars on the body of the 15-192 to get it to fit a Simonton window track, and even then I have doubts as to its performance. 

Because of these qualms, we've come up with an alternative solution: the 15-259 should be able to fit your window track. This shoe uses the Series 159 Coil Balances. We have a whole video that demonstrates how to do this conversion. Take a look below and see what you think. 

A stamp like that indicates that each spring can carry 10 pounds. Seeing as how you have one spring per side, that means your sash probably weighs 20 pounds.

This might complicate matters depending on which of our two solutions you decide to go with: either the 15-192 or the 15-259.

If you go with the 15-259, then you could simply opt for our 10.5 pound spring option. These are a little bit stronger than your originals, providing a total weight coverage of 21 pounds, but I don't think you'll notice the difference. 

If you go with the 15-192, then you'll note that we don't sell a 10 pound option. You could opt for using the 9 pound spring, but that's only going to give you 18 pounds of support. Again, not a big difference, but this time we're pushing it and you may notice a difference.

You could instead opt for two 5 pound springs per side. This will add up to 20 pounds of support exactly. It also means you need to double up on how many covers you buy per spring, since you have twice as many as you did originally. 

It's ultimately up to you which method you go with, depending on which of the two replacement options you prefer and how much work you want to put into this.