Do I have the Series 850?

This resembles the Series 850 crossbow balance. May we have the length, diameter of the spring, and width of the "T" shape shoe? From there we can determine which one you exactly will need.

Thanks for your patience. Unfortunately, we no longer have the S850-30 (30-1/2") with the 1" black shoe. We now suggest going with our S795-30 with a 1" T-lock shoe. You will need to weigh your sash for the spring weight. Refer to the sash weight chart on the product page for more information. In addition, you will also need to change your pivot bar. We usually recommend the 26-021, but our 26-366 may be another option. If you aren't sure what to go with, send us a photo of the pivot bar you're using now.

I'm afraid there's no reliable way to determine the weight of your sash aside from weighing it on a scale. Any common bathroom scale should do.

As for the pivot bar, it should come out. All pivot bars are designed to be removed. It should just be held in with a screw.

If you're having trouble uploading your picture, try reducing its size. Sometimes extra large pictures have trouble getting through.

So it looks like you will need to switch both pivot bars for our 26-021 bars. You should be able to remove your old pivot bar by removing the screw and spraying some WD-40 if it seems like it's still a little stuck.

For your balance option, you will need to choose 30B to support your windows sash weight. 

Thank you! 

Yes, if your old balances installed at the top with a hook then our 26-200 will allow you to install the new balance type that uses a screw tab instead.