Constant force balance system

A home owner from Townsend, DE says:
I need to replace this constant force balance system in a single hung window measuring 35 3/4 x 59 3/4 in an 85 series single hung window. The number is faded but it appears to have the number 9 for LB rating.
Profile picture of Bob
Bob from SWISCO responded:

Thanks for posting. Your pivot shoe looks like our 15-180 Coil Balance Shoe; just double check the dimensions to see if they match your old part. This shoe is compatible with our Series 180 Coil Springs. Each spring in this Series supports a particular amount of weight, and you will need to order the right combination to match your window sash's overall weight. For example, let's say your window weighs 20 lbs. You would want (4) of the S180-540, which supports 5 lbs of weight. You would then install two of each on either side of the window sash, so that each side supports 10 lbs, for a total equal to the overall sash weight of 20 lbs. If you need figuring this out just let us know.

A home owner from Townsend, DE says:
The measurements are correct. I only need to replace 1 side. Can I order the 15-180 shoe and the 9lb coil. What the other plastic piece called at the bottom of the window. I would order that too so all the components on the left side of lower sash are new
Profile picture of Bob
Bob from SWISCO responded:

Very well! You can order our 15-180 shoe and our S180-9 9 lb Coil Spring from our shape. As far as a plastic piece at the bottom of the window, I am not certain what you are referring to. Do you simply mean something like our 15-186 Coil Balance Clip with the 15-182 Coil Bushing? Or were you referring to something else? Take a picture of this piece so we can see for sure. Thanks. 

How to remove window pivot shoes
How to remove window pivot shoes
VIDEO
WATCH >
Anatomy of a tilt window
Anatomy of a tilt window
VIDEO
WATCH >
How to Replace a Triple Coil Balance System
How to Replace a Triple Coil Balance System
VIDEO
WATCH >
Removing a Triple Coil Window Balance
Removing a Triple Coil Window Balance
GUIDE
READ >
Reply to Thread
Use this form to ask a follow-up question or to share your experience regarding this subject.
(your email address will be kept private and is only used to inform you when a response has been made)
Current wait time is 3-4 business days
We promise that one of our experts will personally get back to you as soon as they are able. Thank you very much for your patience and understanding. If your inquiry is time-sensitive, please feel free to reach us at (888) 991-1929 or at help@swisco.com.