Searching for 29" 1 1/8 diameter Kinro single hung tilt in window balance spring assembly

Thanks for posting. I believe we should be able to help, but we'll need a little more information. Can you confirm the diameter of the outer tube? Typically for a spiral balance the diameter is either 3/8"or 5/8". Second, can you tell me the exact weight of the window sash that these balances support? We'll do our best to find what you need from there. 

Perfect. See our S900-28. Choose a Red Tip option, which means the spiral balance will be calibrated to support a window sash in the weight range of 10 through 22 pounds. Let me know if you have further questions.