Atria windows, balance shoes broken, obsolete

Thanks for posting. This looks like a Series 795 Channel Balance. You are correct; your old T-Lock shoe has a grooved stem that our shoes and balances lack; the only thing to do I'm afraid is to replace the balances entirely. To know what balance lengths to select, you're going to have to measure the metal channel from each set, not including the T-Lock Shoe. You'll then need to choose the correct stamp option. Look for stamped codes on the metal channel that conform to our stamp options. If you're uncertain what to choose, you'll need to the weigh the window sash. You can then match that precise weight with one of the weight ranges listed for each stamp option on the product page. See the video below for more details; it covers how to convert an older crossbow balance to the Series 795, which isn't what you're doing; but it also has a lot of detail about the Series 795 in general, so it's worth a look in my opinion.

The Series 795 comes pre-installed with the 15-195 1-1/4" T-Lock Shoe. Just confirm that your old T-Lock Shoe matches the dimensions of the 15-195 (besides the groove in the stem, of course). Judging from your pictures I think it does, but double-check to be safe. If so, then the balance will come ready to install. 

You may also need our 26-200 Balance Screw plug; but to confirm, can you show me the hole in the jamb track where the clip at the end of the balance's nylon cord hooks to? Many thanks. 

Great, thank you! We'll be here.

Perfect, thanks! Yes, I think our Series 795 will work just fine as-is. All you have to do now is match up metal channel length and stamps between your windows. The stamps should be printed right on the old balances so that'll be easy.

Let us know if you have any questions, we're always here to help!

I hope so too! I'm confident our balance will work perfectly as a replacement, but if you run into any issues please let us know. We're happy to help as best as we can.

Off the top of my head, I'd say it's possible that they have different kinds of glass installed. That could increase the weight of the sash enough to tip it into another strength range.

Another possibility is that whoever installed these balances just put in whatever they had laying around, which happens a lot. You may want to weigh your sash just to be 100% sure. Two 26B balances can carry a sash weighing 11 through 17 pounds, while a 26C carries 17 through 22.