Balance spring

Quick Learner from Central fla

Jan 26, 2026 8:51 am

Want to verify these balances they are 30 inches window weighs 24.25 lbs bottoms are. Around 1-16th but looks like may be worn down

4 user uploaded images

4 Replies

Casey from SWISCO

Jan 28, 2026 3:02 pm

Hello,

It looks like you have either our S351-30, with a 15-002 bottom attachment, or S390-30, with a 15-001 bottom attachment. Take a look at the image below to determine which balance you'll need. If yours is over 1" deep but worn down, you'd most likely need the S390. You'll also need a 2940 spring strength option for your replacement balances. Thank you!

Comparison of the S351 and S390 balance shoes.

Quick Learner from Central fla

Jan 28, 2026 6:03 pm

thank you i think it is the s390 as well, looks like they have been worn down , thank you for your help

Casey from SWISCO

Jan 29, 2026 8:34 am

We're happy to help and appreciate your business! Just let us know if you need anything else.