Cables keep jumping off pullys after replacing springs.

I have a 16x7, sectional garage door.  I replaced the two 1/4 × 1 3/4 × 25 inch springs with two 1/4 × 2 x 25 inch springs.i tightened them at 26,24, 22 1/4 turns and the cables keep coming off the drums and wrapping around the rod when I try and cycle it manually..

It seems like you're describing an issue with your segmented garage door, where the cables keep coming off the drum and getting tangled on the shaft when you attempt to manually cycle the door. This can be a challenging problem to diagnose and fix without physically inspecting the door and its components. However, there are a few potential causes for this issue:

Improper cable installation: Ensure that the cables are properly installed and securely attached to the drum and bottom brackets. Make sure they are correctly seated in the cable grooves on the drum to prevent them from slipping off.
Incorrect spring tension: The spring tension plays a crucial role in balancing the door and ensuring smooth operation. If the spring tension is too high or too low, it can cause issues with cable alignment and lead to cables coming off the drum. You mentioned replacing the springs, so it's important to ensure that the new springs are properly adjusted to the appropriate tension for your door's weight.
Worn or damaged components: Inspect the cables, drums, and other hardware for any signs of wear or damage. Worn cables or damaged drum grooves can cause the cables to slip off during operation. If you notice any issues with the components, they may need to be replaced.
Misalignment or track obstruction: Check the alignment of the tracks to ensure they are properly aligned and free from any obstructions. Misaligned tracks or debris in the tracks can affect the movement of the door and contribute to cable issues.
Given the complexity and potential safety concerns involved in working with garage door components, it might be best to consult a professional garage door technician. They can assess the situation, identify the exact cause of the problem, and provide appropriate solutions or repairs.

If possible, we are happy to provide online guidance and help, you can contact us: CHI Hardware Co., Ltd.

Or you can directly send us an email about your problem, and we will reply to you as soon as possible after seeing it.
Email: chi@chihw.com

Stiffer springs (wider diameter) likely cause higher tension, making cables slip. Consider professional help to adjust the new spring tension or replace the springs and opt for springs closer to the original size (1/4" x 1 ¾" x 25").