Bigger Torsion Spring

[sky jumper]

I have two 9x7 doors. one spring just broke. it was a .225 x 1.75 x 29. the other door has a .234 x 1.75 x 33.25 on it. But Menards only has 2" springs in stock. so I got a .234 x 2 x 28. I put it on and wound it (28) 1/4 turns, and it was really tight. the door is still a bit heavy, but the opener works fine.

question - when you go up to thicker wire, and bigger diameter, do you still turn it the same # of turns? I read 7 turns for a 7ft door, but that made no mention of wire size, diameter, or length -- all of which it seems would impact how many times you need to wind it.

I'm hesitant to wind it any tighter as I'm afraid of what might happen.

 

[sky jumper]

here's the new spring installed.

 

[rburke65]

If it’s improperly sized, either the opener will eventually suffer or the springs will. As in everything, you’re trying to reinvent the wheel. There is a science to this. If the doors are the same, then someone has installed an incorrect spring(s). You need to weigh the door and purchase a correct spring. Contact a G Door Company

 

[firebirdparts]

I would agree.

As far as "how many turns", The # of turns per door height would be consistent if two things:
1. the spring is properly sized, and
2. The drums are the diameter you think they are when you spout off this figure.

If you just put a random spring on there, you could attempt to wind it until the door is weightless when closed. Then, if it's consistently weightless throughout its travel, the spring is ideal. But probably, that's not going to be how it works. The spring will not be perfect for the application and the door's apparent weight will change.

If the opener is working, I must say you're not terribly off. They aren't super powerful.

 

[Innovate1]

If it’s improperly sized, either the opener will eventually suffer or the springs will. As in everything, you’re trying to reinvent the wheel. There is a science to this. If the doors are the same, then someone has installed an incorrect spring(s). You need to weigh the door and purchase a correct spring. Contact a G Door Company

Just because the springs are different does not necessarily mean one is wrong. The second one is a larger wire spring with more turns. That's basically the differences that a longer life (more cycles) spring would have although I have no idea if the specified numbers make the springs right for the doors. I think the longer life spring would have the same number of turns. I recently had springs replaced with longer life springs when one broke.

The point about needing the correct spring is correct though - it's more than just grabbing one that's close and winding until the door balances. Since the door is close to weightless I would try putting a few more 1/4 turns on it and see how heavy it is over the travel.

 

[sky jumper]

well it works better now than in the past 10 years that i've owned it, perhaps due to luck. I'm pretty sure the old spring was original circa late '80s. the one on the other door looks to be the same vintage judging by the rust, cob webs, and crud build up.

what I am looking for is the mathematical relationship between wire size, diameter, length and the torque applied to the shaft as a function of # turns. then I know how many turns the larger spring should need, in theory, to match the existing.

it sounds like going past the 7 turns shouldn't be a problem --- that is, it shouldn't break the spring. that was my concern. I don't know how tightly these things can be wound before it becomes dangerous.

the last "pro" door guy I hired insisted on leaving the door heavy because it "helps the door close so you don't burn out the opener". these guys wing it even more than I did. I can only imagine his response if I had asked him to weigh the door...

 

[iamrfixit]

If the door lifts heavy it can and likely will damage the opener. A lot of openers use plastic gears that just won't withstand lifting the excessive weight for long. They're kind of a sacrificial part to protect the opener. Had a 16' door that opened only slightly heavy, but it destroyed the gear on a brand new opener in under a week.

I order most of my replacement springs from DDM garage door, here's a link to your spring as well as some suitable alternative sizes. In stock springs at the home center are usually very limited. It's quick and easy to just order the right spring. I can go to the city and have overhead door cut and make up a spring from coil stock, but it's more expensive and way more trouble than just ordering. They're in chicago and ship to western Iowa in about 1-2 days.

 

[pattenp]

See this video from DDM

 

[bwringer]

The spring should have instructions in the box...?

 

[Terry D]

I have two 9x7 doors. one spring just broke. it was a .225 x 1.75 x 29. the other door has a .234 x 1.75 x 33.25 on it. But Menards only has 2" springs in stock. so I got a .234 x 2 x 28. I put it on and wound it (28) 1/4 turns, and it was really tight. the door is still a bit heavy, but the opener works fine.

question - when you go up to thicker wire, and bigger diameter, do you still turn it the same # of turns? I read 7 turns for a 7ft door, but that made no mention of wire size, diameter, or length -- all of which it seems would impact how many times you need to wind it.

I'm hesitant to wind it any tighter as I'm afraid of what might happen.

I'm not real sure you are supposed to put a 2" spring on a 1.75" cone

 

[iamrfixit]

I'm not real sure you are supposed to put a 2" spring on a 1.75" cone

I'm sure he bought a complete spring assembly, with the winding and stationary cones already installed. Menards doesn't sell just the spring coil.

You can change diameter, wire size and length, but the new spring has to be carefully calculated to the height and weight of the door in order to balance the door correctly. This is often done to extend the life cycle of your springs. The average door configuration is rated for a spring life of about 15-20K spring cycles. Using larger diameter wire with a longer spring can extend the spring life by several times.

The larger and longer springs cost a little more so the door mfr uses the 20k standard to make the door cheaper initially, and guarantees you'll need parts in the future. You can order a new door with extended life springs.

 

[sky jumper]

I found an excellent spreadsheet that calculates the lifting force for various springs/turns combinations. I think this answers my questions and explains why the door opens better/easier with the new spring. I don't know how many turns were on the old spring, but I'm guessing 7-8, so entered 7.5. That produces 114lb lift. The new spring produces 119lb lift with 7 turns. Indeed the door was noticeably heavier with the old spring (as I experienced during recent power outages) and the opener seemed to struggle with it, perhaps it had fewer than 7.5 turns. Now its much lighter, but still not weightless. Based on this I'm guessing the door weighs about 125lbs. I'll put in another 1/4 turn and report back.

 

[sky jumper]

I put in another 1/4 turn. 7.25 turns now. the door is about as perfectly balanced as it could be I think. maybe even a bit too light on the way down. it'll stay put about 1/2 way up depending on where the rollers are in the track. it goes up noticeable faster than before.
here's the link that has the engineering formulas and calculators
http://www.truetex.com/garage.htm