Same-same. The ones with one spring can be converted into two, and the
other way around.
Measure the length of 10 coils of the spring.
Example: 10 coils measures 2 1/4" = .225 wire size. (See chart below for
Jeezus. It's amazing what you need to learn when you DIY!
Here's how I had to determine my "track radius" just now!
Turns out, my 'track radius' is 15 inches.
It's needed for the spring calculator here:
To the next person, you will need these SEVEN datapoints:
1. Right hand wound
2. 2" ID
3. 0.243" wire gauge
4. 26.5" spring length (unsprung)
5. 7' door height
6. 4" drum diameter
7. 15" track radius
I entered those seven numbers, and the spring calculator found:
So I changed the 26.5" to 27", and it only found a spring for a 12" track.
(I wonder: Do most of you have 12 inch tracks?)
Luckily, the chart shows "equivalent" springs for a 15" track but I was
surprised the original spring doesn't fit a 15" track.
Q: What size track do you have?
On Tue, 06 Nov 2012 06:29:28 +0000, Danny D. wrote:
OK. I was measuring the track radius incorrectly.
I'm supposed to measure from the BOTTOM of the track
to the bubble level as shown in this picture:
What I CLEARLY get is neither 12" nor 15", but I get 13".
There is no doubt that is the measurement done the
way explained in that document.
So that's weird!
I'm not sure how common a 13" track radius is, but, it's
going to affect what spring I get if I want to increase
the duty cycle.
On Thu, 08 Nov 2012 15:14:07 +0000, Danny D. wrote:
I was hoping the spring would have arrived before
the weekend - but alas ... there won't be a garage
door spring DIY until the spring arrives.
I ordered a SPB-250-36-00R to replace my old spring.
The numbering system means:
B = 2 inch ID
250 = 1/4" wire gauge
36 = 36 inches long
00 = fractions over 36 (i.e., exactly 36 inches)
R = right wound
The spring itself was $51.50 and the shipping was
a whopping $22.50 plus I added the two 1/2" diameter
18" long metal bars (which cost $8 additional).
They admonished NOT using socket wrenches (3/8 open
end wrenches and vise grips were what else is needed).
Here are the particulars:
1. Old & new spring ID = 2.0 inches
2. Old & new wire gauge = 0.2343" & 0.250"
3. Old & new length = 26.5" & 36"
4. Old & new wind = right hand wind
5. Door height = 7'
6. Track radius = 13" (only affects the duty cycle)
7. Door weight = unknown
8. Ends = standard cones
9. Drum = 4.0 inches diameter
10. Bearing-to-drum distance = 60"-18"B inches
11. Spring stretch ~= 36" + 9 turns = 38.25 inches
12. Old & new duty cycle = ? cycles & 34000 cycles
13. Number of cycles per day ~= 2
14. Door width = 8 feet
15. Total cost (so far) ~= $75
On Sat, 10 Nov 2012 01:56:00 +0000, Danny D. wrote:
That was a wrong number. It is off by 50 pounds!
I had described the door to an installer over the phone
who said it was 135 pounds based on what I told him.
As a doublecheck, given the dimensions of the original spring:
2"ID, 0.243"thick, 26.5"long, 7'tall, 13"track radius
the lift calculates to only about 125 pounds.
However, today I physically MEASURED the weight of the door.
The door clearly weighs 185 pounds!
Something isn't right by about 60 pounds!
Can you get the door to the fully up position? If so, you can
probably lock it in place with a C clamp and then replace the
spring. I'm more familiar with tension springs, but I have seen
the torsion type with the shaft and pulleys. I think you install
the spring, and then wind it up a bit and attach the cables to
the pulleys. Then, remove the clamp and it should be back to
On Tue, 13 Nov 2012 00:25:59 -0600, Jon Elson wrote:
The DDM door site goes into a whole bunch of reasons why installing a
torsion spring with the door up is a very bad idea.
So does the Richard Kinch article.
Sure, it 'sounds' like a nice idea to install the spring when there is no
tension and then just let the weight of the door going down wind the
spring on its own - but they all say that's not the way to do it.
I'm going to have to believe them - and won't even try to put the torsion
spring on at the point of no tension.
It's really easy. Just call Larry like I posted in an earlier post, he
will help you out just by the model # of the door.
FYI: For a 16x7 door you need 32 quarter turns to wind it. The door
should be able to be lifted with two fingers. If it's to "hot" (door
goes up to fast) take a turn or two off. If it's heavy, add a turn or
On Tue, 06 Nov 2012 06:29:28 +0000, Danny D. wrote:
I must have done something wrong the first time, because a
subsequent calculation found the existing spring listed:
ID=0.234" & LENGTH&.5"
12" radius = 123.2LIFT & 15,000cycles
15" radius = 128.2LIFT & 13,000cycles
If I want to increase the duty cycle, I can switch to
multiple smaller shorter springs, e.g.:
$21.08 SPB-187-17-75R & SPB-187-17-75L
ID=0.187" & LENGTH.75"
12" radius = 62.3#LIFT & 20,000CYCLES
15" radius = 64.7#LIFT & 17,000CYCLES
Or, I can switch to a single longer spring:
ID=0.243" & LENGTH2"
12" radius = 122.9#LIFT & 25,000CYCLES
15" radius = 127.8#LIFT & 22,000CYCLES
Or, I can switch to a single thicker & longer spring:
ID=0.250" & LENGTH6"
12" radius = 123.3#LIFT & 36,000CYCLES
15" radius = 128.2#LIFT & 31,000CYCLES
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