Different kinds of springs and other info
Jan 30, 2010 1:14 PM
Location: L.A. area
Joined: Jan 18, 2008
Points: 1161
http://en.wikipedia.org/wiki/Mattress

From the page above:

"Spring mattress core

The core of the mattress supports the sleeper’s body. Modern spring mattress cores, often called "innersprings," are made up of steel coil springs, or "coils."

The gauge of the coils is another factor which determines firmness and support. Coils are measured in quarter increments. The lower the number, the thicker the spring. In general, higher-quality mattress coils have a 14-gauge (1.63 mm) diameter. Coils of 14 to 15.5-gauge (1.63 to 1.37 mm) give more easily under pressure, while a 12.5-gauge (1.94 mm) coil, the thickest typically available, feels quite firm.

Connections between the coils help the mattress retain its shape. Most coils are connected by interconnecting wires; encased coils are not connected, but the fabric encasement helps preserve the mattress shape.

Here are five types of mattress coils:

  • Bonnell coils are the oldest and most common. First adapted from buggy seat springs of the 19th century, they are still prevalent in less expensive mattresses. Bonnell coils are hourglass-shaped, and the ends of the wire are knotted or wrapped around the top and bottom circular portion of the coil and self-tied.
  • Marshall coils are each wrapped in a fabric encasement and usually are tempered. In the case of Beautyrest, high carbon magnesium is added, while the steel itself remains untempered. Some manufacturers pre-compress these coils, which makes the mattress firmer and allows for motion separation between the sides of the bed.
    Bonell springs
  • Encased Coils or encased springs, are a component part of a mattress in which each coil is separately wrapped in a textile material. Encased coils may also be generically referred to as Marshall coils or wrapped coils.
  • Offset coils are designed to hinge, thus conforming to body shape. They are very sturdy, stable innersprings that provide great support.
  • Continuous coils Or Mira-coils, work by a hinging effect, similar to that of offset coils. In a basic sense a continuous coil is simply that, one continuous coil in an up and down fashion forming one row (usually from head to toe) of what appear to be individual coils. The advantages of how firm a support the continuous coil provides it is somewhat tempered with the "noise" associated from a typical Mira-coil unit. The largest company using a Mira-coil design, is Serta Mattress Company, though their coil units are supplied by Leggett & Platt.

Bonell springs are hour-glass shaped, which means their resistance increases with load. They are therefore best suited for firm mattresses. [my emphasis]

Pocket springs provide support along the entire length of the body. This design works to maintain natural spinal alignment throughout the night.

Re: Different kinds of springs and other info
Reply #4 Jan 30, 2010 1:44 PM
Joined: Oct 15, 2009
Points: 966
You have to also consider the number of coils.  The cheaper Sealy has 12 3/4 gauge with 420 coils (queen size).  The most expensive has 14 gauge, but 782 coils.   In my testing the one with the more coils seemed firmer and more supportive.  Not sure if that will last over time.

It is hard to get the information on the coils, but you can find some on US-mattress.

Jim, you were asking about the difference between Sealy and S&F before.  I think they are totally different now.  The ones on US-mattress say 713 individually wrapped coils of 13.75 gauge (queen).  Their top of the line Estate (not on US-mattress) uses a coil inside a coil system (I believe individually wrapped).

Re: Different kinds of springs and other info
Reply #5 Jan 30, 2010 1:51 PM
Joined: Dec 17, 2009
Points: 850
this is just the case, typically speaking as you increase coil count you decrease the thickness of the wire used.......in terms of conformity this makes sense, a finer steel will move more freely with your body's shape. Look at the high end european brands with many thousands of independent springs and the gauge of wire is typically 16 or even higher.   When it comes to interactive coils (bonnell, offset, or continuous) the weakest links in the spring system are actually the lacing wires that hold the unit together.  If you have a really low coil count and large gaps in contact with the lacing wires then the lacing wires are actually more susceptible to being bent out of shape regardless of how thick the wire of the coil itself is.  The gaps between contact in a higher coil count unit will be smaller, so even though the coils themselves are technically weaker the lacing wires are better supported and less likely to have issues. 

Oh man....my brain is going to explode.  No wonder I hate talking about coil mattresses with people lol. 
Re: Different kinds of springs and other info
Reply #6 Jan 30, 2010 2:12 PM
Joined: Oct 15, 2009
Points: 966
Budgy, what do think of the edge support they put on the upper end Sealy's?  Looks like it is just 2-3" of firm foam.  Another cost saver for them?  I don't think they put in their lower priced ones.

 I also think that would reduce the breathability out of the side of the mattress (if that matters).

Re: Different kinds of springs and other info
Reply #7 Jan 30, 2010 2:21 PM
Joined: Dec 17, 2009
Points: 850
there might be some differences in Posturepedics in the US than what I have available to me, there definitely is some differences in Stearns and Foster. 

But they have been using this polyethylene type of foam on the edges for a few years now, I think its at least stronger than the polyurethane edges most companies use, and it also fits into the spring system which is a plus.  But IMO foam encasement of any kind is highly overrated by manufacturers.  I just love it how every time a company has a new edge system they want to show me like they are gonna flip the mattress world upside down lol. 
Re: Different kinds of springs and other info
Reply #8 Jan 30, 2010 3:48 PM
Joined: May 3, 2008
Points: 827
Thanks Jim, Wikipedia still gets you headed in the right direction for those of us who have no idea on coils.  Budgy you think your head is going to explode, think how consumers feel when they go shopping for a bed and you have no idea what is even inside the bed.  When we bought our Spring Air in a small store, there were no pictures or samples of what was inside the thing.  Still I tried looking online and the companies do not tell you much about the mattresses at all.  What does my old Spring Air have???  Since I feel it doesn't give me comfort, and I see no signs of wear, I have to think they were strong springs, LOL.  It was one of those summer/winter flippable mattresses that had silk on one side and wool on the other, that is all I know about it.

I imagine the mattresses made now use the cheapest materials possible, they were too cheap to make them flippable anymore, which I think is a crime in itself.  Then adding foam edging/encasement, what a joke......how long will that foam last when you sit on the eges, LOL.

shocked me, Spring Air is rated worse than Serta???   Serta has made cheap beds forever, Spring Air used to be the best.  What?  Did things change since I bought the Spring Air?  Then the rating for sleeping hot is fair for Tempurpedic????  What?  I don't believe this chart.
This message was modified Mar 5, 2010 by a moderator
Re: Different kinds of springs and other info
Reply #9 Jan 30, 2010 4:23 PM
Joined: Oct 15, 2009
Points: 966
I think Spring Air was rated last by consumer reports as well.  I would avoid that brand and probably Serta as well.  The other S brands might be marginally better.
Re: Different kinds of springs and other info
Reply #10 Jan 30, 2010 4:29 PM
Joined: Dec 17, 2009
Points: 850
keyword being marginal lol. 
Re: Different kinds of springs and other info
Reply #11 Jan 30, 2010 4:30 PM
Joined: May 3, 2008
Points: 827
That really sickens me how good companies sold out to make garbage now.  You can't go by past history of companies that use to make good products anymore.  New management, mergers, and new idiot management gets on board and save money make garbage.

Now we see why Flobeds and latex beds sell good these days.  Also why people take 15 year old mattresses and put new toppers over them, or tear them apart like Jim did.  But I wonder if the springs are still good anymore.  I went to Spring Air websites to see Four Seasons mattresses and boy are they garbage now.  The springs are totally different, they call them zoning softer at the top, you can see they won't last.  The foam is garbage, memory foam too, they put foam around the edges now.  YUCK.  My old mattress is not like this at all!!!!
This message was modified Jan 30, 2010 by Leo3
Re: Different kinds of springs and other info
Reply #12 Jan 30, 2010 10:52 PM
Location: L.A. area
Joined: Jan 18, 2008
Points: 1161
Ha! I am glad I have fellow members here who think the S companies are "criminals"!  It certainly is a crime how they sell such junk and get away with it because they ALL somehow agreed to do change their business model to one of selling junk...

But I do have to hand it to them for figuring out a way to make their product last less time so they can sell more, make it from cheaper materials so they make each one cheaper, and so now they sell more and make more profit!

Maybe we should buy stock in S companies... ?

But that would be wrong...

Budgy, can you comment on how and when this happened? I mean, do the S companies have big Summit Meetings and sit and talk about how they're going to move their business in a certain direction to screw the customers more? ... Or did one company just lead the way and the others follow, or ? Who started the "no flip" thing? Who first decided to make mattresses cheaper and crappier so they'd wear out quicker and people would have to buy a bed every few years instead of every 20 years?

I do find it rather fascinating how this industry has changed over the past 20 years.

What I keep wondering is this:
Let's say one S Co. decided to make a mattress with no flip and lots of cheap pu foam on top. Surely they knew that foam was going to break down and people would hate the bed, no? So weren't they afraid of getting a bad reputation and driving people to their competition? Unless they knew the other co's were going to do the same thing, wouldn't they have been afraid to start making crappier mattresses?

I mean, they don't really believe their mattresses are any good, do they?

I have many such questions!!!
LOL
Re: Different kinds of springs and other info
Reply #13 Jan 30, 2010 11:07 PM
Location: L.A. area
Joined: Jan 18, 2008
Points: 1161
Did some searching on the net and was shocked that there are really no sites other than wikipedia that go into the differences in inner spring types. L&P's own site now just highlights their newest springs, it doesn't even talk about Bonnell, offset, etc. any more... I think they USED to have a good page on the most common types of springs...

Anyway, this is the ONLY other one I could find that talks about various innersprings:
http://www.consumersearch.com/mattress-reviews/innerspring-mattresses

I haven't even read it yet, I just glanced at it and put it here so I can look at it later.

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