Hi Lee,

Many thanks for your question about mattress spring diameters. We're sorry you're experiencing back pain in bed at night. That's no fun and usually, an unsuitable mattress ie the wrong spring tension can only make this worse. This is why it's so important that you do your research, which you're doing now! So at least you're not going to end up in an awkward sleeping position for much longer.

The biggest issue with pocket spring counts in mattresses is that retailers across the board use the number as the indicator of quality or value in a mattress. 3000 springs sound much more enticing than 600 for example.

However, there is a fine line between the right amount and springs for the sake of springs. In a kingsize mattress, you can roughly fit up to 2000 springs (give or take based on the diameter as you've highlighted). Mattresses with 2000+ spring counts either have multiple layers of springs (dual springs / twin up springs) or they use tiny micro or HD springs which are far smaller in diameter, wire gauge and size. Hence you can fit in thousands for the ever 'important' spring count. Well for the uninformed any way!

We've detailed here in our micro springs article why we never use these tiny springs. In summary, they offer very little support, decrease the capacity for important mattress comfort layers. Ie the upholstery that you actually sleep. These are known as the comfort layers of a mattress and sadly are often overlooked in favour of pocket / mattress spring counts.

The ideal number in a single layer of full size pocket springs in a kingsize is between 1000-1600. More than this and the spring diameter gets smaller and smaller to fit more in.

For a twin up or dual layer its between 2000 and 3200. Again the higher the number the smaller the diameter.

Mattress Spring Diameter vs Gauge:

Ok, onto the main part of your question. The spring gauge or thickness of wire is the most important part to consider. This is because its based on your bodyweight. Each pocket spring is designed and manufactured with a weight tolerance in mind. This is to enable it to compress and counter balance the forces (bodyweight) applied to it.

The diameter is the width of the spring, usually tweaked slightly to show different spring counts. However, most high end springs use the 49-51mm. In all honesty, the diameter is not that relevant if looking at 1000-1600 as these will be between 49-51mm. When you're looking at 3000+ spring the diameter shows you how small the springs actually are which you may then start to avoid given the issue with micro springs detailed above.

The gauge based on your weight is the most important factor.

How much to spend:

In terms of which Vispring mattress to buy we would ask you to read our comparison article here, bearing in mind the spring tension you need, possibly a 1.2 gauge given your lightweight and height. Then look at the upholstery you may need, ie slightly softer layers given your bad back and fact you're a side sleeper.

We've detailed below the mattress fibers you will be looking at in your search for a new mattress and how each one feels along with its price bracket to assist.

We hope that helps and gives you further mattress buying guidance. If you have any more mattress-related questions please get back in touch on info@localhost or 0161 437 4419.

Sleep well!
John & Ryan