Sierra Sleep by Ashley
Sierra Sleep 8 Inch Bonnell Hybrid Mattress
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The Sierra Sleep 8 Inch Bonnell Hybrid Mattress is a straightforward pick for sleepers who want the traditional feel of a coil mattress: firm, stable, and true to its rating from the first night. If you have been chasing a supportive spring bed instead of a soft foam sink, this is built for exactly that.
The construction starts with a 13 gauge Bonnell coil innerspring unit, the classic coil layout that has supported value mattresses for generations. Bonnell coils are hourglass shaped and interconnected, spreading weight across the surface rather than letting it concentrate under one spot, which is why the feel stays consistent edge to edge instead of forming soft dips over time. On top sits a 2 inch layer of high density quilt foam and pad, just enough cushioning to smooth the surface without softening the underlying support. The result is a tight top mattress, part of Ashley's 8 Inch Bonnell Hybrid series (model M587), that reads firm and stays firm.
Who It Suits
Back and stomach sleepers tend to do well here: a firm coil surface keeps the hips from dipping and the spine in a level line. Combination sleepers who shift positions through the night also benefit, since a coil bed responds quickly no matter which way you turn. If you have tried memory foam and found it too warm or too slow to move with you, a Bonnell hybrid like this is worth a look. Heavier sleepers who want to feel supported on top of the bed rather than settling into it may also prefer this over a plush option.
It is not for everyone. Side sleepers who need cushioning at the shoulder and hip usually find a firm innerspring too hard, and couples who are sensitive to feeling a partner move at night should know that a Bonnell coil unit, unlike pocketed coils, moves more as a connected system. If either describes you, ask our floor team about a softer or pocketed coil option instead.
Setup and Care
- 13 gauge Bonnell coil innerspring unit for consistent, traditional support
- 2 inch high density quilt foam and pad for a smooth, tight top feel
- Materials suited for allergy sensitive sleepers
- Ships compressed and rolled in a box; allow about 48 hours for it to fully expand once unboxed
- Backed by a 5 year, non prorated warranty
- Pair with a supportive foundation or adjustable base rated for its size and weight
Available Sizes
- Twin
- Full
- California King
Firm is a relative word, and the only way to know how this particular firm feels under your own body is to lie down on it. Come stretch out on the Sierra Sleep 8 Inch Bonnell Hybrid at any of our Kentucky showrooms and see for yourself.
What makes this mattress different
13 gauge Bonnell coil support
A classic hourglass shaped coil unit, interconnected and spread across the surface, the same coil style that has anchored value innerspring mattresses for generations.
2 inch high density quilt top
A high density quilt foam and pad layer smooths the surface just enough to be comfortable without giving up the firm feel underneath.
Genuinely firm, night one and beyond
This mattress sleeps true to its firm rating over time instead of breaking in soft, so what you feel at first is close to what you feel a year later.
Ships compressed in a box
Delivered rolled and compressed for easy setup at home. Allow about 48 hours after unboxing for it to fully expand before judging the final feel.
Suited for allergy sensitive sleepers
Materials are chosen with allergy sufferers in mind, so sensitive sleepers get peace of mind along with the coil support.
5 year non prorated warranty
Ashley backs the Sierra Sleep 8 Inch Bonnell Hybrid with a full 5 year, non prorated warranty.
Part of the 8 Inch Bonnell Hybrid series
Model M587 in Ashley's Sierra Sleep lineup, built around traditional coil support at an accessible price point.
Foundation matters
Pair this mattress with a supportive foundation or adjustable base rated for its size and weight to get the full benefit of the coil support.
A traditional coil build, kept simple
The 8 Inch Bonnell Hybrid keeps its build straightforward and traditional. From the top down: a quilted fabric cover, then a 2 inch layer of high density quilt foam and pad that softens the immediate surface, then the 13 gauge Bonnell coil innerspring unit that carries the weight and gives the mattress its shape. The coils are hourglass shaped and wired together as a single interconnected unit, the same basic layout that has supported innerspring mattresses for generations, tuned here to spread pressure evenly rather than let it concentrate under the hips or shoulders.
Because the comfort layer is shallow and the coil unit does the real work, this mattress reads firm right away and holds that firm feel over time instead of softening the way a deeper foam bed can. At 8 inches total it is a lean profile that pairs well with a platform, foundation, or adjustable base rated for its size and weight.
See the full Sierra Sleep lineup →Built for back, stomach, and combination sleepers who want firm coil support
Back sleepers: a firm coil surface keeps your hips from dipping and holds your spine in a level line through the night.
Stomach sleepers: this position needs firm support most of all, and the Bonnell coil unit keeps the lower back from arching the way a softer mattress can allow.
Combination sleepers: coils respond quickly as you shift positions, so you are not waiting on a slow moving foam layer to catch up to wherever you land.
Heavier sleepers: a firm, coil forward build tends to hold up rather than bottom out under more weight, keeping you on top of the mattress instead of settled into it.
Sleepers moving off memory foam: if a foam mattress left you sinking in too far or sleeping warm, a traditional innerspring like this trades that hug for stable, breathable support.
Probably not for you if: you sleep on your side and need real pressure relief at the shoulder and hip, or you and a partner are sensitive to feeling each other move, since a Bonnell coil unit shifts more as a connected system than pocketed coils do. Ask our floor team about a plush or pocketed coil option instead.
Specifications
| Height | 8 in |
|---|---|
| Feel | Firm |
| Firmness | Firm; a traditional coil forward feel, not medium or plush |
| Construction | 13 gauge Bonnell coil innerspring unit topped with a 2 inch layer of high density quilt foam and pad; 8 inches total height |
| Motion isolation | Noticeable: this is a connected Bonnell coil unit, so it transfers more motion across the surface than pocketed coils or all foam builds |
| Warranty | 5 year, non prorated limited warranty |
Frequently asked questions
How firm is the Sierra Sleep 8 Inch Bonnell Hybrid?
Genuinely firm. A 2 inch layer of high density quilt foam and pad takes the hard edge off the surface, but the 13 gauge Bonnell coil unit underneath is doing the real work, so this reads as a firm, supportive bed rather than a plush or medium feel.
What kind of coils does this mattress use?
A 13 gauge Bonnell coil innerspring unit. Bonnell coils are hourglass shaped and wired together into a single interconnected unit, the traditional coil layout that has anchored value innerspring mattresses for decades.
Who is this mattress best for?
Back, stomach, and combination sleepers who want firm, stable support tend to do best here, along with anyone who found memory foam too soft or too warm. Heavier sleepers who want to feel on top of the bed rather than settled into it often prefer it too.
Is this a good mattress for side sleepers?
Usually not the first choice. A firm innerspring like this does not give much at the shoulder or hip, which is where side sleepers need the most cushioning. Ask our floor team about a plush or pocketed coil option if you sleep mostly on your side.
Does Sierra Sleep offer an at-home trial on this mattress?
No. Sierra Sleep beds, including this one, do not come with an at-home trial. The showroom is where you try before you buy: lie down on this exact mattress at any of our Kentucky locations so you know how it feels before it comes home with you.
How do I set up the mattress after delivery?
It ships compressed and rolled in a box. Unbox it on the foundation or frame where it will be used, remove the plastic wrap, and let it unroll. Give it about 48 hours to fully expand before judging the final feel.
What warranty comes with this mattress?
A 5 year, non prorated warranty from Ashley. Keep in mind that pairing a mattress with a foundation from a different brand can affect warranty coverage, so check compatibility if you are mixing and matching.
Is this mattress a good option for allergy sensitive sleepers?
Yes. The materials in this mattress are suited for allergy sufferers, so you get that peace of mind along with the firm coil support.
Buy it from people you can actually visit
- Free local delivery To your home across Central & Eastern Kentucky.
- Free setup We place and set up your new bed in the room.
- Free old-mattress haul-away The old one goes out the same day the new one comes in.
Independently owned in Kentucky since 2012. Walk in any day (no appointment) and someone who actually knows the floor will help you find the right fit.
Still deciding?
Try it in person at any Kentucky showroom
Walk into any Mattress Overstock location, lie down, and feel the difference yourself. No appointment, no pressure. Our team has over 100 years of combined mattress experience and we're here to help you find the right fit.
