Over the course of the past three years, I have slowly softened up, meaning being comfortable at night is a major priority to me. That’s not to say I pack the cot, it means I like to do my research and see what bag has the best overall quality. Something that will keep me warm and dry, keeps my pack weight and volume down, and lasts. The Mountain Hardware Spark 28 has proved be do all of that over the course of this spring, summer and fall.

Before this year the Spark 28 was called the Phantom 30, basically nothing changed between the two. The lower and upper comfort limits, weight, fill and measurements are all the same. The one thing that did get an upgrade was the zipper. It is a beefier zipper and the bag is red now instead of green, but more on that later.mountain-hardwear-spark-28-09121

As far as my stature, I’m 5’10”, have a 32″ inseam, and a rather skinny build with regular width shoulders. That being said, I move a lot in my sleep. I toss and turn and I like to bend and straighten my legs throughout the night. The Spark 28 is indeed a mummy bag, one where you might not be able to comfortably preform those acts, yet I never got overly frustrated with this style of bag because I knew the intent was to be snug to keep warmth in and weight down. The performance based mummy cut is constricting, and if you move a lot while sleeping, you should maybe consider a more roomy bag or even a quilt. Compared to a sleeping bag tub system, I certainly have a little bit more room for movement, but in the end, it’s all personal preference.mountain-hardwear-spark-28-09128
Being a guy that has always fit between medium and large bikes and medium and large tops, it was nice to know that sleeping bag shopping is much easier. The “regular” length fit me well, with the ability to fit someone up to 6 feet tall, however I think it could comfortably fit someone slightly taller. If you are above 6 feet, consider their tall version for an 30 extra dollars. 

Another important piece of the puzzle when shopping for a bag is the typical temperature you will be using the bag in. One of the main reasons I went with the Spark 28 was because of the cool spring temperatures in Arizona. When you think Arizona, you think warm, desert, and sharp pointy things, at least thats what I thought before I visited a number of years ago. Arizona is a big state, and in the spring and fall, there is a lot of change in temperature from day to night and from north to south. Even the difference between being in a wash and outside of one feels extremely different.Mountain Hardwear Spark 28
Having a bag that can cover the lows of a particular night will have you sleeping much better. Between the mummy bag construction with the quality Q.Shield 800 fill Down, and tight baffle spacing, the bag came in with a EN limit of 28°F and a comfort rating of 36 degrees°F. I have spent only a couple nights at or below 28 where I woke up to frost, but I remained comfortable if not a little cold on the toes. The nylon cinch cord on the mummy hood was a nice touch, and relatively easy to use and find when snuggled up in the bag.  In mild temperatures in the mid 40s, I would decline to use the mummy hood and make sure the bag was not zipped up all the way. This proved to work out well and gave me enough ventilation. I never ended up using it, but if you like, you can also ventilate the bottom of the bag with the dual zipper function.

Durability and Loft Retention
Companies like to treat Down with a DWR coating these days to help retain loft and warmth when wet, something that Down does not do naturally. Mountain Hardwear has taken a serious step in making your bag last, because once the Down becomes wet, you will be in for a miserable night of sleep. Q.Shield Down is Mountain Hardwear’s proprietary treated Down that will keep you happy and your bag functioning properly day in and day out. 

As a testament to the quality of the Down, I have yet to notice the bag breaking down as far as loft is concerned over the course of this year. While it does seem like it takes a bit longer to loft from compression, I think that has something to do with how well the bag is stitched. When stuffing the bag into my saddle bag, the unstuffed side balloons up with air, and takes a bit before all the air can escape. While I did receive the bag with an unwrinkled 10d external nylon weave, the bag now certainly looks used, but shows no sight of wear in the wrinkles. 

A big piece for a functional sleeping bag is the zipper. The worst thing that can happen to you is a stuck zipper in the middle of the night. The Spark 28 has zero issue with zipper snag, and comes with a two-way, #5 zipper that has continued to glide as smooth as the day I got it. Like most bags in the competitive sleeping bag market, on the other side of the zipper comes an insulated Down draft tube to prevent air from entering through the zipper. Even if it’s a simple feature, the ability to zip close the bag from the inside with the dual side zipper makes things so easy. Inside the bag is a small zipper pouch and another velcro pouch for small items, but I have yet to actually use them. It may be good for some hand warmers or small items you would like to keep in your bag, but not lose easily. mountain-hardwear-spark-28-09136

As for the stitching, I have gone over the many seams and have not found any sign of the stitching coming undone, one thing I have noticed when flipping the bag inside out was that some of the stitches have tiny particles of Down trying to sneak out of the zipper tube. This area could prove to be a weakness down the road. Mountain Hardwear Spark 28

Why It Works for Bikepacking 
So how will this bag work for us as bikepackers. Similar to backpackers needs, we need a bag that keeps the weight and pack size down. Between the 800 fill power Down and the nylon interior and exterior lightweight fabric, the bag comes in a 1lb 8oz. But maybe even more impressive is how small it stuffs down. It can easily fit into the smallest size saddle bags on the market and still have room more. Mountain Hardwear Spark 28
The quality zipper and zipper preventative anti-snag panel allows for a fast and efficient entry of your bag, something that I enjoy after a long day on the saddle. Thoughtfully placed baffles and a well designed hood and toe box have me staying warm, but also conformable while laying on my back. There is really not much unique about it’s look, but the design and quality of products that Mountain Hardwear has used makes this bag a winner.Mountain Hardwear Spark 28Mountain Hardwearing Spark 28 – $400.00. For more info and to check out their site head to mountainhardwear.com


  1. Have used a Phantom for the past seven years on 2 cross country bike trips, AT section hikes and kayak overnights. Has kept me warm in the 20’s, still lofts and shows no sign of wear. Great bag!!!

  2. I’ve been using a Mountain Hardware Ultralamina for the past two years and it has been outstanding. Got it because it was the most packable synthetic bag on the market at the time. Because I live in a rainforest, I usually skip down, but this treated fluff sounds like I should give it a whirl. I’ve always wanted a bag that could shrink down to the size of a grapefruit.

  3. Thanks for the review. A comparison photo of it packed size would make a nice add to your review. My current bag is a Mont Bell Ultralight Super Spiral Down Hugger #3 with stuff sack which weighs in at 698 grams (24.62oz / 1 lb 8oz) in its stuff sack but I do keep an eye out for a lighter and smaller packed size bags if there is such a thing. My current option for consideration is a Western Mountaineering Summerlite due to is lower weight and apparently small pack size.

    Knowing how your bag packs down would be helpful in considering it as an alternative.

  4. I have an older Phantom bag and it’s great in every respect except that the zipper snags a lot, which they’ve fixed since then. I’m 6’2″, so I bought the “tall” version, and I wish I hadn’t. It’s made to fit somebody 6’6″ (or maybe even 6’7″ or 6’8″) and built like a pro football player (the bag is extra wide). For a skinny dude like me, I just end up with a lot of extra space on the sides and below my feet, which equates to feeling MUCH colder. I try to pull it closer in so the dead air space is eliminated. I guess the good side is that I have extra room to toss and turn in the bag. If you can fit in the regular size, get that!

  5. Hi Neil, thanks for the review, always great to read about this stuff, especially when you are a gear freak like moi.
    Can you please tell me, do you stuff your sleeping bag straight into your seatbag? No stuff sack or anything? I live in New Zealand so I’m paranoid about stuff getting wet, especially my sleeping kit. Is your current seatbag a tape sealed unit? Thanks in advance, Scott

  6. I’ve had an Ultralamina 15º for four years and have recently picked up the Ultralamina 35º. MH bags are the best. No problems with either bag, ever, even on extensive 30+ day trips. The best part is, you wash them once a year and they come out looking brand new.

  7. Weight? We always want to know the real weight.
    Compressed size?
    I’ve been using the Phantom 45 for three years now. Wearing a single layer of clothing, down sweater and hat can push its comfort zone down into the mid-30s and light-frost morning range. Too bad they don’t have a Q.Shield down replacement for the Phantom 45, which would be even lighter.

  8. More 3-cents…
    I’m 6’1-1/2″ and have the Tall Phantom 45. I like the added space. I don’t feel it makes the bag colder, but then I don’t have the regular length to compare. Unless they are soaking wet, I stash my riding clothes in the bottom of the bag to dry out and stay warm, very nice on cold mornings. My only complaint with the Phantom is its zipper-snagging tendency.
    I do like the color contrast between the inside and outside of the bag, which the Phantom had and the Spark does not.

  9. For a few extra dollars you could have a Western Mountaineering, Ultralite, 20 degree bag.. Down draft collar and draft tube for zipper.. 850 fill, Northern European Goose Down.. (The highest quality down available)..1 lb. 13.oz, stuffs to about the size of a small loaf of bread..

  10. whats the tent?

  11. Deciding between the MHW phantom and lamina. My friend who works for MHW recommended the lamina because of the potential for me to tear that phantom up. Leaving to New Zealand for a month and a half.

    • Neil Beltchenko
      Neil Beltchenko

      well…there has been no tearing on the Phantom, and it is still my goto bag. Excited to hear about your NZ trip, let me know if you have any specific questions about the bag.

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