Rab Mythic Ultra 180 v Sea to Summit SP1 v PHD Minimus K – Which Sleeping Bag for Summer Adventures?

Posted on September 14, 2022 by talkultra

Choosing a sleeping bag for an adventure can be tedious, especially when the costs are so high. Never fear, this article will answer all the questions you may have re a sleeping bag for a multi-day desert/summer adventure or similar.

First and foremost I recommend you read THIS in-depth article on ‘How to Choose a Sleeping Bag for an Adventure.’

In this article, I will look at three down filled sleeping bags:

Rab Mythic Ultra 180

Sea to Summit SP1

PHD Minimus K

SP1 v Mythic Ultra 180 v Minimus K ©iancorless

WHY DOWN?

Down as a higher warmth-to-weight ratio than synthetic fill. In simple terms, a down bag can achieve the same warmth (or be warmer) than a synthetic bag for less weight. A key consideration when weight is crucial.

Is down warmer? If synthetic insulation was the same weight as the down, down nearly always will be warmer. Down traps warm air, while synthetic fibers pack densely to reduce heat loss. Both offer great warmth, especially when you use high quality products.

Is down always best? No, not always. Down cannot get wet. If it does, the feathers clump together, and all insulating power is lost. Synthetic retains heat, even when wet. So, if you are using a sleeping bag in a wet and humid environment, synthetic will probably be the best choice… BUT, many brands now do hydrophobic down which is treated to be efficient in wet conditions.

Size is extremely important in any adventure and quite simply down compresses considerably more than synthetic.

Cost is always a key consideration and typically, down will be more expensive than synthetic.

SLEEPING BAG KEY QUESTIONS

First and foremost, consider several key things before choosing a bag.

Where are you going?
Will it be dry and what are the risks of rain?
Do I sleep cold or warm?
Am I tall or small (sleeping bag length is crucial for comfort)?
Do I have wide shoulders?
Do I need a zip, if so, half zip or full zip?
How light does it need to be?
What temperatures can I expect at night?

Quite simply, a sleeping bag needs to be as light as possible without compromising the above if you are carrying it.

Also consider that it is often a wise choice to choose a sleeping bag that has less warmth and lower weight if you are also carrying top/ bottom base layers and a down jacket. These clothing items can be used to layer and add warmth.

WEIGHTS AND PRICE

Rab Mythic Ultra 180 retails at £550.00 and weighs 400g (900 fill down)

Sea to Summit SP1 Retails at £260.00 and weighs 350g (850 fill down)

PHD Minimus K Retails at £484.00 and weighs 330g (this bag has no zip but has 1000 fill down)

KEY CONSIDERATIONS

Rab

The Mythic Ultra utilizes breakthrough technology with TILT (Thermo Ionic Lining) which in simple terms works a little like a space blanket offering exceptional warmth. The down is hydrophobic treated and therefore can be used in wet/ damp conditions. It is offered in regular and long. It has a ⅛ zip by YKK on the left, an excellent hood with baffles and is provided with a dry bag and a drawstring storage bag.

Sea To Summit

The SP1 is tiny and provided in a zipper storage bag and a small compression sack is provided. Using ‘ultra-dry’ 850 fill down, the bag has excellent water repellent property and warmth. It has a YKK zipper, available in regular and long with excellent hood and baffles.

PHD

PHD are unique in that they make all the products in their factory in the UK. Therefore, it is possible to purchase any bag ‘off-the-shelf’ as a standard product OR you can order and have a product custom made. For example, you can specify, no zip, half zip or full zip. You can ask for wider shoulders, longer length, warmer toe box and so on. All of this comes at a price, so if bespoke is for you, PHD is the place to go. You can see options HERE.

The Minimus bag has a Drishell outer, no zip, standard length, standard width and 900 fill. Should you require the bag a different length, the price varies, short is no extra charge, long adds 8% and extra-long adds 14%. Equally, if you require extra width, slim is no extra charge, wide is plus 11% and extra-wide adds 20%. Need a zip? Short is £25 extra and full is £41.00 extra.

Quite simply, PHD are the Tesla of the sleeping bag world. Great comfort, weight and warmth. It has a mesh bag for storage and comes with a nylon stuff sack*

*stuff sack replaced with dry bag.

HOW THEY COMPARE

First and foremost, weight is a key consideration, and these three bags are so close in weight, it is hard to say one is better than the other. The Sea to Summit wins though, a full 100g lighter than the PHD.

On my scales:

Rab 397g Rab has a tiny eighth zip.

Sea to Summit 344g *Sea to Summit a half zip.

PHD 445g **The PHD has a full-length zip.

When one considers the PHD has a full zip, the weight is impressive. A full zip offers more flexibility and on a hot night, the bag can be used more like a blanket. Not an option with the other two.

Size can be as crucial as weight and the Sea to Summit is a standout packing to an incredibly small size with the compression sack provided – 38g.

The Rab is supplied with a dry bag and I should point out it would be possible to use a smaller bag and compress the Mythic Ultra 180 smaller – 34g

For the PHD I used a generic 4L dry bag – 31g

It’s worth noting though, often when fast packing, it’s better not to store the sleeping bag in a storage bag as it makes for an odd, sausage like shape that does not utilise the space available.

WARMTH

Remember, a sleeping mat is an essential accessory not only for comfort but warmth. I recommend a Sea to Summit ultra light.

The three bags are very similar in weight, fill and design. However, each brand describes their bags warmth differently. The Comfort Rating indicates the minimum temperature where an individual can sleep in a relaxed position and get a good night’s sleep.

Rab – Sleep limit 0 deg

Sea to Summit – 9 deg comfort

PHD – 5 deg typical.

Based on the above if we take Rab 0 deg minimum rating, Sea to Summits 9 deg comfort and PHD’s 5 deg typical rating, it’s fair to assume that all are good for around 5 deg as a good sleeping temperature. In theory, the Sea to Summit should be the one that ‘may’ struggle at 5 deg but that is not the reality after testing. It is a warm bag and certainly trades blows the Rab and PHD. All three perform exceptionally well at 5 degrees or above.

The Limit of Comfort Rating is the temperature range where an individual sleeping in a curled position and fighting against the cold can still sleep through the night – 0 degrees would apply here. I had several summer nights with temperatures dropping and all three bags performed exceptionally well with the addition of Merino top and bottom layers, a pair of socks and the use of a Buff or hat.

COMFORT and FEEL

All three bags win out on feel and comfort. Each have their own attributes. The PHD wins on full comfort as it has a full zip. The Rab though has the best hood of all three bags and a superb baffle to keep out drafts. The SP1 has a half zip, good hood and no baffle.

All are silky smooth to the touch and comfortable.

The Rab with black outer, silver logos and silver TILT lining feels and looks premium. Equally, the SP1 has a superb look of grey/ yellow and excellent logos/ branding. The PHD is a no fuss bag. If the other too are Tesla and Porsche, the PHD is a Land Rover but you know it will get the job done.

VALUE FOR MONEY

These are three excellent sleeping bags offering the best option in their class. Quite simply, you cannot go wrong with any of them. They have all been used and tested in similar environments, conditions and temperatures whilst camping. However, when looking at weight, pack size, warmth and price, we have a clear winner.

The standout is the Sea to Summit SP1 which offers an unbeatable package of low-weight, small packing size, incredible warmth, and a low price. It is half the price of the competition and does not compromise on any features. It’s a winner. More info HERE.

The Rab is a great bag, which offers a little more warmth, larger pack size and just a fraction more weight. The black colour is a plus for me and the hood/ baffles are the best of the three. The zip is of no real use and for me I would prefer either no zip to save on weight or prefer the additional weight and half a zip that offers more practical use. The treated down offers incredible flexibility and certainly if I planned on using one bag for different conditions and environments, the Mythic Ultra 180 would be a great choice. More info HERE.

PHD are always a winner, and they make incredible products. But ‘off-the-shelf’ it’s difficult to justify the cost in comparison to the excellent Sea to Summit SP1. However, long, tall, short, wide, large, small, zip or no zip, PHD will make a bag just for you and it will be perfect. That comes at a price though and it will be arguably, the best sleeping bag you have ever had. More info HERE

The winner – Sea to Summit SP1.

Other to consider: Nordisk (was Yeti) Passion One

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RAB Mythic Ultra 180 and 360 Sleeping Bag Reviews

Posted on August 11, 2021 by talkultra

RAB have produced two state of the art sleeping bags in the Mythic Ultra 180 and Mythic Ultra 360 sleeping bags. Utilising the same technology, both bags offer low weight, small pack size, Hydrophobic Down and the ground-breaking TILT technology – Thermo Ionic Lining Technology. The TILT in real simple terms brings elements of an emergency space blanket incorporated into the design of the bags.

Offering best performance at weight for any comparable bag, both the 180 and 360 have been my ‘go-to’ bags since early in 2020.

Quite simply, amazing levels of warmth for low weight.

The RAB Mythic 180 has 180g of 900+ fill power Hydrophobic down and a comfort limit of 0 degrees and a weight of 390g. It’s a perfect bag for warmer weather and any adventure when low weight, small pack size and warmth are important. Perfect for multi-day racing for Marathon des Sables or similar and, is brilliant for fastpacking adventures when travelling in a self-sufficient manner.

The RAB Mythic 360 has 360g of 900+ fill power Hydrophobic down and a comfort limit of -8 degrees and a weight of 620g. This bag utilises all the same technology of the 180 and quite simply is warmer and heavier. Just like the 180, it’s the perfect bag for racing and fastpacking adventures in colder and more challenging conditions.

Please read How To Choose A Sleeping Bag.

IN USE

Mythic Ultra 360

The recent 18-months have allowed me more time outdoors than ever before and almost weekly I have ventured outside on multi-day fastpacking adventures or overnight trips. The 360 and 180 have been on most of these trips offering low weight, small pack size and incredible warmth.

I am lucky, based in Norway, I get to fully experience the cold of winter and in summer, warm and comfortable nights.

An overnight fastpack in February and I was camping in -18 degrees on snow in a small one-man tent. The Mythic Ultra 360 with a comfort rating of -8 was not going to be enough for a cold night, however, I had planned accordingly carrying Merino base layers, down pants, and down jacket. When all combined inside the Mythic Ultra 360 I was cozy warm. This was an extreme test of the 360 and importantly, I think it’s important to understand how layering is an important element to the use of any sleeping bag. It offers incredible flexibility.

But the true test of the 360 has come on regular trips in Autumn and Spring when the temperatures are hovering around +5 to -5. In these situations, the bag has performed flawlessly providing low weight and incredible warmth all in a small package. The groundbreaking TILT really does perform and as mentioned earlier, it’s like adding a space blanket inside the bag. It’s heat reflective and therefore increases the internal warmth for minimal extra weight.

I consider the bag a game changer for its weight v performance but of course, this comes at a price. Expect to pay around £700 for this technology.

Using 7D ripstop nylon, TILT and excellent design, the Mythic Ultra 360 has been the most comfortable bag I have ever used. One would potentially think that just 360g of down would not be enough, especially for a -8 bag, but that is where the technology kicks in and that is why the price goes up. It’s the perfect bag alpinists, adventurers, and runners.

It has boxwall construction and trapezoidal baffles which allows the down to loft reducing cold spot risk. It has an ergonomically designed collar and hood that closes in around the head and neck reducing cold getting inside the bag and therefore allowing the warm air inside the bag no opportunity to escape. An anti-snag zip guard, angled foot box and short zip are additional features.

As you would expect, internal space is compromised, after all, this helps keeps the weight down. So, this may be a consideration, it’s suitable for someone up to 6-foot tall with comfort. After that, it would come down to personal comfort and needs. Shoulder width is 27 inches, hip width 21 inches and the foot width 16 inches.

FEATURES

The bag comes with a large cotton sack so you can store without compressing the down, it is also supplied with a compression dry bag. It has a ½ length zip on the left only. The down is Hydrophobic, so, it can get wet and retain warmth, an important feature. 7D Ripstop fabric and importantly the TILT technology is a USP to boost warmth thereby facilitating lower bag weight. Tested to EN1357:2016 standards, the Mythic Ultra 360 has comfort of -2, Comfort limit of -8 and an extreme limit of -27 (but I wouldn’t want to be in that situation!)

CONCLUSION

This is a high-performance bag and state of the art. If the cost is no problem and you require small size, low weight, and warmth, the RAB Mythic Ultra 360 should be on your list. It’s an amazing bag!

Mythic Ultra 180

At £550 the 180 has all the features of the 360 above and it has the same measurements: Suitable for someone up to 6-foot tall with comfort. After that, it would come down to personal comfort and needs. Shoulder width is 27 inches, hip width 21 inches and the foot width 16 inches.

It also has all the same features including the cotton storage bag, dry bag, 7D ripstop, TILT, 900+ Hydrophobic down and same great construction.

Quite simply, the Mythic Ultra 180 is a stripped down 360 designed for warmer temperatures and thus bringing even lower weight and pack size.

At 400g, it is perfect for racing or fastpacking when temperatures at night are expected to be 0 degrees or above, as such, it’s a perfect bag for Marathon des Sables or similar multi-day adventures. It’s also ideal for Mountain Marathon events and summer alpinism.

All the pros and cons listed above for the 360 are directly transferable for the 180.

FEATURES

CONCLUSION

Low weight, amazing warmth and small size, the Mythic Ultra 180 is a bag for warmer temperatures when price is no issue and features are paramount. It’s a perfect bag for racing and fastpacking adventures and the Hydrophobic down gives peace of mind in poor weather conditions.

FINAL THOUGHTS

The RAB Mythic Ultra 180 and 360 bags are state of the art and work together with each other offering low weight and warmth for any adventure. I am fortunate to have both and therefore can switch between 180 or 360 based on weather conditions. However, all sleeping bags have greater flexibility when one adds layers. The 360 can be used in much colder temperatures with Merino and down layers. You could argue that this adds extra weight to the overall pack, but, if you are out in in -10 or lower, you will be carrying these layers anyway for day use.

The 180 is a lighter bag and again, adding a layer or multiple layers when inside will increase warmth. A prime example being a race like MDS, many take a very light down jacket for when sitting around, add this inside the bag and the warmth increases.

However, here in the RAB Mythic Ultra, remember the TILT works by reflecting heat, so, one would need to test and try what method provides the best warmth.

Ultimately, if you need a sleeping bag the 180 and 360 offer two great starting points and they should be a consideration.

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