Over the past year we have had the opportunity to test out the Porcelain Rocket Mr. Fusion. The Mr. Fusion is in it’s 2nd version. Owner Scott Felter began developing the first version roughly 2 years ago, he initially announced the concept on August 22, 2014.

Scott was determined to find a way to reduce sway which was an inherent issue with saddle bags. On top of keeping a stable rear load, he was at the forefront of incorporating what we now know as the very popular harness style saddle bags. This style incorporates a dry bag or external stuff sack that is removable from a harness like system that remains attached to the seatpost and saddle rails. Not only does this design prevent sway, but it also creates efficiency during use..

What he came up with was the Mr. Fusion – a modular seat bag system that has proven to be a very popular bikepacking bag for many. Before we take a look at the second edition, we will discuss a few of the differences between their first version (V1) and their latest model (V2)..

Dry Bag.
The dry bag got a huge upgrade in V2. The first version was not waterproof, so I can’t really call it a dry bag but you know what I mean. The uber lightweight cuben fiber dry bag from V1 was nice and it actually held up surprisingly well considering its lightweight material. The upgrade in V2 incorporated an air/water tight RF-welded dry bag which made this system much more bomber. While V1 may have been lighter the bag was significantly wider which didn’t really hinder the function of the system, but gave it a strange look if packed full..

Attachment of Seat Post.
Version 1 came with a Velcro attachment point on the stuff sack/dry bag itself so you had to undo the velcro strap and buckle on the rear of the saddle bag in order to detach your belongings. In V2 the Velcro strap is affixed to the seat post all the time and is one with the harness system. This is nice because you don’t need to mess with that velcro strap during the duration of your trip. To take out the welded dry bag, all you need to do is unbuckle the rear buckle strap and you can pull out the bag. This makes for an easier install as well..

Velcro attachment on version 2

Seat Post Clamp.
The CNCed seatpost clamp is now much easier to take on and off your seat post. Porcelain Rocket makes 3 different sizes to fit most seatpost diameters. Version 1 was kind of a pain in the butt to tug onto the seatpost. Now with a precision machined clamp, it slides on without effort. Again, easier installation and detachment. .

Version 1

The other big change was the harness system. Version 1 was more minimalist, but at times it did not promote an easy installation. The top triangle flap often got stuck in between the bag and seat when installing. Version 2 now comes with a distinct harness, and with that a much more smooth installation. The hard plastic sides also help promote stability, like the system needed any more of that..

Mr. Fusion Version 2 Review

Fitting to your Bike.
We have been able to test version 2 of the bag on a fat bike, hard tail and a size small full-suspension bike. The bag hopped from bike to bike flawlessly. Porcelain Rocket says that you must have 6″ of seat post in order for the bag to properly fit. While I do think you can position the clamp differently based on the load, their recommendation is a great starting point..

We never had any issues with our large hard tail, or medium fat bike, so we decided to play around with it on a small Rocky Mountain Element. We installed the clamp at the 6″ mark on the seat post and took it on a rugged singletrack overnighter. Throughout the course of a 45 mile ride the bag hit the tire about a dozen times while descending technical sections and using all of the travel. That being said, hitting the tire never caused the bag to lose its stability – it just made a sound and rubbed on the fabric of the harness..

As far as seat post clamps go, this could potentially be the most annoying part of the installation. You will need to remove your seat post, put on the clamp and align it to the starting point like we mentioned above. After it is aligned and in position you can tighten it. Porcelain Rocket’s seat post clamp fits most common seat post sizes, 27.2, 30.9, and 31.6. We even tested it on a carbon seatpost even though they do not recommend it. We didn’t worry about damage too much as you could lightly torque the bolts..

Not many bikepacking bags can be considered WATERPROOF. While many are water resistant, seams inherently will let moisture through eventually. With the RF welded dry bag your contents will remain completely dry. The dry bag scrunches down to 5 liters and can be expanded to 13 liters, a great range if you want to use it for a variety of applications including commuting, racing, or expedition riding..

You might be asking yourself, how is this system more stable than regular harness or traditional saddle bags? Whether Scott planned it or not it’s all about the fusion. He combined a custom rack and a bikepacking bag to keep your contents wiggle, wobble and sag free. I’m talking about the 4130 Chromoly mini-rack built by Hunter Cycles. This odd looking rack, attaches to the seatpost clamp. Once the bag is installed, the harness comes with a piece of webbing and buckle that allows you to cinch down the bag, which in turn pushes the bag it into the harness system. Once the dry bag is packed in the system, the rack goes to work, keeping everything in place..

Some would say, “Well it’s a rack. Isn’t this the exact contradiction of bikepacking bags?” That’s a reasonable statement, but the rack itself is not the issue here, if anything it would be the screw that connects the rack and clamp. Even still, I have high confidence and have tested that this system can no doubt take on the roughest of trail, but obviously rides well on dirt roads too. You’re not sacrificing too much weight either with a total weight of 17.5 oz and 12.75 without the dry bag. For reference, the older Revelate Design Terrapin weighs – 17.8 oz, and the Ovega Negra Gearjammer comes in at 13.2 Oz.

As far as durability goes, we did break one side of the compression buckle after tugging on the strap too hard. This was the main strap the holds the dry bag into the harness. Luckily, Porcelain Rocket chose a buckle that works well even with a broken clip on one side. We rode 45+ miles of rough trail with a broken buckle and it didn’t come undone. It is also worth noting that there was minimal impact to the bottom of the bag with the tire rub we experienced on the small frame. The rest of the bag has held up great. The harness is burly, and only a little color fade on the sides is noticeable..

More than ever bikepacking bags have evolved to be user friendly and easy to use, but even the most simplistic ideas evolve. The traditional roots of saddle bags consisted of a one bag system, where you would stuff your belongings into the bag either while the bag is installed on the bike or off the bike during each use. It was kind of a pain..

The harness system has two major improvements from the traditional saddle bag. The harness system is versatile and efficient in that you can take your dry bag on and off your bike, hike with it, bring it to the bathroom with you, use it as a bear bag, or use it as a pillow. After you use it at camp you can stuff it and place it right into the harness in the morning with ease..

That leads to the other pro of harness systems – they allow you to pack the crap out of the bag off the bike. Sleeping bags, down jackets, long johns, socks, hats, or any other soft goods. Then all you need to do is compress it like a dry bag, making sure the air is out and the contents are in. I like to go as far as putting all my weight on top of the bag to ensure the most compact compression. Then I roll it up and push it in..

One thing we should mention about the tapered bag is that you need to be conscious of packing the tapered portion of the dry bag to avoid wasted space. In general, packing your saddle bags tightly insures better weight distribution and makes for an overall better feel when riding..

Overall, the Porcelain Rocket Mr Fusion has plenty of versatility. It’s not the lightest system out there, but we would venture to say it is one of the most stable bikepacking bags on the market. With the updated features such as the included waterproof dry bag, modular harness system, and ease of use, we put this high on our list of saddle bags we have tested. The cost is $185 and yes, that does include everything we mentioned above – dry bag, rack, seatpost clamp, and harness system..

If you missed it, check out our first look video… .


  1. Rob Conklin

    Hi Neil. Do u think this would work with a dropper post on a full squish trail bike? I realize that is hard to predict. My hope is to get a little drop for the descents on the CTR this summer with a small rear bag.

    • Neil Beltchenko
      Neil Beltchenko

      I think it would be a challenge, but if it’s a small dropper, you might be able to get away with rear loading the packing of the dry bag, but it would be very inconsistent. One option is this…Dropper Photo

  2. Carl Rubin

    Hi Niel. I’ll be setting up a new Advocate Hayduke for backpacking and like the stability of the Mr. Fusion rack/holster/dry bag saddle bag ystem.. But I also saw your review of the Restrap saddle bag system which seems like an elegant and lighter system whose design appears to effectively combat sway. How stable is the Restrap bag in terms of sway, and would you rate it as stable/rigid as the Mr. Fusion while loaded and riding trails? Thanks in advance for any thoughts/advice. Carl

    • Neil Beltchenko
      Neil Beltchenko

      It is stable, but not as stable as the PR Mr. Fusion. Also worth noting, the Restrap Saddle Bag is much heavier and not as intuitive. Both bags have their purpose.

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