Feed on the go: Revelate Designs Mag-Tank review

At the start of 2020, I had aspirations of repeating the 210 km Subic-Masinloc-Subic audax after numerous frustrated attempts in years prior. One thing I distinctly remembered about that ride was just how full my back pockets were of stuff…even with the Audax Randonneurs Philippines/Team David’s Salon van ferrying some of my spares for retrieval at the checkpoints.

From the December 3, 2015 Subic-Masinloc-Subic audax. I thought I looked cool here, but my stuffed back pockets definitely countered that.

A lot of it was my long-ride fuel of choice: Growers NutriBars. Back then, the boys of Global Cycling Network had proclaimed loudly that top tube bags were decidedly uncool things. At the time, perhaps they were, as this was years before “bikepacking” was a thing.

Their utility on such a long spell on the saddle, though, was undeniable. I was considering my options when I stumbled on Revelate Designs’ Mag-Tank.


  • Volume: 0.9 L
  • Weight: 128 g
  • Dimensions: 216 mm length x 127 mm height (tapers to 63.5 mm) x 63.5 mm width (tapers to 38.1 mm)
  • Materials: VX21 and VX42 XPac, closed-cell foam, HDPE sheets, 420-denier red and yellow inner lining
  • Made in the USA
  • Single-handed access with effortless magnetic closure
  • Adjustable daisy-chain front attachment with spacer block for stem clamp bolts
  • Wide double-back wrap top tube strap
  • Available in black, blue, or purple
  • SRP: US$60
  • Bolt-on version available for bikes with “bento box” top tube mounting bosses


I had actually ordered this bag at the end of February, hoping it would arrive in time for the March 28, 2020 audax. However, COVID19 happened, and not only did the audax ride vaporize, this thing also got caught in the lockdown, getting delivered a full two months later. That, coupled with my decidedly late work shift for the rest of the year and outdoor riding being a bad idea, basically means I’ll have to test the Mag-Tank’s utility indoors, for now.

The yellow and red inner lining is supposed to help visibility.

Unlike most top tube bags that rely on zippered closures, Revelate Designs’ own Gas Tank bag included, the Mag-Tank instead uses a large flap with an innovative magnetic buckle at the end of a cord loop. This flap covers up a singular, sizable main compartment which runs the whole length of the bag; there are no other pockets apart from this. Revelate Designs uses yellow and red inner linings to help make the contents more visible.

The great thing about the Mag-Tank is that its self-locating magnetic buckle makes opening and closing the flap very easy. A light one-handed pull on the cord loop opens the flap, while closing it requires only that you flick the flap over. The buckle just finds its way home and closes itself! Now that is pretty cool, and the GCN folks will have to agree.

Three energy bars can sit side by side, with enough space to spare for a tiny jar up front.
The Mag-Tank can accommodate a total of five bars when stuffed to capacity.

Granted, the Mag-Tank’s unique design introduces some downsides. As it’s basically a big yawning pocket with a flap, you’re trading security for convenience. While the bag uses water-resistant materials, there’s always the chance of rain working its way past the flap and into the unsealed hole. It’s also not ideal for storing easily-lost little rattly things on a rough trail – better to keep those in your back pockets or saddle bag. The Mag-Tank is perfect for my use case, though: storing multiple energy bars for easy access while riding. I mean, many people call top tube bags “bento boxes” pretty much because of that, and Revelate Designs themselves call their other top tube bag the “Gas Tank.”

Revelate Designs uses a wide and fairly long strap for securing the Mag-Tank to your bike’s top tube. I had roughly 5 cm of excess, which I snipped off.
There’s this neat foam spacer block for the stem clamp bolts.

A top tube bag isn’t much good if it can’t mount securely to your bike’s top tube. The Mag-Tank uses a wide mounting strap for the top tube, which has a grippy lining, doubles over itself, and sticks with hook-and-loop closure. Up front, it uses two hook-and-loop straps that wrap around my fork spacers, threaded through a foam spacer block for the stem’s clamp bolts. This is par for the course for a company that’s made its name on bikepacking bags.

Finally, the sides of the Mag-Tank are reinforced with HDPE plastic sheets to help hold its shape. With the bag cinched down tight against the top tube, there’s no shimmy at all, even when my thighs brush against it while mounting or dismounting.

Hyro with the Mag-Tank equipped.
The Mag-Tank’s flap does form a bit of a cowl behind the stem, but I doubt this is big enough for it to open by itself while riding. At least, not while the magnetic clasp does its job.
You can spot the Mag-Tank mounted on Hyro here. Having energy bars at easy reach is a huge boon on virtual rides with lots of climbing.


I’m afraid my verdict’s a little half-baked this time around, as I’m not in a position yet where I can comment on the bag’s durability or water resistance (although it does fend off my sweat well). Having gone over what I can, though, this is a neat, well-designed product. One could argue it’s a bit on the pricey side, but given its American manufacture and innovative, functional technology, I think it’s a good buy for riders with the “bento box” use case.

Now if I could put it to the test on a real long outdoor ride…


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