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Review: The 509 Cycles Necessary Evil is a blank slate for excellent drop bar riding

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Our Necessary Evil from 509 Cycles has traveled from Ohio’s muddy trails to Florida’s sandy roads and even had a stint on a few CX courses. Overall it’s been a bike that handles itself well across the board. Which is great if you plan on bikepacking one day, gravel racing the next, and maybe, just maybe, doing ‘cross on another. The frame is a winner when it comes to offering a comfortable ride and responsive handling. It’s up to the components you equip it with that determines what kind of riding you’re going to do.

Frame Specifics

509 Cycles Necessary Evil Bag
So far, this is the only frame we’ve had in that is big enough to fit the original Topeak top tube bag in Large. However, the Midloader has since been redesigned.

509 Cycles Necessary Evil D Profile

The Necessary Evil is available in steel and titanium options. The steel version we were on was equipped with rack and fender mounts in addition to 3 cage mounts. It would be nice to see a top tube gas-tank bag mount for easy access on long gravel rides or additional packing options.

Necessary Evil Yoke

Its CNC’d chainstay yoke opens up the BB area for large 650 x 2.3″ or 700 x 47c tires. Additionally, this custom yoke allows for a 435mm chainstay. Next door is a BSA 68 English thread bottom bracket.

509 Cycles Necessary Evil

As seen in our initial writeup, the 57cm steel frame – without pedals – weighs in at 22.17lbs.

Building a trail bike that’s ready to pack

509 Necessary Evil

Starting with the drivetrain, we have a 1×11 setup with a SRAM Force crank, Rival shifters and derailleur, and an eThirteen TRS+ cassette for a 40 x 9-46T gear ratio. This setup worked well on Florida’s rolling hills and the backwoods of Ohio, even when fully loaded.

509 Necessary Evil Seat Post

Our cockpit is set up with a Thompson stem, Salsa Cowbell handlebar, and a Cane Creek eeSilk seat post. The bar drops are slightly flared for increased control and packability, but narrow enough to stay comfortable on the average outing. This setup allowed the bike to be ridden across several disciplines comfortably.

As for the front suspension, a Lauf Grit SL fork offers 30mm of travel, flat brake mounts, and a 12 x 100mm thru-axle. I enjoyed the extra forgiveness the Lauf provided the front end, even if it was a little springy on climbs.

Necessary Evil Tire Clearance

Necessary Evil Wheel

Wrapping up the build are a pair of Industry Nine AR25 wheels mounted with WTB Resolute 700x42mm tires. Naturally, the I9s rolled very well and held strong under load. As for the tires, they did well on hard-packed roads and dry trails, holding firm in all but the wettest conditions.

Spotlight traits across riding styles

Roads & Gravel

Whether it was the Lauf fork, eeSilk seatpost, 43mm tires or its cushy steel build, the Necessary Evil took the chatter out of the road regardless of how chewed up they were. Plus, its geometry and cockpit setup created a comfortable upright position during long hauls. I find the buildout we had was ideal for bikepacking and long days in the saddle thanks to its wide tires, vertical compliance, and ample storage space. With that, don’t expect to set any speed records.

In The Woods

On trails, I found the top tube was slightly short for my liking, making downhills a bit awkward, as I’d have to push myself further back than usual to unload the front wheel. Measuring in at 6,3″ I tend to gravitate to 58cm road and gravel bikes and L-XL MTBs (depending on riding). So naturally, the 57cm frame we had for review would be a touch smaller than what I’m used to. Don’t fret, there are 59cm frames available for the lengthy riders out there. So while the top tube was slightly short for me, it did help while maneuvering around obstacles and during climbs.

David’s cyclocross experience

On Course

Knowing that the Necessary Evil was set up for gravel riding with its Lauf fork and a more gravel-specific 42mm tires, I expected to show up and get dusted by the veteran cross racers. But after the first lap of the course, I was riding right with them. The steering through the tight and technical portions was responsive and crisp despite the more comfortable slack geometry, allowing me to stick on their wheels and pick up on the secrets of this type of riding. And then on the faster portions of the course, the massive 40T x 9-46 gear range gave me more than enough speed to keep up when it came time to drop the hammer. Overall, I would still keep it on gravel roads and trails where it is most at home, but say that the 509 Cycles’ Necessary Evil can still handle the odd cross race if you’re CX-curious.

Ideas to ride away with

The point to be made is that the Necessary Evil is a comfortable and capable bike. What you do with it boils down to how you build it up. One thing you can be sure of no matter what parts are equipped is that it’ll offer a comfortable ride. And if you’re looking for an option that can handle its own on gravel roads and light mountain bike trails, maybe even a go at a cross-track, the 509 Necessary Evil is good option to consider.

509 Necessary Evil


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4 years ago

That chainstay yoke is a hefty chunk of metal. Maybe stainless is too stiff to be crimped, but I would do something to lighten that up.

Involuntary Soul
Involuntary Soul
4 years ago
Reply to  mudrock

i don’t think prople who are buying steel frames like these cares about weight, there are tons of light carbon options out there

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