RockShox MegNeg Upgrade Kit

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Even MORE Negative Volume! RockShox MegNeg Review

Find yourself wanting more out of your rear suspension? This $90 air can kit will transform the way certain bikes ride and provide you with the ability to tweak the shape of your air spring.

Rating: Vital Review

Introduced alongside the Lyrik Ultimate fork and Charger 2.1 damper update, the MegNeg air can kit more than doubles today's already large negative volumes. This results in a noticeable and tunable boost of mid- and end-stroke support (and a lot more pumping). Join Vital MTB's Product Editor, Brandon Turman, in the video above, to learn how it came to be, what the tuning process is like, the upsides, downsides, and an overview of what types of mountain bikes will benefit the most from a MegNeg upgrade.

MegNeg Air Can Highlights

  • Allows you to tune negative volume with Bottomless Rings
  • Provides 64-111% more negative volume than a standard air can
  • Compatible with RockShox Deluxe and Super Deluxe shocks
  • Available in 550, 650, and 750 kits to fit Metric shocks with a stroke between 47.5-75mm
  • Includes air can, Bottomless Ring volume spacers, seals, grease, oil and decals
  • 325psi max pressure rating
  • MSRP: $90 USD

The MegNeg Effect

You might be wondering, "What does negative volume do?" Its primary purpose is to counteract the positive air spring (the one you put pressure into), helping to get the shock moving and improving bump compliance.

It turns out adding a bunch of extra negative volume does make another slight improvement in the initial stroke, something we've seen a focus on in the past several years, but that initial feel is not where you'll really notice a difference. The mid-stroke, that's everything from sag to 2/3rd travel, is where the MegNeg makes its biggest mark. Notice how the spring curve is straighter, helping to bring the mid-stoke closer to that of a coil?

Because you're adding more negative volume, more pressure is required to reach the same sag point (240 vs 200psi in the example shown above). The MegNeg makes it possible to run these higher pressures to get the mid- and end-stroke support you desire without compromising the off-the-top feel. As a result, the shock is also going to be harder to bottom.

The MegNeg works well with bikes having more linear, less progressive leverage curves. On very progressive bikes it may add too much support and you'll feel more bumps. Transition's current range tends to be on the more linear end of the spectrum, making the bikes good candidates for the MegNeg. A 160mm travel Patrol Carbon was used in this test.

The ability to choose from 0 to 4 rubber-band style "Bottomless Ring" volume spacers in the negative chamber provides more control over your suspension and the character of your bike. The percentage of volume increase depends on how many spacers you are running. Each spacer equates to a 12% change in negative volume:

  • Stock Air Can - 100% negative volume
  • MegNeg with 0 Bottomless Rings - 211%
  • MegNeg with 1 Bottomless Ring - 199%
  • MegNeg with 2 Bottomless Rings - 188%
  • MegNeg with 3 Bottomless Rings - 176%
  • MegNeg with 4 Bottomless Rings - 164%

"It's for the tweakers." - Dave Camp

What's The Bottom Line?

The MegNeg inches RockShox air shocks closer and closer to that coil feel while maintaining the ability to make quick pressure changes and adjust bottom-out support. It's fun to wrap your mind around and experiment with, seeing what works and what doesn't work for your bike and riding style specifically. There's a lot of tuning capability here, and this product will help people create more enjoyable rides.

If you are constantly banging off the bottom of your bike's travel, have that sucker stacked full of volume spacers, run the lowest suggested sag value and still aren't getting the support you're after, you absolutely want to consider the MegNeg.

You can tune compression stacks all you want, but addressing the spring curve is always more impactful. This is an excellent upgrade for a reasonable price and will make a big difference on bikes that could benefit from added mid- and end-stroke support. You've got to be willing to do some back-to-back testing though!

Visit www.rockshox.com for more details.

Vital MTB Long-Term Rating: 5 Stars - Spectacular


About The Reviewer

Brandon Turman - Age: 33 // Years Riding: 18 // Height: 5'10" (1.78m) // Weight: 170-pounds (77.1kg)

"I like to have fun, pop off the bonus lines on the sides of the trail, get aggressive when I feel in tune with a bike, and really mash on the pedals and open it up when pointed downhill." Formerly a mechanical engineer and Pro downhill racer, Brandon brings a unique perspective to the testing game as Vital MTB's resident product guy. He has on-trail familiarity with nearly every innovation in our sport from the past several years and a really good feel for what’s what.

Video by John Reynolds and Brandon Turman

Specifications

Product RockShox MegNeg Upgrade Kit
Features The MegNeg provides an increase in negative air spring volume, which (coupled with the resulting positive pressure increase) adds mid-stroke support, giving a plusher initial feel, and adding more bottom-out support using fewer tokens. It also allows you to tune the negative volume using Bottomless Rings.

  • Kit includes MegNet air can, Bottomless Rings, seals, and decals
  • Compatible with Deluxe and Super Deluxe shocks
  • Available in three sizes to fit three air can sizes
  • Miscellaneous RockShox model ID: SS-UPK-MGN-A1
    Price $90
    More Info

    RockShox website

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