DVO Topaz Air Shock

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DVO Topaz T3 Air Shock
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Tested: DVO Topaz T3 Air Shock

The Topaz is a true gem in DVO's expanding lineup, offering very impressive sensitivity and some less common but very useful tuning options for discerning riders.

Rating: Vital Review
Tested: DVO Topaz T3 Air Shock

When it comes to improving a bike's performance, one of the key areas to consider is suspension. Combined with your tires, it is by and large responsible for controlling your bike's interaction with the trail beneath you. DVO, short for Developed Suspension, has a long history in our sport and knows a thing or two about how to perfect that interaction, maximizing traction and control on your mountain bike. Whether your goal is outright comfort, speed, or a combination of the two, their suspension products offer the tuning means to make it happen. We've been torture-testing the DVO Topaz T3 Air shock for well over a year and dialing in our ride. It offers some unique design features compared to the majority of rear shocks on the market.

Strengths

Weaknesses

  • Use of a bladder system

When it comes to improving a bike's performance, one of the key areas to consider is suspension. Combined with your tires, it is by and large responsible for controlling your bike's interaction with the trail beneath you. DVO, short for Developed Suspension, has a long history in our sport and knows a thing or two about how to perfect that interaction, maximizing traction and control on your mountain bike. Whether your goal is outright comfort, speed, or a combination of the two, their suspension products offer the tuning means to make it happen. We've been torture-testing the DVO Topaz T3 Air shock for well over a year and dialing in our ride. It offers some unique design features compared to the majority of rear shocks on the market.

Strengths

Weaknesses

  • Use of a bladder system helps create an ultra-supple feel
  • Eats up square-edged hits
  • Quickly adjustable bladder pressure and negative air spring volume introduce new tuning options for many
  • Volume reducers can be added without removing shock from bike
  • Quick three-position compression adjustment allows on-the-fly customization for varying trail types and sustained climbs
  • Excellent quality internals
  • User serviceable
  • Great customer support
  • Additional tuning options may be overwhelming for some (keep reading though, you'll learn!)
  • Lack of preset tunes or a public DVO-verified base tune database
  • Large compression adjustment lever may interfere with some water bottle mounts in firmest position
  • Difficult to detect detents on rebound adjustment knob

Highlights

  • Intended Use: Trail, all-mountain and enduro riding
  • Spring: Air; volume reducers can be used in both the positive and negative spring
  • Damper unit: Compression loader system with bladder
  • Compression: Three position dynamic adjustment via easy access lever (internally tunable if needed)
  • Rebound: Nine clicks of dynamic adjustment via piston and shims (internally tunable if needed)
  • Rubber bladder pressure can be adjusted from 170-200psi
  • Bushing: 15mm IGUS bushings with 6mm, 8mm or 10mm mounting hardware options
  • Cooling fins on piggyback reservoir for improved heat management
  • Five standard eye-to-eye/stroke options
  • Six metric eye-to-eye/stroke options and six trunnion options
  • Specialized Enduro and Stumpjumper-compatible options
  • Weight: 390 grams (verified, 200x57mm size)
  • Carrying case, shock pump, and volume reducers included
  • MSRP: $500 USD

Bladder Versus IFP in the Topaz

While there are several small details that all add up, the main feature that sets this shock apart is the use of an easily-adjustable bladder instead of an internal floating piston (IFP) inside the finned reservoir. This is a trickle-down from DVO's Jade Coil downhill shock.

A bladder is basically a ballon made from a stretchable material that can expand or compress. On the Topaz, it is filled with air and seated to the reservoir end cap.

An IFP is more common in mountain bike suspension, and is a moving piston with at least one o-ring seal that slides up and down inside the reservoir.

Both a bladder and IFP separate air (or nitrogen) from damper oil within the shock and are used to pressurize the system. As a shock is compressed, oil is displaced within the system and starts to compress the bladder or IFP. When the shock goes to extend again, the bladder pushes the oil back in the opposite direction. Pressurizing the bladder or IFP helps keeps the rebound chamber from cavitating during quick compressions.

As DVO describes it, "Cavitation occurs when vapor bubbles form in the suspension fluid due to a decrease in pressure."This video clip is an example of cavitation in a shock. When cavitated, the subsequent rebound stroke produces zero damping while the cavitation bubble collapses. In short, you don't want it to happen.

Increasing bladder or IFP pressure increases the shaft speed at which cavitation will occur. DVO capitalizes on this fact by making their bladder easily adjustable from 170-200psi with a shock pump, and makes the general statement that lighter riders can run less pressure and heavier riders should run more.

Pressurizing the air spring, like normal.
Pressurizing the bladder, a less common adjustment option.

Adding pressure to the bladder does not create damping – instead, it acts directly on the shock damper rod area and adds to the overall spring force during both compression and rebound. In an IFP system, tuning via IFP pressure creates added breakaway forces (the force needed to get the shock moving), so it is typically set to a predetermined pressure and left alone essentially hidden inside the shock. Overcoming breakaway force has lead to larger negative springs and systems like RockShox's Counter Measure. Bladders have reduced breakaway force compared to IFPs due to a lack of seal friction, however.

Those seeking to tune out some of the chaos of bumpy trails will be very pleased with the shock's relatively low breakaway force and ultra-supple feel – this alone makes it a worthwhile upgrade.

"The real benefit of using a bladder over an IFP," DVO says, "is when the shock is working dynamically or in riding situations. As the shock is compressing and rebounding at a high velocity, it can sometimes have a difficult time changing directions. An IFP usually has a moment of hesitation [commonly known as "stick-slip"] due to stiction between the outer o-ring and the inside surface of the reservoir. With a bladder that can't happen and you get unmatched small bump sensitivity with a seamless transition from compression to rebound."

So why don't we see more bladders used in mountain bike shocks? They're used in many motocross applications, after all, and several forks have them as well. The most commonly cited downside of bladder-based systems is the possibility of air permeation through the bladder membrane into the damper fluid.

"Bladders can be costly on the production side," DVO adds, "and take skilled technicians to properly bleed and install. On mass-produced suspension products that isn't something they're willing to invest in."

Tuning Tips and Observations

For this test we paired the a 190x51mm Topaz with a first generation Transition Smuggler. With just 116mm of travel out back and a longer-than-stock 150mm out front, we like to think of it as a "little" bike with big ambitions. The front end and geometry allow us to ride some pretty hairy terrain, and doing so requires rear suspension that can keep the pace.

Going into the tuning process we knew that the Smuggler is only slightly progressive – meaning it relies on the shock to help add some bottom-out support. By reducing the air volume of the positive air spring with volume spacers, the shock becomes more progressive. As shown in this how-to video, DVO's split-ring volume spacers allow you to make changes while the shock is still mounted to the bike, reducing overall tuning time and complexity:

DVO's straightforward statement will help guide you while tuning the shock:

"The negative chamber is responsible for counteracting the forces of the positive air pressure. This is your beginning stroke. The positive pressure is your air spring. This controls your mid-stroke and bottom out. In the Topaz, the two chambers work together to create a seamless transition throughout the stroke."

DVO provides a wealth of knowledge via their tech website, including setup, tuning, and service procedures.

There is, of course, more to it. While going through the tuning process and bracket testing over a dozen combinations of settings (sag, positive air volume, negative air volume, bladder pressure, and rebound), here are a few observations that helped us arrive at a preferred setting:

Pick a sag percentage you'd like to use and try to stick with it. Doing so helps keep one variable constant, and most bikes are designed for best pedaling performance around a specific sag point. In our case, Transition suggests 33% for the Smuggler. Using a set sag percentage as a baseline also eliminates the confusion associated with the various pressure changes that will be required as you modify the air spring.

The DVO logo on the damper body is very conveniently placed. On our 190x51mm shock, 25% sag was near the center of the DVO logo and 35% at the bottom of the little square that surrounds it. This may not be true of all sizes, however.

The first time we went from minimum to maximum bladder pressure (170 to 200psi), we could feel the bike absolutely come alive when pumping various trail features. It went from a deeper/plusher/more supple feel to a more supportive ride with a more immediate response. Those wanting to add "pop" or a fun/lively feel to their rides will likely appreciate the addition of bladder pressure. Extra pressure does transmit more of the terrain, but not in a way that's very detrimental over sharp bumps, in our opinion.

Extra bottom-out support can be gained both by adding spacers to the positive chamber and by adding bladder pressure.

Adding a single spacer to the negative spring can help calm chassis motion while pedaling and provide additional support in the early part of the stroke. A downside on our bike was a notable increase in small bump feedback, however, which is something the shock handled incredibly well before a negative spacer addition. If you're not already maxed out, adding bladder pressure also improves initial support and may be a better way of achieving the initial feel you're after with less impact on small-bump performance.

The combination of several (in our case, three or more) positive spacers and high bladder pressure can lead to feeling like there isn't enough high-speed/end-stroke rebound during deep compressions. Increasing the rebound adjustment deadened the bike's initial and mid-stroke response before addressing the issue. Instead, try one less positive spacer and a little (~3-4%) less sag. This provided us with close to the same bottom-out support and a more controlled rebound feel. There was also an added benefit of improved initial support, and only a very slight loss of initial sensitivity.

After a fair amount of experimentation, here are our preferred settings for a 175-pound rider on the first generation Transition Smuggler in most terrain:

  • 32% sag
  • 2 volume spacers in positive air chamber
  • 0 volume spacers in negative air chamber
  • 190-200psi bladder pressure

On The Trail

During our first ride on the Topaz, we immediately noted a drastic improvement in bump sensitivity compared to the recently-serviced RockShox Monarch that it replaced. This supple feel results in a quieter chassis, better control, and better traction. We chalk this up to the negative spring, bladder design, and even the mounting hardware that rotates remarkably smoothly in the IGUS eyelet bushings.

Our settings have changed many times since that first ride as we've narrowed in on what feels best for our riding style and terrain. At the settings outlined above, the bike exhibits the most consistent feel throughout the stroke while helping the bike to keep speed in many situations. On a scale of sufficient, good, and great, the bike currently has good initial-stroke suppleness for small bumps; great support while pedaling, pumping, and jumping; and good bottom-out support with controlled rebound during big compressions. Turning those "good" characteristics into "great" is the next tuning task, which may be achievable with damper tweaks.

The T3 compression adjustment provides easy-to-use access to three compression settings via a large lever. Unlike many shocks, the firmest setting does not come anywhere close to locking the shock out, allowing the rear wheel to still track the ground well.
Open
Medium
Firm

The T3 compression adjustment provides easy-to-use access to three compression settings via a large lever. We run the open setting most often, medium on sustained trail climbs or smooth/flowy/bermy/jump-heavy terrain, and the firmest setting when it's time to really mash on smoother climbs. Unlike many shocks, the firmest setting does not come anywhere close to locking the shock out, allowing the rear wheel to still track the ground well. It does add enough compression to quiet any excess shock movement down and make a difference in both pedaling performance and when shifting your weight around, however. Those wanting a firmer setting can make the change via compression shims, but most inside the ~160-230-pound range will find it useful.

We've noted no glaring damping issues with heat management on longer descents. We also appreciate that the shock doesn't get as sticky-feeling as most do when it's really cold out.

Long Term Durability

DVO suggests a full service once a year, every 100 hours of ride time, or every 50 hours of ride time if ridden in an area where the shock is subjected to extra wear. Thanks to a user-serviceable design without the need for specialty tools, service can be performed in the comfort of your garage. DVO provides a detailed rundown of how to do that in this service document.

Should you happen to be at an event with a tech expo, be sure to keep an eye out for a DVO tent. Ronnie and the crew will gladly get you taken care of.

During the last 15 months our shock has seen rides in mud, moon dust, and everything in between. We had a service done around the nine month mark while also addressing a leaky Schrader valve on the air spring. To this day the action of the shock is still very smooth.

Thanks to a user-serviceable design without the need for specialty tools, service can be performed in the comfort of your garage.

There has, however, been some recent and concerning wear occurring on the damper body that will eventually lead to worn seals. Removing the air can to inspect the inside of the shock revealed wear on the metal lip just above the dust seal, near the white bushing. No dirt or other contamination was found. DVO says this can occur when there is a frame alignment, bearing, or hardware issue, and will generally only occur on one side of the shock as it did on ours. They've only seen the issue a handful of times. An initial inspection of our frame bearings revealed no glaring issues, and the linkage moves freely with no play. Given the sudden nature of the wear, it's likely that something is amiss.

DVO backs the shock with a two-year warranty.

Things That Could Be Improved

More defined detents on the rebound adjuster would be great, and the compression lever often feels a bit too easy to turn. The compression lever's size may also prohibit the firmest setting from being used on bikes with a water bottle.

DVO provides a wealth of knowledge via their tech website, including setup, tuning, and service procedures. A larger, more complete database of DVO or frame manufacturer confirmed base tunes would be helpful for many. There is currently an archive of user-submitted tunes, but these can be hit or miss. Having something backed by DVO or frame companies could ensure a better starting point for most users.

As previously noted, we feel the shock could also use a bit more high-speed rebound damping for use on the Smuggler. DVO does make the tools/knowledge/resources available to make almost any change happen, however, and support is just a quick phone call away if you have a question or need advice. When we reached out about how to tackle this on their digressive damping design, DVO said they "suggest lifting the stack to eliminate the dish on the rebound side of the mid-valve, which will make the damping a little more consistent through the entire range." This is something we'll try in the future.

What's The Bottom Line?

The DVO Topaz air shock made a substantial improvement to the suspension performance on our Transition Smuggler test bike, and with enough tuning time the quickly-adjustable bladder system has allowed us to find a setting that brings the bike to life while maintaining excellent traction and control. Those seeking to tune out some of the chaos of bumpy trails will be very pleased with its relatively low breakaway force and ultra-supple feel – this alone makes it a worthwhile upgrade. Quality internal components, a user-focused design, and excellent customer support make it serviceable at home, which will save you both time and money in the long run.

Visit www.dvosuspension.com for more details.


About The Reviewer

Brandon Turman - Age: 31 // Years Riding: 16 // Height: 5'10" (1.78m) // Weight: 175-pounds (79.4kg)

"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 new innovation in our sport from the past several years and a really good feel for what's what.

Photos by Courtney Steen and Brandon Turman

Specifications

Product DVO Topaz Air Shock
Riding Type Trail
Spring Type Air
External Adjustments T3 compression (pedaling/traversing/descending), rebound, bladder pressure adjust
Available Sizes 216mm x 63.5mm
216mm x 57.5mm
200mm x 57mm
200mm x 51mm
190mm x 50mm
Weight 0 lb 11.6 oz (330 g)
Miscellaneous High flow Jade piston, reservoir cooling fins, and high quality Trelborg seals
Adjustable air can volume (both positive and negative sides) via "tuning band" spacers
CNC/forged exterior
Specialized-compatible version available for StumpJumper and Enduro models
6mm, 8mm, or 10mm mounting hardware options
Price $500
More Info

dvosuspension.com

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