DVO released their Topaz T3 Air shock last spring. You can think of it as the rear-end counterpart of their Diamond fork model—essentially a lightweight, heavy-hitting bit of suspension for all-mountain and enduro bikes with its healthy-sized air can, external reservoir and a bevy of tuning options.
But is the Topaz a viable alternative to other popular shocks in this niche? Models such as the Monarch Plus RC3 or Fox DPX2? To find out, I bolted this thing onto an Ibis Mojo HD3 and rode it for a season.
DVO Topaz T3 Air Details
• 3-position, compression-damping adjuster
• Adjustable rebound damping
• Tunable air volume/bladder-pressure adjust
• Five different eye-to-eye/stroke options
• Specialized Enduro and Stumpjumper-compatible versions available
• Weight: 390 grams (200x57 size)
• MSRP: $500 USD
The Topaz is a bit of a tuner’s shock. There are the typical adjustments—a three-position compression adjust lever that lets you toggle through what amounts to be open/trail/climb settings on the fly as well as an easily-accessed rebound damping knob with 9 clicks of adjustment.
You can also mess with the shape of the shock’s spring curve by adding or subtracting volume spacers to either/both the positive and negative air chambers. In other words, if you correctly dialed in the sag and you still feel like the shock is blowing through its travel, you can add a spacer or more to the positive chamber. If you feel, on the other hand, that the shock moves too quickly through its initial stages of travel, you can add a spacer to the negative chamber.
While volume spacers are, of course, nothing new in the world of suspension, one thing that does set the Topaz apart from a lot of other shocks on the market is that it features a bladder instead of an internal floating piston (IFP) and that has an impact on both suspension performance and tuning.
Bladders and IFPs seek to do the same thing—reduce the risk of cavitation. When I originally published this story I poorly worded my explanation of cavitation. As several readers quickly noted—air and oil mixing could more accurately be described as aeration or elmulsification. Whereas cavitation is the result of low pressure behind the internal floating piston allowing the shock’s damping fluid to shear or separate into a gas. The nitrogen charged-pressure behind an IFP or, in this case, the air pressure in the bladder, puts positive pressure on the oil to resist the formation the low-pressure pockets (what I was clumsily referring to as “air bubbles”) on the other side of the IFP/badder. Thank you, readers, for pointing out the distinction. There’s a reason IFPs and bladders exist—to provide you with consistent performance when your shock shaft is cycling like mad and you really need your suspension to refrain from suddenly surprising you with some bullshit behavior.
While IFPs clearly work a charm, some suspension manufacturers in the motorsports world prefer bladders, which they contend are more reliable. IFPs rely on a tight seal. Drag a seal back and forth a whole bunch and you get friction and heat. Excess heat can also muddle your shock’s performance on sustained descents (that’s fundamentally why there’s that piggyback reservoir hanging off the shock in the first place—to help cool the damping oil). Anyhoo, a bladder is essentially a mini balloon, so it’s not adding a seal that must drag back and forth along the inside surface of the reservoir. Thus, no additional friction and added heat. Sweet. Why don’t we see more bladders in shocks then? Truth be told, IFPs work well and bladders, manufacturers like DVO claim, are more expensive to manufacture shocks around.
The use of a bladder, however, also gives you another tuning option. To wit, you can unscrew the green cap on the external reservoir and adjust the pressure inside that little balloon. There’s a fairly narrow range of adjustment here—just 30 PSI, but it makes a substantial impact on shock feel. Adding pressure makes the shock firmer throughout its entire stroke. Reducing pressure does the opposite. In other words, changing bladder pressure allows you to essentially shift the entire spring curve up or down, as opposed to changing the shape of the curve, which is what you accomplish with those volume spacers.
Some people live to fiddle with their parts. I prefer to ride. Besides, you can go blind if you get carried away with the fiddling. That said, I appreciate having the option to tune my shock—a few PSI here and there make a world of difference. I wound up settling on 205 PSI in the air spring and 180 PSI in the air bladder. The Mojo HD3 tends to ride pretty high in its travel, regardless of which shock is bolted to it and I didn’t feel the need to add a spacer to the negative spring. I opted for a single spacer in the positive chamber.
While the pictures below show the shock off the bike (I had to weigh it), you can usually add or subtract volume spacers with the shock still on the bike, which makes tuning a whole lot easier. Simply let out the air, take off the ring, and slide down the air can. Because the volume spacers are, essentially, slotted plastic clips, they just snap in place. No need to unbolt the shock from the frame. Nice.
Once I got the shock dialed, I proceeded to ignore its health and well being for a season. To its credit, it never complained or got glitchy. The Topaz replaced a fairly plain-Jane inline shock and the bike’s big-hit performance radically improved with the addition of the DVO shock. Same holds true for suspension performance when the impacts come quick and don’t let up for long stretches. Was the rebound damping particularly consistent because of the bladder, the reservoir, the extra ribbed-for-pleasure “cooling fins” on said reservoir? Who the hell knows? The shock just worked.
Adding a bit more ramp to the end of shock stroke is as simple as letting out the air, unrolling the O-ring, pulling down the air can and adding a volume spacer to the positive chamber. You can also add or subtract volume spacers from the negative chamber to change the Topaz's beginning stroke behavior.
The Mojo HD3’s DW-Link suspension is pretty damn efficient regardless of which shock you are running and I could often leave the Topaz Air wide open. The 3-position compression adjuster, however, does work. It’s a bit more subtle than some compression adjusters—the firmest setting isn’t quite as firm as what you might experience with some other shocks, but I didn’t actually consider that a drawback as I rarely require more compression damping than what was on tap with the “Medium” middle setting. Again, squat isn’t a huge issue with DW-Link.
I’m looking for something to complain about here, but honestly, the Topaz doesn’t leave a lot of room for complaints. I guess the detents on the rebound damping knob are a bit more subtle than I’d like (makes it a bit harder to keep track of the clicks when you are in the fiddling process), but it just required a bit more attention on my part during the initial set-up phase—it’s not like I’m tweaking rebound damping more than once in a blue moon.
In short, the Topaz T3 is a performer. It’s not inexpensive, true, but the DVO is priced on par (a hair less, actually) than its main rivals in this niche. Pinkbike's Take