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Existentialism-- Just a bloody good excuse to go riding...

Thursday, October 18, 2012

Review: DSP Dueler FR 7.875 x 2.25

Once again the good folks from DSP dropped off a package last week. This time around its one of the new, smaller boinks aka Dueler FR shocks. Prior to this the smallest available was the 8.5 x 2.5"

These new available ones comes in:
7.5 × 2.0  (E to E 190mm, Travel 51mm) 
7.875 × 2.0  (E to E 200mm, Travel 51mm) 
7.875 × 2.25  (E to E 200mm, Travel 57mm)
 with either a 400 or 500lb Kronos Ti Coil.

Being popular sizes on many  frames in the market, this would surely open up the option for those who may want to find something a little different from the few usual brands.

Spotting the same quality finishing as their bigger cousins, there is the lasting hard coat anodizing. Something my oldest Dueler can bear witness to after 2+ years of abuse with just minor fading. Usual attention to details for their shock are pretty much the same. What's done right all along are applied to these new shocks as well. The long of it, has already been covered in my earlier review of the 8.5" x 2.5"

Of course, just looking at the new graphics on this one would you make you 0.5 seconds faster.
In addition all the Kronos Ti coils now receives an anti-UV lacquered surface. While I'm not really a big fan of glossy things.. but the easy cleaning and keeping the spring stain-free  is something that can be appreciated.

It is comparatively light when pitted to other similar sized coil shocks out there. Running an air shock with piggy will probably set you back by 430-480gm. For the 7.875" x 2.25" here with a 400lb coil at 642gm, this would be less than ~150-200gm difference (that's less than 1/2 lb for all ya metric-challenged readers).

If you are looking for that coil performance with the "lively" ti spring feel, just  stop right here and  just go look for the nearest distributor. Pricewise, its not about being competitive. They just sweep the table up from the competition if its only based on this one factor at ~60-70% for what you have to shell out with other big brands...

More importantly is whether it works.. So far from using the bigger ones, it I'll just summarize it as  "Simple shock mechanisms with easy operation of adjustments that has actual usable range and pretty much fuss free" (at least for me).

It would seem like a repeat of what has been reviewed previously. However the time it has taken for these smaller shocks to be tested  and made available only recently says something else. The internals probably received some tweaks as innards like shimming and seals etc would obviously have to be fitted into a smaller volume of shock body and the respective sizing of the internal bits have been reduced?

Wouldn't be to hard to think how changes are needed to overcome some of the constraints and the mechanics as space within shock body, x-sectional areas diminishes.

It is easier to make a bigger shock work well but as size diminishes, it gets harder to cram and tune everything within yet still suit a broad range of riders with varying weights.

Size comparison between the 7.875" (top) and a 8.5" (bottom)

Compression knobs are the familiar, non-indented ones. ~2.333 turns of adjustment on both the hi and lo comp.

The only noticeable difference vs the bigger Duelers is the rebound range. Apart from being stamped  with the letters "FR", it is 1 full revolution less (max 2 turns on my piece) compared to 3 on the bigger size shocks. Spec data indicates info for force/loads up to 1.5 turns of the rebound.  Maybe something to counter/offset with the workings of others internals within?

Left: Dueler FR 7.875 x 2.5" Right: Dueler 8.5" x 2.5

Quite frankly those numbers are like reading off a weather chart for me. All I can gather is that this shock probably runs a different rebound to whether things work-- well that's what the real life test riding is for eh!

The Ride
'Nuff with the maybes and e.theorizing... time to break out the my nerve-ending enriched butt for some test and calibration of the shock.

Nothing big and adventurous as its just the first ride to set things up for a long term review.. 

As luck would have it the sky decided to pour half the Pacific over our head just before the start. Well , that just puts things back in my favorite element--  Wet-"n"-Wild roller coaster ride. Nothing better to test traction...

The setup
Riding weight 170lb
The Dueler tag-team with a Vengeance Coil 170mm up front on a small De Vinci Dixon running the Spivot design.  2.5 Minion DhF upfront and a death grip 2.35 Hans Dampf pulling rear duty completes the essential things that would interact and relate to the shock's performance.

Initial Shock Setting
Lo comp --fully open
High Comp -- 3/4 turn from minimum
Rebound -- half a turn from minimum

Comparative feel with other shocks
A quick word... some bikes are optimized to run on air shock and coil may not always feel as good. This is supposedly one of those where an air shock coupled to the design is said to have a very firm and efficient pedaling platform.

However having rode this bike with its stock air shock and another brand of coil shock, it certainly felt ok for both air a nd coil. The other coil shock left a lot to be desired though. With fully open compression settings, the damping still felt too stiff for the bike and no matter how the rebound is tweaked in relation to the compression-- the bike just keeps kicking up in the rear.
All of these gives a good idea for comparison when swapped out for the Dueler FR. Objectively it could also be attributed to just the coil itself. The 400lb steel coil of the last shock might not have been all that close to 400. Definitely felt a lot harder compared to the Kronos 400lb on the Dueler now.

As far as various brands of coils goes, be it steel or titanium.. the DSP Kronos has always felt to be the most accurate. I say "felt" because I have no access to actually test these things, so will have to let it rest at that. But given their published data of +/- 1.5% tolerance its the tightest range in all brands I have seen.

Difference was immediately noticeable. No "dead" feel. My earlier concern that the 400lb coil might be too stiff quickly dissolved. In fact with the Dueler, it actually sag  more than expected (~40%) giving rise to a new concern-- Bottoming Out.

Only 400lb or 500 lb option--where's the rest?
Based on the feel of the previous coil shock and some calculation I had originally requested a 350lb spring but was t/old only 400 and 500lb are available with the Dueler FRs...not too sure why as the bigger Duelers can be ordered with a ti coil range from 250-500lb. 

40% is a lot of sag on a 5.7" trail bike but with an efficient pedaling platform design there was no noticeable squatting even when gunning hard on the pedal. And hard it was, because it was practically a non-stop pedaling the entire time, catching a break only in corners and small jumps.

The test and thoughts...

Down and Popping
Great traction by the Dueler in combination with the 2.35 Schwalbe Hans Dampf even in the entirely wet ride. So much so that it was actually the front that washed out a couple of times. Firm spring on the fork isn't exactly what I normally use so not gonna fault anything here...a little more time to set up the front and things would certainly have been a lot better.

The trails had some small features, when taken at speed it gives a couple feet drop with one to 1.5 bike lengths going forward. Nothing big but enough to test impact on landing...

No hard bottoming out of the shock. Given the significant rear sag, a couple of hard thuds was expected. Granted the huge signature rubber bumper on Duelers would have helped slow things down quite a bit towards the end of the travel, still it is not very common to get this amount of rear plush compliance without having to worry on heavier hits. Can't entirely say if it one or the other but it wouldnt be too much to say the tuning on the Dueler on this particular suspension design is a perfect wet dream ride comes true.

What I think is a signature and central piece in all Dueler shocks that at first sight seems to take away a good portion of travel on the damper rod.... Rather understated but in all my ride experience with them-- a very crucial piece that helps control the last inch or so of travel on the bike. Not some uber hard rubber meant to simply stop the travel preventing shock body and lock ring knocking into each other. This actually compresses all the way down to ~0.25" which in the process helps to ramp things up nicely at end of travel to prevent harsh bottoming out.

One thing omitted was to check pressure in the piggy resevoir. It should come default from the factory at 150psi though. If it is, then for the first time I actually have a shock that is literally "plug-"n"-play" right off the start.

Taking it through the climb, like any coil shock vs an air can between the legs, that quick snap to propel up and over obstacles are normally lacking in coils. While that is true but this is where the traction mediated in part by the shock shows up positively. Supple enough to bite down, enabling the bike to claw up and forward but not too much of that "sucked down" feel that's energy sapping. The rear was munching up square edges and rocky clumps with nary a kick. Something that otherwise my sit bones will be in vehement protest. Overall climbing feel was significantly light and surprisingly easy on this 15.5kg rig running coils on both ends.

One other thing to note.. The low-speed compression was set to fully open during the entire ride... On another drier day will try cranking up some lo-comp to see if there is enough firmness to gun through the slopes a la singlespeed mode.

Everything seems good with the Dueler FR at this point but I would like to find out if there are things that can be improved. The test so far might be on a suspension design that gels well with the particular tuning on the Dueler. Objectively it would be good to test it out again on other suspension designs, maybe a DW and some multi-link SP to reconfirm some of the thoughts so far. So stay tuned...

Twas actually more than just the Dueler FR shock testing on Sun.. A double bike test running  the same trails and sessioning various places on both bikes. Lots of good cross comparison data gathered.. but more of those thoughs on another write-up.


  1. I want that shock for my bike, Were can I buy that?

    Jacob of biking Philippines

    1. Jacob... send an email to
      Just let them know read it from here and see how they can arrange something out with you.
      Cheers Dennis