DSP Bighorn Adjustable Seatpost...

Package dropped......The pre-release Bighorn Adjustable Seatpost from DSP Racing is finally here and in some really impressive packaging too!

Having owned multiple  adjustment seat posts, expectation of any new adjustable post is high. It may seem to be picking bones but the cost of such components are not cheap and the smallest bit failing means a lot of annoyance and frustration when using and or dealing with warranty returns.


Initially from pictures on the website, it look like a chimera of 2 other in the market. But there are some interesting features mentioned like the "sensitive valve control" and their much highlighted saddle clamping/adjustability design that caught my attention. In any case having owned and still using the Dueler shock and their Ti springs, my expectations has been on the high side even before it arrived... a long term review of the Dueler on my EG will be done soon...

Visually...
Although some parts may look similar to some other posts in the market but on seeing the actual thing, the Bighorn is in a class of its own. A very stiff and beefy piece with a solid dust seal and yes, the much mentioned head clamp.

Massive and intricately machined to accept the actuation mechanism and lever. Once cable is tightened, nothing protrudes out of it. In this regard I already have in mind a simply mod to mud-proof the cavity without resorting to some ugly lump of anti-gunk covering.

No extra tiny bits but everything is contained within the one piece post... only need to thread the shifter cable through. No guessing and approximating how much cable is needed to get the correct tension. Very easy to install compared to other brands of hydraulic posts used.

The link between the name Bighorn and the clamp design is pretty obvious. for me,  it conjures up image of golden scarabs, pharoahs and pyramids....

Collar seal looks to be good, wider and higher than most other posts. That should help keep most of the grit and water out. Air pressure guide is included in the instruction manual. Mine came as per specifications at 100psi under ambient temperature. Stanchion size is of a slightly larger diameter compared to at least 2 other brands. I would think bigger confers more stiffness and less play over time.... but let's see.

Small attention to details are apparent. A small return spring is incorporated in the lever pushing down on the actuating mechanism. This together with the very short distance between compressing should ensure a better return even when trail condition starts getting gritty and without the benefit of any DIY mud-proofing contraptin. Some post when getting clogged suffers from the return stroke of the lever during rides. This leads to a loose tension in the lever and makes any attempt to work it not possible, something many of us have no doubt experienced.

Left: Note the return spring on right side of picture.
Right: shows how everything is contained within the recessed cavity when in position in a rather neat Tranformer-ish looking cephalic package

Remote Lever

Remote levers, from fork lock out controls to adjustable seat post has appeared in all shape and sizes. The Bighorn's thumb down "gas-pedal" design is not unique. However, machined into a small footprint, together with the ergonomics it offers, it is one of the better ones in my opinion. It can be positioned really close to the control if one so chooses. Profile wise it doesnt extend much more than the controls I'm running so there is little of any unsightly protrusion and lesser probability of knocking into it. An improvement could come in the form of a small section of flexible hose at the lever end.. this could help greatly in the cable management for some although it would probably add a few more grams.

Lever finishing is actually a light gun metal grey anodized hue. This should appeal to Hope fans that runs components of the same color.

Installation.
The  clamping on both sides are independent. As mentioned the clamps are massive which probably makes them strong but fitting to thinner racing type saddles would need a little patience, like the WTB Silverado I picked at random from my saddle bin. Not a big issue and once the rails are snapped in place, fore/ aft + tilt adjustments are super easy.

Once satisfied  just tighten both 4mm screws down good. For designs like this.. when the screws are not quite tight the saddle can be rotated almost a full 360 degrees!. This allows easy reach into the cable set screw and adjustment valve without having to dismantle everything. A big plus especially when on the trail.

Everything was ultra tight and it almost didnt budge when I tried to push the saddle down after installing!! Ok that freaked me out a little. Put my full weight and jump on it before it started working. Full compression took another few more hard ass thumping on the saddle

After this initial little episode, everything was working as it should. However judging by the looks of it, it will be at least another few hours of use before the seals and all will fully break in. Actual smoothness can only be determined then so I wont comment further.

So far everything looks good and sturdy. An adjustable post that looks to be able to take some abuse on the trail (remains to be tested for a period before I would stamp a pass on this). But all the strong beefy features makes this by far the heaviest I have weighed. The piece here, a 30.9mm size comes in 25g more than the stated weight of 605gm. Nothing I will worry unduly over if everything works well though.

+1 for the details to the finishing. Quality machining.

One last thing I wondered is whether color kits would be offered in the future... Not that the current color combo is unacceptable but having things like color kits is always a good way to sway some that matches things  right down to the last spacer on their bikes.

Its Friday evening now, so trail testing is just a few hours away...  ... ... (To Be Continued)...   ...


.....
Sat 07 Jan
Quick urban ride today as there is no time for the trails. The return on the post is fast even though its not broken in yet (as evidenced when lowering the post where it requires sitting down hard on it with my weight). The fast return speed is something I always wanted over my other hydraulic posts. On this aspect, only a mechanical dropper on another of my bike can match it so far. For those that prefer a little slower, this can probably be adjusted via the air pressure at the other end of the post.  No hiccups so far, works as it should.

Sat 08 Jan

Move it up and down a couple of hundred times... mostly loose enough now for a very smooth action. Twisted saddle forcefully enough to test for any side to side play... None.

Was gonna test the Bighorn, then keep it for another bike build and revert to another adjustable post in the meantime . But I'm liking the smooth operation of it, looks like its a stayer on the EG.

[Update] 14 Feb 2012
A little caution on the M4 clamping bolts for the rails. Use anti-seize! I would really  prefer if the design can incorporate M5 bolts instead... Its a double edge thing with anti seize- you got to check the torque more frequently as they tend to back the screw out a bit over time. In the case of M4 bolts, anyone who has experience with other components that need relatively higher torque (as in the case of the DSP post here ) would know it can be a bit finicky to deal with. Not tight enough- it slips... tightened down hard steel M4 can strip the alu thread on the component easy when taking them off and usually accompanied by that sickening "crackling" sound. I am putting attention as the screw thread built into the post itself to secure the clamps if stripped renders the whole thing useless.... the most likely solution in such a situation would be to tap a helicoil.. but I'm not sure if that is possible as the thickness and space in there might be a constraint. Ok Im just being paranoid-me as usual... always thinking of disasters before it happens..

[Update 2] 26 Feb 2012
Check the air pressure in the post...
With all the things going on, there is not much riding done over the last few weeks. Pushing it down by hand is a lot easier and I thought things have finally broken in. But in the last 2 rides I felt the return stroke of the post was not "working right"...Signifiacantly slower and sometimes it doesnt come up. Would need an additional butt thumping to get it up. In any case even if it comes back up-- it was slow and always the last bit (~1/4") would remain stuck down  and can only be lifted up by hand. Logically al lof this would point to an insufficient air pressure in the post...

Took out post today and checked the air pressure located on the bottom! Stock presta valve was not loose and it contains an o-ring but pressure has dropped to <50psi. It was set at 90+ psi after checking it on the first day and hadn't been fiddled with since.

Reset it back to 100 psi... The day one feeling with lots of resistance when pushing down by hand came back. But lowering while sitting on the bike is not an issue, although the last bit would require to drop the full weight down and release the lever fast. slow on letting go and a bit would pop right up. Return stroke on the other hand shot right back up, fast and nothing sticking this time....

Putting 2 and 2 together-- so it seems that modulating the pressure pumped in does 2 things. It gets harder to compress toward the end but a certain amount of pressure is needed to get the return stroke smooth.

The working range given for ambient temperature is between 80-120 psi. How much to pump in I believe would be dependent on rider's weight. If you are lighter-- go with the lower end, otherwise it gets really stiff towards the end of the stroke. Heavier rider would probably not have so much of an issue.

So for lighter riders, experiment with 5 psi upwards increment from an initial 80 psi to find your sweet spot for return speed and being able to comfortably compress it all the way.

Mine at riding weight of 170 lb (yup have gained a couple of pounds) is good with 90-95 psi in the post....

All in, its not a big issue. Even if there is a need to check the air pressure every couple of months, its a relatively easy and 2 min job during regular bike maintenance. Looking on the bright side-- this gives a user friendly way to tune as opposed to some other posts where the air presurre is in accessible and requires a lot more effort to take apart in the first place... nevermind about putting things back

[Update]: June 2012
No more dropping air pressure... nothing done as it operates fine. At the same time I gotten my hands on the one of the later batches spotting  a change to M5 bolts on the clamps. That pretty much solves the only thing that has been nagging at paranoid me even though the first piece didn't fail so far. Well M5 are M5-- like all my favorite trusty stems withthis size of bolt, they definitely clamp better and is easier to work with.

[Update]: May 2014
Still work like a charm.. Only needed a top up in the air chamber. Otherwise at low pressure there is a a little sag. There has always been a a tiny bit of the stanchion that can never be fully compressed (around a ~1/4"). Doesn't realy bother me as most time the drops are sufficient. This fraction of an inch "leftover" on fulll compression of the post has stayed the same even without signs of getting worse. Pretty much fit and forget... Oh from the DSP site-- looks like there is a whole range of available colors now on the newer post and other improvement as well.