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Anybody ridden the new DHX RC4?

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Anybody ridden the new DHX RC4?
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flag scrider
Posted: Jan 2, 2010 at 10:58 Quote
Go with Elka. 600$ custom tuned to your weight and riding style and bike. You can't go wrong with that shock.
flag dezim
Posted: Jan 2, 2010 at 13:09 Quote
scrider wrote:
Go with Elka. 600$ custom tuned to your weight and riding style and bike. You can't go wrong with that shock.
+1 heard nothing but good things about that shock
flag schwimble
Posted: Jan 2, 2010 at 13:45 Quote
i just built my new bike up yesterday and got out on it for the first time today. its a session 88, with a RC4. im coming off the older session with the DHX5 on it, so il be able to make a fairly good comparison.

first things first. out of the box last year the DHX5 felt really good, very little stiction(sp). i dialled in the factory suggested settings and did very little fettling after that. i thought this shock felt really good the whole yr, it soaked up anything i threw at it, with no trouble. mind you by july-august it was starting to feel a bit sticky, (it needed a service badly).

to the RC4 then. ive only got out on it once but heres my first impressions. VERY sticky out of the box!!! the shock felt like crap for the first few runs, but i expect this to sort itself out as the shock gets worn in over the next week or so (forks always do, so why not shocks too). i think the increase in sticktion is down to the much largerr diameter shaft which will greatly increase the surface contact area between the shaft and the seals/bushing etc. Rebound works, simple as. the bottom out seems to be the very same as the DHX5, it works too. the compression though.... Well its a biatch to tune right, i could not get it going the way i wanted. i had the low speed compression wound all the way off, and the hi speed pretty much all the way off as well, 4 clicks from fastest i think. the compression still felt too slow though, which is a bit frustrating. Now, in the shocks defense it is bloody cold here at the moment, may -1 or -2. im thinking this might be slowing the shock down, i do not know for sure, as a) i dont know how the shock works and b) i dont have any experience with riding in the cold (proper cold).

anyway, thats my thoughts on it so far... if im feelin like it il let ya know what i think of it in a few rides time.....adios
flag stryke
Posted: Jan 2, 2010 at 14:08 Quote
Unsecure image, only https images allowed: http://gi257.photobucket.com/groups/hh209/4DV8NWNDAH/IMG_3277.jpg
vivids are cool shocks
flag Pitcrew
O+
Posted: Mar 1, 2010 at 8:15 Quote
Not to dig...but im looking into getting a RC4 for my Glory. Im sick of my Roco leaking. From what ive been reading the RC4 is what im looking for, but ive also read it a shim stack shock and that means nothing to me. Im racing in the Sport class this year and im looking for another edge that i can afford. Can i buy a rc4, bolt it on my bike and go with out making to many adjustments until i can really ride it at a mountain and not have it feel as bad as my Roco?
flag
Posted: Mar 1, 2010 at 8:21 Quote
Go with ELKA!!!

Iv'e ridden many shocks in the past, the Elka blew me out of the water.

Link here talks about the RC4 and how people are having issues with it. Usually being harsh in the Bottom out.



http://www.ridemonkey.com/forums/showthread.php?t=229008
[Quoten]Yep, but that affects the compression damping on the RC4. The "boost valve" is a pressure relief valve that's held closed by oil pressure (oil pressure in the resi = air pressure in the resi), with a spring that's preloaded to hold it open early in the travel. On the original DHX, the propedal knob adjusted the preload on that spring via a reverse thread - in other words, turning up the propedal backed off the spring preload, so there was less spring force trying to hold the valve open against the oil pressure. This spring preload is not adjustable on the RC4 (pretty sure it's still in there though - they might have just put a bypass circuit in there instead, in either case the result is more or less the same).

As the shock compresses, the shaft displaces oil into the reservoir, which in turn compresses the air/gas in the chamber, resulting in higher air pressure which as I said before means higher oil pressure. This higher oil pressure means a higher force holding the boost valve closed, ie higher level of compression damping further into the stroke. This is why the RC4 is a legitimately progressive design - it's exactly the same principle the 5th Elephant and Manitou Gangbang shocks work on, except the pressure relief valve (boost valve/CVT valve) on those was on the main piston rather than in the reservoir. Dyno plotting any of these shocks using a CVP results in a large degree of hysteresis because of this - the compression curve can be significantly different in two difference positions in the travel even at the same speed.

FWIW, I own a CCDB, an RC4 and spent months riding an Elka. I'd happily rock any of them really, though I'll sum up the pros and cons of each briefly:

RC4:
Pros
- Independent HSC/LSC controls that work fairly well
- Smoother than the DHX5
- Adjustable progression via bottom out resistance
- Generally worked well, wasn't hypersensitive to setup

Cons:
- the air spring effect in the RC4 makes getting the right spring a bit confusing. Not a big deal once you've got the right spring (I needed a 300 to get the same sag as the CCDB with a 350!), it rode fine in the Sunday and the Legend.
- Rebound was more linear than the Elka or the way the CCDB can be set up, needed to be set a bit slower to prevent kicking. Not a big deal though, especially if you like your rebound on the slower side.
- Even with LS/HS settings maxed out, the level of compression damping wasn't that huge - I typically ran both LSC and HSC near maximum. A heavier rider or someone on a higher leverage ratio bike might find that they couldn't get enough though, but keep in mind I like a fairly firm compression setup compared to most people.

Elka:
Pros:
- Super controlled
- Very effective HSC/LSC adjusters
- Very easy to set up because most of the tuning is done for you in the factory
- Rebound curve worked really well for me, was poppy and lively without ever kicking, made it easier to find the sweet spot in the range
- Best user's manual ever for sure, the setup advice is absolutely spot on.
- Stable and planted.

Cons:
- Largish shaft diameter creates some of the air-spring effect the RC4 has, not to the same extent though and like the RC4 it wasn't a huge issue on the Legend or the Sunday I was on - affected sag and spring rate a bit but not a real cause for concern.
- Had some mechanical issues with stuff coming loose inside the shock, Elka say they've since sorted it with redesigned parts. No real surprises there, first-generation products almost always have those kinds of hiccups. If they've fixed that properly then I can't come up with any serious criticisms of the shock. Make it even smoother somehow? haha

CCDB:
Pros:
- Highly adjustable. Duh.
- Adjustable LSR/HSR as well as LSC/HSC mean you can be very very picky about aspects of the ride and tune it to suit
- Very stable, compression damping is very effective and you can really control the bike's behaviour well.
- Lower stiction than anything except the BOS Stoy
- Every click makes a small but distinct difference to the ride
- Huge range of adjustment... though this can be a bad thing too.

Cons:
- As I had the old tune, it seemed like the damping at very low speeds was a bit excessive, making the shock feel pretty dead, but then I had to crank the HSC a bit more than I would have liked to get the low-mid speed support I wanted. I suspect this was due to the poppet valve shims being too soft and opening too easily, meaning the LS circuits (both compression and rebound) had to be closed more than I would have liked. I think basically this created very linear, perhaps even digressive LS curves whereas I would have preferred that it was a bit more progressive in order to increase suppleness at the very low end of the speed range. The BOS Stoy definitely delivered that characteristic - at pushing-on-the-seat speeds it felt like there was almost zero damping, yet the low-mid range damping was very strong. Hopefully the new tune has fixed that - I've heard the damping can be set up a lot lighter. I'll most likely get my shock reworked with the new tune prior to this season so I'll update my opinion then.
- Let's not kid ourselves, this shock takes a while to set up. Each adjustment makes the difference it says it does, but it does take a while to figure out the relationship between riding characteristics and which adjuster you need to turn. It is very possible to set one of these up like utter crap - especially if you don't know what you're doing.
- Actually pretty easy to bottom out on bikes that aren't inherently progressive, especially in g-outs and whatnot, unless you want to really crank the compression and deal with the resulting deadness.[/Quoten]
flag dezim
Posted: Mar 1, 2010 at 9:29 Quote
I know a few people who ride the Elka. I have heard nothing but great things about them.
flag brandon22111
Posted: Dec 9, 2010 at 23:07 Quote
I have a 2010 giant faith 0 and I have the opportunity to upgrade to a dhx rc4 that is tuned for a glory 0. What do you think of the upgrade. With it tuned to the glory do you think it will feel like crap or
Since it's a similar bike just the glory is dh vs the faith freeride it will work great. Do you think it's work upgrading?
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