[Steve M]

http://www.rotorburn.com/article/a866a3/Review_Fox_40WC_and_DHX_RC4

Warning: very tech nerdy and rather long - recommend getting a beer before reading it

 

[William42]

awesome review man, thanks

 

[IH8Rice]

so do you feel that the RC4 is worth the extra $200+ option on some bikes?

 

[Steve M]

so do you feel that the RC4 is worth the extra $200+ option on some bikes?

Over what? A DHX5?

 

[IH8Rice]

Over what? A DHX5?

yes, over the normal DHX5. particularly on the Revolt

i know the article said:

the RC4 is unquestionably better than Fox's previous benchmark shock in the DHX5.0

but i didnt see anything that made that really supported the statement...maybe i missed it


(sorry if you didnt write the article)

 

[LukeD]

i have an rc4 on my sunday (took some time in the machine shop to get it on) and surprisingly enough I started with the same exact setting that the article did. I too bounced around with different springs, 250, 300, 350 before finally settling on a 300lbs ti spring with 150psi in the chamber. The shock does feel more linear than a normal dhx, but worlds better than the vivid. I could never get the vivid set up right on the sunday, it always felt too linear... like i had a spring that was too heavy on it. with the rc4, once in the travel it tracks really well and sits into the travel where you want it. made my sunday feel like a totally different bike.

 

[IH8Rice]

The shock does feel more linear than a normal dhx, but worlds better than the vivid. I could never get the vivid set up right on the sunday, it always felt too linear...

can you explain this part please?

 

[scottishmark]

I could never get the vivid set up right on the sunday, it always felt too linear... like i had a spring that was too heavy on it.

As IH8Rice says. I would've said too linear = too soft a spring as there was no rising rate to control the bottom out & rising too much = too heavy a spring as not getting anywhere near full travel.

 

[davetrump]

can you explain this part please?

hhah, yeah please do

more linear than a dhx? is that even possible? and to me that is what makes the dhx a sub par shock... especially on my sunday.

vivid on a sunday was night and day better... compression damping is your friend.

sorry, but i am not a fan of a shock that blows half its travel just from the rider leaning back. and can not be tuned to do othrwise.

hopefully this was addressed in the RC4 by the tech department and not just the marketing department. unfortunately fox usually only delivers in one of these areas :biggrin:

that review that was linked to above does not have me too convinced....

seems like despite claims, both fork and shock were under damped, and on the rc4 in particular the LSC had little effect without cranking up the HSC.

i wish fox would ditch all the air pressure stuff and go back to a nitro charged damper with simple and effective adjustments

 

[IH8Rice]

i wish fox would ditch all the air pressure stuff and go back to a nitro charged damper with simple and effective adjustments

i remember reading a dirtmag article on how some guys were still using pimped out Vanilla RC's only a few years back.

the article does talk about the shock being linear, in order to get more LSC......

On the trail, the RC4 feels a bit more linear than the old DHX, mainly because it allows you to run a fair bit more low speed compression damping and use that to prevent the bike blowing through its travel, whereas by comparison the old DHX in stock guise didn’t really let you run much low speed compression damping before it just became harsh

i was mainly asking about his post, which didnt make sense to me

 

[davetrump]

i remember reading a dirtmag article on how some guys were still using pimped out Vanilla RC's only a few years back.

the article does talk about the shock being linear, in order to get more LSC......


i was mainly asking about his post, which didnt make sense to me

yup... continue reading and you get this

"The separate high/low adjusters are handy here, but like with the fork, to get any significant LSC out of the shock, the high speed adjuster needed to be wound in close to full."

lsc/hsc will always have some overlap and when one is adjusted in/out ehough it will have an effect on the other... but having to dial HSC all the way in (which should be fairly light on a dh bike) to get adequate LSC (which should be the set heavier on a world cup dh race bike) is not mu idea of ideal.

fox does a lot of tuning to the shim stack for thier riders but unfortunately these setups do not make it into the production shocks. same goes for other shocks on the market but i still think fox sets it's "what will work best for every bike/every person" tune a bit too light.

 

[IH8Rice]

but having to dial HSC all the way in (which should be fairly light on a dh bike) to get adequate LSC (which should be the set heavier on a world cup dh race bike) is not mu idea of ideal.

but i still think fox sets it's "what will work best for every bike/every person" tune a bit too light.

i ado agree with you. there will be overlap, but having the HSC at its extreme end, just to get LSC almost defeats the purpose of the HSC.


and they probably left it as it is because it they feel it could be "one shock works for all"

 

[boogenman]

so do you feel that the RC4 is worth the extra $200+ option on some bikes?

For your new ride:

 

[IH8Rice]

if i could buy the frame without shock, i would

 

[LukeD]

hhah, yeah please do

more linear than a dhx? is that even possible? and to me that is what makes the dhx a sub par shock... especially on my sunday.

vivid on a sunday was night and day better... compression damping is your friend.

sorry, but i am not a fan of a shock that blows half its travel just from the rider leaning back. and can not be tuned to do othrwise.

hopefully this was addressed in the RC4 by the tech department and not just the marketing department. unfortunately fox usually only delivers in one of these areas :biggrin:

that review that was linked to above does not have me too convinced....

seems like despite claims, both fork and shock were under damped, and on the rc4 in particular the LSC had little effect without cranking up the HSC.

i wish fox would ditch all the air pressure stuff and go back to a nitro charged damper with simple and effective adjustments

ok maybe linear is the wrong word. my friend's dhx is SOFT. i mean u barely push down on it with a pinky and it moves. from there it kinda seems like it blows through the travel a bit. the RC4 is nowhere near as soft when u sit on it, but once the bike is into the travel it gets really soft and then stiffens up near the end stroke. make sense? i just ride the damn thing and know what i like and don't like lol as for the vivid, it just felt stiff all the way through for some reason.

 

[boogenman]

Buy the frame with the DHX and sell it. That is what I did with my previous CCDB's.

 

[davetrump]

i ado agree with you. there will be overlap, but having the HSC at its extreme end, just to get LSC almost defeats the purpose of the HSC.


and they probably left it as it is because it they feel it could be "one shock works for all"

yup... but until some more trustworthy reviews come back i will not write an RC4 off just yet. I got a chance to ride some "factory" ones that were great so maybe they keep some of that for the production ones.

i think what is often overlooked when people read reviews is that a shock will be very different on different bikes.

the one in that review is stated to have a rising to linear suspension rate... why one would make a bike like that i do not know but it could explain why there was trouble getting LSC/HSC setting right.

On the bike you were asking about (revolt) the suspension gets very progressive in the last bit of travel... so in theory this same shock would be very different on these two bikes.

that said... because of this i think having a good range of adjustments THAT ACTUALLY WORK is most important when a company is making one generic shock for all bikes/riders. as mentioned in that article, dyno testing of an old dhx revealed that the compression adjustments did absolutely nothing.

Vivid's have 3 base tunes, plus working range of adjustments, Rocco's can be rebuilt/tuned easily, cane creek has largest adjustent range (and now have low leverage tune), BOS are all custom jobs (as are elka).... and fox? still one for all and limited adjustment (unless you get custom tuning done)

 

[boogenman]

davetrump, what are you running on your revolt? a vivid?
Any idea why theframe comes with a DHX? Ska Todd? DW? chime in here?

Sorry for the derail

edit: DW is too busy watching the shuttle launch and thinking about acceleration in zero gravity.

 

[davetrump]

davetrump, what are you running on your revolt? a vivid?
Any idea why theframe comes with a DHX? Ska Todd? DW? chime in here?

Sorry for the derail

edit: DW is too busy watching the shuttle launch and thinking about acceleration in zero gravity.

I have a "A" tune Vivid on mine.... DHX came with the bike because at the time RC4's where not available

it is my understanding that the next production run will ship with RC4's

again... shock choice is personal and what works for one will not work for another

I like the vivid for for the same reason LukeD doesn't... it is not so much a debate about btter or worse products just pros/cons and differences and figuring out which might suite one rider better than another.

personaly i like stiff forks and a good amount of LSC on both ends of my bikes... no it does not feel amazing in a parking lot but it delivers on a trail. and i will sacrifice a bit of feedback through the bars for a ride that keeps a stable and consistant geometry... and that will always be the trade off that needs to be balanced out for each person.

some people love that kind of setup while other hate it

edit: having ridden both a dhx and vivid on my previos bike i liked the vivid more... that would be the reason for switching it on the revolt. it has nothing at all to do with the ride quality of the revolt... which might i add is simply awesome and would be regardless of shock choice.

 

[IH8Rice]

On the bike you were asking about (revolt) the suspension gets very progressive in the last bit of travel... so in theory this same shock would be very different on these two bikes.

that said... because of this i think having a good range of adjustments THAT ACTUALLY WORK is most important when a company is making one generic shock for all bikes/riders. as mentioned in that article, dyno testing of an old dhx revealed that the compression adjustments did absolutely nothing.

Vivid's have 3 base tunes, plus working range of adjustments, Rocco's can be rebuilt/tuned easily, cane creek has largest adjustent range (and now have low leverage tune), BOS are all custom jobs (as are elka).... and fox? still one for all and limited adjustment (unless you get custom tuning done)

id love to just get rid of the Fox all together for the new bike, and ideally get a CCDB. its been well over 8 years since i rode a DH bike w/ a Fox and at that time i hated it. now obviously comparing a shock built today to 8 years ago is pretty unfair, but i like the CCDB's ability to keep all of it's adjustments completely seperate.

the Curnutt shocks that ive been using for 2 1/2 years now have been pretty good IMO, but i want something better than pretty good....and if im gonna spend another $200 for the RC4 w/ the Revolt, then id rather sell the DHX and buy a CCDB....if itll work with the Revolt that is


does this make sense?

 

[dhr-racer]

fastidiousness
A noun
1 fastidiousness
the trait of being meticulous about matters of taste or style; "neatness and fastidiousness of dress"
Category Tree:
abstraction
╚attribute
╚trait
╚cleanliness
╚fastidiousness

 

[EM-EFER]

The 40 WC is stiffer then the RC2. Is it better? For me, yes.

Reasons I like it-

I like stiffer and progressive forks.

Reasons other might not like -

Unless your doing mach 1000 the thing does not like small bumps. I don't mind because I like to skim through things and dislike forks that dive.

Anyway... Don't spend $200 more.

 

[Steve M]

yup... continue reading and you get this

"The separate high/low adjusters are handy here, but like with the fork, to get any significant LSC out of the shock, the high speed adjuster needed to be wound in close to full."

lsc/hsc will always have some overlap and when one is adjusted in/out ehough it will have an effect on the other... but having to dial HSC all the way in (which should be fairly light on a dh bike) to get adequate LSC (which should be the set heavier on a world cup dh race bike) is not mu idea of ideal.

fox does a lot of tuning to the shim stack for thier riders but unfortunately these setups do not make it into the production shocks. same goes for other shocks on the market but i still think fox sets it's "what will work best for every bike/every person" tune a bit too light.

The reason you have to dial the HSC adjuster in a fair way is because the HSC is actually quite light. Running the HS adjuster all the way in doesn't actually net you a CCDB-style super-duper-heavy compression setup. Unless you are 100kg+ or on a particularly high leverage ratio bike, you should be able to get plenty of LSC - keep in mind that I do like a LOT. Also remember that as I mentioned, I was running 150psi in the air chamber - you can still boost that up to 200psi to increase the range overall. I don't really see how you're interpreting what I said as the shock lacking in compression damping.

yup... but until some more trustworthy reviews come back i will not write an RC4 off just yet. I got a chance to ride some "factory" ones that were great so maybe they keep some of that for the production ones.

i think what is often overlooked when people read reviews is that a shock will be very different on different bikes.

the one in that review is stated to have a rising to linear suspension rate... why one would make a bike like that i do not know but it could explain why there was trouble getting LSC/HSC setting right.

On the bike you were asking about (revolt) the suspension gets very progressive in the last bit of travel... so in theory this same shock would be very different on these two bikes.

that said... because of this i think having a good range of adjustments THAT ACTUALLY WORK is most important when a company is making one generic shock for all bikes/riders. as mentioned in that article, dyno testing of an old dhx revealed that the compression adjustments did absolutely nothing.

Vivid's have 3 base tunes, plus working range of adjustments, Rocco's can be rebuilt/tuned easily, cane creek has largest adjustent range (and now have low leverage tune), BOS are all custom jobs (as are elka).... and fox? still one for all and limited adjustment (unless you get custom tuning done)

Why would one make a bike like that? The suspension rate is very similar to a Sunday, albeit at an overall higher leverage ratio, so maybe go and ask DW. It's not highly progressive, but what it works well at is preventing the bike from blowing through the mid-travel, giving you a fairly predictable feel - it does require either a lot of compression damping (which suits me fine) or a progressive shock (eg DHX/RC4) to run it super soft without bottoming out frequently.

FWIW, I've run a B-tune Vivid in this bike too, had to run a 400lbs/in spring to keep it up enough because it lacks any form of progression - the compression adjuster isn't as effective as the RC4s, nor does it deliver the same amount of compression damping as is available from the RC4. Hopefully that puts your mind at ease

Also, re-read what I said about the dyno testing. I simply said that the Propedal adjuster had the same effect as increasing the air pressure, which was to increase compression damping at all speeds. There was plenty of compression range, but the HSC got excessive if you wanted plenty of LSC.

Edit: also, some of you don't seem to know what "linear" means. It doesn't mean "blows through travel because there isn't enough damping", it means the damping isn't progressive. DHX5s don't blow through travel because they're too linear, it's precisely because they're not linear enough - there isn't enough support early in the stroke (without making it overly harsh at high speed). The RC4 allows you to get more support at lower speeds, earlier in the stroke, so that you don't have to have a severe ramp up at the end (ie a progressive shock) in order to avoid bottoming out or any of that kind of thing.

 

[toodles]

Are you saying the shock is 100% better than an Avy? And does that make it 150% better than a DHX, or 200% better? How much flow does it have?

Nicely written mate

 

[demo8razor]

i remember reading a dirtmag article on how some guys were still using pimped out Vanilla RC's only a few years back.

I was told by Darren I believe at Push that the vanilla rc was a better platform to customize in their eyes than a dhx is.

 

[Udi]

as mentioned in that article, dyno testing of an old dhx revealed that the compression adjustments did absolutely nothing.

You didn't even do the dyno test, I fail to see how you can agree with that specific statement, and it's amazing how you managed to twist something out of that line that didn't actually exist.

Like Socket said, all adjusters on the DHX do plenty (I've seen the charts he printed), the only real issue is that when you crank the LS compression damping too much (via PP or Boost) the HSC starts getting too heavy as well. I will agree that they do dive in the early part of the stroke fairly easily, but I found it was correctable, you just had to deal with a slightly harsher ride (or revalve it to better suit yourself).

If you're going to say that the Roco can be "tuned/rebuilt easily" then the same applies to a DHX, Fox by far make the most user friendly rear shocks when it comes to rebuilding (IFP bleed screw, standard schrader valve, no non-standard tools needed). There's nothing stopping you from reshimming the DHX just like a Roco, IMO it's easier/neater to work on to boot.

Finally, BOS are not custom jobs, you just get one of four base tunes (or a fifth one reserved for the makulu) - and in my experience their catering to specific bikes / rider weights is less than perfect.

I'm yet to find a perfect shock, plenty of ups and downs in every single one, but there hasn't been one that puts all the pins in a row yet.

 

[Kanye West]

If you're going to say that the Roco can be "tuned/rebuilt easily" then the same applies to a DHX, Fox by far make the most user friendly rear shocks when it comes to rebuilding (IFP bleed screw, standard schrader valve, no non-standard tools needed). There's nothing stopping you from reshimming the DHX just like a Roco, IMO it's easier/neater to work on to boot.

Sorry, but your opinion is wrong.


J/k, I've been waiting to use that one on you.

Re-shimming the main piston is the same on both, as is bleeding for the most part and IFP depth setting. Accessing the valving at the base of the reservoir and tuning it accordingly is significantly easier on the Roco however (wrench flats + ease of valve removal).

 

[Udi]

Yeah the fox is just a little neater, no phillips heads screws (even one is enough to be an annoyance haha). But I think the roco and fox are both right up there, the other shocks are more painful for a myriad of reasons - no standard air valve on a lot of them, no IFP bleed screw on a lot of others, etc. Not sure about the roco (hopefully it's the same) but on the DHX you can pop the rebound needle out in your bath really easily too, air likes to hide around that one on all shocks so it's nice to be able to assemble it under oil.

I think the old fox falls behind for not having a conventional LSC/HSC adjuster at the reservoir end anyway, looks like the new one addresses that fairly thoroughly however. I'm not sure I like the idea of the huge shaft and inherent air spring feel though.

 

[William42]

I gues the question is, how many moar shimz did it need to get proper HSC? could he have called Craig at Avy?

 

[Kanye West]

Yeah the fox is just a little neater, no phillips heads screws (even one is enough to be an annoyance haha). But I think the roco and fox are both right up there, the other shocks are more painful for a myriad of reasons - no standard air valve on a lot of them, no IFP bleed screw on a lot of others, etc. Not sure about the roco (hopefully it's the same) but on the DHX you can pop the rebound needle out in your bath really easily too, air likes to hide around that one on all shocks so it's nice to be able to assemble it under oil.

I think the old fox falls behind for not having a conventional LSC/HSC adjuster at the reservoir end anyway, looks like the new one addresses that fairly thoroughly however. I'm not sure I like the idea of the huge shaft and inherent air spring feel though.

If I remember right Marzocchi only used the Phillips head bleed screws through '07 and went to a 2 or 2.5mm allen/button head after that.

The rebound needle comes out just as readily in the Roco, same as the DHX, 5th or Swinger. That is especially useful on the SPV shocks when you need to bottom the needle out against the bolt and again on the adjuster to verify the proper range with the compression side spacers.

 

[Udi]

Pretty sure that's actually not true for the swinger, and I haven't tried it on a 5th. On the swinger though, you could pull out some of the way, and then it would stop... possibly need to remove the eyelet from the shaft to get it out, which is usually a tough job on any shock without proper clamps.

 

[Kanye West]

I should have said when changing over to a shim-stack, and having to retain the same stack height, sorry.

1/2" clamp blocks can be made with a drill bit and a saw if you absolutely need them, but usually require some attention with a deburring tool and some sandpaper afterwards...

 

[buckoW]

I did some testing on the RC4s with 2 different compression tuned versions. They had a different piston design in each shock. I tried both of them with 150psi and 200psi in the piggyback. One shock was tuned for the Athertons with heavier compression and it suited my frame and I perfectly. I thought the shock was excellent with a good LSC adjustment range and no spiking. It was nice and firm but still somehow felt reasonably plush. I did lots of back to back runs on a very fast, steep and rocky trail with unlimited uplift access to get the shock dialed in and the Fox tech even had a nitrogen tank in his trunk for fine tuning the air pressure in the RC4 and another shock I was testing.

I am very impressed with the firmer compression tuned damper. The lighter compression tuned one was great for the total plush buttery feel but I don't run my bikes like that anymore. My wife preferred the lighter compression tuned damper and I liked the heavier comp tuned shock with the LSC cranked all the way up, 200psi and the HSC left almost wide open and the bottom out adjusted to 2 lines showing.

Fox is now custom tuning their OEM shocks for a manufacturer's preference. I think it is great that Fox offers that level of custom tuning on OEM shocks. I was very impressed with everything I saw and tested.

 

[toodles]

Roco loses points for making me drive around tring to find a obscure massive allen key to undo the shaft seal head. Bloody Italians.

Any worse and they'd still use the imperial system.

 

[Kanye West]

Roco loses points for making me drive around tring to find a obscure massive allen key to undo the shaft seal head. Bloody Italians.

Any worse and they'd still use the imperial system.

Huh?? Don't recall anything on the shaft seal using an allen. You mean a crescent wrench for just undoing it from the body? An adjustable works just fine for that. I don't even know what size that one is. 22mm or 24mm would be my guess.

 

[toodles]

Nah to get the seal out of the seal head... Stupid allen key on the retention ring.

 

[buckoW]

Hey Socket

Great review. I like reading your stuff.

I think this is not exactly correct,

"After the first day of testing, Ken rebuilt the damper with an additional shim in the stack, which made a significant difference and finally gave the fork the heavier compression damping I was looking for. It has to be mentioned that even for someone with Ken’s expertise and all the right tooling, servicing the fork from beginning to end can take 2-3 hours if the sealed FIT damper needs to be rebuilt and bled. This is an unfortunate detraction from the appeal of the fork in my eyes, given how easy it is to service some of the competitors’ forks."

Gary from Suspension Center in Switzerland does my forks in front of me in under an hour with shim tunes and all. One of his techs also did one of my forks in around the same time.

Was it the bleed that took so long?

Oh and another thing,

"Obviously reliability can’t be commented on without owning the forks long-term, but there doesn’t appear to be any reason why they’d differ from the existing 40RC2s, so find a mate who’s owned a 40 for a while and ask them how they fare in that regard."

The rubber bladder in the 2009 cart doesn't come loose like the older ones did. So it is more reliable then older 40's.

 

[dhkid]

Yeah the fox is just a little neater, no phillips heads screws (even one is enough to be an annoyance haha). But I think the roco and fox are both right up there, the other shocks are more painful for a myriad of reasons - no standard air valve on a lot of them, no IFP bleed screw on a lot of others, etc. Not sure about the roco (hopefully it's the same) but on the DHX you can pop the rebound needle out in your bath really easily too, air likes to hide around that one on all shocks so it's nice to be able to assemble it under oil.

fair play on rebound needle bit, never knew anyone bothered doing that. really anal! you can get the rebound needle out of the roco that way too, just requires a bit more force. and its a bit of a nightmare putting it back together, have to be careful not to destroy the o ring on the rebound shaft.

what i like about the roco is you have loads of shims to start of with, and with such a low oil weight, there is more to play around with. the shims in the piggy back are the same id as the main piston too, so can be switched around.

further more, the dhx rebound bleed effects lsc quite a bit which doesn't happen in the roco.

btw, are you still running the dhx air on the sunday?

 

[Steve M]

Hey Socket

Great review. I like reading your stuff.

I think this is not exactly correct,

"After the first day of testing, Ken rebuilt the damper with an additional shim in the stack, which made a significant difference and finally gave the fork the heavier compression damping I was looking for. It has to be mentioned that even for someone with Ken’s expertise and all the right tooling, servicing the fork from beginning to end can take 2-3 hours if the sealed FIT damper needs to be rebuilt and bled. This is an unfortunate detraction from the appeal of the fork in my eyes, given how easy it is to service some of the competitors’ forks."

Gary from Suspension Center in Switzerland does my forks in front of me in under an hour with shim tunes and all. One of his techs also did one of my forks in around the same time.

Was it the bleed that took so long?

Oh and another thing,

"Obviously reliability can’t be commented on without owning the forks long-term, but there doesn’t appear to be any reason why they’d differ from the existing 40RC2s, so find a mate who’s owned a 40 for a while and ask them how they fare in that regard."

The rubber bladder in the 2009 cart doesn't come loose like the older ones did. So it is more reliable then older 40's.

Cool, that's good to hear. Ken said he expected the process time to drop to under 2 hours once he had the bleed process down pat, but yeah it is the bleeding that takes time, and Ken is EXTREMELY particular about it - if it's not perfect (I watched him do it, and what I thought was fine a couple of times, he said still had air in it), he'll pull it back apart (or at least open it up to bleed again, he's made his own bleed tools and everything) and start again. If you get the bleed right first go it doesn't seem too bad time-wise. In either case though, it's definitely not as simple as just pouring 150mL of oil into the top of a Boxxer or whatever.

Also good to hear about the bladder issue being fixed, a couple of people I knew had issues with that.

 

[Rider15]

The Cane Creek only runs on an 8mm diameter shaft, and is claimed to run very low reservoir pressures due to its design making it impossible for cavitation to occur.

What is cavitation and what happens if cavitation occurs?