If you get a root-beer colored Rux, RM is gunu implode
In on this build! A fucking Lahar was the last thing I was expecting
In on this build! A fucking Lahar was the last thing I was expecting
Ohlins it worth it?
- Thread starter konastab01
- Start date
Let's discuss the technical benefits of the latest fashion.
Preferably ad nauseam until fashion changes.
Yeah the small shaft works much better (not what she said...) in modern frames.
It's a better performing shock than most current shocks (including its replacement the X2), but possibly more importantly it's a lot more reliable, and can be had quite cheap now. It's one of Fox's best products, nothing fancy, just the end result of a long development cycle that resulted in very polished final product.
Indeed - the RC4 and the DHX5 are fairly reliable and robust designs given stock configuration. I've ridden FOX running gear exclusively for rear suspension and have owned both shocks stock and tuned (by PUSH) in various platforms (including a PUSH'ed RC4 on a Gen. 4 Demo 8, which is a leverage monster) and never had any issues.
By get rid of, what do you mean? Replace and keep as spare, replace and sell, or replace and trash?
Change and sell the old ones, although thinking about going 27.5 front means that I need the specific fork so I pass on the dorados as they were 26.
Heres a question Lahar currently has a 220 x 2.8 shock fitted, could I fit a 240 x 3 and just extend the plates at the front to accommodate the extra 20mm?
That the 26 and 27.5 specific dorados are both the sameI know a secret..............
Probably not identical but you could certainly run a 27.5 wheel in a 26 fork.
The two 27.5 dh forks I've ridden (fox and rockshox) use too much offset IMO, the worst being fox. I don't know what Manitou does between the two models but you might actually like the 26 one better.
The two 27.5 dh forks I've ridden (fox and rockshox) use too much offset IMO, the worst being fox. I don't know what Manitou does between the two models but you might actually like the 26 one better.
Interesting, Im not set on the Dorado I just read some good things about the new one and that Ive kinda always wanted one since I started downhill all they years ago.
Missed the set I was talking about another option that could be good is the bos forks, heard a lot of good things about the newer models.
Missed the set I was talking about another option that could be good is the bos forks, heard a lot of good things about the newer models.
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FYI all Fox 40s fit 27.5" wheels too (with loads of clearance), you don't need to buy the 27.5-specific ones if you don't like the offset. The 2015+ version with lightened lowers comes in 26 (and clears 27.5).
I've found most of the current BOS forks to feel pretty good (ridden a fair few Idylle Rare FCVs now), so I think that's probably a solid choice. I prefer conventional forks because they are noticeably stiffer in torsion than inverts.
Keep in mind the BB will get higher with a 650 front wheel, and it's already a touch on the high side on those bikes - so the last thing you want to do is raise it even more. The shock I mentioned is easy to find in the 222 size you're chasing (It's 8.75x2.75" - came on a lot of V10s and Treks):
http://www.ebay.com/itm/162557225313
I've found most of the current BOS forks to feel pretty good (ridden a fair few Idylle Rare FCVs now), so I think that's probably a solid choice. I prefer conventional forks because they are noticeably stiffer in torsion than inverts.
Is the current shock the original shock size?
Keep in mind the BB will get higher with a 650 front wheel, and it's already a touch on the high side on those bikes - so the last thing you want to do is raise it even more. The shock I mentioned is easy to find in the 222 size you're chasing (It's 8.75x2.75" - came on a lot of V10s and Treks):
http://www.ebay.com/itm/162557225313
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I wasn't set on getting 27.5 specific forks but if the 26" 40's fit the wheel then I might just get a older set of them and get ohlins carts put in them thats another option. The original bos forks from what I heard years ago where up to much but they seem to have come on leaps and bounds in the last few years. Are the dos fork the same will the 26 take a 27.5 wheel with enough clearance?
I passed on the ohlins shock because of the piggyback on it was the side by side one and Im pretty sure after measure the space to wouldnt have fitted. So its still up in the air about what shock I'm gonna get, I'd like Ohlins front and back but its gonna have to be the standard one if I do and at £700 retail its not cheap, my mates got a Cane creek I could get cheap and then get it serviced and upgraded and then there the RC4 which you suggested.
To keep the bb lower Im gonna manufacture some new plates at the front, thats one of the upgrades in the plan to keep the BB the same or lower it slightly, gonna get offset bushing too to make it slacker also.
I passed on the ohlins shock because of the piggyback on it was the side by side one and Im pretty sure after measure the space to wouldnt have fitted. So its still up in the air about what shock I'm gonna get, I'd like Ohlins front and back but its gonna have to be the standard one if I do and at £700 retail its not cheap, my mates got a Cane creek I could get cheap and then get it serviced and upgraded and then there the RC4 which you suggested.
To keep the bb lower Im gonna manufacture some new plates at the front, thats one of the upgrades in the plan to keep the BB the same or lower it slightly, gonna get offset bushing too to make it slacker also.
I don't *think* the BOS 26 fits a 27.5 but I'm not sure. I'd buy the 27.5 version if you decide to go with the BOS - they're expensive so it may as well be somewhat futureproof. @Mo(n)arch might know the answer. If you go with the 40, there's no need to replace the stock RC2 damper (make sure you get the 2011+ one with the twin blue compression adjusters on top), it's great.
For shocks, if you actually want the best performance and reliability you won't do much better than those 2015 RC4s I linked - dead stock. The CCDB is prone to bushing wear and if the linkage isn't very stiff they can also snap shafts. It's probably fine if you aren't putting bulk lift miles on it. It's also a waste of money for an inferior shock IMO.
Anyway, there are plenty of reliable and excellent performing options, I have a feeling you want Ohlins more for the wank factor but in reality it's not actually proven to be an upgrade (or proven at all in the MTB world). By all means do it if it makes you happy, but just keep in mind it'll be more money for a gamble and not likely to be some huge performance advantage; "common" factory suspension has come a LONG way in the last few years.
Basically - just decide what you want - wank factor or the best performance, because that will give different answers for the best product choice. The best performing options are cheaper, as a bonus.
The linkage idea sounds cool. Can't you just position the holes in your new linkage such that it doesn't need offset bushings though?
For shocks, if you actually want the best performance and reliability you won't do much better than those 2015 RC4s I linked - dead stock. The CCDB is prone to bushing wear and if the linkage isn't very stiff they can also snap shafts. It's probably fine if you aren't putting bulk lift miles on it. It's also a waste of money for an inferior shock IMO.
Anyway, there are plenty of reliable and excellent performing options, I have a feeling you want Ohlins more for the wank factor but in reality it's not actually proven to be an upgrade (or proven at all in the MTB world). By all means do it if it makes you happy, but just keep in mind it'll be more money for a gamble and not likely to be some huge performance advantage; "common" factory suspension has come a LONG way in the last few years.
Basically - just decide what you want - wank factor or the best performance, because that will give different answers for the best product choice. The best performing options are cheaper, as a bonus.
The linkage idea sounds cool. Can't you just position the holes in your new linkage such that it doesn't need offset bushings though?
I never tried 27,5 on my Tues, but I don't think it would be a good match - obviously depending on the Tire size and the weather you ride.
Personally I'd go with the 27,5" option if you wanna go futureproof. Used ones hover around 1.000€ in yurp.
The important thing though is that parts aswell as service partners are now available.
I cannot say anything bad about my BOS fork, but I still think that my next DH bike will be entirely coil sprung.
Btw.: Did someone convert a Idylle air to coil?
Personally I'd go with the 27,5" option if you wanna go futureproof. Used ones hover around 1.000€ in yurp.
The important thing though is that parts aswell as service partners are now available.
I cannot say anything bad about my BOS fork, but I still think that my next DH bike will be entirely coil sprung.
Btw.: Did someone convert a Idylle air to coil?
I totally get you the Ohlins is a bit of fashion I'm not gonna deny it and the only actual feedback I have is someone who is potential sponsored by them although he did say it was the best suspension he had ever rode.
Ive actually had a shock from Ohlins on my motocross bike before and it was good but tbh I wasn't that fast to properly take advantage of it in reality and maybe that would be the same the DH bike with it on it.
@Udi Do you know what size the slim shaft RC4 is is meant to be, might have found a 2014 one(is this the same as the 2015?) with a Ti spring so willing to give that a blast and take your opinion on board regarding how good they are. As much as you want the best looking thing its always better to have a little more in your pocket to go towards something else.
Interesting on that the 40's from 2011 are dead on and they fit the 27.5 too, where as the Bos might only take the the 26" if I went for them
Potentially I could and then avoid the offset bushings, I'll defo try a few different way to lower the BB and make it slacker and with the bushings being pretty cheap its not a hassle If I dont use them in the end.
Still gotta think about all the other stuff that i wanna change too but I'm starting on the main things first.
Ive actually had a shock from Ohlins on my motocross bike before and it was good but tbh I wasn't that fast to properly take advantage of it in reality and maybe that would be the same the DH bike with it on it.
@Udi Do you know what size the slim shaft RC4 is is meant to be, might have found a 2014 one(is this the same as the 2015?) with a Ti spring so willing to give that a blast and take your opinion on board regarding how good they are. As much as you want the best looking thing its always better to have a little more in your pocket to go towards something else.
Interesting on that the 40's from 2011 are dead on and they fit the 27.5 too, where as the Bos might only take the the 26" if I went for them
Potentially I could and then avoid the offset bushings, I'll defo try a few different way to lower the BB and make it slacker and with the bushings being pretty cheap its not a hassle If I dont use them in the end.
Still gotta think about all the other stuff that i wanna change too but I'm starting on the main things first.
@konastab01 The small shaft is 12.7mm diameter (1/2"), whereas the fat shaft one is 15.875mm. It's only the 2015 one that has the smaller shaft but you can usually tell by looking at it which year it is, the newer one says "air assist rate" on the piggy adjuster, whereas the old one says "bottom out adjust"
Not sure if I was clear, but the 40 is pretty much the same from 2011-2014 and then 2015-2017 are air sprung and have a lighter chassis. Anything with the kashima and blue comp adjusters on top is good (rest depends on preference). I found the newest Boxxer team/coil and newest BOS idylle are both very good too.
Will be rad to see when it's all finished anyway, I saw xy9ine's in Whistler, cool bikes.
Not sure if I was clear, but the 40 is pretty much the same from 2011-2014 and then 2015-2017 are air sprung and have a lighter chassis. Anything with the kashima and blue comp adjusters on top is good (rest depends on preference). I found the newest Boxxer team/coil and newest BOS idylle are both very good too.
Will be rad to see when it's all finished anyway, I saw xy9ine's in Whistler, cool bikes.
I haven't seen it done, but just FYI definitely don't use the BOS coil internals because they suck (they use a really tiny spring that undergoes plastic deformation after some riding time and permanently shrinks). I've had to fix a couple. If I was coil converting one, I'd use a spring from something else. The BOS air spring on the other hand is pretty good in my book.
I'm sure the BOS has its merits, but I must say, as a guy that usually complains about everything, I have very little to complain about with my fox 40. It's light, stiff, the adjustments work, the breakaway is slick, and the axle works. I don't really know what else you could want...!
A hydraulik bottom out control and an open oil bath with a one year service interval and yet decent damping. That's what BOS offers.
@Udi : You mentioned above that the last gen RC4 was a better performer then the new DHX2 is. Can you explain this to me? I understand the reliability part, but what in general do you mean by this?
Isn't newer = better? Is the progression control important to you?
Reasons for my questions: First I am a guy around 90kg, so external HSR control looks very tempting to me. I suck at jumping and always had some kind of bucking sensation in the past, which leads me to the opinion that for people over lets say 80-85kg stock HSR settings are a little too light on most dampers.
And second: RC4s are bloody cheap right now and I think I could have one in my future (maybe with some special tune).
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There isn't many 2015 RC4's going in the UK, but i'll be keeping a eye out. I think thats what Im gonna go for and get ti spring and get it tuned to my weight.
Yeah I didn't want my stoke to generate bias, but really, the 40 is an awesome fork and it makes me happy to ride every time. I really rate the stiffness (over everything else, hands down) and the little touches that have been there since 2005 (like the axle that doesn't clamp the lower legs together) plus the damper being one of the best out of the box just makes it a class act. Like I said, most other forks on the market are really polished now too, but I've always had a choice and this is mine.
Full disclosure though, we are both running coil RC2 versions from memory (mine's a coil-converted new one) and to me that's the icing on the cake. I ran the Float on and off and ditched it after giving it a fair go, it wasn't bad, just wasn't perfect. BOS's air spring feels better to me than the Float.
Thanks, you'd think I'd know that having owned each year but apparently not.
Maybe worth adding here the Float system changed for 2016-2017 year model as well, better for very light or very heavy riders with the air negative spring compared to the coil negative from 2014-2015.
The lizards would not approve of you even suggesting this isn't the case. Newer is always better and every possible upgrade should be purchased immediately!
@Mo(n)arch
I will send it for a full service soon and will ask for a softer hsc tune since I run it full open. I might at the same time ask the tuner to do something on the rebound too, if it is fixable of course.
It would be nice if @Udi could explain a bit more of the rebound disadvantage. I have a hard time getting the rebound working completly to my likings on my X2 and I cannot pinpoint the source of my feeling... it is not very bad but I have to choose between a slight bucking when pumping rollers and some loss of traction when riding standing on the uphill. I have been quite methodical doing laps with A to B comparison but I might also have been slightly overwhelmed by the extent of tuning available compare to the previous shocks I had...
I will send it for a full service soon and will ask for a softer hsc tune since I run it full open. I might at the same time ask the tuner to do something on the rebound too, if it is fixable of course.
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Can't I just stay out of trouble for once?
Anyway, basically, just because a shock has a HSR adjuster doesn't actually mean that you can add more rebound at higher shaft speeds. In fact, in the case of a twin-tube shock with a poppet valve controlling the damping, the opposite is almost always true. Think about it - the purpose of variable orifice damper was always to allow the damping curve to digress. A ported-only damper will follow a progressive curve w.r.t shaft speed. A poppet valve assembly by nature allows a large amount of flow through the spring loaded poppet in relation to the LS port.
Linear (i.e. removing the progression of a ported damper) or digressive compression damping is very useful in offroad applications because shaft speed in compression is essentially unrestricted: how hard can you hit something? Of course there are realistic peak values, but these values are much higher than in rebound - since rebound shaft speed is essentially restricted by the spring rate.
Digressive rebound is very useful in onroad applications, because there is a lot of steady state cornering and large amounts of LSR in relation to HSR tend to reduce normal force variation at the contact patch mid-corner. Compared to using primarily LSC for this purpose, LSR keeps the dynamic CoM lower (= less L/R load transfer = more traction, since rubber has a digressive coefficient of friction proportional to the normal force), and in most cases there are no jumps on road circuits so we aren't concerned about managing pitching moments.
This is not the case in off-road, specifically in a rear shock, because digressive rear rebound curves tend to result in forward pitching of the rider. Of course you can correct this by running more overall rebound damping, but then the ratio of LSR:HSR is suboptimal for best traction.
The CCDB shock is actually just a slightly modified version of the Ohlins TTX25 FSAE shock. This is an onroad shock for university students building small-scale road racing cars. Fox hired the CC guy, hence the X2, which is non-coincidentally very similar in function to the DB. When was the last time you saw a motocross bike with a dual-flow poppet valve rebound adjuster? Maybe they exist now for the same marketing reasons we have these shocks in MTB, but mostly they just use conventional shocks with a single rebound adjuster.
It wouldn't be impossible to correct the problems by designing an entirely new valve, possible because of the modular design, but difficult due to space constraints. It obviously just requires a different valve design on the rebound side, rather than using basically the same valve, as this "engineer" has done. I suspect Vorsprung may have something in the works to address this, but I can't say for sure. For me personally, they are the only company I'd trust to address the issue correctly.
On the other hand, it's very easy to control the linearity or progression of the rebound damping curve in a conventional shock (rebound controlled entirely though main piston), often the port size in the rebound direction is miniscule compared to compression for precisely this reason. It's also very easy to tune the relationship internally to perfection if needed.
Anyway to add insult to injury, under heavy use conditions both of those shocks have some durability issues (the CCDB is definitely worse, but the DHX2 has carried on some flaws also). While CCDB shafts break completely on some frames, sideloading causes accelerated sealhead bushing wear in other frames on both shocks. Obviously the air versions (of both) are a little better supported, hence less problems. Just as obviously, this means more friction.
Unfortunately, companies have to release new products to maintain sales. The small-shaft RC4 is a humble (and excellent performing as stock) shock which most people wouldn't even consider because there's nothing "cool", "custom", or "exclusive" about it. Thanks to the X2, Fox sales and market acceptance has skyrocketed. One must appreciate that sales and marketing are necessary for these companies to exist and thrive, it just means that not every new design is actually the best. Many people blindly consider *all* new products to be the work of the marketing devil, others consider *all* the latest to be the greatest. I think a wise guy once said the path in the middle is often the right one, and this case is no exception.
Anyway, basically, just because a shock has a HSR adjuster doesn't actually mean that you can add more rebound at higher shaft speeds. In fact, in the case of a twin-tube shock with a poppet valve controlling the damping, the opposite is almost always true. Think about it - the purpose of variable orifice damper was always to allow the damping curve to digress. A ported-only damper will follow a progressive curve w.r.t shaft speed. A poppet valve assembly by nature allows a large amount of flow through the spring loaded poppet in relation to the LS port.
Linear (i.e. removing the progression of a ported damper) or digressive compression damping is very useful in offroad applications because shaft speed in compression is essentially unrestricted: how hard can you hit something? Of course there are realistic peak values, but these values are much higher than in rebound - since rebound shaft speed is essentially restricted by the spring rate.
Digressive rebound is very useful in onroad applications, because there is a lot of steady state cornering and large amounts of LSR in relation to HSR tend to reduce normal force variation at the contact patch mid-corner. Compared to using primarily LSC for this purpose, LSR keeps the dynamic CoM lower (= less L/R load transfer = more traction, since rubber has a digressive coefficient of friction proportional to the normal force), and in most cases there are no jumps on road circuits so we aren't concerned about managing pitching moments.
This is not the case in off-road, specifically in a rear shock, because digressive rear rebound curves tend to result in forward pitching of the rider. Of course you can correct this by running more overall rebound damping, but then the ratio of LSR:HSR is suboptimal for best traction.
The CCDB shock is actually just a slightly modified version of the Ohlins TTX25 FSAE shock. This is an onroad shock for university students building small-scale road racing cars. Fox hired the CC guy, hence the X2, which is non-coincidentally very similar in function to the DB. When was the last time you saw a motocross bike with a dual-flow poppet valve rebound adjuster? Maybe they exist now for the same marketing reasons we have these shocks in MTB, but mostly they just use conventional shocks with a single rebound adjuster.
It wouldn't be impossible to correct the problems by designing an entirely new valve, possible because of the modular design, but difficult due to space constraints. It obviously just requires a different valve design on the rebound side, rather than using basically the same valve, as this "engineer" has done. I suspect Vorsprung may have something in the works to address this, but I can't say for sure. For me personally, they are the only company I'd trust to address the issue correctly.
On the other hand, it's very easy to control the linearity or progression of the rebound damping curve in a conventional shock (rebound controlled entirely though main piston), often the port size in the rebound direction is miniscule compared to compression for precisely this reason. It's also very easy to tune the relationship internally to perfection if needed.
Anyway to add insult to injury, under heavy use conditions both of those shocks have some durability issues (the CCDB is definitely worse, but the DHX2 has carried on some flaws also). While CCDB shafts break completely on some frames, sideloading causes accelerated sealhead bushing wear in other frames on both shocks. Obviously the air versions (of both) are a little better supported, hence less problems. Just as obviously, this means more friction.
Unfortunately, companies have to release new products to maintain sales. The small-shaft RC4 is a humble (and excellent performing as stock) shock which most people wouldn't even consider because there's nothing "cool", "custom", or "exclusive" about it. Thanks to the X2, Fox sales and market acceptance has skyrocketed. One must appreciate that sales and marketing are necessary for these companies to exist and thrive, it just means that not every new design is actually the best. Many people blindly consider *all* new products to be the work of the marketing devil, others consider *all* the latest to be the greatest. I think a wise guy once said the path in the middle is often the right one, and this case is no exception.
I hope this thin shaft RC4's is as good as you say because I'm holding you responsible if its shit.
Sorry Udi!
Sadly there are not so many people with your level of knowledge on the technical side and with feedback from the fields willing to share...
If we do meet in person one day, remind me of buying you a beer!
At least I am glad that the theory and my observations go in the same direction!
Thanks for the link to the Öhlins damper with a lot of Dyno curves! I will into that when I get some time off.
@Udi Whats your thoughts on the Avy DHX5 upgrade or that is to be avoided because of the lack of parts?
http://www.avalanchedownhillracing.com/Fox DHX/Fox DHX 5.0 Speed Sensitive Adjuster Kit.htm Thats the link to it!
http://www.avalanchedownhillracing.com/Fox DHX/Fox DHX 5.0 Speed Sensitive Adjuster Kit.htm Thats the link to it!
I used to have one on my trail bike. Nice shock, factory IFP is rubbish though and shit the bed quickly but Craig rebuilt mine with his parts.
Next thing to discuss since we have covered suspension.
Brakes, now it has old saints right now, new saints or magura m7 or the new 6 pot hopes that are dropping later this year?!
Brakes, now it has old saints right now, new saints or magura m7 or the new 6 pot hopes that are dropping later this year?!
If you want a (relatively) safe and trouble-free option just get Hope V4s. I think they're priced well on CRC atm (altho may be out of stock in some colors / options).
I wouldn't bother with the 6-pots personally, I reckon it's a wank + they'll be heavy. Magura have horrible levers and unfortunately Shimanos aren't nearly as reliable/consistent as those lovely M800s were (though the new ones are winners for sheer stopping power).
If you want to check out something super wanky (of course you do) which actually has performance to back up the ludicrous pricing - unlike what's available in suspension - check out the trickstuff direttissima. Best brake I've ridden, both for outright power and power:weight ratio. I have no idea on long term reliability, and pricing is as they say "if you have to ask".
I wouldn't bother with the 6-pots personally, I reckon it's a wank + they'll be heavy. Magura have horrible levers and unfortunately Shimanos aren't nearly as reliable/consistent as those lovely M800s were (though the new ones are winners for sheer stopping power).
If you want to check out something super wanky (of course you do) which actually has performance to back up the ludicrous pricing - unlike what's available in suspension - check out the trickstuff direttissima. Best brake I've ridden, both for outright power and power:weight ratio. I have no idea on long term reliability, and pricing is as they say "if you have to ask".
I am curious about ohlins suspension after watching Bruni and his demo on track last week. His run wasn't the fastest but it definitely looked the smoothest almost unreal smooth. The bike looked so composed under him and his upper body looked so steady Like a top mogul skier through a mogul field. I was saying to myself that he made the course look so smooth.
I've seen Gwin do exactly that (except running Fox) on countless occasions, and IMO it's got little to do with the suspension and almost everything to do with the rider. Keep in mind that the human body has substantially more travel than the 8" available on a DH bike, and this coupled with line choice will have a far bigger impact on what you describe.
Just one example (this track looked quite rough under everyone else that day):
In this case his run was the fastest too.
Just one example (this track looked quite rough under everyone else that day):
Of course UCI blocked that video.