When Push introduced their coil-sprung
ElevenSix shock back in 2015, it wasn't long before they started hearing the question, “When are you going to make a fork?” That still hasn't happened, but the Colorado-based company's release of their new ACS-3 coil spring conversion kit could help to satiate some of that demand. The kit replaces the air spring in a Fox 36 or a RockShox Pike, and features a pneumatic bump stop that can be set between 5-50 psi to adjust the amount of end-stroke ramp up.
Push ACS-3 Coil Conversion Kit• Manufactured entirely in the USA
• Pneumatic bump stop, seven spring rates
• 2015-2017 Fox 36 Float or TALAS 160mm kits are available now
• Fox 36 140, 150 and 170mm travel models and 2018 140 -170mm kits arrive in late July.
• RockShox Pike kits coming soon
• MSRP $389 USD
• www.pushindustries.com Why would someone pull apart a perfectly good air-sprung fork to drop in a coil conversion kit? It comes down to small bump sensitivity - as refined as today's air-sprung options are, for the most part they still don't quite match the feel of a coil. They're closer than ever, but on the trail the difference is noticeable. Of course, a coil is heavier than air, and the ACS-3 will add 210-285 grams to a Fox 36 Float, or between 65-150 grams to a 36 TALAS, all while leaving your wallet $389 lighter.
There's also the fact that dialing in the correct spring rate is a little trickier with a coil fork, since it's not as easy as just adding or subtracting a few pounds of air. To that end, Push will be offering seven different springs rates in 5-pound increments that will accommodate riders between 125-230 pounds, with two firmer rates in the works that will be available in August.
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InstallationWhat if I want to switch back to air?It is possible to uninstall the ACS-3, but it's not as easy as pulling it out and putting the original air spring back in – the inside of the stanchion tube needs to be free of any imperfections, and after riding with a spring bouncing around inside there's a good chance that won't be the case. What does that mean? Well, if it's a FLOAT fork, a new CSU will be required, or there's the option of installing a TALAS air cartridge instead. In either case, it's something to keep in mind before making the conversion, but Push are confident that riders won't want to go back after switching.
Initial ImpressionsI'm in the midst of testing Niner's '
Push Edition' RIP 9 RDO, which came equipped with an ElevenSix shock and a Fox 36 Float that had an early version of the ACS-3 installed. It's quite the suspension combo, and I've found myself purposely aiming for the roughest sections of trail simply because of how ridiculously plush and smooth it feels - it makes you want to blast full speed into a chunky rock garden just to see what will happen. The coil-sprung fork and shock work together to create a sort of 'hover bike' sensation, one where you can feel the ground underneath you, but the impacts are muted enough that it feels like you're gliding right over them. I'm still experimenting with different settings as far as air pressure in the bump stop goes, but lately 20 psi has been working for me - there's enough ramp up to provide a supportive end stroke and eliminate any harsh bottoming out.
So, is it worth it? That's the big question, and I need to put in some more ride time in before making a more definitive answer. Of course, there's no getting around the fact that $389 is a hefty chunk of change, especially when the Fox 36 and the RockShox Pike both work very well in their stock configurations. That being said, there is something special about the way a coil sprung fork feels out on the trail, and I can see riders purchasing the ACS-3 to breathe new life into a fork that's lost some of its luster.
FOX 36 FLOAT 160mm fork: the ACS-3 kit adds 210gr-285gr depending on spring rate
Modifying a solo air shaft into a dual-air style shaft with a valve at the bottom of the leg might be a work around but getting an older lyrik spring assembly or the TF-tuned one is probably the way to go( if you have non boost forks).
I'm genuinely interested, the only neg I've ever truly known was originally you couldn't get volume spacers for the dual position. So that was truly a negative. But they have since addressed that issue.
The only other negative reviews I've heard are off hand comments on the interwebs, and you are saying that's not where your getting your info. Heck, many of the negative comments I even see are from people who haven't ridden them....???
Also, you can for sure swap out your lowers if you don't like the offset?
Tire clearance on my 38mm CF rim with a 2.5 WT DHF is plenty spacious for mud clearance.
Right out of his ass...
Not trying to be snarky. Just asking an honest question.
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The trade off is that coils don't control bottom out at all, they won't 'catch' you the same way all air forks do, so the damper has to have very good high speed compression/rebound or the fork will pack down. The other big trade off is that coil forks are much harder to tune to each rider, you can't just add/remove air to change the ride, you need new parts. That's what killed off mass market coil forks more than anything, the need to stock five different springs for each model to cover the weight range of riders. I really like coil forks, they seem to work better the faster you go, but they do require more time and money to get set right.
On an unrelated note pertinent to @Fix-the-Spade 's prior comment, just about every air spring for the last 10 years has incorporated some kind of pressurized negative chamber to combat seal static friction (to make them "smoother off the top"). The more successful of those designs tend to make the negative chamber user tuneable instead of using a transfer port (even Rockshox was doing this in like 05-08 with their "dual air" designs). My experience with DVO forks tells me that you can get a very smooth air spring with enough preload on the air spring.
Just about everything else he said comparing air to coil I agree with.
Wait what? The Pike , Lyrik and Yari all use the same airshaft. Is there a taper or something lower in the stanchions that would make the diameter smaller?
"For the $389, sell the Lyrik and buy an Ohlins 36 coil. A lot more tuning options as well."
He manufactures in-house coil conversions, custom hydraulic cartridges and custom parts for Fox, RS...
www.crconception.com/web_images/2017_spring_kit.bmp
I have a crconception hydraulic cartridge in my 160mm Pike, no more air tokens required, it's butter smooth with great mid-stroke support.
The Fox RC2 damper itself is very good.
@nunomelo77 I'm aware of their product line. I'm also aware of their offsets. Like I said, they had an opportunity to do something and they chose not to.
I really hope that Push raises the bar and develop their own coil fork.
Try getting a hold of one though, I ordered an RXF 36 coil, wont get it till January 2018.
I went from a Boxxer WC, to a Pike, to a 36 (all on different bikes) but the 36 just never felt as good as the pike.
Even after a rebuild was done, they felt marginally better, but I still couldn't get the fork to feel how I could with my Pike through it's stroke and breakaway force.
And then the Helm was on sale, and it matches my CCDB Coil CS, so I wen't with that over the Pike/Lyric
Try adding 2 of the orange volume spacers and make sure you follow through with the transfer shaft adjustment. That will add substantially more ramp up with the smaller volume.
If its not enough, add more spacers...
I'll see myself out...
400$ for a coil and some lil machined bits. Lol.
I/m sick of seeing Fox and RS only and lonely.,lot of money on maintenance A normal rider dont need what a racer have to have ,one race one revision.
But they were also arrogant in having comunication with their custumers and for many reason they fall.
20cc of lubrication on a leg fork and no wear and no stiction and supple rides ?And also believe in santaclaus?
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How did you find the change to a linear spring rate? Do you bottom out much (this has an air bottom out spring but the Tftuned one doesn't iirc?)?
Have you noticed the increase in weight?
Mainly I'd just like to improve the small bump sensitivity though - have you noticed a big difference?
The fork feels initially softer and MUCH more active. After putting that to back of mind and just riding the standouts are; feels softer but somehow firmer in the midrange too so, the fork absorbs more and does support better in the midrange. What I found was if you go out to mash the fork, you'll gobble travel but if you just ride as you would normally you are fine. My initial thought after 1st ride was that air forks/shocks are good only for manufacturer who wants to run one set production line good for everybody. You may look at your Air shock on the back and think POS after this...
Feedback is better too (not harshness just more...connected) great for pushing max lean. Yes if you lift the front wile walking the bike you notice very slight weight gain but not while riding.
I would say bottom out force is maybe less although I've not had an issue yet. Actually I find myself riding like a fool, pushing the front like crazy now, confidence is very high.
TF do send 2 spring options depending on weight and riding requirement. They also exchange a spring for a postage charge.
I remember feeling the lack of sticktion on an old Marzocchi a few years back and it blew me away how smooth it was. My pike jars on small bump stuff so this should go a long way towards improving comfort and traction, and your review certainly suggests it is a very noticeable improvement. Reading around on here the whole bottoming out thing that the Push system caters for with its air damper seems a little overkill - the general consensus is that if you bottom out you're under sprung and that is an easy fix!
In relation to the rear I'm stuck with air due to the suspension curve being wrong for coil, but I can live with that - my legs can take it but over the course of long rough downhills my hands are getting beaten up, and grip is always more preferable on the front!
Thanks again!
Kinda like the Manitou MARS spring?
Its a whole different issue, but damn its next to impossible to get an entire bike (especially wheels) that are rated for some of us bigger cats...
I'm not even mad, I'm impressed
Great article. Looking forward to more reviews down the road!
www.mtb-news.de/forum/t/coil-ghetto-umbau-fuer-pike-29-mit-rock-shox-teilen.833400
There are a few inherent differences between air and coil:
- An air spring requires additional seals. Seals = more drag, which equates to more feedback at the handlebars. It's most obvious on small bumps but it's exists on all impacts. This also means you need to break down your fork and grease the seals regularly to keep it feeling as good as possible.
- An air spring acts differently at different temperatures, so over a rough descent it can get stiffer as the air heats up.
- A coil spring has a linear rate, where-ever you are in the travel the increase in force to move the next increment stays the same until the coils run out of room to compress. An air spring on the other hand requires a high level of force at the beginning of travel, then drops down a lot at the mid-stroke, then ramps up at the end. That's the nature of an air spring. You can design a linkage to offset that to give you a mostly linear progression that's close to a coil shock. However as our forks are telescoping you're stuck with the air springs natural characteristics. The biggest downside for air is that you can either tune it for small bump sensitivity and you'll have a less supportive mid-stroke, or you can tune it for a supportive mid-stroke and you'll have harsh small bump. Conversely with a coil fork you'll have a more supportive mid-stroke, but you don't have the same end-stroke ramp you get with an air fork, so you may wind up running a higher spring rate than you'd prefer; however, the Push system basically puts an air spring at the last 1/3 of travel to manage this, theoretically giving you the best of both worlds.
None of this is exclusive to DH, it's all applicable to trail riding as well.
Yeah, there are several ways to tackle the problem.
Long story short, the shitty rebound characteristics you encountered weren't because it was a coil fork.
2015 Pike spring = $400
'k off!
www.mtb-news.de/forum/t/coil-ghetto-umbau-fuer-pike-29-mit-rock-shox-teilen.833400
Too expensive for what you get IMO
If anyone actually understands the nonlinearities in an air spring they will also understand that if you choose the correct coil spring rate, it will be roughly just as hard to bottom out. If anyone is complaining about bottoming out a coil spring, they are likely just running undersprung and need to go up a rate. Air springs also have many other issues (like friction, and requiring greater compression damping to compensate for the mid-stroke rate reduction), so once you remove those problems you will naturally need more spring force (again) to support the rider.
PUSH has just made up a problem to justify a ridiculous price for something that Fox used to offer as a no cost option - in a package that worked absolutely beautifully. See the 2011-2013 Fox 40, or 2012-2013 Fox 36 VAN RC2 (inverted FIT). On the bright side, hopefully this will encourage Fox to bring back the real deal.
"seven different springs rates in 5-pound increments that will accommodate riders between 125-230 pounds."
7 spring rates at 5 pounds will only span 35 pounds.