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
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.
Push aren't the first company to offer a coil conversion, but the pneumatic bump stop does set their kit apart from the options currently on the market. The air pressure is adjusted via a Shrader valve on the top cap, and can be set between 5-50 psi
The red portion of the ACS-3 allows the spring to rotate under compression, while the mechanical negative spring underneath is designed to provide a predictable top out. The lower plunger assembly is 100% CNC machined by Push.
What 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.
Push will initially be offering seven different spring rates, with two more on the way.
I'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.