PUSH Industries Fox 36 coil spring replacement kit air spring bump stop

Coil spring or air spring? Since the introduction of the air spring, this seems to be the source of constant debate. Air springs offer enhanced tuning capabilities and progressives suspension curves, yet coil springs offer that supple off the top feel through the beginning and midstroke that you can only get with a coil. For years we’ve seen more and more air spring suspension systems in search of the lightest possible system, but lately we’ve noticed a few coil systems popping back up.

Brands like PUSH have even gone as far as creating new, purpose built coil shocks for enduro bikes like their Elevensix rear shock. In an effort to match the performance of the rear to the front of the bike, PUSH turned their attention to the front of the bike with a sort of coil/air spring hybrid which looks to offer the best of both worlds…

PUSH Industries Fox 36 coil spring replacement kit air spring bump stop

PUSH Industries Fox 36 coil spring replacement kit air spring bump stop

Named the ACS-3 for Advanced Coil System, the system is a complete drop in assembly for the air side of a Fox 36 suspension fork – though Rock Shox Pike kits are on the way. Inside the kit you’ll find the Air Bump stop, Preload cap with two spacers, chosen spring, and the Lower Plunger Assembly.

PUSH Industries Fox 36 coil spring replacement kit air spring bump stop
Photo c. PUSH

PUSH Industries Fox 36 coil spring replacement kit air spring bump stop

PUSH Industries Fox 36 coil spring replacement kit air spring bump stop

Available with one of seven different spring rates, the color coded springs are made from “precision wound high tensile CrV-Si suspension spring that is shot peened, preset, and powder-coated to ensure the lightest possible spring with the most exact rate.” Combined with the lower spring bearing (above, red cylinder), the spring is allowed to rotate on its perch which is said to improve small bump compliance as it keeps the spring from binding on the mount. Each spring also comes pre-wrapped to cut down on noise.

Part Number Description Fork Model Model Year Travel Rider Weight Range
ASY-1090-110-0030 Replacement Spring Assembly (Red) FOX 36 2015-2018 160mm 125-140lbs
ASY-1090-770-0035 Replacement Spring Assembly (Yellow) FOX 36 2015-2018 160mm 140-155lbs
ASY-1100-800-0040 Replacement Spring Assembly(Orange) FOX 36 2015-2018 160mm 155-170lbs
ASY-1100-800-0045 Replacement Spring Assembly(Blue) FOX 36 2015-2018 160mm 170-185lbs
ASY-1163-800-0050 Replacement Spring Assembly(Green) FOX 36 2015-2018 160mm 185-200lbs
ASY-1180-760-0055 Replacement Spring Assembly(Black) FOX 36 2015-2018 160mm 200-215lbs
ASY-1180-760-0060 Replacement Spring Assembly(Gray) FOX 36 2015-2018 160mm 215-230lbs
Spring rates start with the red spring at 125-140lbs rider weight, and top out with the gray spring for a 215-230lb rider.
PUSH Industries Fox 36 coil spring replacement kit air spring bump stop
Photo c. PUSH

PUSH Industries Fox 36 coil spring replacement kit air spring bump stop PUSH Industries Fox 36 coil spring replacement kit air spring bump stop

The real magic though, comes from the Air Bump Stop – a clever integration of both coil and air springs. The pneumatic bump stop allows the spring to offer a linear curve throughout the initial and mid stroke, but once the bump stop is engaged, it controls bottom out with adjustable air pressure. Factory set at 20 psi, PUSH says that running 5-20 psi will result in a more linear feel, while running 20-50 psi (50 psi max) will provide a more progressive spring curve for the most bottom out resistance. To adjust, simply remove the cap and inflate or deflate with a standard low pressure shock pump.

PUSH Industries Fox 36 coil spring replacement kit air spring bump stop

The kit also includes a preload cap with two additional preload spacers. Designed to be used with or without the spacers, PUSH says the two additional spacers can be used to adjust the static sag or ride height of the fork.

PUSH Industries Fox 36 coil spring replacement kit air spring bump stop PUSH Industries Fox 36 coil spring replacement kit air spring bump stop

Pricing and availability

On the scale, our 160mm Fox 36 27.5″ kit came in at 411g for the entire kit, and 224g for the blue spring. We’re assuming this will add a bit of weight, but will confirm once we pull out the 36 internals to verify.

PUSH is rolling out the new kits one by one, but for the initial launch kits are available for 2015 – 2017 Fox 36 Float or TALAS 160mm forks. Fox 36 140, 150, and 170mm travel kits as well as 2018 Fox 36 140-170mm kits will be available in late July. Rock Shox Pike kits will also be available, though no time is given for their availability. Finally, PUSH mentions that kits will not be available for Rock Shox Lyrik or Yari forks since the inner diameter of the stanchion is too small.

Sold for $389 for the complete kit, additional springs are available for $80, and everything is made completely in the USA.

PUSH Industries Fox 36 coil spring replacement kit air spring bump stop

Lower Leg Service Kit

While you have your fork apart, it’s also probably a great time to perform a lower leg service – assuming it isn’t a brand new fork. To make services easier (and less frequent), PUSH has a new lower leg service kit with almost everything needed for the initial service. The 32mm chamferless socket above is not included in the kit, but seems to be a beautifully machined alternative to the other chamferless sockets on the market. The kit does include enough Maxima Plush 10 wt lower leg fluid and PUSH SOS assembly lube for 5 services, and one set of PUSH ULF fork seals with foam rings, crush washers, and the awesome PUSH fork seal installation tube and a 60cc syringe. The Lower Leg Service Kit sells for $105, and additional seal kits will sell for $36. PUSH claims that their seals double the service interval of any fork – which, be honest, is probably closer to a more realistic service interval for most of us.

Shown here as a preproduction tool, the chamferless socket will be available as a stand alone tool for $40 each, or as a kit of five sizes (24, 26, 28, 30, and 32mm). Production tools will be hard anodized and include laser engraving for the socket size with the PUSH logo. Each socket includes a 3/8″ drive, as well as wrench flats which double as a finger hold.

ACS3 Fork Coil Conversion Kit for FOX 36 FLOAT/TALAS

7 COMMENTS

  1. The weight of the Fox 36 air shaft as far as I recall is about 120-150 grams. So the added weight here is around 300 grams. Which makes this fork to weigh around 2300 grams. Why to spend so much money if you can buy right now and excellent fork with titanium spring and great dumper with 170mm of travel that weights only 2150 grams? I mean the new 350 NCR.

  2. comparing this state of the art engineering that will improve the rides of tens of thousands of Fox forks (hundreds of thousands?) to one of the last products of a dying company is ridiculous. I love shopping for deals on eBay, Jenson USA / Chain etc, but THAT Marzocchi company died. The new Marzocchi is owned by Fox and postitioned as a low end line, and the only Ti will be the color of the decals.

  3. Zach – any word on whether using this kit prevents going back to a stock air spring? I don’t see anything stopping the coil spring from marking the internal surfaces of the stanchions, and – correct me if I’m wrong – that surface is still used to seal against in Pike 35 air spring (unsure of Fox 36)..?

      • I think this is just a decision thats permanent, you go for this kit, theres no going back. Shrink wrap is not going to fix anything.

        Also, a short note from a shop mechanic who gets to work on suspension thats been worked on by the owner at home. There is nothing that you can buy from Home Depot that should go into your suspension fork. Stop complaining about the price of proper rebuild kits and damping fluid. Just get the right tools and do it right or pay someone else to do it right. Its definitely not saving you any money anyway.

  4. It will probably scratch it, but if you’re paying what Push is asking, you won’t be worrying about it. Why would you convert it if you ever thought you might go back? Kinda misses the point…

COMMENT HERE: (For best results, log in through Wordpress or your social media account. Anonymous/fake email comments may be unapproved or deleted. ALL first-time commenter's posts are held for moderation. Check our Comment Policy for full details.)

This site uses Akismet to reduce spam. Learn how your comment data is processed.