Fast Suspension's 3-Way Yari Damper Upgrade - Eurobike 2017

Aug 30, 2017
by Paul Aston  
Eurobike 2017



Fast Suspension


Fast Suspension has been working on a plug and play damper to replace Motion Control damper units in RockShox Yari and Revelation forks. Why only these two models? Fabien Glatre, owner and engineer at Fast says that the Yari is becoming one of the most popular forks at the moment due to the huge numbers specced on eMTB's. He thinks the Yari has a great chassis but is let down by the damping performance of the Motion Control system, especially on heavier eMTB's which have much more sprung weight and blow through the mid-stroke too easily. Most riders try to overcome this by adding more volume spacers, but a better solution is said to be to add more compression support in the mid-stroke. This new cartridge gives independent control over three phases of compression damping: low, medium, and high.


Riders can externally adjust compression for low (0-150 millimeters per second) shaft speeds and medium (150-700 millimeters per second) speeds using the purple and black adjusters. High-speed (anything over 700mm/s) can be adjusted internally by switching shims in the lower valve and can be done by the consumer.

The unit will employ nitrogen filled, closed cell foam which will work as a compensator, and turns the damper from an emulsion type system into a closed cartridge type by sealing against the stanchion wall.

Fast Suspension
The Allen key bolt next to the adjusters can be removed to remove any unwanted pressure build-up in the cartridge.

Fast Suspension
Riders can switch shims themselves in the lower part of the cartridge to adjust high-speed compression.

The units will cost €259 and be available in October, along with a series of instructional videos that help riders get the best setup from their on-trail feelings.


Fast Suspension


Fast also have some new upgrades for their Holy Grail shock. There is a new compression lever that either leaves the shock open, increases high-speed in the middle position for harder hitting riders or in case you take a rare trip to the Rampage and need more support for big stuff, and the third position increases total compression to improve pedaling performance.


Fast Suspension


Fast have also been developing a new, larger IFP (internal floating piston) reservoir for the Holy Grail shock. This unit pictured is in the prototype stages and will have a more refined finish, but during dyno testing the shocks temperature increases to 78ºc, a full twenty degrees less than their standard reservoir which heated to 98ºc on the same test run. This should keep riders shocks more consistent when arms and legs are struggling towards the end of long tracks.


Fast Suspension


Fast must have missed out on the memo from the bike industry, though, as both of the above parts are available as upgrades to existing shocks, so you don't need to buy a whole new product to get the latest performance.


68 Comments

  • + 27
 For those who want to dy/dx themselves
  • + 11
 It's a very integral product for Yari owners.
  • + 15
 Are you sure about the shaft speeds? At 150 m/s (upper threshold of "low speed"), one would blow through the travel of the fork (180 mm) within roughly one millisecond... In millimeters per second the numbers look slightly more reasonable.
  • + 35
 Haha, 700m/s is over mach 2. That's gonna be a rough landing Smile
  • + 4
 @SleepingAwake: Yes those numbers Sound off. Vorsprung Suspension mentioned shaftspeeds of 8 m/s for a shock. Assuming a high leverage Ratio of 1:3 that would give you axle Speeds of 24 m/s for the rear. Assuming front and rear Wheel beeing in the same ballpark i would say max 25m/s...
  • + 0
 Speed of the oil passing through the valving
  • + 2
 I missed the last part out your reply. 700mm/s sounds reasonable for a high Speed Event. with the comments from the vorsprung Videos i get 2500 mm/s as absolute max for shaft Speeds.
With the Kinematic equations:
V²=V²_0 +2a(Delta)x
i get for a initial velocity of 0 m/s to 700 m/s on a 160 mm fork an acceleration of over one Million meters per second. that would tear appart anything i know of.
  • + 6
 @bmxRC009: Even oil Speeds in that Magnitude would be rediculus. the perassure woud tear appart the entire damper
  • + 16
 Found a German NASA guy ^^^
  • + 4
 That explains why suspension is so expensive! lol

And if bike forks can get to Mach 2, I wonder how fast those MX suspension goes!
  • + 4
 @Caiokv: there was a recent article, I believe on PinkBike, that stated MTB's actually have the highest shaft speeds. Moto surprisingly was lower.
  • + 1
 @mtnbykr05: Yeah I remember that one. Has to do with sprung weight vs unsprung weight ratios.
  • + 1
 I think it was a typo that has since been updated; it was posted meters per second first, now its millimeters per second.
  • + 1
 @hamncheez: good Looks like we were right. It is a easy mistake to make when moving away from SI base Units.
  • + 0
 Did they change it from m/s to mm/s after your comment?
  • + 5
 @bmxRC009: a German NASA guy, you say? Perhaps it's Wernher von Braun.
  • + 3
 @thrasher2: yeah thats what sparked the discussion Wink

@LAT2: if you look into his political afiliations you will find most Germans wont like to be compared to him but i hope it was in good Spirit as he sure was a brilliant who was much more talented than i am.
  • + 2
 @Luneec: For sure! Badly worded, bad taste "joke". It was more the idea of where NASA's rocket skills came from. Sincere apologies.
  • + 7
 @LAT2: no bother. he built the most powerfull engine ever; the Saturn V thrusters.

I think it is good that People know the creators of such marvels of Engineering but i think it is also important to know the dark sides.

But hell this is cycling lets get out on the Trails and ride our bikesand make sure such Things never happen again, plu i think having fun on your bike is a good step towards that
  • + 1
 That's the speed fox forks blow through their mid travel
  • + 0
 @allballz: shaft speed most definitely can have an effect on shaft speed. If the unsprung weight is lighter, it will react to impacts much quicker. Takes a higher level of energy to displace a greater mass. This same energy will also dictate shaft speeds, that if the same force is applied to something at a lower mass, the object will displace quicker.
  • + 1
 Sorry, Sprung/unsprung weight most def can have an effect on shaft speed*.
I know, you'll now tell me you are an engineer and some shit. I don't know how you can't obviously see how the mass of an object will determine the the energy needed to move and can dictate the speed on which it moves. There is a reason why when it comes to suspension, unsprung weight is a massive factor to how it responds to terrain.
  • + 5
 Never used to think much of this kind of upgrade but having taken a pair of 2013 boxers and binned the crappy low speed damper and replaced it with a charger the difference was night and day. Definitely on board with the whole upgrade damper units ting.
  • + 0
 don't blow the bladder up. I burst mine and sram can't supply the simple rubber tube until mid October. fucking cunts
  • + 7
 Waou! High speed compression for Mach 2 speeds! Amazing!
  • + 4
 More oil less heat. More oil more weight. I prefer the reliabity and performance of more oil. Too bad the bike industry feels the opposite.
  • + 10
 sadly reliability is harder to measure. weight is a very simple and easy to compare number. Also most People dont tend to push their suspensions to the Limit or have ever experienced oil foaming or losing ist viscosity.
  • + 1
 @Luneec: yep weight is a simple measure.
For simple thinking.
Your probably correct most people wont push the limits.
  • + 1
 Whether it is good or bad bothers me little but i laugh at the amount of people who blow money on suspension '' upgrades'' and ''custom tuning'' yet have little idea how to set up the stock stuff, which in MOST cases works pretty bloody well. Placebo affect anyone?
  • + 2
 If anyone from Fast is reading this, tell me why I should choose this rather than the Avalanche upgrade for my Yari. Much appreciated.
  • + 1
 Because it is cheaper and less of a hassle to setup. Ofcourse if you have the cash go Avalanche!
  • + 2
 Meters per second? Are you sure? Meters per second of what? Lowers vs crown speed? I am sure a fork will never compress faster than 150 m/s.
  • + 2
 I think you have a typo- 700mps is about 1565 Miles per Hour... Don't think anyone is compressing their fork that fast. should be 700 MILLIMETERS per second.
  • + 1
 It would be interesting to see how this compares to the new charger 2 damper upgrade now available.. I think they are both around the same price
  • + 3
 It's ok when it's in a three way
  • - 1
 Your marketing based on E-bike spec data? These control knobs are cool and all but already exist on the current forks and are better integrated. Not much performance gain, expensive.
  • + 2
 They exist on 1000$+ forks.
FAST is aware of that fact. What they are trying to accomplish is to bring the Yari to the same level, because (as said in the article above) there is a ton of them out there and a lot of people are looking for possible replacement or upgrade options.


I deliberately bought a bike with a Yari because it was cheap, knowing that in no time there will be lots of aftermarket upgrades available, turning my cheap fork (with great chassis) into something that´ll blow any stock Fox 36 out of the water for a fraction of the price.
From personal experience i can say that FAST upgrades are great. My FAST Boxxer WC beats any currently available stock dh fork on the market by a mile, so (depending on execution) i´m quite sure these knobs do in fact provide a lot of performance gain, especially considering the Yari is a much worse fork than the Boxxer WC to begin with, so there´s even more to gain from it.
As long as companys like FAST or Avalanche exist i can confidently state that i will never again buy any of the top class fork offerings and rather go with an upgraded Damper in a low budget fork (as long as companys keep the chassis the same).
  • + 1
 @jake294 good upgrade for you
  • + 0
 Why wouldn't you simply swap the Yari for a Pike and pay the difference when you buy the bike?
  • + 0
 oh the fun we could have with an sonicboom when we shaft reach the speed of sound
  • + 1
 Purple is the new black , hm?
  • + 0
 You can pick up a charger damper for the same price or possibly cheaper and put it in the Yari to make it a Lyrik RCT3
  • + 1
 Is the Holy Grail available in metric sizes?
  • + 0
 haha, ebikers need more compression because of their fat *sses.price: just 259 basic burgers
  • + 1
 That takes the Yari up to Lyrik money.
  • + 9
 Yeah, but heaps of Yaris are specced OEM. Seriously considering this myself, I'd never bother spending the extra on x01 over GX, or a model higher brake, but definitely happy to spend on my suspension.
  • + 0
 @mbikes1: Do it. I have a Yari on my park bike and it's the stiffest fork I've ever owned, even compared to another high end fork from a different manufacturer.

I went with an Avalance cartridge inside my Yari because Craig's design really has something to offer if you jump a lot.

This Fast thing is neat but it seems the biggest difference is they added some adjustable shims where the vanilla MC damper just has an adjustable orifice. Can't see enough details to really understand what they did yet, though.
  • + 2
 No trunion mount shock, so it's already obsolete.
  • + 2
 @WaterBear:

Waterteddybear - how's that avy damper for trail/am riding?

My Stumpy came with a Yari 150 and it may be more cost effective to upgrade the damper vs sell it for cheap and then try to get into a Lyrik.
  • + 0
 I hate that emotorcycles are driving mountain bike innovation...
  • + 1
 Whys that?
  • - 3
 So you pay between 400/500 for a Yari... and then spend +250€ (+63%/50%) more for a single damping unit?
Right....
Learn to look ahead +20m and keep your brake drag low = more fun & speed for 0$€£
  • + 1
 That doesn't work at ALL when you ride steep terrain!
  • - 1
 How much is a new Charge damper? If less than 259 Euros...FAIL
  • + 4
 Can you put a charger in a Yari?
  • + 3
 to be fair, the fast unit is better than the charger -i have been using the pike specific unit for 1.5 years and its way better. (charger is massproduced -fast is not, it has propper high/lowspeed compression adjustment(24 clicks each). The time i bought it it was 160 € though....
  • + 2
 @qualitybarnbro: apparently it may take a Lyrik charger damper... singletrackworld.com/forum/topic/yari-charger-upgrade
  • + 3
 @qualitybarnbro: Yep a lyric charger in the Yari, cheaper than this upgrade
  • + 6
 @qualitybarnbro: Probably a better damper than Charger though, and way more adjustable.
  • - 3
 @Losvar: Probably not. The MC top assembly looks very similar to what Fast have, just without the shims. It's very possible that the Charger offers at least the same adjustments if not more.
  • + 1
 @Nicksp894: I looked into this upgrade. It's surprisingly hard to find a Charger intended for the new Lyrik. I couldn't find any online that were actually in stock. Most of the ones available are upgrade units for older 26" Lyriks.
  • + 3
 @WaterBear: a lot of assumptions in your answer...
Keep in mind that the compression kit from Fast will be customed valved according to the customer needs while the Charger is made to fit everyone.
  • + 0
 @Happymtbfr: Of course, I am assuming the worst. The point I'm making is you can't jump right away to the conclusion that it's probably much better than a Charger, "custom valving" aside.
  • - 1
 @qualitybarnbro: No you can't. A lot of Yari owners tought about that since the release.
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