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My 2c after three months / over 500 miles on the Essential: it feels almost too good to be true initially, but the performance of the fork doesn't degrade over time and as you get used to its slightly different feeling (and a longer offset in my case), it just rides better and better. I too have had problems with hands going numb and the Essential is giving me the best riding comfort of all forks I've ridden so far without sacrificing performance and stability.
The grip 2 seems to choke and end up a bit harsh no matter how you set it up. Bumps just felt sharp in the hands.
I'm so glad you brought this up - my Edge had been lying around for a while and I just put it back on my bike and noted to achieve my preferred sag I was 18 psi below the last time I had it on the bike (usually I'm 68 psi for 21% and yesterday I only pumped it up to 50), and it just didn't feel right. I unscrewed the 10 mm bolt on the airside and voila, I huge amount of air came out. Is this leaking from the negative chamber into the uppers? So odd...
nope, its just air trapped , same thing happens with RSU forks.. that's why you got all of those bleed ports these days
On the Smashpot thing, personally I wish someone would make a simple coil conversion that is just the coil. I feel like ACS3 and Smashpot overcomplicate the whole system, adding weight, complexity, and inconsistency to something that is already heavy but has the benefit of simplicity and consistency when done without those mechanisms (e.g. RXF36/38, Cane Creek Helm, Formula, etc). Every fork I've ridden with a coil had enough progression from the air trapped in the lowers and the damper was capable of controlling the movement without these other things needed.
Maybe do what Ohlins did and add a spacer at the bottom of the seal head that reduces volume in the lowers, but other than that - I just wish there was a simple coil conversion for the air forks that didn't involve an airspring or second damper.
I don’t necessarily agree - I fart my lowers all the time on other bikes (Zeb and Lyrik) and never hear a thing. Additionally, It’s only a problem on the air side for me, and looking back, when I remounted the fork this time, the air side almost seemed locked out. I didnt think much of it and just depressurized and pumped it back up, but looking back, perhaps the negative chamber just emptied into the uppers.
Yes it sounds like you have a leaking negative spring. There shouldn't be a large amount of pressure in there at all, there might be the faintest hiss from the fork being assembled fully extended and compressed down, or from huge changes in temperature/altitude but what you describe is a leaking spring, especially the way it felt almost locked out
I had similar thoughts. Where the f did that air come from. However if it would be a leak there will be more air regardless of your fork is sitting around or beeing riden. So id say lets recheck later and if there is constantly air trapped there must be something wrong. Thats what i wanted to do originaly. However the fork has since then performed flawless and at one point i decided to not touch a running system.
Oh man, I guess it depends on riding style, but without the Smashpot’s HBO, I’d be bottoming like crazy (paired to a charger 2.1 and another with Avy cart). The trapped air isn’t nearly enough, especially on the ebike with the HBO fully closed
last time i checked, there was no smashpot for inverted single crown forks so could you discuss this somewhere else?
needed to save todays story from Intend
@Skunk Works Suspension did you already have the chance to try out the flash? i am very eager to hear your opinion on this one, also compared to the edge. cheers
Unfortunately not yet, other than in the driveway. There are a few other projects to take care of first, but soon!
There are some slight updates between forks; the brake hose guide is now a compression molded carbon piece instead of simply being cut from a carbon plate, and the rebound knob is bigger and easier to turn.
Compared to the Edge, the Flash crown is larger and has more overlap on the legs.
Hello! One of my friends that got the same fork wonders what air pressure do you typically put into the fork and what’s your weight? I understand that might not be super relevant to anything, but still interesting. Thank you
Also, Spomer, spam is a real issue indeed, but you’re cutting off new users from registering - not all countries have access to us of a payment systems
start with weight in kg = psi
it’s all on the website:
www.intend-bc.com/fork-setup/?v=d88fc6edf21e
Yes, the kg to psi is a good starting pressure.
It also depends on what air cap you are using, I weigh 175# and run around 80 psi with the max volume air cap.
With the "linearizer" dynamic 3rd chamber, I was running 10-15 psi less (and around 120psi in the linearizer).
Travelizer or Linearizer? 😂 I swear, Cornelius just fuck with us with those names.
I also add more air pressure with my max++ volume air cap setup.
Yes, linearizer. ☺️
"kg in psi"
Man we do like to mix our metric and lunar freedom units in mountain biking.
they could have done a table and put it on a sticker but why should they if you have a simple to remember ballpark figure?
Kg x 6.895 kPa just doesn't have the same ring to it.
That's not even close to the worst one! Fox currently mixes metric and imperial sized shims in the same shim stack...italian threaded bottom brackets were/are 36mm by 24 threads per inch....no one is truly all metric or all imperial
please do not reply in this thread, just PM me or email sspomer@vitalmtb.com - i don't want this thread derailed.
- but to address "not all countries have access to us of a payment systems" (did you mean USA?). can you elaborate more? specific country or payment type? afaik our system takes any kind of credit card (a global form of payment) for the signup process. thanks!
(for those who don't know b/c they've been here for a while, a few months ago we implemented a one-time $1 fee for new signups to prevent spam. the spam was so out of control no matter what we did. now, the spam is done (aside from the spammer who actually spent $1 yesterday only to get shut down LOL).
AGAIN, please don't discuss this any further in this forum thread...stick to rad fork talk...i'll delete this in a couple days.
Kg x 51.716746 mmHG is so much easier, since my shock pump reads in mmHG already.
I just find it funny how much we mix metric and standard measurements in MTB.
There's nothing wrong with it
I also enjoy when I do climate testing and I can just state "tested at -40°" since it's the crossover between F and C. I'm tempted to use Kelvin just to mess with my boss. Yes, I am that big of a nerd.
I had typed out a big post to this thread... and somehow hit refresh and lost it. So I'm going give the abbreviated version...
I have been testing a 170mm push 9.1 (v1 with the air hbo) for the last week and have 4 rides on it. I have been testing it on my SC bullit so that I could get a lot of descending in on it.
Here's the short summary:
Spring Rate: I'm 175lbs running a green spring (50lb) with 40psi in the air bottom out. I'm technically on the stiff side as the green spring spans 185-210. Despite that, I had several HUGE bottom out events with very loud metal on metal noises. I've run into this before with acs3 kits where I have to run 1-2 springs higher then I would run on a smashpot and will still have hard bottom outs. For example, I have two forks with smashpots, with 45lb and 50lb rates and am able to use the hbo to control bottom out events and rarely experience harsh or audible bottom outs. I believe that pushes air plunger bottom out system is simply not up to the task, so it's good that they are switching to a hydraulic setup. I also feel like push is using a bit too much spring pre-load in general as the bike/fork does not settle into it's travel under it's own weight. My experience with coil forks and proper pre-load is that when setup right, the fork will sit 2-3mm into it's travel... I tried multiple springs with this 9.1 and it did not do that with the blue/green or black springs.
Damping: There is enough damping force available from the damper where I don't feel that anyone will be wanting for additional damping... That being said, similarly to the hc97 in the past, I do find that there is a theme of more harshness then there needs to be for the requested level of support. I find that if I try to unwind LSC or HSC independently, that the harshness will go away, but not until there is no where near enough support from the damper. Overall, I think the damper is good, better then a grip 2 vvc, better then an hc97 charger 2.1... but I'm not sure it's better for me then say a grip x2 or a mrp lift damper.
Chassis: This is the biggest point of concern for me... I have never, in my life, struggled to hold a line or end up on the trail where I planned to end up like I do with this fork on my bike. I can feel some of the advantages that are lauded with USD forks like less bind when the fork is loaded up on the brakes and the right mix of being active, but maintaining geometry in those circumstances. However, there is a noticeable lack of accuracy out of the front end of the bike. It was honestly so bad that I actually tried two separate front wheels (reserve HD/AL with dt350 front hub and a Reserve 30 Carbon with 1/1 front hub). It was slightly better with the 1/1 hub and the carbon front wheel, but still completely un-acceptable from my pov. To further that point, I can visually see the front wheel turn towards the left when I hit the front brake. In addition, if I lean the bike over turning to the left and stab the brakes, I can not only feel the side knobs change how they are digging into the ground/pavement/dirt but I can hear the sound the tire is making change. This is something that is hard to quantify, as it's hard to separate what you think you're feeling vs what you are... but the bike is noticeably harder for me to slice through janky off camper rock moves, large features with big compressions and any chunky feature that has direction changes in it.
I did notice that the fork seems to perform better when you have tons of weight in your hands all the time. I'm for the most part, a weight the front of the bike with my feet rider, with select inputs of heavy hands on the bars to get the bike through sections. The only way I could get this thing to feel better, was to constantly have what felt like a ton of weight in my hands all the time. It did not solve the above mentioned in-accuracy of the front wheel in technical sections... but it starts to get the fork to feel closer to how I'm assuming it was intended to feel.
When going in a straight line and not braking, the fork does have some amount of magic sauce going on. The problem for me is that once I'm braking heavily with the front brake, steering/leaning the bike, or guiding it through technical sections... that magic sauce immediately dissapears and I'm left with a question machine of where the front end of the bike is going to end up.
Other notable things:
-This particular fork weeps oil from under the crown on the daper side of the fork. This is oil that is coming out of the bleeder assembly.
-There is always air build up in damper side fork leg for whatever reason. For what it's worth, I am continually either starting or descending into sea level (50-100') and climbing to 1,000-1,500. I'm not sure if that's playing into this or not... but it's strange.
-The brake adapter setup is fiddley and I would have much preferred a standard 180mm post mount. Instead, they use these individual spacers and their proprietary post mount setup. These are a bit of a pain to deal with, and if you were to lose one, you're completely screwed.
-The fender... is not so great and needs more development.
-There is no way to deal with this thing without needing a torque wrench most of the times you were to touch it. The axle mount definitely needs one, changing springs needs one to deal with the lugs... Not a huge deal... but it's notably annoying.
-The custom pin socket for taking out the air (soon to be hydro) bump stop is fiddly, easy to have walk out on you and annoying.
-The damper is noisy but not annoyingly so and it's not a sound that I find displeasing. It's got that smooth, non cavitation sounding squelch to it that reminds you it's doing work. It's not a silent fork however... I didn't grease the spring enough during one spring swap, and I was left with some clanking and clicking.
Overall, It's a decent product. I do not think I like it as much as a zeb/38 with a smashpot and grip x2 or mrp lift damper. I do not find the chassis to magical or significantly better then a zeb/38 with the bushings checked and clearanced with a .07 or .1 die. I am thankful that I got the chance to try this fork out without putting my hard earned money down... I would be immensely bummed had I purchased this fork. I have no doubt that the support from push and more time on it would help it get to a place where I would be happier with it... but the gap between where it is now, and what I'm looking for is wide enough that I don't think it would ever match my expectations for a 2k+ fork. I prefer the 38 stanchion forks that I currently have in my fleet over this product.
Next I'll be putting my 170mm smashpot, zeb, mrp lift damper fork back on this bike so that I can fall back and validate my impressions of the 9.1. I'll be demo'ing a fox podium within the next 2 weeks so that I can give my impressions on that and compare it to the 9.1
A couple of notes to consider.
Spring Rate. Yes, you're in the camp of riders that we developed the Sub Chamber system for. The V2 Sub Chamber is 100% backwards compatible with that fork.
Chassis. This is a tricky one as the the front hub plays a significant role in how the chassis performs. This is why there's such a broad range of rider feedback in regards to stiffness with inverted forks. My guess is that FOX didn't want to roll the dice with this variance, which is why they committed solely to the 20mmx 110 boost configuration. Our recommended hubs include Chris King, I9 Hydra, and Hope Pro. These hubs provide large and robust bearing interfaces, as well as providing options for Torque Cap hub end caps for more aggressive riders. In the case where you're on a full-power E-MTB I would recommend Torque Caps with a more robust hub to get you the desired stiffness. Unfortunately, the I9 1/1 hubs don't utilize a compatible Torque Cap.
So, why not just og 20mm? We can, but then riders have to get a new wheel, or at least a front hub and relace. We opted to build something around stock wheel compatibility. With that in mind, a lighter rider on a traditional MTB with that same fork and wheel setup that you're running may have a completely different experience. I have ridden both the DT hubs, as well as the I9 1/1 hubs with our fork, and they would rank at the lower end of the spectrum as far a support and stiffness go with our NINE ONE. The DT hubs IMO require Torque Caps to meet the minimum performance requirement, and the I9 1/1 would most likely be better if they offered a compatible Torque Cap end cap. I actually am prototyping some 1/1 end caps this week to have a look.
Darren
Interesting timing as I have been going through some hub/axle stuff as well.
Fully Floating System
What is found on inverted dirt bike forks; the fork axle can pass competently through the non-disk fork lug, and the hub end cap does not make contact with the ND fork lug. When the axle is tightened, the hub is pulled against the disk side fork lug, just like the Cannondale Lefty. Hub width has no effect on chassis alignment.
Non-Floating System
A system where the fork axle bottoms out on the outside of the fork lug and squeezes the hub between the fork legs. Maximum pressure and contact with the hub end caps, larger end caps such as Torque caps can make a difference in system stiffness (**see note below). Hub width (wider or narrower) can have an affect on chassis alignment as the fork legs can be splayed in or out.
"Partially" Floating System
The fork axle can pass through the non-disk lug, but the hub end cap has contact with the ND lug as well. If the hub is too wide, it can splay the legs outward and cause chassis alignment issues.
For fully floating and partially floating systems, the disk side hub end cap can have a notable effect on stiffness. The non-disk side has little to no contact with the fork lug and therefore the diameter of the end cap will not really effect system stiffness. On the 9.1 there is a small lip on the fork lug that the end cap rests against, but the majority of the stiffness improvement seen with Torque caps come from the larger contact area between hub/fork lug when tightened by the axle.(**see note below) There is no force pushing the ND end cap against the fork lug like there is is a non-floating system.
The I9 1-1 Torque end cap does not work with the PUSH 9.1 as the fork axle simple goes inside of it and cannot tighten the hub to the disk side lug. There is nothing for the axle to push on.
However, as I believe the ND side end cap does not has much (if any) effect on system stiffness for the PUSH 9.1, the end cap diameter is not as significant and there is no advantage to using a large Torque size end cap on that side. You can simply use the standard I9 1-1 end cap on the ND side, and use the Torque cap on the disk side where the larger diameter can improve system stiffness.
If PUSH has data that contradicts my thinking, or has tested the I9 1-1 "hybrid" end cap setup I run with this fork, I would love to see it along with pics of the testing setup, etc.
I am a huge fan of testing and data collection, but just saying that A is better than B without actual numbers and information to back it up is not very useful. Saying that, see my note below as I don't want to be a hypocrite. If I still had access to that information, I would provide it.
** Although I don't have numbers or pics of the testing setup, I was involved with testing Torque caps when RS came out with them 15+ years ago. It was around the start of the switch from QR to 15mm front axles, and we tested Torque caps on a open dropout fork (using a 9mm DT RWS thru axle) and compared data to the same fork that used the new 15mm thru axle (with standard size end caps). The forks were mounted to a steel test table and weight was applied to create a twisting force and deflection measured.
The Torque cap/9mm QR setup was stiffer torsionally than the 15mm axle fork. This was attributed to the larger contact area the torque caps had with the dropouts on the QR fork. This was all done in the Specialized test lab and setup by test engineers.
That's a pretty damn informative post, thanks. I only know just enough to be dangerous here... so please bear with me.
Question, I have to assume that there is an impact to stiffness based on how the front hub axle/end cap interface works? I've long thought that the end cap design of the dt350 is a standout weak point of the overall hub design. It seems like the 350 end cap/axle design is based on some baseline amount clamping pressure like a QR style axle would provide.
I've looked at a few other front hub designs, and there does seem to be some variation in how much the front axle protrudes past the face of the hub bearing, and into the end cap. In contrast, the i9 1/1 hubs, the end caps have shoulders that protrude into the axle, opposite what the oneup hubs, dt 350s & i9 Hydra hubs are doing. I have to assume that this aspect of the hub/end cap interface has an impact on stiffness when used in an USD fork. So, which standard would technically be optimum for this type of usage where the front hub axle/end cap configuration becomes a significant factor in front end performance?
Lastly, in my case what was most noticeable was a torsional stiffness issue. I had never really considered that torque caps would be beneficial in that way. Is it the total surface area of the face of the end cap to the face of the fork dropout that is contributing to this or is the lip of the dropout that makes contact with part of the circumference of the end cap?
I do understand how the torque caps can be a contributing factor in fork stiffness... but I have to admit that I have ridden a torque cap fork with standard, non-torque cap end caps for a ride or two and it was not immediately obvious and wasn't so impactful that I would discern it quickly. In contrast, what I was feeling in front in my trial of the 9.1 was immediately significant.
I think these USD forks are going to highlight a need for a re-design and re-think of the front hub/axle/end cap interface. It seems that we've been going along fat, dumb and happy without much innovation or re-evaluation on this part of the bike... and this whole stiffness discussion is going to change that.
I agree that DT Swiss hubs, due to how the end caps simply rest on the bearing face, are the worst in terms of helping torsional stiffness. Any hub where either the axle or the end cap goes all the way through the bearings will be better.
I don't know if the I9 1-1 system (where the end cap goes through the bearing and into the axle) or the CK/OneUp/Hadley system (where the axle goes all the way through the bearings and the end caps then go over the axle), is better. I would assume the latter would be stiffer, but have no data on this.
"Is it the total surface area of the face of the end cap to the face of the fork dropout that is contributing to this or is the lip of the dropout that makes contact with part of the circumference of the end cap?"
The testing at Specialized showed that it was the increased surface area and larger diameter of the contact between fork/hub that increased the torsional stiffness. This was also with a RockShox fork, so the axle system maximized the benefit of the larger contact area. Below is a pic of the PUSH 9.1 with a Chris King torque cap hub installed, and there is no contact between the fork lug and hub end cap on the non-disk side. The larger diameter torque cap does nothing in this case.
As for the lip, it really can't be in solid contact with the end cap or the system would be over constrained from a design stand point. If the axle is located by the bore in the fork lug, then the lip cannot also have a solid contact with the hub end cap OD due to production tolerances. Everything would need to be perfect every time with the fork and hub. If the fork lip/hub interface was a few thousandths of an inch off, it would either not make contact at all, or have an interference fit making it difficult to install the axle and perhaps be a source of creaking. The lip mostly serves to help locate the hub when installing the wheel, I don't think it makes meaningful contact with the hub end cap once tightened.
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