MTB Tech Rumors, Innovation and Prototypes

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MTB Tech Rumors, Innovation and Prototypes
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Posted: Jan 13, 2022 at 12:05 Quote
It's not on all their frames, it just works on all their frames.

It doesn't give you a full-carbon Gnarvana or Smash or Megatrail. Just allows you to turn those bikes in a full-carbon Trail Pistol.

A full carbon Gnarvana would be bitching.

Posted: Jan 13, 2022 at 12:18 Quote
PHeller wrote:
It's not on all their frames, it just works on all their frames.

It doesn't give you a full-carbon Gnarvana or Smash or Megatrail. Just allows you to turn those bikes in a full-carbon Trail Pistol.

A full carbon Gnarvana would be bitching.

id rather have the aluminum rear on a gnarvana. not much heavier and would trust that in the gnar a good bit more.

Posted: Jan 13, 2022 at 12:43 Quote
PHeller wrote:
It's not on all their frames, it just works on all their frames.

It doesn't give you a full-carbon Gnarvana or Smash or Megatrail. Just allows you to turn those bikes in a full-carbon Trail Pistol.

A full carbon Gnarvana would be bitching.

Yeah, as a Megatrail owner I was a little bummed out. They have had the full revved Pistol out for a while so thought this was going to be bigger than just that model.

Posted: Jan 18, 2022 at 8:46 Quote
Reading about the Chickadeehill's new shock and also reading some interesting critiques of the idea elsewhere, it got me thinking about the new Super Deluxe HBO.

The advantage to HBO is that it allows you to run a more linear spring rate without worrying about bottom out progression. That's why it's a nice thing to have on coil shocks.

Traditional Air shocks rely on volume spacers (lowering the volume) to add progression to the spring curve. When we add a larger negative volume, you get a more plush initial stroke, but still can achieve bottom out protection through a lower positive chamber volume. However, you can get a more linear stroke by adding as much positive volume as possible.

HBO on an air shock is removing the concern of the end-stroke ramp up or progression so you can have that early/mid stroke spring rate being more linear and coil like.

Normally I would not be excited by Rockshox or Fox suspension innovations, but this one has me waiting patiently.

Posted: Jan 18, 2022 at 8:52 Quote
How will HBO work compared to the megneg?

Posted: Jan 18, 2022 at 10:57 Quote
newbermuda wrote:
How will HBO work compared to the megneg?

They are different things. A megneg is a air can that increases the size of the negative chamber in order to increase small bump sensitivity as well as aiding to cushion top out events. The HBO is a hydraulic circuit that is designed to work at controlling end stroke characteristics and bottom out events. So effectively you could have a shock with a Megneg type air can or large negative chamber while also having an HBO. They would work in tandem and it is a benefit because theoretically you can maintain a larger positive chamber in this system by not needing to add as many if any volume spacers which in turn should benefit the mid stroke characteristic of the shock by not ramping up too early in the stroke.

Posted: Jan 18, 2022 at 11:40 Quote
MegNeg increased the negative chamber volume which in effect, lengthens the "pull" curve of the negative spring rate. It still relies on a specific air pressure to prevent bottoming and that pressure is usually still too high to allow a really supple initial stroke (small bump sensitivity).

Think of Air Chambers as springs:

Large Volume = Long Spring (more room to slow things down)
High Pressure = Stiffer/Stronger Spring (powerful, but twitchy brakes)
Low Volume = Shorter Spring (less room to slow things down)

We want as much room to slow things down as possible with predictable modulating brakes.

The normal negative chamber of the Super Deluxe was rather small, and, using the equalization dimple, was therefore relatively strong. It helped get the shock moving by overwhelming the longer, lower pressure positive chamber spring, but it only did so for say, the first 30% of the stroke (or 10% beyond the sag point).

The problem is, as that small chamber expands, it quickly loses its ability to "help".

So, you expand the negative chamber volume with MegNeg, and add the same amount of pressure, and it effectively allows the negative chamber to "help" longer into the stroke. So now you're getting the "help" of the MegNeg until say...50% of the total stroke.

Remember however that a larger spring also loses spring rate, so now you've gotta up the pressure to get the same amount of "help" (opposite of support, I guess). The MegNeg "helps" move the shock further into its stroke for a longer section of stroke but as a result requires more pressure (upping the spring rate overall).

On a graph, the MegNeg is about equal in terms of spring rate around sag, and stays flat a little further into the stroke than the Debonair can, then is actually higher spring rate across the rest of the stroke. The downside to this is that in order to get the improved support of the mid-stroke that MegNeg offers, you've gotta raise the overall spring rate to a point where it is the SAME as the Debonair - even at the sag point. This means the shock doesn't feel anymore plush at the beginning of the stroke, it's just more supportive in the middle (due to higher overall spring rate).


What we want out of a shock is that classic "bike drop test" look - where the rear is so plush in the initial stroke that it'll move under the bikes relatively low weight.

You get that by having a really low spring rate at sag (which might actually feel bouncy, or a little soft when pedalling) then it ramps up really quick to support you at 35% stroke, then really linear (at this higher spring rate) across the mid stroke (35-80%) - then swings way up at the end to help with bottom out.

Traditionally with air shocks its really difficult to get the initial stroke super plush without sacrificing the overall stroke of the shock. Usually, super plush initial means bottom out. Bottom out protection means too firm elsewhere.

Ok, lets jam it full of tokens! Sweet, now we can run a low pressure, lots of progression, and have bottom out protection. I guess you could say this shortens the effective mid stroke (in terms of what your tuning damping around).

What many riders have found is that when you run a lot of tokens and lower air pressure, you end up with a plush initial stroke, but you end up riding around in the mid-stroke. You've lost the first 50% of the stroke. Between the equalization port and the damping, many shocks are just not designed for optimal performance ridden like this. The end stroke of the shock is hard to control with damping. You're working with too little stroke too late. You've effectively created a short, really progressive spring where it's super soft initially, and really harsh/firm at the end, but short springs are hard to tune around.

The alternative is no tokens (more volume, ie, larger spring) to get a more linear spring rate. Downside? It's a little firmer and loses it's small bump sensitivity, but it ramps up nicely into the LONGER mid-stroke. It lengthens the spring, giving the compression and rebound damping the ability to have some time to work.

With HBO, I can control the length and softness of the bottom out bumper. On most air shocks, the bottom out bumpers are pretty small, due in part because air shocks have natural progression and in theory you shouldn't be bouncing off them. Coil shocks have less natural progression, and are more linear, and therefore have longer more "tuned" bottom out bumper "cones."

With HBO, you can tune that bottom out bumper's stiffness with a twist of the knob.

I can run more damping, a more linear spring rate (no tokens), and a lower air pressure, and I won't bottom out. The lower air pressure is a lower spring rate, supported by more damping across a longer effective spring, but relying on the HBO (turned out to the end of the curve) to prevent bottoming. I think this will be the optimal setup for out of the box tunes.

Or, I can run a bunch of tokens, really lower the air pressure, turn the HBO up (further into the spring curve) to help slow the shaft speeds down closer to mid-stroke (where typically the damping would struggle with too much progression). This may be interesting with custom tunes, but may be possible out of the box as well. In my research on the topic, it sounds like compression and rebound damping goes out the window as soon as you've engaged the HBO system, so too much progression may still feel wallowy due to damping difficulties.

If SRAMs is anything like EXT's, it'll be a "cup" that a portion of the the damper piston slides into at the end of the stroke. The portion of the pistons that slides into the cup will have its own adjustable compression damping and it's own progression (bleed off). Turn the HBO "up" and you'll hit the transition pretty hard, turn it down, and it'll be more subtle.

Disclaimer: I'm not a shock tuner or nor a suspension engineer. I just think about this stuff on the pot.

Posted: Jan 18, 2022 at 11:52 Quote
notsosikmik wrote:
newbermuda wrote:
How will HBO work compared to the megneg?

So effectively you could have a shock with a Megneg type air can or large negative chamber while also having an HBO. ...theoretically you can maintain a larger positive chamber in this system by not needing to add as many if any volume spacers which in turn should benefit the mid stroke characteristic of the shock by not ramping up too early in the stroke.

Yep, this.

I'm not sure MegNeg would be needed. Remember, we want the negative spring to be higher pressure to help get the shock moving, then fade off quickly once we're there in the mid-stroke. We no longer need the high pressure positive spring to deal with bottom out events, so we wouldn't a MegNeg "helping" too far into the stroke, and because we don't need as much pressure in the positive spring, we can actually shrink the negative, as the shock will be more sensitive due to lower positive pressures.

Posted: Jan 18, 2022 at 13:00 Quote
This is not the same as the dual positive chamber system that Chickadeehill and EXT are looking to use but the dual valves reminded me of this MRP shock that was featured in a spotted article over 2 years ago and was said to be close to production. Wonder what happened with this thing.

https://www.pinkbike.com/news/spotted-mrps-prototype-air-sprung-shock.html


MRP prototype air-sprung shock.

Posted: Jan 18, 2022 at 14:01 Quote
My source made it sound like it was still in the works, but that COVID related supply chain issues were holding it up.

There is also some other interesting stuff happening over there, and some disappointing news as well.

Posted: Jan 24, 2022 at 21:57 Quote
Someone made a post on Reddit claiming to have spotted a mountain bike with suspension that appeared to be made by Bilstein, which if you aren’t aware is a manufacturer of high end suspension components for trucks and cars. No image posted though, so take it with a grain of salt

Posted: Jan 25, 2022 at 7:34 Quote
matt-15 wrote:
Someone made a post on Reddit claiming to have spotted a mountain bike with suspension that appeared to be made by Bilstein, which if you aren’t aware is a manufacturer of high end suspension components for trucks and cars. No image posted though, so take it with a grain of salt
Very interesting. Possibly considering an entry into the eMTB market with how fast that sector is growing and the need for heavier duty suspension? Or just a guy with custom suspension branded as bilstein?

Posted: Jan 25, 2022 at 9:00 Quote
Bilstein yellow looks a lot like Ohlin's yellow...

Bilstein has also just got into the motorcycle world.

https://www.motopinas.com/motorcycle-news/bilstein-launching-motorcycle-suspension-this-year.html

Posted: Jan 25, 2022 at 9:26 Quote
Maybe they will be doing some weird OEM suspension spec for a GasGas, BMW, or Ducati eMTB?


 
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