MegNeg

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MegNeg
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flag vanhuette
O+
Posted: Apr 13, 2021 at 18:26 Quote
So update on my situation of my megneg with max ~310 PSI (currently with 2 positive tokens and 1 negative band). The shock feels good in a lot of ways, very supple small bump, but I want a little more midstroke support and more progression / bottom out resistance.

Thought #1
Based on the graph posted by R-M-R, the megneg gives you the supple small bump, supportive mid stroke, and progressive ramp up vs standard only with the ~20% EXTRA PSI compared to standard can. It would stand then that it you added the same 20% PSI into the standard can, that curve would be shifted upwards and the result would look something like this:

photo

Now this would feel awful and woody with harsh small bump, but with (somewhat) similar mid and bottom out support. Now, if I’m correct, this illustrates that by decreasing the negative space (by adding negative bands) to the megneg while maintaining the same PSI, you would create a curve that was a combination between the blue and yellow curves. The small bump wouldnt be quite as good, but overall it may be a step towards what I need.

Thought #2:
Similarly, if I added a positive token to the megneg, it should create a curve that looks something like this: Similar through small bump and midstroke, but ramped up bottom out resistance.

photo

In order to test this, I added 2 negative bands to the megneg but maintained my ~310 PSI. I tested it on the road quickly and definitely noticed a change in the small bump compliance - my sag is now 28% compared to my previous 30% and it feels more firm, but unable to test the progression until I can get back out on the trails.

If this doesnt give me the support that I need, my options are go to 4 negative bands (but lose small bump) or add back in a positive token (back to stock 3). WIll report back once Ive ridden.
flag R-M-R
Posted: Apr 13, 2021 at 18:40 Quote
vanhuette,

You have the right idea. We could make minor adjustments to your curves, but you clearly get the concept, and that's what matters.
flag DMal
O+
Posted: Apr 13, 2021 at 20:05 Quote
So I tried a Meg Neg on my Sight and ended up preferring the regular air can. With the Meg Neg, I was at around 35% sag with 4 bands and 0 tokens and still found the bike felt a bit oversprung and harsh. The dynamic ride height felt too high.

Because I was too curious, I ended up getting a coil shock (Cane Creek DB Coil CS). I thought I might not like it for the same reasons I didn’t like the Meg Neg, but it actually feels great, and I prefer it to the Super Deluxe with regular air can. I’m running about 26% sag with the coil, and it’s more supportive than the air shock yet more sensitive, and I haven’t felt a harsh bottom out.

So why do you think I like the coil shock but didn’t like the Meg Neg? My theory is that the reduced friction of the coil allows it to stay active even at a higher spring rate. Also, it’s possible that what I felt was excessively high dynamic ride height with the Meg Neg may have been associated with the rampy part of the air spring curve.
flag ashmtb85
Posted: Apr 13, 2021 at 20:26 Quote
DMal wrote:
So I tried a Meg Neg on my Sight and ended up preferring the regular air can. With the Meg Neg, I was at around 35% sag with 4 bands and 0 tokens and still found the bike felt a bit oversprung and harsh. The dynamic ride height felt too high.

Because I was too curious, I ended up getting a coil shock (Cane Creek DB Coil CS). I thought I might not like it for the same reasons I didn’t like the Meg Neg, but it actually feels great, and I prefer it to the Super Deluxe with regular air can. I’m running about 26% sag with the coil, and it’s more supportive than the air shock yet more sensitive, and I haven’t felt a harsh bottom out.

So why do you think I like the coil shock but didn’t like the Meg Neg? My theory is that the reduced friction of the coil allows it to stay active even at a higher spring rate. Also, it’s possible that what I felt was excessively high dynamic ride height with the Meg Neg may have been associated with the rampy part of the air spring curve.

How much do you weigh? Is it possible the air can had an excessively firm base compression tune? Might be worth a retune.
flag vanhuette
O+
Posted: Apr 14, 2021 at 9:50 Quote
R-M-R wrote:
You have the right idea. We could make minor adjustments to your curves, but you clearly get the concept, and that's what matters.

I think the interesting part of this is that people think and talk about the megneg backwards - it doesn’t give more mid and end stroke support, adding the PSI to your shock does that. What it DOES is give you more supple small bump so that the extra PSI doesn’t make your shock feel terrible.
flag DMal
O+
Posted: Apr 14, 2021 at 9:56 Quote
ashmtb85 wrote:
DMal wrote:
So I tried a Meg Neg on my Sight and ended up preferring the regular air can. With the Meg Neg, I was at around 35% sag with 4 bands and 0 tokens and still found the bike felt a bit oversprung and harsh. The dynamic ride height felt too high.

Because I was too curious, I ended up getting a coil shock (Cane Creek DB Coil CS). I thought I might not like it for the same reasons I didn’t like the Meg Neg, but it actually feels great, and I prefer it to the Super Deluxe with regular air can. I’m running about 26% sag with the coil, and it’s more supportive than the air shock yet more sensitive, and I haven’t felt a harsh bottom out.

So why do you think I like the coil shock but didn’t like the Meg Neg? My theory is that the reduced friction of the coil allows it to stay active even at a higher spring rate. Also, it’s possible that what I felt was excessively high dynamic ride height with the Meg Neg may have been associated with the rampy part of the air spring curve.

How much do you weigh? Is it possible the air can had an excessively firm base compression tune? Might be worth a retune.

I'm about 170 lbs. I believe the 2020 Sight comes with a M/M tune. At my weight, I would think I would be right in the middle of the intended window for a stock tune. But is it possible that the Meg Neg does better with a lighter compression tune given the greater support from the spring?

In any case, I sold the air shock and am committed to the coil, so I won't be trying the Meg Neg again. I am just trying to increase my understanding of why one setup feels better than another.
flag R-M-R
Posted: Apr 14, 2021 at 14:33 Quote
vanhuette wrote:
R-M-R wrote:
You have the right idea. We could make minor adjustments to your curves, but you clearly get the concept, and that's what matters.

I think the interesting part of this is that people think and talk about the megneg backwards - it doesn’t give more mid and end stroke support, adding the PSI to your shock does that. What it DOES is give you more supple small bump so that the extra PSI doesn’t make your shock feel terrible.

There's little understanding of suspension physics and many people who think they understand it are incorrect.

An alternate way to phrase it is that a more potent negative spring reduces force early in the travel, allowing you to add force in the middle and end. There's a certain amount of total support that works for every rider, and various spring and damper modifications allow us to change the distribution of that support.
flag PabloMoll
Posted: Apr 16, 2021 at 11:13 Quote
Speshie wrote:
portermoab wrote:
Posted in the Santa Cruz forum, but it might be helpful to folks on this thread as well.

Figured I’d write this up as I read all of the MegNeg posts prior to purchasing and had to learn a lot about shock curves and the different factors at play. At the outset, I would highly recommend watching this video as I’ve yet to find a better explanation of shock curves: https://www.youtube.com/watch?time_continue=39&v=3HeL5NNHbFw&feature=emb_logo

I also noticed that a lot of posters don’t include the kind of information that’s needed to really be useful (rider weight, pressures, terrain, previous setup, etc).

Bike/Rider Info:
- 2020 Bronson V3 (carbon, XL)
- 2.5 DHF Exo front tire (22psi); 2.4 DHR II Exo+ rear tire w/ Cushcore (24 psi); Raceface ARC30 alloy wheelset
- Rider weight approx. 160lbs geared up
- I live in Moab and gravitate towards technical, fast, and chunky trails (I’m not really into flow trails); I also like pedaling/big climbs

Previous setup: Rockshox Super Deluxe+ with one GnarDog token (terrible name) which equals 2.5 regular tokens; 180 psi at 30% sag; 4 clicks of rebound dampening (i.e., 4 clicks from fast). My biggest complaint with this setup is that I was regularly blowing through all of the shock’s travel. Not harsh bottoming out, but a rough, sometimes unstable ride. On repeated hits, it would sometimes feel like the rear wheel was hanging up, which I believe was due to the shock being too deep in its travel (even though I had rebound as fast as possible without compromising other ride qualities).

Started by removing the GnarDog token, so 0 tokens in the positive air chamber. I recommend starting with 0 tokens, as any tokens will have some effect on the progressivity of the midstroke and it just adds another variable that has to be factored in. I also started with 0 bands as I wanted to see the full effect of a large negative air chamber on the shock/ride quality. Notes below:

0 bands/0 tokens. 225 psi for 30% sag. 4 clicks of rebound dampening. Tested on a typical fast, chunky Moab trail. Initial stroke was amazingly soft yet very supportive in the midstroke. Climbing platform actually felt better than stock, as the midstroke was very supportive and seemed to stay higher in the travel. The main issue was that repeated hits in fast, chunky terrain were harsh, which I believe was due to the midstroke being too progressive for my weight. I was using all but 10mm of travel, with all but 5mm on a few drops. Even with these issues, it still felt better than the stock shock setup. Decided to add 2 bands to see if I could mellow out the progression a bit, while keeping the initial suppleness and midstroke support (while also using more of the travel regularly).

2 bands/0 tokens. 228 psi for 30% sag (unsure why the pressure actually went up 2psi here). 4 clicks of rebound dampening. Tested on a typical fast, chunky Moab trail. This completely cleared up the harshness that I was experiencing with 0 bands in rough, repeated hit sections of trail. The initial stroke was slightly less soft, but not enough to really notice. Midstroke was still plenty supportive for climbing. The bike felt really planted and stable through rough sections of trail with repeated hits. Followed up by taking the bike to the Colorado high country. There was a lot of high altitude climbing and the midstroke support was great. Rode high in the travel when climbing but still was soft in the initial stroke. Felt great other than I added one click of rebound dampening (5 clicks), although I may adjust down again for chunkier Moab riding. All told, 2 bands/0 tokens feels excellent. Better than anything I’ve ridden before and feeling like it’s pretty much dialed.

Possible next steps would be going to 1 band or 3 bands.

With 1 band, I would expect slightly softer initial stroke with a bit more midstroke support. I would be paying attention to see if the midstroke/endstroke harshness returned whether I wouldn’t be using enough of the travel. I would also expect a bit more pop from the shock.

With 3 bands, I would expect to lose a bit of initial stroke suppleness and lose a bit of midstroke support. I would be paying attention to see if the pedaling platform was still supportive enough or if it felt too soft and whether I was blowing through the travel. I would also want to see if the shock felt a bit dead as I would expect it to lose some pop. I could always end up adding one token in the positive chamber to address any endstroke travel issues (one toke to ramp up the progression at the end). But, adding a positive token would have some effect on the midstroke progression and would likely result in messing with the bands again (possibly adding another band—4 bands total—to mellow out the midstroke progression a bit).

I hope this info is helpful for anyone trying to work through getting the MegNeg dialed. Curious to hear any thoughts or feedback on the above info as well, as I’m still in the learning process.

If you’re willing to spend some time learning about shock curves and positive/negative air chambers, have enough awareness to know how your bike is riding, and want to take the time to dial it in, then it’s hard to see how you can go wrong with the MegNeg addition.

Good points. I’ve just fitted one to a 2020 Specialized Enduro. I’ve started with 0 bands and 0 tokens like you did. It feels initially more supple but due to me being quite the noob, I find it hard to diagnose what I’m feeling on any given ride, if that makes sense. It feels better than the stock air can but I would like to try tune it and see where I end up. With 0 tokens I haven’t bottomed it out yet, even after casing some pretty decent drops. Next step would probably be similar to yours - to add a band or two and see how it feels.

Did you ended up trying more bands? Your input would be helpful. I'm installing one in a Spz Enduro also. At 30% SAG uses full travel too easily. Cheers!
flag NinjaTheDude
O+
Posted: Apr 20, 2021 at 23:30 Quote
Looking at getting the Megneg for my 19 Trance 3. I'm about 215lbs with gear and just wanted a better feel from the shock with having to buy a whole another shock. The terrain I ride is most Rocky and Sandy (Las Vegas area). Would this be a good fit for me?
flag vanhuette
O+
Posted: Apr 20, 2021 at 23:45 Quote
vanhuette wrote:
In order to test this, I added 2 negative bands to the megneg but maintained my ~310 PSI. I tested it on the road quickly and definitely noticed a change in the small bump compliance - my sag is now 28% compared to my previous 30% and it feels more firm, but unable to test the progression until I can get back out on the trails.

If this doesnt give me the support that I need, my options are go to 4 negative bands (but lose small bump) or add back in a positive token (back to stock 3). WIll report back once Ive ridden.

So Ive now added the 3rd positive token back in trying to improve bottom out, but overall It’s still not as supportive as I would hope. I was so happy with it initially because of the small bump compliance but once I was riding hard the support didnt hold up.

Overall, at 230lb I’m not loving this shock setup. I’m confused because as far as I can figure the megneg shouldn’t be changing the bottom out resistance by much? Yet I seem to be blowing through all the travel even at max PSI.

Aside from spending $800 on a new shock or losing 20 lbs I’m not sure what my options are
flag R-M-R
Posted: Apr 20, 2021 at 23:58 Quote
NinjaTheDude,

That generation of Trance has high support in the mid-stroke, so it doesn't "need" a MegNeg like some bikes do. If you like a very firm, "XC race" feel, you may want to keep the smaller negative spring. If you like a softer initial feel and more support deep in the travel, often thought of as more of a "DH" feel, you may prefer the MegNeg.


vanhuette,

Without getting a new shock or a bike with a lower leverage ratio that better suits your weight, your options are to have the shock tuned for more compression damping support and/or go over the maximum pressure with more volume in the positive spring (fewer tokens), since the maximum pressure is based on minimum volume (maximum tokens).
flag NinjaTheDude
O+
Posted: Apr 21, 2021 at 0:41 Quote
R-M-R wrote:
NinjaTheDude,

That generation of Trance has high support in the mid-stroke, so it doesn't "need" a MegNeg like some bikes do. If you like a very firm, "XC race" feel, you may want to keep the smaller negative spring. If you like a softer initial feel and more support deep in the travel, often thought of as more of a "DH" feel, you may prefer the MegNeg

I appreciate the response and yes I'm going for a more DH feel. I'm still new to all this but it doesn't hurt to try new things right?!
flag R-M-R
Posted: Apr 21, 2021 at 1:43 Quote
The ratio of impact on ride feel to price is high for the MegNeg. I'm a fan of large negative springs and I feel designs like this should be standard for air shocks. So yeah, go for it. The only concern is that ideal pressure for your weight will be around the maximum.
flag modvelo
O+
Posted: Apr 28, 2021 at 7:55 Quote
Great info here, appreciate the discussions.
I just bought one and am looking to upgrade my Commencal Supreme (new style rear triangle)
Will report back once I try it.

Does anyone know how progressive the supreme's linkage is? and where I could find out how much?

Thanks
flag ThunderChunk
O+
Posted: Apr 28, 2021 at 7:57 Quote
modvelo wrote:
Great info here, appreciate the discussions.
I just bought one and am looking to upgrade my Commencal Supreme (new style rear triangle)
Will report back once I try it.

Does anyone know how progressive the supreme's linkage is? and where I could find out how much?

Thanks

Good timing, I was just about to ask if it works on the new 2021 supreme. Been considering adding it to mine but not sure if it will work. No complaints as to how it rides as is so not sure if I need it.

 


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