MegNeg

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MegNeg
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Posted: Feb 1, 2020 at 18:21 Quote
prenderville wrote:
Hi all, I have a trek slash 9.8 2019 and would like to upgrade my shock to the Meg neg. I was wondering would it be compatible with my shock. Deluxe RT3, re activ with thru shaft

Cheers !

Yes, it is compatible!

Posted: Feb 2, 2020 at 20:24 Quote
Hi Guys,
After reading through this thread, I think I understand what the MegNeg can offer. I’m a pretty light guy so does that mean for me I can run more sag and maintain some mid stroke support? Please correct me if I’m wrong.

Posted: Feb 2, 2020 at 21:10 Quote
That's the general idea, but you can't take the idea too far. A little more sag and / or a little more midstroke support.

Have a look at the chart below (thanks to hh2435). The chart shows what would happen if three different springs were all set up at 30% sag. You can see the MegNeg is a little more compliant from full droop (topped out) to sag, then more supportive from there onward. The MegNeg is more resistant to bottoming out, with this set-up, because there is more "area under the curve", i.e. a larger region below the MegNeg line.

Another way to set up the chart could've been to match the force at full compression. This would lower the MegNeg curve, indicating it's considerably more supple in the early stroke, creates more sag, and is similar from about 50% onward. This would bottom out a bit more easily, as the area under the MegNeg curve is slightly less.

A third way to set up the chart would be to match the areas under the curves, which translates to similar bottom-out resistance. The chart would show a little more compliance in the early travel, a touch more sag, and a touch more support in the middle to late travel, ending with maybe a few pounds less at bottom-out. The difference isn't huge.

If you really want to maximize the MegNeg's effect, don't use any volume reducers in either the negative or positive chambers. This will allow you to keep your sag about the same, have slightly more compliance in the early travel, more support in the middle to late travel, and less force at full compression. Total bottom-out resistance will be about the same and you'll get the "midstroke" support that's the main reason to run a MegNeg.


Posted: Feb 2, 2020 at 21:56 Quote
R-M-R wrote:
That's the general idea, but you can't take the idea too far. A little more sag and / or a little more midstroke support.

Have a look at the chart below (thanks to hh2435). The chart shows what would happen if three different springs were all set up at 30% sag. You can see the MegNeg is a little more compliant from full droop (topped out) to sag, then more supportive from there onward. The MegNeg is more resistant to bottoming out, with this set-up, because there is more "area under the curve", i.e. a larger region below the MegNeg line.

Another way to set up the chart could've been to match the force at full compression. This would lower the MegNeg curve, indicating it's considerably more supple in the early stroke, creates more sag, and is similar from about 50% onward. This would bottom out a bit more easily, as the area under the MegNeg curve is slightly less.

A third way to set up the chart would be to match the areas under the curves, which translates to similar bottom-out resistance. The chart would show a little more compliance in the early travel, a touch more sag, and a touch more support in the middle to late travel, ending with maybe a few pounds less at bottom-out. The difference isn't huge.

If you really want to maximize the MegNeg's effect, don't use any volume reducers in either the negative or positive chambers. This will allow you to keep your sag about the same, have slightly more compliance in the early travel, more support in the middle to late travel, and less force at full compression. Total bottom-out resistance will be about the same and you'll get the "midstroke" support that's the main reason to run a MegNeg.


Thanks a lot man, I understand a little more now (i think). I think the MegNeg is probably suited for aggressive riders who push their bike a lot or heavier riders.

Posted: Feb 2, 2020 at 22:13 Quote
BillyBoy0519 wrote:
Thanks a lot man, I understand a little more now (i think). I think the MegNeg is probably suited for aggressive riders who push their bike a lot or heavier riders.

I wouldn't characterize it that way. Heavier riders often hit the "maximum" pressure limit and still have too much sag.

Here's a different way to look at it: instead of accepting the regular air spring as normal and thinking about why a person would want the MegNeg, let's imagine the MegNeg as normal and think about why a person would want the regular air spring. What riding style, terrain, or bike would benefit from the S-curve profile of the regular spring? It's difficult to make a case for the regular spring.

Posted: Feb 6, 2020 at 5:52 Quote
I just installed the MegNeg on a Trek Slash 2019...No tokens on the positive air chamber, 2 bands on the negative air chamber. I can definitily feel the shock being more supportive in the middle portion of the stroke, which I feel has increased straight line speed stability, however, I can't feel the shock being more plush as some of you say. Taking a look at the graph, 30% sag for my shock would be around 17.25mm right where it should be "more supple" since it should require less force to move in that portion of the stroke but, since it's sag, I don't use that portion of the stroke, so all I can feel is the shock being more supportive than before being a little bit harsh. Does this make sense to you?
R-M-R wrote:
That's the general idea, but you can't take the idea too far. A little more sag and / or a little more midstroke support.

Have a look at the chart below (thanks to hh2435). The chart shows what would happen if three different springs were all set up at 30% sag. You can see the MegNeg is a little more compliant from full droop (topped out) to sag, then more supportive from there onward. The MegNeg is more resistant to bottoming out, with this set-up, because there is more "area under the curve", i.e. a larger region below the MegNeg line.

Another way to set up the chart could've been to match the force at full compression. This would lower the MegNeg curve, indicating it's considerably more supple in the early stroke, creates more sag, and is similar from about 50% onward. This would bottom out a bit more easily, as the area under the MegNeg curve is slightly less.

A third way to set up the chart would be to match the areas under the curves, which translates to similar bottom-out resistance. The chart would show a little more compliance in the early travel, a touch more sag, and a touch more support in the middle to late travel, ending with maybe a few pounds less at bottom-out. The difference isn't huge.

If you really want to maximize the MegNeg's effect, don't use any volume reducers in either the negative or positive chambers. This will allow you to keep your sag about the same, have slightly more compliance in the early travel, more support in the middle to late travel, and less force at full compression. Total bottom-out resistance will be about the same and you'll get the "midstroke" support that's the main reason to run a MegNeg.


Posted: Feb 6, 2020 at 13:04 Quote
PabloMoll wrote:
I just installed the MegNeg on a Trek Slash 2019...No tokens on the positive air chamber, 2 bands on the negative air chamber. I can definitily feel the shock being more supportive in the middle portion of the stroke, which I feel has increased straight line speed stability, however, I can't feel the shock being more plush as some of you say. Taking a look at the graph, 30% sag for my shock would be around 17.25mm right where it should be "more supple" since it should require less force to move in that portion of the stroke but, since it's sag, I don't use that portion of the stroke, so all I can feel is the shock being more supportive than before being a little bit harsh. Does this make sense to you?

That makes sense. The region between zero compression and sag is felt most when descending quickly over rough ground. The rear wheel will be skipping on and off the ground, so the MegNeg can slightly soften this sensation and increase traction.

Referring to the chart, your reducers in the negative chamber have raised the blue line closer to the red line in the region prior to the sag point. You could remove these and either have a tiny bit more sag or keep your sag by increasing air pressure, which will also raise the force curve throughout the rest of the chart.

The MegNeg can make the shock feel more "plush" if you use more sag and allow the "midstroke" region to dip close to the red line. Compared to the standard air can, this will slightly reduce the force in the top half of the travel and at bottom-out, while maintaining similar support around two-thirds travel. Not a huge difference, but a difference nonetheless.

Posted: Feb 23, 2020 at 11:21 Quote
Anyone got recommendations for following set up:

Trek slash 2019 carbon frame
Trek thrushaft shock with megneg fitted
Rider weight circa 73kg

Currently have 1 volume spacer and 2 bands. It's fine but can't really notice the difference. Think I'm running around 190psi Vs around 165 before megneg.

Any ideas would be welcome....my knowledge of suspension kinematics is relatively basic.

Posted: Feb 23, 2020 at 11:28 Quote
Start with zero bands on the negative side to feel the full effect. You'll probably want a little more pressure to maintain the same sag, which will also mean you may want to remove the reducer on the positive side - a fully empty shock.

This will give you the "full MegNeg experience", which is somewhere between a traditional air shock and a coil. See if you like it. If not, we can discuss how to bring it closer to a more traditional configuration.

Posted: Feb 23, 2020 at 12:21 Quote
R-M-R wrote:
Start with zero bands on the negative side to feel the full effect. You'll probably want a little more pressure to maintain the same sag, which will also mean you may want to remove the reducer on the positive side - a fully empty shock.

This will give you the "full MegNeg experience", which is somewhere between a traditional air shock and a coil. See if you like it. If not, we can discuss how to bring it closer to a more traditional configuration.

Thanks, really helpful. will do and report back

Posted: Feb 25, 2020 at 13:34 Quote
Just picked up a 2020 Giant Reign 2 (the 27.5er, not the 29er). Shes got a 62.5mm stroke trunion mounted RockShox Deluxe Select+ to get me 160mm out back.

Been a great bike but I have found that I am up to 3 tokens in the rear shock to get bottom out support (actually going to go 4.5T with a gnar dog + 2 regular as i still find i bottom out, stock the bike came with 2 tokens) with the ~30% sag I like that is necessary for smaller bump smoothness. Im probably around 185lbs geared up and a pretty aggressive rider

Im thinking the MegNeg is gonna do me the trick to get this bike riding exactly how I wish. 0-1 bands in the neg chamber, 1 or maybe 2 tokens in the positive at a similar sag number. Whatcha yall think?

Posted: Feb 25, 2020 at 17:12 Quote
Yep, sounds reasonable. Start with zero reducers on the negative side to get the full effect, since you're already in a pretty extreme situation.

Posted: Feb 26, 2020 at 9:34 Quote
R-M-R wrote:
Yep, sounds reasonable. Start with zero reducers on the negative side to get the full effect, since you're already in a pretty extreme situation.

Now.... to find a 57.5-65 megneg can in the USA.....

Posted: Mar 11, 2020 at 9:24 Quote
Hey.

I am unfortunately forced to use megneg on my Capra 29... I know that it can negatively impact suspension feel but currently I don't have another option..

So please tell me how should I set up number of spacers in the negative and positive chamber to achieve effect as similar as possible to standard air can ?


I don't actually see the progressivness however of this megneg... Charts show more linear characteristics, more "coil like" as advertised, so I don't understand the problems with progressive bikes.


 
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