MegNeg

PB Forum :: SRAM
MegNeg
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Posted: Jun 24, 2022 at 12:40 Quote
MT36 wrote:
Where I live, we have a lot of small and medium size rocks, and lots of flat corners with loose/"marbley" trail surfaces. I feel the megneg is good at replicating that coil feel 0-30% travel stroke on this sort of terrain, in terms of traction and plush feel, over rapid small/medium hits.

For big hits, I could see where it may not be as plush, because the megneg gets so progressive deeper in the travel. It sounds like you may want to try a higher psi/less sag and fewer bands, without knowing your tune settings.

But when you're riding those small rocks the bike is already sagging since you're on it, so do you actually use that 0-30% range? I don't think you're starting from 0%. And if you're jumping around and hitting stuff harder I think you're using over 30%.

I've played around with everything. Couldn't get the Megneg to feel how I want on the kind of terrain I ride (with my specific bike). Very happy with the Super Deluxe and stock can over the Deluxe tho.

Posted: Jun 24, 2022 at 13:00 Quote
HollyBoni wrote:
MT36 wrote:
Where I live, we have a lot of small and medium size rocks, and lots of flat corners with loose/"marbley" trail surfaces. I feel the megneg is good at replicating that coil feel 0-30% travel stroke on this sort of terrain, in terms of traction and plush feel, over rapid small/medium hits.

For big hits, I could see where it may not be as plush, because the megneg gets so progressive deeper in the travel. It sounds like you may want to try a higher psi/less sag and fewer bands, without knowing your tune settings.

But when you're riding those small rocks the bike is already sagging since you're on it, so do you actually use that 0-30% range? I don't think you're starting from 0%. And if you're jumping around and hitting stuff harder I think you're using over 30%.

I've played around with everything. Couldn't get the Megneg to feel how I want on the kind of terrain I ride (with my specific bike). Very happy with the Super Deluxe and stock can over the Deluxe tho.

Gotcha. It is hard to say... what you write is definitely logically sound. I am not sure exactly how much of that first 30% I'm using. I think the shock extends past the sag point to stay connected to the trail over features unless I am weighting into the bike to load the suspension. I run a lot of sag, close to 35%. I did notice a coil like feel in roughly the first half of travel, then it got very progressive in the latter half of travel, or about the point of travel where I am pumping aggressively and boosting airs. Also, the shock became so much more active; the first ride on the bike I kept getting thrown in the back seat, off balance, because the shock was literally pumping small imperfections in the trail and the bike was accelerating. I am probably very sensitive to how the bike feels in this sense.

The bike I ride has a very linear suspension curve, and it seemss like if you put the megneg on a frame with a more progressive suspension curve, it doesn't work as well. Which is interesting because I feel like it is fashionable to have more progressive suspension curves on bikes these days.

Posted: Jun 24, 2022 at 13:24 Quote
MT36 wrote:
Also, the shock became so much more active; the first ride on the bike I kept getting thrown in the back seat, off balance, because the shock was literally pumping small imperfections in the trail and the bike was accelerating. I am probably very sensitive to how the bike feels in this sense.

Did you slow down your rebound? Big Grin More pressure=the shock extends faster.

Yeah my frame is 20% progressive, the graph is basically a straight line. However with the Deluxe at 30% sag even with 2 volume spacers it felt like I was blowing through the travel way too easily, and when I went up in air pressure the rear became way too harsh and chattery. So that's why I gave the Megneg a try.
All of this could be damping related since everything feels very nice with the Super Deluxe and stock can.

Posted: Jun 24, 2022 at 13:38 Quote
Did you slow down your rebound? Big Grin More pressure=the shock extends faster.


HA!!! good point I hadn't thought of that. Yeah, I run my rebound just a click or two from open and didn't switch it with the meg neg, and my megneg recommended pressure is 265psi. thank you

Posted: Jun 24, 2022 at 13:55 Quote
MT36 wrote:
I hear you. I do get the sense that there can be a more involved tuning process involved with the Megneg, because now you are tuning the negative chamber in addition to all the other parameters (psi, positive tokens, rebound, etc).


I do agree re all the possible tuning variables but I am not entirely convinced it's that involved when it comes to the use of full travel. For sure, the one simple thing is that if you aren't using full travel with an open Meg fitted then your only option is to run more bands in the negative (and lower psi in positive) which takes you further away from what the Meg is trying to do in the first place and making it more like a stock shock.

On the one hand it seems like it's been marketed as giving a linear-like feel, but I suspect that its only really going to work in that config with super heavy/gnarly riders who have the ability to compress a shock thats running 300 odd psi.

I suspect I will be ending up with 4 bands and the least amount of psi I can get away with to give 30% ish. Whether the Meg in this configuration will feel markedly different to my stock can at the current 25% I'm not sure. Possibly, given it's still 64% more neg. I'll find out soon Smile

I enjoy playing with stuff like this so it's no big deal. I'll sell it on if it doesn't work out.

Posted: Jul 9, 2022 at 8:01 Quote
For those of you with the Norco Sight, I had Fluid Function do a special tune on my shock last year, I thought I'd get his advice before trying a MegNeg, here's what he had to say

"The original tune in your shock would have been overpowered by the Megneg's increased air pressure; with your tuned shock it will work well together."

So it's not a surprise that alot of you were unsuccessful setting up a MegNeg on your Sights.

My MegNeg setup is 25% more psi then the standard aircan for 30% sag. No negative bands and 1 positive token. I've only gone for 1 ride, so hard to comment on setup up, but definitely notice improved small bump compliance, used most of my travel (3mm left) and no bottom out.
Mid-stroke definitely wasn't harsh, need to do a janker trail to get a better opinion.

Posted: Jul 11, 2022 at 9:29 Quote
Well I have finally managed to do some testing, and to say that surprised/shocked is an understatement.

Bike is a 2020 Haibike AllMtn 3.0. Stock rear was a RS Deluxe Select+. I am 85Kg.

I was running zero positive tokens and about 170psi for 25% sag. As you can guess from that, I am not a hitter. So you would think I am the last person who would need a MegNeg. I didn't need any more mid or end stroke support, and truth be told I only went into it because I thought it might help with sensitivity. But I was absolutely prepared to accept that a consequence would be increased mid and end which I didn't want.

To start at the far end of the available adjustments I went with 4 negative bands, zero positive tokens and 200psi for 30% sag. Went out to a bike park for a day and have to say, I'm amazed. The small bump around sag is better for sure. Exactly what I wanted. But the surprise was that the mid and end doesn't seem much harsher than it was stock! I deliberately went super hard on the pump track to try and bottom out but only got about 95% so thats all good.

It feels really good, and I have to say, linear. And yes I did blow through the mid a little on the stock can, but I never bottomed out so I assumed that running the extra positive pressure in the Meg would annoy me but it actually works. I know it shouldn't, but it does! Comparing it to stock (and every other air can I've had) I can genuinely feel an improvement all through the travel. 'Predictable' is a word I would use. I kinda never really knew where I was in terms of travel point with the stock can, but now because of the linear ramp I can almost feel whereabouts in travel I am. Not that we really need to know of course but it's the best way I can describe the feedback of the bike.

It's so good I don't even feel like I want to play with bands/tokens. Either way, the Meg is staying on!

Posted: Jul 21, 2022 at 21:58 Quote
mphtech wrote:
4xv1973
I am running one on a 2018 Trance. Could not be happier!
As has been suggested, start with 0 bands/0 tokens and go from there.

I've just ordered one for my '17 Trance with Super Deluxe RC3. I weigh 180lb and run about 195psi for 30% sag. Currently running a Pike 160 up front.

The rear shock came on my frameset with what I believe is (zero) volume reducers. I don't recall ever having a problem bottoming out though.
I have no issues with the rear travel as-is, but thought since I've turned the front end into butter with a PUSH coil conversion, I wouldn't mind getting a tad more small bump compliance in the rear. I generally need to drive a few hours to ride rough terrain so it's going to be a challenge to test back to back with the various spacers unless I spread it out on separate days.
I'm curious what you ended up using in the end, and what the various settings / combos changed on your ride. (limiting total travel, making things mushy or firm, etc)
If it's too much to talk about here, would you mind sending me a PM? It would be a big help in what to expect while I spread out the testing. Thanks

Posted: Jul 22, 2022 at 1:18 Quote
ztbishop wrote:
mphtech wrote:
4xv1973
I am running one on a 2018 Trance. Could not be happier!
As has been suggested, start with 0 bands/0 tokens and go from there.

I've just ordered one for my '17 Trance with Super Deluxe RC3. I weigh 180lb and run about 195psi for 30% sag. Currently running a Pike 160 up front.

The rear shock came on my frameset with what I believe is (zero) volume reducers. I don't recall ever having a problem bottoming out though.
I have no issues with the rear travel as-is, but thought since I've turned the front end into butter with a PUSH coil conversion, I wouldn't mind getting a tad more small bump compliance in the rear. I generally need to drive a few hours to ride rough terrain so it's going to be a challenge to test back to back with the various spacers unless I spread it out on separate days.
I'm curious what you ended up using in the end, and what the various settings / combos changed on your ride. (limiting total travel, making things mushy or firm, etc)
If it's too much to talk about here, would you mind sending me a PM? It would be a big help in what to expect while I spread out the testing. Thanks

Simply bring some tools and change the volume reducers on the trail. If there is space in the frame, you can add or remove positive reducers without taking out the shock and just sliding down the air can. To change negative reducers you'll have to remove the shock, but it's no big deal.

Posted: Aug 5, 2022 at 10:40 Quote
But let the air out first!

Posted: Aug 7, 2022 at 5:06 Quote
ThinkTank45 wrote:
But let the air out first!

Yeah and try not do it while riding the bike, stop and get off for a bit.

Posted: Sep 17, 2022 at 9:59 Quote
I have a 2022 SDU on a 2022 specialized Enduro. I'm 220 running about 250-260psi with 3 tokens to get about 28% sag.

Overall, the shock feels good, but I want a little more bottom out support. It sounds like the megneg will help with bottom out.

The question is, how much more pressure will I need to run? I'm worried about going over the 325 max psi. I heard 20-30psi additional, but some people have said 20% more air.

Can anyone give an idea if I will still be under 325 with a megneg?

Thanks.

Posted: Sep 17, 2022 at 16:58 Quote
coxr650l wrote:
I have a 2022 SDU on a 2022 specialized Enduro. I'm 220 running about 250-260psi with 3 tokens to get about 28% sag.

Overall, the shock feels good, but I want a little more bottom out support. It sounds like the megneg will help with bottom out.

The question is, how much more pressure will I need to run? I'm worried about going over the 325 max psi. I heard 20-30psi additional, but some people have said 20% more air.

Can anyone give an idea if I will still be under 325 with a megneg?

Thanks.

The extra pressure needed varies depending on what you're trying to achieve. I love the feel of the largest negative air chamber possible while running the fewest positive tokens. As others have noted, it takes easily 25% or more to get there.

You don't have to go that far. You could start all the way at the other end and just keep the same number of positive tokens and put 4 negative bands in. That would absolutely not take 25% more pressure those achieve the same sag, while still providing a small improvement in both OTT suppleness and bottom-out resistance. From there you can experiment to keep yourself under the max pressure limit.

Good luck!

Posted: Sep 19, 2022 at 5:31 Quote
You should be fine. RS recommend starting the megneg tune with your original pressure, plus 20% more psi. If you run 260psi, plus 20% puts you at 312psi, so you have some room to play around before you hit 325psi.

I would personally start the tune with minimal positive and negative bands (maybe zero or one in each side), since you can run the recommended pressure. I feel this is the best place to start the tune.

Posted: Sep 19, 2022 at 13:20 Quote
Thanks. I may need to try one one. The SDU rides really nice, but some more bottom out would make it about perfect.


 
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