MegNeg

PB Forum :: SRAM
MegNeg
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Posted: Jun 20, 2021 at 11:08 Quote
DMal wrote:
coleboyb wrote:
DMal - I've read your posts and you have almost taken the words out of my mouth on how you describe it.. I'd like to give it a good try though. If I take the last token out and run lower pressure won't I bottom out of I'm close now?

Yeah, for sure. I am not trying to talk you out of the MegNeg by any means! I am simply saying that returning to your previous best setup is a good way to confirm that you’ve actually improved things.

But yeah, less air or fewer positive tokens are really all you can do. Although the positive tokens mostly impact the end of the travel, in my experience, they do initiate ramping at a point in the travel that can feel like mid-stroke.

Some people never want to use full travel. I am more of the opinion that you should bottom out, as long as it doesn’t feel like a hard clunk.

I agree, I'm taking apart the shock as we speak to try 0 positive tokens and see how it feels. I want to use full travel too as long as it's controlled. Have you tried it with 0 tokens and 0 bands? just wondering how that felt if you can remember. thanks for the input

Posted: Jun 20, 2021 at 11:59 Quote
Realistically, you should be bottoming out several times on a legit downhill. No need to keep that little extra bit of travel for a rainy day. There are internal bump stops to prevent damage.

Posted: Jul 1, 2021 at 17:17 Quote
Anyone here have experience with this on a 2021 carbon stumpjumper? I'm trying to figure out how progressive the bike is and I'm not sure, so I don't know how much it would benefit from the MegNeg upgrade?

Posted: Jul 2, 2021 at 22:55 Quote
Just installed my Megneg on a 2020 Mega. Haven't been out for a ride but when cycling the shock I can here a little hiss or squish from the shock right around the 18% stroke mark. Is this just the shock equalizing or do I have something else going on. Browsed the forum and used Google but didn't come up with anything.

Posted: Jul 3, 2021 at 8:17 Quote
IeatRocks wrote:
Just installed my Megneg on a 2020 Mega. Haven't been out for a ride but when cycling the shock I can here a little hiss or squish from the shock right around the 18% stroke mark. Is this just the shock equalizing or do I have something else going on. Browsed the forum and used Google but didn't come up with anything.

Just curious how much do you weigh and how many positive tokens do you have installed? I weigh 150 lb and running like 35% sag with no spacers I still couldn't get full travel. The bike felt harsh and overly progressive/damped so I switched to a coil with a light tune. When I read about people running so little sag with megneg which increases bottom out resistance I find this so surpsining. I have a 2020 mega 275.

Posted: Jul 19, 2021 at 19:31 Quote
hillbomber12 wrote:
Anyone here have experience with this on a 2021 carbon stumpjumper? I'm trying to figure out how progressive the bike is and I'm not sure, so I don't know how much it would benefit from the MegNeg upgrade?

SJ EVO is 19%.
Just purchased the Megneg for mine ran it with just the GnarDog token both at 3 and 4 bands. Im not so sure I understand the tuning properly. First off the mid stroke was insanely supportive. The idea being i was at 245psi effectively increasing spring rate. It felt almost way to stiff of a spring rate and I'm not a light guy (195lbs kitted up). At that point I felt a huge loss in traction to the rear esp in wet conditions. Now from watching Vital MTBs Brandon who discussed the megneg in detail if I were to take out the 4 bands the mid stroke would become much more supportive. He even complain about how he missed the extra support when he went from zero band to 4 bands. If this is the case I dont see me getting the megneg to help make the SJ EVO poppy similar to the Jeffsy. So far thet was the best feeling bike Ive ridden.

Posted: Jul 19, 2021 at 19:39 Quote
DMal wrote:
I don't want to colour your testing too much, but my experience with the MegNeg on the Sight is below. I'm about 5 lbs lighter than you. I ended up preferring the regular air can to the MegNeg, but am now running a coil shock, which I like better than both.

DMal wrote:
My MegNeg experiment has come to an end. I am back on the regular air can and like it much better. But I am glad I tried out the MegNeg. Being able to manipulate the positive and negative volumes so easily allowed me to learn a lot.

My weight: 77 kg/170 lbs.
Location: North Vancouver, BC (trails tend to be slower, steeper, more on the technical side)
Bike: Norco Sight 2020
Shock: Super Deluxe Select+
Fork: Zeb Ultimate 160, 68 psi with 1 token, HSC 3-4 clicks from closed, LSC and rebound by feel

Initial setup: regular air can, 197 psi (31% sag) 2 positive tokens

First MegNeg setup: 250 psi (31% sag), 1 positive token, 2 negative bands
Impressions: way too firm, dynamic ride height too high, felt like I was being pitched forward, tons of support while pumping on flatter trails.

Next MegNeg setup: 235 psi (35% sag), 1 positive token, 4 negative bands
With this setup, I was trying to see if, by reducing negative volume, I could run a lower air pressure to reduce what I felt was an excessive spring rate past the sag point, while avoiding too much sag by making the negative spring smaller.
Impressions: similar to the first setup but less harsh, with lots of support. Felt okay while smashing down a rough, fast trail, but not compliant enough at lower speeds. Felt almost like the shock was overdamped in HSC. I figured out that raising the bars 5 mm was necessary to balance the higher rear dynamic ride height.

Final MegNeg setup: 235 psi (35% sag), 0 positive tokens, 4 negative bands
I took out the final remaining positive token to see if some of that harshness I was feeling was due to end of stroke ramp. This setup felt better when going slightly slower, but that harsh, spikey feeling remained. I also did feel a couple bottom-outs, but would probably choose this setup if sticking with the MegNeg.

After getting to the point where the MegNeg was as un-MegNeg as possible, things were feeling better but I still felt like the bike was riding too high, and it felt a bit unstable. The higher ride height was rattling my confidence on steeper, slower terrain and in corners.

Going back to the smaller air can, the bike feels settled again. I can push it into corners and feel like it’s more glued. I found I needed to drop by bars back down again, which also feels better in terms of being able to load up the front wheel. The stock air can and lower pressure is definitely less supportive, and if I were riding high-speed trails or bike park, the MegNeg may have stood a better chance of working for me.

But long of the short, I found the bike hard to ride with the MegNeg, and now it has gone back to being fun. I felt like I gave the MegNeg a fair chance, and experimented with with a few setups, but I just like the stock can better.

I had similar impressions going from a Lyrik B1 air shaft to the C1, which reduces the influence of the negative spring. I found that the slightly softer midstroke made the fork ride smoother overall, whereas the B1 sort of sags then firms up substantially. So maybe I just like a more compliant midstroke.

I think the choice to run the MegNeg comes down to preference, the bike you ride and your local terrain. But it’s not a slam dunk upgrade in all cases.

I had a very similar experience with the megneg. While I would like a smaller amount of midstroke support coming off the Jeffsy onto the SJ EVO. I felt the megneg was so overwhelmingly supportive to a fault. I feel with the SJ my energy is being sucked up by the bike instead of propelling me down the trail. The Jeffsy I could force into a turn or off a lip and increase speed. The SJ is like riding a Cadillac, i can push and pull all I want but its just just keep its glued.

Posted: Jul 20, 2021 at 16:25 Quote
I've been playing with my settings on my megneg and I found this the same as you at first. I've now been running 4 bands and no tokens (ramp up is not there letting me use more travel). I've lowered the pressure so on my biggest hits I'm using all my travel and it works great on gnarly faster rides.. I do find that the trail I ride alot that is slow and technical that it can feel a bit more supportive in the midstroke, it seems to like the faster big hits better. I rode it all weekend on 3 different trail systems and it worked really good. You will have to play with your rebound settings to get it to feel right depending on your pressure... just my 2 cents.

Posted: Jul 20, 2021 at 17:52 Quote
ashmtb85 wrote:
IeatRocks wrote:
Just installed my Megneg on a 2020 Mega. Haven't been out for a ride but when cycling the shock I can here a little hiss or squish from the shock right around the 18% stroke mark. Is this just the shock equalizing or do I have something else going on. Browsed the forum and used Google but didn't come up with anything.

Just curious how much do you weigh and how many positive tokens do you have installed? I weigh 150 lb and running like 35% sag with no spacers I still couldn't get full travel. The bike felt harsh and overly progressive/damped so I switched to a coil with a light tune. When I read about people running so little sag with megneg which increases bottom out resistance I find this so surpsining. I have a 2020 mega 275.

I am about 175lbs without kit so probably 180lbs with shoes, fanny pack, and water. I am running 4 bands in the negative side and no volume spacers in the positive side. At 220 psi I am sitting at 35% sag. I will very regularly use all me travel but it is very very rare that I actually feel the shock bottom out. I do want to play around with volume spacers in the positive side as at 220psi the shock is not harsh but seems like it could feel a little better. 200-205psi feels great but I sit at 40% sag. I also plan tho throw on the stock air can just to compare.

Posted: Jul 21, 2021 at 8:50 Quote
I have had a megneg on 3 bikes now, (2) Commencal Mega 29’rs, and SC Hightower. Have found that the fewer bands I use the harsher it gets. Just falls through the beginning stroke and hits a wall. I have found that 3-4 bands works best for me and have tried it with no bands and 1 and 2 bands. I have ran mostly no tokens and am now trying 1 in my ‘21 Mega 29. Works really well. Couldn’t imagine using a gnar dog token and less than 3 bands. That would be very harsh.I am 155lbs and ride steeper rough stuff.

Posted: Jul 21, 2021 at 12:22 Quote
Hi everyone - I have been trying to read through all these posts and am getting lost in the weeds!! Just purchased a 2021 Bronson V3 - had the Cascade link and MegNeg installed. It currently has 2 negative bands and Gnardawg. It just doesn't feel right to me. I have to crank up the PSI to 275 +/- and I am 185 all geared up...just odd to me. I am getting a lot of pedal strikes too. I am thinking of just going with the Cascade link or just the MegNeg. Can anyone point me in the right direction to use both together. I ride in northern VT, lots of fast sections of rooty, rocky technical terrain with some jump lines mixed in. Several days at the bike park as well. I am coming off a bike with a Push 11-6 coil and was hoping to find the sweet spot between planted like a coil, but more poppy than my last bike. I am confused too about the tokens - I thought my stock RS came with 3 tokens installed, but my mechanic said he put the gnardawg back in. Isn't that equiveleant to 2.5 tokens. So, shouldn't that come out with the MegNeg right away. I am also toying with the idea of a Storia coil...if anyone has time on one of those on the Bronson. I will be the first to admit that I have a very hard time understanding all the finer points of suspension set up - I just like to ride bikes hard and fast, chunky, steep, rock drops to flat type of stuff. Please help! Thanks everyone.

Posted: Jul 21, 2021 at 19:23 Quote
godzilla78 wrote:
Hi everyone - I have been trying to read through all these posts and am getting lost in the weeds!! Just purchased a 2021 Bronson V3 - had the Cascade link and MegNeg installed. It currently has 2 negative bands and Gnardawg. It just doesn't feel right to me. I have to crank up the PSI to 275 +/- and I am 185 all geared up...just odd to me. I am getting a lot of pedal strikes too. I am thinking of just going with the Cascade link or just the MegNeg. Can anyone point me in the right direction to use both together. I ride in northern VT, lots of fast sections of rooty, rocky technical terrain with some jump lines mixed in. Several days at the bike park as well. I am coming off a bike with a Push 11-6 coil and was hoping to find the sweet spot between planted like a coil, but more poppy than my last bike. I am confused too about the tokens - I thought my stock RS came with 3 tokens installed, but my mechanic said he put the gnardawg back in. Isn't that equiveleant to 2.5 tokens. So, shouldn't that come out with the MegNeg right away. I am also toying with the idea of a Storia coil...if anyone has time on one of those on the Bronson. I will be the first to admit that I have a very hard time understanding all the finer points of suspension set up - I just like to ride bikes hard and fast, chunky, steep, rock drops to flat type of stuff. Please help! Thanks everyone.

Nothing will every replace the feel of a coil. If you really liked the coil I would toss one back on or at least have one you can swap over for DH days. I can address the Cascade link but what I can address is the Megneg. At 180lbs ish I have to run 230psi to hit 30%sag and that is with 4 bands. With 2 bands 275 psi sounds about right. I would try all 4 bands as this will bring it as close to the stock can as it can be and see how she goes. It'll give you a bit more support but wont be super progressive. I am still trying to dial mine in fully, the stock can smoothed out the small to medium stuff like a dream but it would sink through travel on jumps, compressions, and corners. It's still plush but not quite as good as the stock can but I don't have that g out feeling when the bike compresses now.

Posted: Jul 21, 2021 at 20:13 Quote
Thanks for the useful information! I actually ordered a DB IL coil…I think the coil and cc link will give me what I am looking for.

Posted: 2 days ago Quote
Hello everyone. Here are some thoughts of mine about megneg and suspension tuning in general.

Some background with megneg: I just bought megneg for my sons (less than 40kg geared up) Bronson V3. Before the megneg he was on 30% seated sag (who has patience to balance for riding position sag anyway) with 110psi and 3 tokens. Results, bent shock bolt, torn bottom out o-ring and bent bottom out metal plate on top of the inner shaft (btw if you've dropped the travel indicator o-ring from the shock shaft you've probably broken the bottom out o-ring at least on 210x55 super deluxe).

So obviously try megneg. Now with megneg with 132psi, two tokens and two bands 28% seated sag still bottoms out. We tried 145psi and the bottoming out is only on 1.5m drops to flat and I believe it's not harsh anymore. I didn't measure the sag as I was more keen to get rid off the bottoming out and keep the bike from further damage. The rider seems happy but he didn't complain albeit bent the 8mm bolt. So there is more testing to do. I could try less bands and more pressure to get to right sag and not bottom out but will it be too soft on mid travel? Or I could add the 3rd positive air chamber token. But how can a 11y old tell the difference? Once I get my hands on shockwiz I may have more info on how to proceed.

This sure is hard and time consuming way to tune bikes this way. Andrextr has a spreadsheet for air shock force calculation but without air chamber dimensions of megneg its not very accurate (spreadsheet published before megneg). I think rockshox should publish charts or a web page for figuring this out. I mean, why is there a topic with 34 pages about an air can of a rear shock? It shouldn't be this complicated. Maybe we should be talking about rider preferences and correct force curves on shocks rather than absolute values which are dependent of mostly rider weight, rider preference and leverage ratio of the bike.

Just my two cents.

Posted: 1 days ago Quote
vastamyrkky wrote:
Hello everyone. Here are some thoughts of mine about megneg and suspension tuning in general.

Some background with megneg: I just bought megneg for my sons (less than 40kg geared up) Bronson V3. Before the megneg he was on 30% seated sag (who has patience to balance for riding position sag anyway) with 110psi and 3 tokens. Results, bent shock bolt, torn bottom out o-ring and bent bottom out metal plate on top of the inner shaft (btw if you've dropped the travel indicator o-ring from the shock shaft you've probably broken the bottom out o-ring at least on 210x55 super deluxe).

So obviously try megneg. Now with megneg with 132psi, two tokens and two bands 28% seated sag still bottoms out. We tried 145psi and the bottoming out is only on 1.5m drops to flat and I believe it's not harsh anymore. I didn't measure the sag as I was more keen to get rid off the bottoming out and keep the bike from further damage. The rider seems happy but he didn't complain albeit bent the 8mm bolt. So there is more testing to do. I could try less bands and more pressure to get to right sag and not bottom out but will it be too soft on mid travel? Or I could add the 3rd positive air chamber token. But how can a 11y old tell the difference? Once I get my hands on shockwiz I may have more info on how to proceed.

This sure is hard and time consuming way to tune bikes this way. Andrextr has a spreadsheet for air shock force calculation but without air chamber dimensions of megneg its not very accurate (spreadsheet published before megneg). I think rockshox should publish charts or a web page for figuring this out. I mean, why is there a topic with 34 pages about an air can of a rear shock? It shouldn't be this complicated. Maybe we should be talking about rider preferences and correct force curves on shocks rather than absolute values which are dependent of mostly rider weight, rider preference and leverage ratio of the bike.

Just my two cents.

The key is understanding what the MegNeg does, which in the nicest possible way, it seems like you don't..... if you're trying to reduce bottoming out, the MegNeg is not the right tool to focus on. Air pressure and bottom out tokens will do that.


 
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