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Discussion Starter · #1 ·
I just got my new 2007 Epic Marathon M5. It will replace my old S-Works Epic that I have really grown accustomed to. My old bike had the 2004 Fox Brain rear shock with tuneable bump threshold. I am trying to figure out the following:

1. Can my new Specialized AFR Brain shock be setup similar to my old Fox one? Have they changed the brain shock's characteristics? My new manual says that I (rider weight 170 lbs) should have my shock set at about 100psi. I used my included "sag meter" tool to see that my body weight compressed the shock about 10mm -- In comparison, I used to ride old one w/ about 105-110 psi and my bump threshold (blue lever) setup right in the middle. I tended to have the rebound dialed on the faster end of the spectrum. With that pressure setting, it was dialed pretty good so that if I sit on the bike, it would gradually sag into the ideal zone of about 10mm. It would remain there w/ a more rigid "hardtail" feel until I hit a large enough bump and my shock would open up. When the trail smoothed out, it instantly returned to that nice firm "hardtail feel".

2. Is my travel supposed to feel steppy? With the new shock, I had the top blue dial on the inertia valve set to the firm end of things, turned clockwise. I was feeling like that was giving me more of the old hardtail feel. As I drop into the travel, it feels kind of grabby, like I am moving through the travel in steps. Is this a symptom of something mal-adjusted? (I do like my bike to feel like a hardtail until I hit a bump.)

3. Anyone know of any place to view setup or tuning instructions? I guess I can just keep trying the "trial and error" method. I have already viewed the pdf manual from the Specialized website. I would imagine the team mechanics are still figuring this new shock out, but it's been out there for quite a while now. Also, since I have only done one ride on the bike, maybe there is still some break in time needed.

Thanks much!
cdb
 

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Discussion Starter · #2 · (Edited)
Some more thoughts to add to the discussion on the new 07 AFR shock setup...

Now that I've ridden my new 2007 M5 Epic Marathon a couple weeks, maybe 6-7 times, I'm starting to get a better idea of setup. One of the things I'm noticing still, is that there seems to be this "bobbing zone" between topout extension and the point where my body weight settles into the shock, roughly 10mm into it (based on my preload air pressure). This is noticed while riding along on smooth asphalt and say I hit a small rise that doesn't open up the shock, but might lift my center of gravity up enough to extend the shock out of the sag zone. I have started to hypothesize that maybe it's due to my rebound being too fast that I notice the bob. I have turned that down some to slow the rebound some. It helps eliminate some of the bobbing.

With the new shock, you seem to be able to settle down into the shock to that preload sag point much faster than with the old shock. Before, it took maybe 8 seconds. Now, it is pretty much instantaneous. You can tell this by sitting on bike w/ one foot barely touching the ground and alternating off/on touching the ground. You can see the bike lift/drop immediately.

To help eliminate the bob, I am also riding w/ my bump threshold (blue knob on top of the brain) turned all the way clockwise to maximise the firm "hardtail" feel I want while just riding along. A side affect of this setting is that I feel that the suspension isn't opening up as quickly when I DO hit a bump. It seems a bit firm still at that point.

Just to add to the discussion, eliminating other contributing factors, my tubeless tires are inflated to 30psi, which is plenty firm, and there is no play laterally or vertically in the rear end when the bike is stationary.

I would like to hear some further feedback from other folks out there who are using the new shock on their bike, especially those that have spent time using the old Fox Brain shock, pre 2007. Any tips? Suggestions? Your thoughts are greatly appreciated.

CDB
 

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The Other Dude
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After a bit of trial and error, then talking to some people, i got mine setup to what i feel is perfect for out east coast, wet, rocky, rooty conditions. I am also running tubeless tires (hutchinsons spider 2.1 tubless with 32psi)Now i realize suspension setup is a very personal thing, so what works for me, may not work for others, with being said, this is how i have mine setup:

I am about your weight, i am 170lbs also, give or take 1 or 2 lbs depending on the day, and Mike McAndrews asked me to try my air pressure at 105.........i think he was right on the money with that suggestion. I really love it, it gives me around 7-8mm of sag. I have my blue knob turned 3 clicks off of full hard tail. With that setup i have no sensation of bobbing at all. He told me to take the bike out on a flat paved surface, make sure the o-ring was as the top of the shock, and sprint as hard as could, stand up and put whatever rider input i wanted into the shock, then check the shock. Sure enough, as he said, the only movement i got was that 7-8mm of travel that we had set the bike for. I was then told to do the same thing on an uphill.......same results.

Remember with rebound the + symbol is MORE dampening which is a SLOWER rebounding shock, and - symbol is LESS dampening which will give you a FASTER rebounding shock.....sorry if i insulted you, but alot of people (myself included at first) where not aware of this. Rebound is tough, i have to say it is the knob i play with the most! I change my rebound settings for the trail we ride that day, some people put it one place and leave it there, i like to dial mine into the terrain.

Now onto the trail, i was told the shock was setup for "trail condition riding." As your have probably found out this new shock reacts MUCH faster than the fox one does. Sometimes it opens up and closes before we ever realize it. I like it much better, it is a much smoother/fluid feeling shock in my opinion, especially when you are on fast singletrack!

I hope this helps you out! I have a couple other options Mike gave me that i can relay you if you dont find settings that you like, such as the air pressure. He said the pressures in the manual are simply a "guide" and can vary greatly depending on the rider, and their riding style. I am hoping i am getting this right....but he said that Ned weights a good bit less than we do and he has his air pressure WAY higher than we do because he like his air spring super stiff in the rear, and only to activate a little bit when it needs to.


I hope this helps!
 

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Discussion Starter · #4 ·
jut8 said:
this is how i have mine setup:

I am about your weight, i am 170lbs also, give or take 1 or 2 lbs depending on the day, and Mike McAndrews asked me to try my air pressure at 105.........i think he was right on the money with that suggestion. I really love it, it gives me around 7-8mm of sag. I have my blue knob turned 3 clicks off of full hard tail. With that setup i have no sensation of bobbing at all. He told me to take the bike out on a flat paved surface, make sure the o-ring was as the top of the shock, and sprint as hard as could, stand up and put whatever rider input i wanted into the shock, then check the shock. Sure enough, as he said, the only movement i got was that 7-8mm of travel that we had set the bike for. I was then told to do the same thing on an uphill.......same results.
Thanks for the tips! I put a little extra pressure into my shock the other night and tried out the test you describe. Before I left, I pumped it up to about 110, so I got about 7-8mm sag. I wasn't noticing as much bob, and I ended up doing a series of short accelleration tests, followed by stopping to examine the o-ring movement. Each time, I was getting more like 18-20mm. Then I stopped and did the static sag test again to notice that I was now getting that same greater amount of sag. So I bagged it until I could try again w/ more pressure. Something funny was going on.

I stopped by the shop today to get the new AFR shock part installed (per the bulletin that went out) and we re-set my pressure to get me about 7-8mm sag. I had to put in about 125psi. I will run it through the protocol again and see if things get better! I would also point out that I currently weigh more like 175 now, BTW. Based on the quick ride back to the car, I would bet that 115 would be a better pressure for me.

jut8 said:
Remember with rebound the + symbol is MORE dampening which is a SLOWER rebounding shock, and - symbol is LESS dampening which will give you a FASTER rebounding shock.....sorry if i insulted you, but alot of people (myself included at first) where not aware of this. Rebound is tough, i have to say it is the knob i play with the most! I change my rebound settings for the trail we ride that day, some people put it one place and leave it there, i like to dial mine into the terrain.

Sometimes it opens up and closes before we ever realize it. I like it much better, it is a much smoother/fluid feeling shock in my opinion, especially when you are on fast singletrack!
No offense taken, always good to mention the obvious. Yeah, I had fiddled w/ that when I first got the bike to confirm which direction did what. I'm on the same page as you on how it works!

I also agree w/ the mind trickery. It so much more quickly returns to full rigid that maybe I have fooled myself into thinking it didn't work, even though I plowed into that curb full seated. Of course, if it didn't work, I'd have gotte a pretty good buck! It locks right back out instantly, which is a neat improvement from the old Fox Brain.
 

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Sorry you got less user feedback. I saw this topic and didn't know how to respond to it :thumbsup:

It seems great that your bike is working properly. Do you know how much it weighs?
 

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Discussion Starter · #6 ·
goldenraptor said:
Sorry you got less user feedback. I saw this topic and didn't know how to respond to it :thumbsup:

It seems great that your bike is working properly. Do you know how much it weighs?
I threw it on the scale at the shop and it said 26.8lbs w/ ti candy pedals and a flite TT. Everything else stock. The wheels are the bulky part. I'm building up some stans race wheels w/ the light rotors too. I will also stans up some standard fasttrak tires. My old epic is about 24.5lbs w/ a sid world cup and linear pull brakes. With the new heavier fox fork, and discs, I was counting on gaining some bike weight. The performance of those two components is well worth the weight penalty. Wow the Fox is a world of difference compared to the sid noodle! This is also my first experience w/ disc brakes and that is also quite an eye opener for me. I've been racing semipro for about 5 years now, and racing for 12. I had no idea they were that sweet. Hopefully the new bike will help me make further grounds as I enter the pro field this season.
 
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