[BmxConvert]

I've got a 2010 Demo 8 II. I like the geometry of the bike. I'm not liking the suspension.

Everything I've been able to read has said to run a 50lbs lower spring rate than spring calculators suggest. The fast guys around here have said they;ve found the same thing on their Revolts as well. Dropping to a 50lb lighter spring and bumping up the bottom out/compression is the way to go on an RC4.

Is this correct?

I'll let the Moar Shimz gurus here on RM make some suggestions:
I'm 155-160with gear running a 350 spring. I have my LSC and HSC backed off all the way(full open). Minimum air pressure setting. I think something like 6 or 8 clicks on the rebound.

My demo feel harsh on small bumps and small drops(under 2 feet).

It feels alright on larger stuff. Nothing spectacular. It certainly doesn't feel bottomless. Adding air pressure, or turning in the bottom out even a 1/2 turn makes the suspension on smaller stuff feel similar to riding a hardtail.

I get bucked dropping 3-4 foot drops at speed mid course with 6 or 7 clicks of rebound(i think, I'll double check). If I bump up to 8 it feels great but the bike jumps like ****, and it feels as though the rear shock is actually getting stuck down.

Finally Fox doesn't appear to make a 300lb 2.75 spring. Manitou, Marzocchi, Rockshox and Cane Creek do.
Marzocchi springs are 1.40 ID. The others are 1.43 correct? Am I going to run into issues running a 1.43ID spring on the RC4?

Guide me please!

 

[Raingauge]

Try looking for a Vivid spring.

I'm running a 300#/in spring on my Revolt w/ RC4. Its a 1.50" ID Ti spring for a Vivid. I use Obtanium centralizers and don't have any problems.

 

[Kanye West]

Manitou springs are the cheapest. Same thing all around.

 

[tuumbaq]

I know this is gonna sound silly but make sure to rely on SAG not spring rate and take into account that LSC affects your sag as well.

Unless you can accurately measure its rate, even ti-springs are usually off by a good 20-30 pounds, sometimes even more...Once you're set you can really start messing around with the suspension.

Ive had several Demo's and altought they all had great geo/build, the suspension is **** on that bike...Its WAY too active and it has a dead feeling at the same time...Horrible tuning IMO.Hence why Ive moved away from that bike.(not that its a bad bike but I just think it doesnt make sense for a bike of that price to have such ****ty valving ).I havent had a Demo in 2 years now but had a chance to try both the 2010 and 2011 version and this is how I would get started...but I may be completely wrong ;-)

I would recommend you have that shock custom valved if you can.Otherwise I'd run quite a bit more LSC.The bike EATS up its first bit (and middle as well ) of travel like no other bikes Ive found.I'd try running the LSC halfway in to start with and bump the pressure up to 160 psi( it should help giving you a bit more top and mid stroke support and make the whole thing more "poppy").Hopefully it'll smooth out the harsh feeling you are describing and give you a livelier ride ...

Remember everything should work in harmony...One simple LSC setting on its own can feel terrible but once you add others into to the mix , the whole thing starts making more sense... including the fork.If not setup right it will make the rear end feels like crap.

 

[tuumbaq]

I know this is gonna sound silly but make sure to rely on SAG not spring rate and take into account that LSC affects your sag as well.

Unless you can accurately measure its rate, even ti-springs are usually off by a good 20-30 pounds, sometimes even more...Once your set you can really start messing around with the suspension.

Ive had several Demo's and altought they all had great geo/build and Ive always thought the suspension is **** on that bike...Its WAY too active and it has a dead feeling at the same time...Horrible tuning IMO.

I would recommend you have that shock custom valved if you can.Otherwise I'd run quite a bit more LSC.The bike EATS up its first bit (and middle as well ) of travel like no other bikes Ive found.I'd try running the LSC halfway in to start with and bump the pressure up to 160 psi( it should help giving you a bit more top and mid stroke support and make the whole thing more "poppy").Hopefully it'll smooth out the harsh feeling you are describing and give you a livelier ride ...

Remember everything should work in harmony...One simple LSC setting on its own can feel terrible but once you add others into to the mix , the whole thing starts making more sense... including the fork.If not setup right it will make the rear end feels like crap.I havent had a Demo in 2 years now but had a chance to try both the 2010 and 2011 version...I may be completely wrong with my advices but this is how I would get started at least ;-)

 

[Kanye West]

LSC does not affect sag. Air pressure, air can size, and springrate affect sag.

 

[Speed]

Finally Fox doesn't appear to make a 300lb 2.75 spring.

Guide me please!

For some dumb reason the 300 X 3.24 is the right spring for a 2.75 shock. I guess the lighter spring coils make it too short. I have a 350X3.24 on my 8.75 X 2.75 Van R and it fits just fine. Still have plenty of room to remove the spring if needed

 

[NoUseForAName]

For some dumb reason the 300 X 3.24 is the right spring for a 2.75 shock. I guess the lighter spring coils make it too short. I have a 350X3.24 on my 8.75 X 2.75 Van R and it fits just fine. Still have plenty of room to remove the spring if needed

350*3.24 fox doesnt fit on my 2.75 stroke shock.

 

[norbar]

Manitou springs are the cheapest. Same thing all around.

My 250x3.0 manitou was strangely heavy though (compared to other steel springs).

As for the 3.25 its a fox thing. Other companies use 3.0 and are fine. Ive seen ppl run ti 2.75 on 3.0 inch shocks.


As for the 50lb lighter - in case of rc4 it probably applies to all frames. I run a 250 lb spring being 155lb with a 2.6 lev ratio on my legend.

 

[tuumbaq]

LSC does not affect sag. Air pressure, air can size, and springrate affect sag.

Really??? Well Im pretty sure it does to an extend my friend.Try measuring your sag with no compression at all and try again with everything closed...Let me know how that goes for ya

 

[Kanye West]

I have, many times. It doesn't do anything. If you bounce around on the suspension (like you are supposed to when measuring sag, on anything) and let it settle, the only things exerting a static force within the shock are: coil, and air pressure. LSC is a needle that controls flow.

Leave everything cranked in or cranked out. If you're measuring the sag correctly, you'll get the same results every time. I always take an average of three measurements after bouncing around on the suspension a bit.

 

[Pslide]

I have, many times. It doesn't do anything. If you bounce around on the suspension (like you are supposed to when measuring sag, on anything) and let it settle...

Just out of curiousity, how are you measuring sag after you've bounced around on it? I usually use my bottom out bumper...

 

[Kanye West]

I have someone measure the i2i. Accurate enough that way.

Just sitting on it slowly CAN let LSC and parasiting drag on sliding surfaces slightly influence the sag, albeit incorrectly and misleading.

 

[cableguy]

Has anyone tried a different shock on 2010+ Demo 8 like Elka, Vivid or Avy?

 

[wood booger]

Has anyone tried a different shock on 2010+ Demo 8 like Elka, Vivid or Avy?

I am curious as well, I think the RC4 has issues w/ small bump sensitivity in general.

Mine feels super nice when landing, feels like a perfect tranny even when it's not, but handles small choppy stuff like crap.

 

[BmxConvert]

I am curious as well, I think the RC4 has issues w/ small bump sensitivity in general.

Mine feels super nice when landing, feels like a perfect tranny even when it's not, but handles small choppy stuff like crap.

That's precisely what I find. I'm really wanting to just get rid of the RC4 altogether and go for a Vivid as they are pretty darn cheap.

I'll try getting a lighter spring and bumping up the compression settings again, but I have my doubts.

 

[buckoW]

A lot of people are over sprung on an RC4. Don't worry what the numbers say on the spring and get a spring with the right amount of sag. I think less spring and more pressure, LSC and HSC and if you are bottoming then add a little bit of bottom out to stop it.

I think if you have no pressure and no damping then it is normal that it doesn't feel good. Drop a spring rate and set the shock up right before getting rid of it.

 

[BmxConvert]

I'm currently not bottoming it out. But I will try another spring before I dump it. I'll keep it as a spare even if I do.

 

[norbar]

I'm currently not bottoming it out. But I will try another spring before I dump it. I'll keep it as a spare even if I do.

Just measure the sag as Ben suggested instead of looking at the spring number. I ride a 250 and mine feels quite good. A bit like a cushion but far from being too hard or anything. I understand thats its a different bike but just measure it and you are going to be fine.
As for bottoming out the rc4 - I dont see that being a problem. Bottom out adjustment works wery well.

 

[BmxConvert]

I have measured it. I know I need a lighter spring.

 

[norbar]

I have measured it. I know I need a lighter spring.

So why you want to dump it? Mine felt pretty crap with a 50 lb firmer spring too.

 

[BmxConvert]

Todays ride with the lighter spring, more low speed compression(3 more clicks) and 1 more added click of rebound(slower) and the bike felt better.
I still like my Session10 and Foes Fly more.

The session is set up to feel completely dead through the whole suspension and it feels great. It is also still lively when jumping and pumping.
The demo feels dead and stuck in its travel. I bumped up the pressure and extra 10psi and found myself getting really squirrely with the rear end. Jumping still feels like junk. It takes tons more energy to hop/pop off stuff.

 

[BmxConvert]

I've been running the 300lb spring for a little while now and I'm still not getting along with the shock.
I've got the bike with 31ish% sag. The bike still feels choppy on the small stuff. Bigger hits feel good now. The rebound still is either too fast or slow enough that the bike doesn't pop off stuff worth beans and takes alot more effort to get the bike off the ground.

I'm at a point where the rebound where I'm going back and forth one click in either direction trying to find a happy medium. To me, this seems wrong.

Is there any further advice anyone might have?

 

[crohnsy]

Has anyone tried a different shock on 2010+ Demo 8 like Elka, Vivid or Avy?

Loving my Elka on my Demo 8. It pedals well, soaks things up when I need it to.

I have the Demo 8 I, so I am coming off the DHX 4, which worked well enough but once I got the Elka on there it changed the bike for the better. Huge improvement.

 

[Raingauge]

That's precisely what I find. I'm really wanting to just get rid of the RC4 altogether and go for a Vivid as they are pretty darn cheap.

I picked up a used Vivid and will be sending it to Push this winter. Custom tuned shock with 4 way adjustment for less than the price of a new shock.

My RC4 doesn''t cut it on the small bumps.

 

[dilzy]

I've been running the 300lb spring for a little while now and I'm still not getting along with the shock.
I've got the bike with 31ish% sag. The bike still feels choppy on the small stuff. Bigger hits feel good now. The rebound still is either too fast or slow enough that the bike doesn't pop off stuff worth beans and takes alot more effort to get the bike off the ground.

I'm at a point where the rebound where I'm going back and forth one click in either direction trying to find a happy medium. To me, this seems wrong.

Is there any further advice anyone might have?

Drop another 50lb off the spring. I'd say bring that up to 35% sag, then try that.

 

[BmxConvert]

I picked up a used Vivid and will be sending it to Push this winter. Custom tuned shock with 4 way adjustment for less than the price of a new shock.

My RC4 doesn''t cut it on the small bumps.

I was just looking today. Neither QBP or BTI have the "high" tune(C?) Vivids in stock in an 8.75x2.75. I'm pretty sure that's the route I'll go. I figured that since a good portion of the Specialized riders are on Sram, they should be pretty compatible with the Demo(despite me being a **** ton slower and weaker).

Drop another 50lb off the spring. I'd say bring that up to 35% sag, then try that.

35% sag doesn't sound too fun on a bike as low as this bike is. Perhaps that's what I need to do to, but I'm not sold on running that much sag. Does anyone even make a 250lb 2.75" spring?