[Slater]

Wondering what settings any of you dudes with a CCDB on a demo 7/8 are. I've always had issues with the back end of mine tracking, and while it is better with the CCDB, it still doesn't feel like its "on rails" like many other DH bikes. I seem to have some chatter that I just can't get rid of, especially in corners. The back end seems to step out on me when you throw it into a corner much sooner than most other bikes I've riden. Anyone experience anything like this with their demo and successfully tune it out?

 

[Eastern States Cup]

Wondering what settings any of you dudes with a CCDB on a demo 7/8 are. I've always had issues with the back end of mine tracking, and while it is better with the CCDB, it still doesn't feel like its "on rails" like many other DH bikes. I seem to have some chatter that I just can't get rid of. Anyone experience anything like this with their demo and successfully tune it out?

Get ahold of Richie Rude.

 

[Slater]

Email Sent, Thank you.

What about the rest of you guys? I'm all ears.

 

[jonKranked]

have you tried contacting Malcolm at Cane Creek? He should be able to provide some good advice.

 

[Udi]

I'd say the back end stepping out abruptly is a lot to do with the geometry of the bike, namely the chainstay length (which has been incredibly short on all of them, ~16.8 and even shorter on the latest iteration I believe). In my experience it means you get more rear traction up to a point, but breakaway is more abrupt and less controllable than a bike with longer (~17.2" +) stays.

I just learned to ride with it / around it when I owned one, it's not something you can really tune out. The chatter you mention can probably be alleviated with better shock setup though.

 

[slyfink]

what tires do you run?

 

[Slater]

Haha UDI it's funny you should mention that because I have been wondering in the last 6mo or so if that is the reason. It is probably also exaggerated in my case, because my frame is a Large. In this case my front center/rear center ratio is even farther out of wack, making the weight distribution even more funky than a bike with longer stays. I have learned to ride around it for the most part too, but it never ceases to freak me out when I'm at higher speeds and there is an immovable object on the outside of a turn.

Tires are DHF's.

EDIT: Just talked with Malcolm and he had indicated that they have heard of/experienced a problem similar to this on other pre-2011 demos. He said that because the leverage rate has barely any ramp, and actually inflects near bottom out, there is very little "support" (my term) in the mid/end of travel. I've verified this in Linkage, from the sag point to bottom out, the older demos only ramp ~8%. Hence why they bottom so easily. He said this leads to people often running a stiffer spring, or more compression than they ideally should. I'm very comfortable with how the bike acts near bottom out (which he says is HSC and HSR), so he recommended that I back the LRC and LSR off completely, and start turning them in together. I've been running a lot of LSC and LSR, and perhaps it is too much. Guess I've got some testing to do this weekend!

 

[buckoW]

Haha UDI it's funny you should mention that because I have been wondering in the last 6mo or so if that is the reason. It is probably also exaggerated in my case, because my frame is a Large. In this case my front center/rear center ratio is even farther out of wack, making the weight distribution even more funky than a bike with longer stays. I have learned to ride around it for the most part too, but it never ceases to freak me out when I'm at higher speeds and there is an immovable object on the outside of a turn.

I'll give Malcolm a call today to see if he has any input.

Tires are DHF's.

Try and get more weight over the front through lower bars and longer stem. Your center of mass sounds like it is too far back. Maybe try your headset without the dust cap for starters to see if it helps. I would go so low that manuals start to be a problem and then come back up a hair. What does your cockpit setup look like now?

More compression in the rear will get more of your weight over the front as well.

 

[4130biker]

I've noticed this with my demo- I've always had to run a very stiff spring to make the bike act right. Not the end of the world- but makes me curious what a different bike that tracked better would be like...

 

[Slater]

but makes me curious what a different bike that tracked better would be like...

Its amazing. haha

I got flat bars about 8mo ago, and that did help a with my weight distribution. Stem is standard direct mount, with no spacers under the crown or anything. Boxxer is as low as I can get it. Save for buying a new fangled drop stem I'm as low as I can get in front.

 

[buckoW]

Its amazing. haha

I got flat bars about 8mo ago, and that did help a with my weight distribution. Stem is standard direct mount, with no spacers under the crown or anything. Boxxer is as low as I can get it. Save for buying a new fangled drop stem I'm as low as I can get in front.

Is it still easy to manual?

What about removing the top cap of the head set and slamming the crown like this?

and maybe run a little more compression in the rear to get the rear to ride a little higher in it's travel.

 

[Slater]

It's not easy to manual, but never really has been. Gotta put some effort into it, but I'm fine with that. I might remove the dust cap and see how much lower I can get the front, but IIRC its only about 5mm or so.

I thought the same thing that running more compession in the rear to keep it higher in travel, which is what I've been doing. I run more LSC than just about anyone I know. However, Malcolm indicated that when you run too much compression it will start to lose traction, regardless of rebound settings. Guess we'll see this weekend.

 

[4130biker]

Try and get more weight over the front through lower bars and longer stem. Your center of mass sounds like it is too far back.

I'm curious and don't understand this concept- it seems like the more weight on the rear tire, the less possiblity of it losing traction and "stepping out".

Are you saying that the extra weight will make the tire break away easier in a turn?

I've had a pretty nasty knee smash last summer from the rear of my demo flinging off the side of the trail in the middle of a rough corner so fast that my feet just stayed on the (flat) pedals. I feel like cornering is one of my stronger skills, so I'm interested to know more about this to set my bike up better.

I can see how running spring that is too stiff for the demo could diminish the bikes ability to track the ground, I'm just not getting the "weight forward" thing...
Thanks

 

[4130biker]

Its amazing. haha

It sounds funny, but it's one of those things that I really haven't had enough time on any different bikes. First bikes were freeride bikes, and I'm on my second demo- so it's pretty much only been demos or bikes w/ short stays for me.

 

[Slater]

Its funny you say that because I snapped an SX Trail, then got the Demo as a replacement. So for years I was the same way. Then I spent half a day on a Sunday, and ooooh weee. Then more bikes after that, and realized that most other DH bikes handled better.

What we're talking about with the weight distribution is that basically since the stays are so short, and the cockpit is so long, that too much weight is on the rear tire. So much that it overloads the tire and breaks free prematurely. This is of course not to say that it can't be riden much harder, and tires load much more. Just not by people with our skill level.

The problem of course is that you can only change the weight distribution/COM a small amount with bar positioning. The vast majority of your weight acts through your pedals, in which case geometry (and stay length) dominate your weight distribution.

 

[Biffff]

I have a Demo with a CCDB. I run the high speed Comp all in, 8 clicks of LSC, HSR in the middle, and 20 clicks of LSR. I just recently had the shock rebuilt with the new tune and it seems to react much better to trail chatter and be more active over all.

 

[Slater]

Very interesting, thank you for the info.

I went to a dirt lot last night near my house and dicked around with the shock a bit. Pulling out all my LSC didn't seem to have much of a difference, but pulling out all the LSR made the bike noticeable more supple. We'll have to wait and see at speed really pushing it, but so far it looks like I was over-damped on rebound.

 

[4130biker]

Its funny you say that because I snapped an SX Trail, then got the Demo as a replacement. So for years I was the same way. Then I spent half a day on a Sunday, and ooooh weee. Then more bikes after that, and realized that most other DH bikes handled better.

What we're talking about with the weight distribution is that basically since the stays are so short, and the cockpit is so long, that too much weight is on the rear tire. So much that it overloads the tire and breaks free prematurely. This is of course not to say that it can't be riden much harder, and tires load much more. Just not by people with our skill level.

The problem of course is that you can only change the weight distribution/COM a small amount with bar positioning. The vast majority of your weight acts through your pedals, in which case geometry (and stay length) dominate your weight distribution.

That makes sense about the overloading- I'm looking forward to trying out some different bikes- my demo is great, but I'll probably just get a new bike before I buy a new shock. Interesting info, that'll influence what I get next. Thanks.