1. The most important thing about buying a new bike is to make sure it fits. The only way you'll know if the bike is right for you is to size up the bike and make sure that the bike's geometry matches your body's geometry. Ask questions and do some research.
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  1. #1
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    Fork and shock setup for technical parts

    I have a Cannondale Rush with a Lefty Speed DLR and Fox RP3. Last weekend I did a 55km ride in mixed terrain. I had a really hard time on a more technical part consisting mainly of wet roots and rocks. Now I was wondering if it might be related to the fork and shock setup. How do you guys set it up for technical parts knowing that I won't be changing the pressure? I suppose I don't lock out the lefty but maybe I should adjust the rebound? As for the RP3, should I use maximum, medium or soft Propedal and adjust rebound?

    Or maybe there are other factors (bike setup related) that have a big effect on how you perform on technical parts?

    Thanks.

  2. #2
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    Quote Originally Posted by Kimv View Post
    I have a Cannondale Rush with a Lefty Speed DLR and Fox RP3. Last weekend I did a 55km ride in mixed terrain. I had a really hard time on a more technical part consisting mainly of wet roots and rocks. Now I was wondering if it might be related to the fork and shock setup. How do you guys set it up for technical parts knowing that I won't be changing the pressure? I suppose I don't lock out the lefty but maybe I should adjust the rebound? As for the RP3, should I use maximum, medium or soft Propedal and adjust rebound?

    Or maybe there are other factors (bike setup related) that have a big effect on how you perform on technical parts?

    Thanks.
    Well first thing I would say is that your preload (air pressure) should not be heavily related to what terrain you ride. If you were going to do some big drops then I would suggest that you bump up the pressure to resist bottoming out, but that isn't relevant here. You should set up your static sag and then adjust it in 5-10 psi increments until you are using all of your travel on typical terrain without bottoming out.

    As for rebound, you want it fast enough so that the fork doesn't pack down through those technical parts and slow enough so that the fork doesn't spring up like a pogo stick. I tend to find that a little bit on the faster side is better, but it's really a personal preference thing. Same thing applies to the rear suspension, enough rebound to keep it from pogo stick mode but not so much you pack up.

    Pro pedal; well I tend to believe that you paid an awful premium for that heavy linkage you might as well use it. The Pro Pedal (PP) has two settings: open and PP while the PP has three settings: 1, 2, 3 (well, depending on what model you have). I tend to keep the PP full open unless I was doing long boring fireroad climbs with no features. The rougher the trail, the more having the suspension active will help you both uphill and downhill. Especially on the downhill you want the suspension fully active to deal with everything to the full ability of the valving. When you are on those long boring flat climbs, you can choose the appropriate PP setting for your bike and preferences. I found that 2 worked quite well for my needs, but so did 3. Really depended on if I was grinding the dirt road up or taking the mostly smooth trail up. If you keep propedal on, or if you lockout the fork, you are actually limiting the fluid flow through the fork which causes reduced performance of the suspension.

    On of the biggest other factors that affects your comfort level on technical terrain is your riding position. If you're stretched out way over the front of the bike, you won't be nearly as comfortable as someone with a more neutral position on the bike. That is one of the reasons you see so many riders with wide bars and short stems. The body's ability to move around and the additional leverage over the front of the bike really makes a nice position for tech riding. I suspect you can get more comfortable with a little more practice in that sort of riding as well. You can honestly ride any bike in any terrain if you are comfortable enough with your skills, sometimes it takes time more than technology.
    Don't you hate it when a sentence doesn't end the way you think it octopus?

  3. #3
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    Dear OP, you did not mention what is the consequences of your current setup. Did you washed out?
    Bike wise, tire design & pressure plays an important role on roots and rocks. More so when it's wet. Body english is another.

    Try hitting the roots square or hit em at the junction for best possible grip. Also some speed will help. If you're going too slow, roots and rocks will bog you down too much.

    Check out this video:
    Lars N Bars Video - Pinkbike

  4. #4
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    Quote Originally Posted by Kaizer View Post
    Dear OP, you did not mention what is the consequences of your current setup. Did you washed out?
    Bike wise, tire design & pressure plays an important role on roots and rocks. More so when it's wet. Body english is another.

    Try hitting the roots square or hit em at the junction for best possible grip. Also some speed will help. If you're going too slow, roots and rocks will bog you down too much.

    Check out this video:
    Lars N Bars Video - Pinkbike
    Thanks. I felt that the suspension and especially the front one was working against me. Like when coming of a rock the bike wanted to suddenly stop, even push me backwards and I lost my balance. It didn't bottom out though.

    I know that the suspension setup isn't the only problem. I definately have to work on technique etc. But I prefer to have the bike setup sorted out so the only limiting factor is myself.

  5. #5
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    Sounds like a big rock if you're having problem coming off it rather than going up the rock. It's kinda contradicts when you say the bike suddenly stop and it push you backwards. Usually when a bike suddenly stop, it pushes the rider forward towards the handlebar, not pushes the rider towards the rear wheel?

    Anyway, from what I read/know when hitting a rock garden, best to have a quick rebound setting rather than slow. So that the suspension doesn't packs up. When I was running FS previously, I'm the type that set and forget type of person. I will usually set the rebound to be as fast as possible without it feeling like a pogostick. I also run the rear one or two clicks slower than the front.

  6. #6
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    Quote Originally Posted by Kaizer View Post
    It's kinda contradicts when you say the bike suddenly stop and it push you backwards. Usually when a bike suddenly stop, it pushes the rider forward towards the handlebar, not pushes the rider towards the rear wheel?
    .
    Yeah, I explained it wrong. I mean I feel like the fork applies a backwards force to the bike with me on it so that it comes to a sudden stop. This obviously makes me go forward on the bike due to inertia.

  7. #7
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    Oh, that explains it. So it's kinda big rock? Look on YouTube for G-Outs tips for MTB. Basically just to shifts your weight towards the back in anticipation of the 'being pushed forward'. Be cautious on the timing though. Again, it's more of a technique issue.

    Bike setting wise, a shorter stem/longer fork/more air pressure on the fork will help out a bit. But that will screw up other things you encounter along the trail.

  8. #8
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    Quote Originally Posted by Kaizer View Post
    So it's kinda big rock?
    It's a rather narrow trail constantly circling around small trees. The underground is rocky with many obstacles of about 30cm (1ft). The obstacles are mostly just the shape of the rocky underground and roots, so not just loose rocks on the ground. A single obstacle is no problem but it's the succession of them which makes that the front wheel is already climbing the second obstacle while the back wheel is still going up the first one. Since it's quite shaky and bumpy I figured I'd need max travel (110mm on my bike). Hence my question about rebound since it's the only changeable parameter (suspension wise).

    I was running on 2.1 Michelin XCR Mud, by the way. I think I might change those as well for next time. Thinking about 2.1 or 2.25 Schwalbe Nobby Nic.

  9. #9
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    Sounds techie trials rather than trails... LOL

    Try to run quicker rebound. Also maybe less sag? Also study the line choice, maybe?

  10. #10
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    Quote Originally Posted by Kimv View Post
    I was running on 2.1 Michelin XCR Mud, by the way. I think I might change those as well for next time. Thinking about 2.1 or 2.25 Schwalbe Nobby Nic.
    Bigger tires are great for grip but on a FS bike they won't help a ton with absorbing rocks. They might, however allow you to ride over more things than a more narrow tire, but it's hard to say. I honestly like riding with the biggest tires I can fit. Currently on a pair of 2.4 Fat Alberts.

    Perhaps you're just too far over the front of your bike when you approach these obstacles. You have to move backward when the front wheel drops down or you will risk the dreaded OTB (over the bars). One of the easiest ways to more easily get backward or at least get your center of balance sorted is to lower your saddle for technical terrain. The two most common ways to do that is a QR seatpost clamp which you stop and change your height as you ride or a dropper seatpost. I know that my wife's riding became much better when I set her up with a dropper seatpost because she suddenly had enough room to move around the bike instead of feeling like she was going over the bars all the time. When she approaches a tech section she drops the saddle with a lever on the bars. The dropper post is nice because you can adjust it on the fly, normal saddle height for climbing and low saddle height for things like rock gardens and other technical riding. The main drawbacks are the fact that it's expensive and they have questionable durability records. One of the poorest reviewed dropper seatposts, the Joplin, has spent a hard couple of years on my wife's bike with not even a single complaint from me and my very stringent ex-mechanic standards, so take those reviews for what you will.

    I would start by lowering your saddle when you come to that section. Each time you start to feel comfortable, lower it a little less. If you get comfortable riding it with the saddle all the way up, then no problem but if you never feel comfortable with the saddle high, consider a dropper seatpost. I'd consider a dropper post anyway because you'll always have a trail section which is a challenge somewhere you go.
    Don't you hate it when a sentence doesn't end the way you think it octopus?

  11. #11
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    Since it's quite shaky and bumpy I figured I'd need max travel (110mm on my bike). Hence my question about rebound since it's the only changeable parameter (suspension wise).
    Your assessment seems accurate but you have other parameters: sag, oil wt and tire pressure.

    As Kaizer sugggeted, experiment with sag. Confirm that you are at 25% of full travel and then measure actual travel after hard impact. You should not rely on the User Manual to determine appropriate air pressure.

    Oil weight is probably fine but if your compression seems a bit too fast or easy, you can slow it down with heavier oil, i.e. 10w.

    Tires pressure. You didn't mention what psi you were running. Lower pressures not only provide more cushion but are also faster. I would start a 30 psi and go down from there.
    Joe
    Chicago, IL

  12. #12
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    Just for clarification, your trail sounds similar to Mont Sainte Anne ... which is a very tough trail to negotiate. Going slow, out of the saddle is normal.

    Are your rides similar to this?
    Joe
    Chicago, IL

  13. #13
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    Quote Originally Posted by joeinchi View Post
    Just for clarification, your trail sounds similar to Mont Sainte Anne ... which is a very tough trail to negotiate. Going slow, out of the saddle is normal.

    Are your rides similar to this?
    The particular section I'm having problems with has about the same underground as the rocky descent part in the film yes. Only it is more turning, there was more mud between the rocks (had a storm the night before), it is less descending and situated in a rather densely forested area requiring to avoid small trees.

    I will have another go at it this Sunday and I'll set the bike up on Saturday (during the week it is in commuter configuration), just waiting to see what the weather will be like. I'll make sure to adapt the sag, I don't think it bottomed out around 25% so I'll try some more. At the same time I'll set the rebound to fastest and lower it as I go until it feels comfortable. If this doesn't seem to be any better i'll lower the seat a bit while I'm there.

    As for the tires, I'll go again with the XCR's but lower the pressure. They were pretty good on the rest of the muddy ride and I expect the same conditions. Last time I was around 40psi which is probably too much. Although your suggested 30psi is marked as minimum pressure on the tire sidewall.

    Thank a you all for your useful advice. I will take it to heart and let you know how it went.

  14. #14
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    Wow, that's a pretty tough trail if "it is more turning, there was more mud between the rocks"

    I think you will be pleasantly surprised by how nice the bike feels with lower tire pressure. Along with cushion and speed, you'll also experience more grip in the corners.

    But as the video points out, you need to use arms and legs as additional suspension components when going over technical sections. And start slow--use brakes and choose your lines carefully. As you gain experience, you will be able to add speed but technical riding definitely requires practice.

    Enjoy!
    Joe
    Chicago, IL

  15. #15
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    Your issues may very well include line choice and lack of momentum.
    The suspension of your bike sucks if it's different than mine. Really. It sucks. Big time.

  16. #16
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    Quote Originally Posted by joeinchi View Post
    Wow, that's a pretty tough trail if "it is more turning, there was more mud between the rocks"

    Enjoy!
    It's a small portion of a 53km ride. But it's a quite beautiful route. At one point I have to cross a little river over slippery immersed rocks, carrying the bike on one shoulder while holding a tiny wooden railing that some other bikers made with branches and rope

    Maybe next time I'll make some pictures.

  17. #17
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    Just a heads up, I wouldn't go to 30 psi on a tire that isn't tubeless; might have issues with the bead coming off the rim. At least, that's what I think. Try 33-36 psi maybe? While we're on the issue of suspension though, what exactly is external rebound? Is it the rebound adjusting dial on the fork? Or is it something else?

  18. #18
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    i have never put more than 30 psi in a tire and only once had a pinch flat. And that is using tubes. Your pressure is way to high that's probably where the bouncing feeling comes from.

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