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  1. #1
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    Rotec RL9: Tyre rub on seat tube normal?

    I recently bought a Rotec RL9. The bike looks awesome and rides great, but the rear tyre badly rubs the seat tube when I compress the suspension. The back of the seat tube has a 3" long by 1" wide rubber mark left on it. It's pretty obvious when compressing the suspension into the face of a jump, and landing, that the tyre is buzzing away against the frame.

    The manufacturer and importer have suggested that my size (6'7" 260lb) would give me a more rearward centre of gravity than normal, and this combined with not having a heavy enough shock spring are to blame. They've sent me a 600lb and 650lb spring to test but I haven't had a chance yet. I'm concerned since the 500lb spring I'm currently using gives me the correct amount of sag.

    I'm sure they have a much better understanding of how these things work than I do... but I would have thought no matter how light the spring was I should be able to get full suspension compression without the tyre rubbing? Sure a too-light spring would have me bottoming out more than normal, but is tyre rub normal?

    Surely the frame is designed to avoid this kind of thing happening? Wouldn't using a much heavier spring just limit the travel to "fix" the issue?

    Please enlighten me!!!

    Thanks

  2. #2
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    if you're hitting the seat tube, youre more than likely blowing through your travel fast and bottoming out. are you using the Rocco WC? i think thats what they spec'd the frame with. try adding a lil more air pressure in the bottom out resistance valve, or add a bit more compression.

    tire rub happens on some frames. but you shouldnt be doing it by just boosting or landing jumps.

    step up in spring rate, and adjust the compression should do the trick.

  3. #3
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    Quote Originally Posted by brillantesdv
    if you're hitting the seat tube, youre more than likely blowing through your travel fast and bottoming out. are you using the Rocco WC? i think thats what they spec'd the frame with. try adding a lil more air pressure in the bottom out resistance valve, or add a bit more compression.

    tire rub happens on some frames. but you shouldnt be doing it by just boosting or landing jumps.

    step up in spring rate, and adjust the compression should do the trick.
    Thanks for the reply. Yep I'm using the Rocco WC. I'll have a play with the settings and springs. Under what circumstances would it be normal to have the tyre the frame?

  4. #4
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    technically never...since it IS hitting your frame. ideally you dont what to get that deep into travel too often.

    i have a Sinister R9 (9 inches of travel as well), and rarely get into the last inch of travel unless i take a big hit like a big drop.

  5. #5
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    I have a friend who has the same bike, he is a big guy also (6'6 and 260) the back of his seat tube is now silver instead of orange, and he has a nice flat spot on his seatpost collar. He only bottoms out on really big hits with bad transitions though. He is also running these arrowhead tires that are taller than any tire I have ever seen. He says the tires don't rub if he uses his nevegal 2.5's.

  6. #6
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    I'm using 2.5 Kendas on the back of my Rotec and I only get some buzzing of my saddle, which I just need to more forward a bit, but nothing on the seat tube.

    You definitely need a heavier spring... I'm 230 pounds, and I think the 500# spring is a bit soft for jumping. Luckily, I suck at jumping, and don't do it very often so it's not an issue.

    Also check the pressure on the WC. I bumped mine up, and it helped a lot with the rubbing on the saddle.

  7. #7
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    All Rotec RL9's rub at full travel.

    Actually, a large percentage of 9" travel bikes buzz the seat tube or the seat at full travel. It's more common then you'd think. Not everyone has the problem, but that's cause they're not using full travel.

    The Roco is a very linear shock. Putting more air in the chamber will not help. It isn't a bottom out valve, like on the DHX.

    Do NOT run to stiff a spring. Running to stiff of a spring may stop your bottoming out, but only cause you're no longer getting full travel. Which wouldn't be that big of a deal. but it will ruin your small bump compliance. Choose your spring rate based on sag, NOT bottom out.

    The solution? Add a 1/8" spacer or two under the bottom out bumper of the shock. I get 'em from Home Depot or Lowes. It looks just like a regular steel washer only they're nylon. Your shock shaft is 1/2", cut a "notch" out of the washer slightly smaller then the shaft. 3/8" is about right, The washer should now look like the letter "C" instead of and "O". Snap it onto the shaft under the bottom out bumper and you're good to go. One washer will shorten your travel by about 3/8", 2 washers will lose your 3/4" of travel. One is usually all it takes, unless you're running a really big tire.

    This will cure your rub, without ruining your ride with to stiff a spring.

    Or you could just live with the rubbing. It's not bad enough to hurt the bike, other then cosmetics.

  8. #8
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    Run a higher then normal spring, I am light and run i 400-425lbs and I have not bottomed my Rotec RL9 with a Roco WC since I changed over from the 5th with lower spring. 500 is way to low for your weight and size....

  9. #9
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    Quote Originally Posted by RickyD
    All Rotec RL9's rub at full travel.

    Actually, a large percentage of 9" travel bikes buzz the seat tube or the seat at full travel. It's more common then you'd think. Not everyone has the problem, but that's cause they're not using full travel.

    The Roco is a very linear shock. Putting more air in the chamber will not help. It isn't a bottom out valve, like on the DHX.

    Do NOT run to stiff a spring. Running to stiff of a spring may stop your bottoming out, but only cause you're no longer getting full travel. Which wouldn't be that big of a deal. but it will ruin your small bump compliance. Choose your spring rate based on sag, NOT bottom out.

    The solution? Add a 1/8" spacer or two under the bottom out bumper of the shock. I get 'em from Home Depot or Lowes. It looks just like a regular steel washer only they're nylon. Your shock shaft is 1/2", cut a "notch" out of the washer slightly smaller then the shaft. 3/8" is about right, The washer should now look like the letter "C" instead of and "O". Snap it onto the shaft under the bottom out bumper and you're good to go. One washer will shorten your travel by about 3/8", 2 washers will lose your 3/4" of travel. One is usually all it takes, unless you're running a really big tire.

    This will cure your rub, without ruining your ride with to stiff a spring.

    Or you could just live with the rubbing. It's not bad enough to hurt the bike, other then cosmetics.
    EXACTLY `!!!

    perfect answer, now there's a man who knows his Rotec. Excellent bike too

  10. #10
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    Quote Originally Posted by RickyD
    Do NOT run to stiff a spring. Running to stiff of a spring may stop your bottoming out, but only cause you're no longer getting full travel. Which wouldn't be that big of a deal. but it will ruin your small bump compliance. Choose your spring rate based on sag, NOT bottom out.
    the OP said he was rubbing by just compressing on jumps. i dont care how much travel you have, you shouldnt be even coming close to bottoming by just boosting jumps.

  11. #11
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    Quote Originally Posted by brillantesdv
    the OP said he was rubbing by just compressing on jumps. i dont care how much travel you have, you shouldnt be even coming close to bottoming by just boosting jumps.
    No problem. I wasn't really contradicting you. I was merely making the point that the RL9 WILL rub a full travel. If it doesn't you're not getting full travel.

    I agree that he should not be bottoming pressing into the face of a jump. He is definitely running to soft a spring. I'm 200lbs and ran a 500lb spring (which later turned out to be only a 450 after PUSH stuck it on their test equipment).

    At 260 I'd guess the 600 would probably be about right. 650 seems like it would be to stiff to me.

    But my main point was you should not be setting spring rate based on bottoming out. Sorry, but that's completely bass akwards. Also your suggestion to add more air to the chamber would be completely ineffective on a Roco since the air chamber does not effect bottom out. Roco's simply aren't progressive shocks. Get a 5th or a DHX if you need a progressive shock.

    But as long as we're adding to the dialog. Let me tackle the confusion of the OP, based on the statement that he was getting the correct sag with the 500lb spring. I too had the correct sag with mine. Actually it was a little short, I was getting only 7/8" of shock stroke with my 500lb (but tested at 450lb) spring. But I was still bottoming very easily. Never had a bike do this. I curious if any other Rotec riders have experianced this? I actually took the entire bike down to PUSH and left it with them for a few days. Even after reworking the shock, I still got to little sag, but used full travel fairly easy.

    Never figured it out in the end. But it wasn't a big issue. My guess is Rotec's don't follow the rules of most other bikes and may require a little not by the book tweeking. The bike had incredible small bump compliance, despite the fact that I was getting slightly less sag then what in normally considered correct.

    Don't have the bike anymore. Had a couple quirks, but it was wicked fast. That bike laid pavement where ever it went.

    I miss it. May get another.
    Last edited by RickyD; 06-30-2009 at 09:24 PM.

  12. #12
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    guess i gave kind of a vague answer to the OP. but yes i agree completely with you. i have a Roco WC also, and i know the bottom out valve doesnt do much.

    he said he was getting correct sag with his spring, so obviously next step is mess around the other settings. just sounded like he hadn't tried it. my theory is try every setting you have first, then start asking the message boards ;-)

  13. #13
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    Ummmm, what? Roco's are some of the most progressive shocks I've used. I don't call DHX's "progressive" because they typically go from no damping to an abrupt wall - that's not progression. 5th's are actually fairly linear but evenly and heavily damped. Romics are probably the most linear shocks I've come across, but they're also one of the best tracking.

    Believe me that reservoir PSI does make a difference on a mountain bike, especially if you consider what the "realistic" values for it are. The 180-200psi recommendation is somewhat of an arbitrary range with a large margin for safety built into it. Try running 200psi in another shock with the same reservoir diameter and piston depth, or running 125 psi in the Roco. If you're having bottoming issues with the Roco at 33% geared-up-rider sag, reset your IFP depth by letting out the air, compressing the shock, and pumping it up to extend the shock. Not real exact, but it's a pretty rudimentary way of getting the IFP back to where it needs to be without cracking it open.
    805

  14. #14
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    Quote Originally Posted by DHidiot
    Ummmm, what? Roco's are some of the most progressive shocks I've used. I don't call DHX's "progressive" because they typically go from no damping to an abrupt wall - that's not progression. 5th's are actually fairly linear but evenly and heavily damped. Romics are probably the most linear shocks I've come across, but they're also one of the best tracking.

    Believe me that reservoir PSI does make a difference on a mountain bike, especially if you consider what the "realistic" values for it are. The 180-200psi recommendation is somewhat of an arbitrary range with a large margin for safety built into it. Try running 200psi in another shock with the same reservoir diameter and piston depth, or running 125 psi in the Roco. If you're having bottoming issues with the Roco at 33% geared-up-rider sag, reset your IFP depth by letting out the air, compressing the shock, and pumping it up to extend the shock. Not real exact, but it's a pretty rudimentary way of getting the IFP back to where it needs to be without cracking it open.
    Well I guess you could call up Darren a PUSH and debate it with him. I had the shock down there twice, the second time I left him the entire bike. According to him, there is absolutely not way to make a a Roco progressive. The air chamber does not work the same way that it does on a 5th or DHX. Both of those shocks have Volume adjustments the Roco does not.

    The reality is, progression should come from your frame anyway, not your shock. Whats weird is the Rotec has a nice progressive design and should ramp up well, but I never really got it the way I wanted with the Roco. Top that off with the ridiculously narrow rebound range (about a 1/3rd of a turn total) and it was a PITA to get it dialed.

    If I get another, I'm gonna have Craig build me any Avy.

  15. #15
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    Breaking what others say

    IMO....honestly for your weight I would go up 50 to 100 pounds on the spring and get less sag (maybe 25%)......this is why....your ramp up rate is faster and has more force then someone weighing 150 or even 200.

    I also would use a "spacer bumper" in the shock....use only one
    the trick is ENJOYING YOUR LIFE EACH DAY, don't waste them away wishing for better days

  16. #16
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    Wow! Some really specific advice and experiences with the same bike/situation. Much more information than I expected! Thanks heaps!

    I'm riding on the weekend so I'll start with the 600lb spring, check the air pressure and see how I go. I don't mind it rubbing at full travel if I'm not reaching that point so regularly. I guess the fact that I am, is an indication that the spring is too soft.

    Thanks again. I'll post my results.

  17. #17
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    Quote Originally Posted by RickyD

    If I get another, I'm gonna have Craig build me any Avy.
    That's what my friend has on his, and he couldn't be happier

  18. #18
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    I ran the 600lb spring yesterday. The bike felt a lot better. I wasn't blowing through the travel so quickly and there was no tyre rub at all. I didn't measure the sag but it didnt look/feel much different to the 500lb spring, which is good.

    I won't use a spacer at this stage, but if I do start using all the travel on some of the rougher tracks I'll look at that option.

    Thanks again for all the advice.

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