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Thread: Suspension hitting hard on 2012 RT

  1. #16
    Nickname: Droid
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    One thing you've not mentioned is your weight when riding, and how your bike is typically loaded. Factory shocks, whether standard or ESA, are a compromise in setup. Factory shocks are best set for the "medium" rider. So for North America, I would guess that to be a rider abour 5'-8" tall and about 225 lbs in full riding gear. If you are a rider at the light end of the scale, the factory setup may seem harsh and you'd need to adjust to the lightest preload and softest damping rates. A rider at the heavy end of the scale would need the highest preload and harder damping rates. But not being in the 'mid-range" of the factory setup limits the range of how the suspension can be set for you. That's why one bike may ride great for one rider and for crap for another. But a quality suspension is set up for each specific rider, his weight, his bike loading, his riding style, at the middle range of the suspension. This gives the best initial ride with broader adjustment capability.

    On short, sharp bumps (actually drop-offs) if the rebound damping is too high, the shocks are always trying to restrain the extension of the suspension slower than it could extend to "step" down the edge, and the bike feels like it just drops or falls over the bump. In some cases of multiple sharp bumps in a row, high rebound damping actually causes the suspension to keep compressing almost to the point of no active suspension until it has a chance to "stretch".

    But then on the bigger bumps/dips, too high a compression damping causes the suspension to "stiffen up" too quick and not allow full travel to be absorbed by the spring. On bikes with no rebound damping it gives the feel of the bike pogoing over the bumps.

    On the older Jap bikes many of us grew up on, the easy (cheap)answer was to "over-sprung" the bike and "under damp" the compression damping, with no rebound damping. But all better suspensions are usually lighter, longer springs and more refined damping. The lighter spring allows for easier initial wheel travel and the better damping slows the suspension action near the limits.

  2. #17
    Ponch ponch1's Avatar
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    I ride with the ESA set to two helmets and normal damping most of the time. The only time I really bottomed it out was on the Apache Trail, and there I had to set it to comfort to soften the ride.
    My Motorrad
    BMWMOA 162849 | BMWRA 41335 | VROC 8109-R | VBA 19

  3. #18
    Rally Rat
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    I did not read your original post close enough. (Just wasn't listening )
    "
    I still had the same problem. Bike pounded me on expansion bumps on the highway. girlfriend (passenger) too.

    Once I cranked the preload all the way up and rebound only open 1/4 turn it rode like it should. Smooth as can be with both of us on the bike. We took back roads from northern Pa to northern NY for a whole day. Ride was superb.

    I can not keep my rear shock preolad on LOW or the rebound on soft or the bike beats the crap outa me.
    I took the rear shock out and am sending it to get a slightly stiffer spring.

    Like I said earlier, Spring too soft, the compression valve in the shock works too hard making the bike beat me up. a little stiffer spring will make for a softer ride under those conditions.

    I also have issiues with getting proper sag with a passenger and load. Bike is supposed to carry almost 500 lbs payload. When I put the "little woman" on and all our stuff, the bike sits 2" or 58 mm too low. More proof my rear spring is just too weak. We are no where near the 500 lb load limit.

    Riding solo, no bags, the adjuster is on "Normal" Anything below that and I have too much sag. This is when the ride gets harsh, especially expansion bumps on the expressway.

    I guess what I am saying is try 2 helmets and at least normal for damping.

    Its costing me $110 plus shipping my shock to get a slightly stiffer spring.


    David

  4. #19
    Insatiable Cruiser rtwiz's Avatar
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    Quote Originally Posted by DROOT153718 View Post
    I did not read your original post close enough. (Just wasn't listening )
    "
    I still had the same problem. Bike pounded me on expansion bumps on the highway. girlfriend (passenger) too.

    Once I cranked the preload all the way up and rebound only open 1/4 turn it rode like it should. Smooth as can be with both of us on the bike. We took back roads from northern Pa to northern NY for a whole day. Ride was superb.

    I can not keep my rear shock preolad on LOW or the rebound on soft or the bike beats the crap outa me.
    I took the rear shock out and am sending it to get a slightly stiffer spring.

    Like I said earlier, Spring too soft, the compression valve in the shock works too hard making the bike beat me up. a little stiffer spring will make for a softer ride under those conditions.

    I also have issiues with getting proper sag with a passenger and load. Bike is supposed to carry almost 500 lbs payload. When I put the "little woman" on and all our stuff, the bike sits 2" or 58 mm too low. More proof my rear spring is just too weak. We are no where near the 500 lb load limit.

    Riding solo, no bags, the adjuster is on "Normal" Anything below that and I have too much sag. This is when the ride gets harsh, especially expansion bumps on the expressway.

    I guess what I am saying is try 2 helmets and at least normal for damping.

    Its costing me $110 plus shipping my shock to get a slightly stiffer spring.


    David
    David:

    I'm not understanding. You and your GF were in perfect comfort with the preload adjusted almost full and shock adjusted full on, so adjust it full on! When she's not on it and you don't have bags, back the pre-load down a turn.

    Here are some things you need to know.

    1st...The damping screw only has about 1.5 turns total range. Screw it in all the way. Try it, then back out by 1/4 turns until it's too sloppy, then screw it back in 1/8 or 1/4 as needed using the test road. Past 1.5 turns, it's pulled away from the shock and it's just a screw turning in the housing. It seems like there's 20 turns of adjustment, but there's only 1.5 turns. You can remove the screw and shine a flashlight in there to see what's going on. There's a metal button on the side of the shock. The long screw pushes it in. The farther the button is pushed down, the more damping, but the screw only contacts the button for 1.5 turns.

    2nd....I don't think you need a new spring. The springs on those stock shocks are really strong...too strong, at least with mine. If you and your SO and luggage can go cross country in comfort, the spring is OK.

    3rd...But the dampers are not very strong. They need to be almost all the way in.

    4th... Get over the idea that less spring or less damping is going to be more comfortable. This is why you think you need the spring all the way loose and the shock backed out all the way. You're hitting the stops on these bad roads. The stops inside the shock are bits of hard plastic...very harsh and it's very hard on the Paralever casting to bottom out a lot.

    The spring preload is to adjust the level of the bike loaded with what you have to carry on it. It should sink about 1/4 to 1/3 of total travel with a static load on it...You and your stuff. I use a wooden paint stir-stick from the hardware store.

    With bike on center stand, and the right side bag off, place one end of the stick on the rear casting so the stick comes straight up from the axle of the rear wheel. Put a piece of tape on the back bodywork above the wheel so the stick intersects. Pencil a reference mark on the stick where it intersects with one edge of the tape.

    Then load the bike and measure the difference by reaching back and putting your thumbnail at the point on the stick where it now intersects the edge of the tape. (You need a helper to hold the bike, probably.) Mark the spot where your thumb nail is. Measure the distance between the two marks. It should be around 1.5 to 1.75". Adjust the spring until it is.

    The damping adjustment only changes rebound damping. The farther you screw it in, the slower the bike's rear suspension recovers from a bump.

    If it's too "fast", the rear will sort of baby-buggy. The front of the bike will feel very unstable and on edge in turns. If the shock is too slow, going over a series of bumps will "pack up" the suspension. Suspension compresses from the bump and can't recover in time for the net one. It keeps sinking down until it's at the bottom of travel.... VERY uncomfortable.

    There is no compression damping adjustment on the stock setup. It's fixed at one rate...probably for the best. You can get confused enough with just the two adjustments. I have high and low speed compression damping on my rear Wilbers shock. I have actually made the bike more comfortable by increasing compression damping before. That's because the bike was bottoming and a little compression damping stopped it from hitting the bump-stop.

    I'm 190 or so lbs. with gear on. There's plenty of spring for me and a passenger and gear on the stock shock.

    I wouldn't waste my money on a new spring for the stock shock. Doesn't sound like the answer to me...and it doesn't solve the problem of the front shock being rock hard over bumps. Either talk to Beemer Werks or figure out how to adjust what you have.

    If you can swing it, aftermarket shocks are well worth the investment. They're rebuildable so they last about forever, requiring rebuilding every 20K or so (mine is at 30K and it's fine.) The damping is just so much nicer and you get more adjustments. Beemer Werks will ask you how much you and your passenger weigh, what model of BMW and some questions about how you ride. Then they'll send you a set of shocks that are already adjusted pretty damned well.

    Whether you get new or used or adjust your current shocks, you should understand what's going on with your suspension...just how it works. If you know that, you can recognize symptoms when you ride and make educated adjustments instead of stabbing in the dark.

    You can offset some of the cost by modding your aftermarket shocks for your new bike when you get one ...or you can sell them.

    In fact, you can look for a set of used ones on BMW classifieds and eBay. Make sure you get good, rebuildable ones. Send them to Beemer Werks for tune up and you're set.

    Keep the stock shocks and re-install them when you trade or sell your current bike. I used my Ohlins on two different RTs with only some minor changes done by a tech in TN. I've had my Wilbers serviced twice already. They're working better than new.

    Hope you figure all this out...Have fun!



    David: Apologies. I'm getting mixed up between riders here. You are talking about ESA bikes and I'm talking about manual suspension RTs. Sorry about that...Some good info in this post for others, though, I think.

    Doh!
    Last edited by rtwiz; 02-05-2013 at 05:11 AM.

  5. #20
    Rally Rat
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    No need to quote the post above this one.

    Acording to rtwiz my rear spring is not too soft. Read my post again. With full load, bike sits 2" too low in the back.

    With 45 mm sag (140*.32 or 1/3) and only ME (200lbs) on the bike I get 38" from ground to the top of the back rack.

    Turn the preload (ride height) all the way up, add rest of load, girlfriend (who really is little 5'1") and measure again. I get 36" measured at the same place. Headlight points to the sky. And my spring is too strong? This on a 12 R1200R. A new bike.

    Just me and girlfriend, no side cases preload all the way up, I get 37" which figures out to be about 70mm sag.

    You seem to think I am not too bright, could you please explain how my spring is too stiff?
    Go ahead, school me.

    David
    Over and out

    Apologies to original poster we seem to have wandered a little. I still stand by my thought that too weak of spring or not enough preload can cause the compression damping that is built in to the shock to make the bike feel harsh on what seem to be small bumps at high speed. This was explained to me by a motorcycle suspension person.

  6. #21
    Insatiable Cruiser rtwiz's Avatar
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    Quote Originally Posted by DROOT153718 View Post
    No need to quote the post above this one.

    Acording to rtwiz my rear spring is not too soft. Read my post again. With full load, bike sits 2" too low in the back.

    With 45 mm sag (140*.32 or 1/3) and only ME (200lbs) on the bike I get 38" from ground to the top of the back rack.

    Turn the preload (ride height) all the way up, add rest of load, girlfriend (who really is little 5'1") and measure again. I get 36" measured at the same place. Headlight points to the sky. And my spring is too strong? This on a 12 R1200R. A new bike.

    Just me and girlfriend, no side cases preload all the way up, I get 37" which figures out to be about 70mm sag.

    You seem to think I am not too bright, could you please explain how my spring is too stiff?
    Go ahead, school me.

    David
    Over and out

    Apologies to original poster we seem to have wandered a little. I still stand by my thought that too weak of spring or not enough preload can cause the compression damping that is built in to the shock to make the bike feel harsh on what seem to be small bumps at high speed. This was explained to me by a motorcycle suspension person.
    David:

    Too many posts on too many forums. Sorry about my post. I apologized at the end of my post if you got that far. I'll do it again. Sorry. My theory was right but not an appropriate answer to your situation. MY bike is non electronic and the stock rear spring is massive on it. Not sure who I got you mixed up with. I'm gonna take a break for a while.

    Take care,

    -RTW

  7. #22
    Rally Rat
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    I spent a good part of the day making a spring compressor. You got me thinking If the new spring is too stiff,
    I would have to send the shock to calafornia to get it changed. No way during riding season. I am using a set of automobile strut spring compressors to make one that fits this shock and spring. Once its off, I order the new one.

    One set screw I cant get loose. I even heated it with a torch.

    David

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