1200GS rear suspension

Discussion in 'Hacks' started by Vagabond25, Mar 12, 2018.

  1. Vagabond25

    Vagabond25 Been here awhile

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    I'm due for a new rear shock, and I'm looking around at the aftermarket options out there. What make/model would you recommend? Ohlins? Nitron? Something else?? Considering the fact that I weigh about 185lbs/84kg, what load setting should I have the new shock adjusted to, to account for the tub and payload?

    Ohlins' STX46 only go up to 230lbs, which seems especially light after I deduct my weight. I'm only left with 45lbs for payload, which is nowhere near enough if I have a adult female pillion (the normal arrangement if I have a pillion at all). Does that mean I ought to be looking at the TTX39 instead as those can be set all the way up to 350lbs? Or, does the sidecar take a percentage of the total payload and then confound the mathematics?

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    #1
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  2. cycleman2

    cycleman2 Long timer

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    Rear shocks can be a hot topic. Similar to an oil thread. I have a very heavy duty 550 lb Progressive Shock on my R100RT, monoshock. It is a really heavy duty item and I only need to put in about 1/2" of preload on the spring to have it work for me with a load. It is adjustable for rebound, damping etc. I don't know if they make one for your bike or not. I weight about 220 without gear and with the rig loaded up with the spouse and travel gear my total weight is around 1275 lbs. Empty weight of the rig with bike is about 735. I've always found that the stock shock is too light even without a sidecar or a pasenger. They are fine for solo riders but as soon as you add a passenger they aren't stiff enough.

    If you check out how to set up a suspension, you want to have about 20% sag ( or in other words about 20% of your travel should be used up when you sit on the bike ) with or without a sidecar. Depending on the load in the sidecar it may only actually add 35-50 lbs of actual weight to the bike. The big thing is sidecar side loading of the bike. Stiffer is always better when it comes to handling.
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  3. Vagabond25

    Vagabond25 Been here awhile

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    This is precisely the expertise I was hoping for... broken down in simple terms. I'll poke around for a more in-depth thread on setting up the suspension. Thanks a lot!

    btw, what oil do you recommend? :lol3
    #3
  4. Alaskahack

    Alaskahack Adventurer

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    Great topic really going to be following this thread.

    My Outfit is a 2009 GS with a DMC 72 DX I've been running this since for the last 7 years on the original ESA suspension, I haven't had any problems with the suspension yet but seven years is a long time and I'm curious on what My options might be thinking my best option would be changing the ESA shocks,but not sure.






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  5. Wolfgang55

    Wolfgang55 Long timer

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    Good topic w/ great pix
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  6. Strong Bad

    Strong Bad Former World's Foremost Authority

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    I had Works Performance build all three shocks for my GSA/Dauntless rig.

    Gill (RIP) put a remote reservoir shock on the rear so it could be placed in spot with better air flow. The reservoir is plumed so that the oil passes all the way through rather than back and forth, creating much better cooling (note the two hoses for shock fluid one in and one out).

    Beemer shock res.JPG

    All that being said, after Gill passed, Works blew up and closed leaving people screwed. His daughter Starr has moved the equipment to AZ and is re-opening as Worx. Further discussion here: http://advrider.com/index.php?threads/works-performance.1245821/
    #6
  7. Vagabond25

    Vagabond25 Been here awhile

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    Impressive!

    Thanks for the link. What a headache! And, such an tragic epilogue to Gill's hall of fame reputation.
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  8. davebig

    davebig Another Angry Hun !

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    I'm afraid cycleman is correct WTF !!!!! But actually what several of us have down with pretty decent result is weigh the pusher , steer and sidecar wheels separately and the whole rig and take the info to http://epmperf.com/hyperpro-high-performance-motorcycle-suspension/
    Klaus the epm principal deals with the NL and they have specific ideas that work well. A local race car shop, metal recycling center or simply use a single scale with block about the same thickness under the other 2 wheels for best results put you in the saddle full tank and usual load.
    It might feel a little stiff at the start but it's way better than undersprung ! Springs hold the vehicle up, shocks damp the spring, the adjustment is about when the shock moves !
    #8
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  9. cycleman2

    cycleman2 Long timer

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    Yes what I do is put a 2x4 under each bike wheel & sidecar wheel. Jack up one or the other, replace 2 x 4 with the bathroom scale, lower the wheel onto the scale. Repeat and add them all together to get the total. With the seat & gas tank off the bike, ( I was doing some work on the bike during the winter ) Weight on Sidecar Wheel 175 lbs, Weight on Front Tire 230 lbs and Weight on the Rear Tire 265 lbs. This is with the sidecar & bike sitting empty and set up for travel with a load ( lean out & toe in ). Bathroom scales are not the most accurate, but good enough, you just have to make sure that the scales can read the weigh. Some only go to 300 lbs and others will go to 400 lbs.

    What you are striving to get is a set up that will just allow about an inch or so of sag ( long travel suspensions ) give a bit more, when you sit on the bike. That amount of initial preload puts the spring into its ideal working range. If you add more weight then you can dial in more preload. The big problem is that stock street bikes are set up for a 185 lb rider. I've seen cases where one had to use 41 clicks ( out of 44 ) preload just to set the proper sag for a solo rider. Clearly if you added a passenger the spring rate was too light. In street bike applications on the front forks I always use linear springs. You arrive at the right spring weight by adding the bikes weight, your weight with gear and if you use a tank bag, you add that as well. They have a calculator on the site to figure the right spring ( Sonic Springs ). Of course with leading links they are a bit different but still the same principle applies and you adjust them to have the 1" or so of sag. You want a firm but not harsh ride.
    #9
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  10. DRONE

    DRONE Dog Chauffeur

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    Like Davebig, I weighed my rig (2008 GSA with DMC M72DX) and sent all my info to Klaus at EPM. I let him figure out everything, except I told him that I did not want an external adjuster on the rear -- I just wanted a traditional monoshock. Very pleased with what he came up with.

    Off topic but, based on that one photo in Post #1, it looks like your rig needs a DeDome modification which is super easy to do on the '08 GS.
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  11. Vagabond25

    Vagabond25 Been here awhile

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    I just got off the phone with Klaus, and will be working with him to get my rear end upgraded. Thanks for the help, guys.
    #11
  12. davebig

    davebig Another Angry Hun !

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    Good now if you'd like to fix the front so that 2 front fenders are not banging into one another I have another R12gs front telelever that moves the ball joint mount back an inch and raises the front to almost stock height.
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    Stock mounting point
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    Modified to pull the front end back in you may want to PM DRONE and get an image of his r12

    http://advrider.com/index.php?threads/dedone-trail-reduce-mods1100-1150gs.786238/
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  13. Vagabond25

    Vagabond25 Been here awhile

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    RE: DeDome modification... PM's sent to you both, Drone & DaveBig. Thanks for the help, gents.
    #13
  14. 81twins

    81twins Adventurer

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    I have also done the DeDome mod with the assistance of Dave and Drone which was a great modification to my 09 GS rig. Like Alaskahack I have the ESA which I am considering replacing and so will follow your progress.
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  15. Vagabond25

    Vagabond25 Been here awhile

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    Now I just need to get a few minutes alone in the garage! :beer
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  16. davebig

    davebig Another Angry Hun !

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    Your going to have a whole new deal !
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  17. DRONE

    DRONE Dog Chauffeur

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    Two-week turnaround including shipping? Wow!

    By the way, love those HyperPro shipping boxes.
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  18. Vagabond25

    Vagabond25 Been here awhile

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    It's about damn time I post a pic of the new setup... HyperPro on the rear and a custom-built telelever up front. IT FEELS LIKE A WHOLE NEW RIG!!
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  19. davebig

    davebig Another Angry Hun !

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    The front of your rig sets at the stock height and you like the way it goes :lol3:clap:clap

    For Claude and Jay its really easy to have done to the r12 oil heads especially if your moving the ball joint 3/4 to 7/8".
    #19
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