Author Topic: Vague “news” about rear spring rates & sag.  (Read 1304 times)

0 Members and 1 Guest are viewing this topic.

  • Offline PJ69   gb

    • Z900 Pro  ‐    219
    • ***
    • Topic Author

    Offline PJ69

    • Z900 Pro
    • ***
    • Topic Author
    • Posts: 219
    • Country: gb
    Vague “news” about rear spring rates & sag.
    on: Dec 27, 2021, 07.33 pm
    Dec 27, 2021, 07.33 pm
    So when I picked up my rear, I spoke at some length with Richard at Maxton about ride height, static sag, sag while seated and ideals.

    I received a technical dump of information and a brief summary of the actual  facts (from Maxton’s experts) versus what t’internet bro science has conjured up as fact:

    1. Static sag (bikes weight resting on the springs) about 10mm. Can be measured on a sky lift. Just see how much play there is when lifting the rear in free flight to take up any slack and add it to the 10mm.

    2. Sag is a completely arbitrary figure. There is no ideal for most modern bikes due to the multiplying link set up used to compensate the cheap stock shock and the anticipation each manufacturer has about pillion seat utilisation.
    Each manufacturer has their own view of the weight of their target rider (usually an Asian Racing Snake), and therefore sets the multiplying link ratio to suit their ideal.

    What happens here is that an 80kg load (for example) will cause a sag of x on one bike and something different on another. Also any additional weight won’t cause a linear increase in sag on this pivoting link type of set up, and again will be different across manufacturers.

    The only guidance I was given about sag and spring rate & pre load and ride height was fairly standard and generic:
    If you want more turn in with less stability, raise and stiffen (higher N/mm figure) the rear; if a slower turn in and more stability is desired or acceptable, lower and soften (lower N/mm) the rear.

    For my weight in all my gear, mixed track day and road use they’ve fitted a 13.5 N/mm spring, according to the printed figures on the coil. I’ll let you know what they do on the front when I get them back in January.

  • Offline Marco   gb

    • Z900 Master  ‐    870
    • ****
      #1

    Offline Marco

    • Z900 Master
    • ****
    • Posts: 870
    • Country: gb
    • Bike: Z900 Performance Ed
    • Town / City: Carrickfergus
    Re: Vague “news” about rear spring rates & sag.
    Reply #1 on: Dec 27, 2021, 09.13 pm
    Dec 27, 2021, 09.13 pm
    This is pretty much exactly what I was told by a friend who works for Ohlins in MotoGP.  He also said to keep your chain at the loose end of the recommended slack as a tight chain hinders suspension movement.  I always use Bridgestone tyres and he told me they have stiff sidewalls so to run lower pressures.  Other manufacturers tyres will obviously be different.
    You just need to fiddle until it's right for you after you get the basics from someone who knows what they are talking about.
    ZH2 now but still hanging about like a bad smell.

  • Online zed9   us

    • Forum Supporter
    • Z900 God  ‐    4568
    • *
      #2

    Online zed9

    • Forum Supporter
    • Z900 God
    • *
    • Posts: 4568
    • Country: us
    • Bike: 2017 z900
    Re: Vague “news” about rear spring rates & sag.
    Reply #2 on: Dec 28, 2021, 04.40 pm
    Dec 28, 2021, 04.40 pm
    I had my factory suspension resprung and revalved by a suspension expert. I shipped him my front and rear suspension. I gave him my weight, my weight in full gear, the bikes wet weight and my riding style. He said "I know what you need".
    He pre-set all available settings for me at his shop before he shipped them back and told me not to touch anything for at least two months to see if I was happy with what he set. I was. It's been two years and I never touched any of the adjustments including preload so I have no idea what settings he  used but the bike performs perfectly.

  • Offline SocalZ   us

    • Z900 Junior Member  ‐    1
    • *
      #3

    Offline SocalZ

    • Z900 Junior Member
    • *
    • Posts: 1
    • Country: us
    • Town / City: SALTON CITY
    Re: Vague “news” about rear spring rates & sag.
    Reply #3 on: Mar 05, 2022, 11.24 pm
    Mar 05, 2022, 11.24 pm
    That sounds very tempting.  Who's your suspension expert? Would like to do the same thing ?
    Thanks

  • Online zed9   us

    • Forum Supporter
    • Z900 God  ‐    4568
    • *
      #4

    Online zed9

    • Forum Supporter
    • Z900 God
    • *
    • Posts: 4568
    • Country: us
    • Bike: 2017 z900
    Re: Vague “news” about rear spring rates & sag.
    Reply #4 on: Mar 06, 2022, 03.16 pm
    Mar 06, 2022, 03.16 pm
    *Originally Posted by SocalZ [+]
    That sounds very tempting.  Who's your suspension expert? Would like to do the same thing ?
    Thanks
    This is the second time I used him. His name is Jamie at Daugherty Motorsports.
    http://daughertymotorsports.com
    He is a one man shop and he is expert. Call him early in the morning before he gets busy or maybe late. He doesn't have a fancy website or a lot of time to talk. Mine was the first z900 suspension he upgraded.
    Basically, he'll want your weight in your undies then with full gear and the bikes wet weight. He'll ask you if you ride street or on track. Then when you get into your riding capabilities, depending on how busy he is, he'll cut you off and say "I know what you want". And he does.
    I paid $650 total (plus shipping to him but not for the return) for front and rear, new springs and revalving and oil plus he sends the suspension back to you with the clickers already set and pre-load adjusted. And there's never a tooling scratch on anything.

    When you take your suspension off try this..
    Place one end of your fork against a wooden floor then force it down to see the rebound rate. Then turn the clicker to adjust. You'll find that there is no perceivable difference no matter what you do. In other words, they don't do a thing.
    Then try it when you get them back (without changing the clicker adjustment) to see the difference.

  • Offline Its about speed   us

    • Z900 Pro  ‐    142
    • ***
      #5

    Offline Its about speed

    • Z900 Pro
    • ***
    • Posts: 142
    • Country: us
    • Bike: 2017 Z900 ABS
    • Town / City: REDDING, CA
    Re: Vague “news” about rear spring rates & sag.
    Reply #5 on: Mar 06, 2022, 08.18 pm
    Mar 06, 2022, 08.18 pm
    "When you take your suspension off try this..
    Place one end of your fork against a wooden floor then force it down to see the rebound rate. Then turn the clicker to adjust. You'll find that there is no perceivable difference no matter what you do. In other words, they don't do a thing."

    And all this time, I thought I was nestled down into OEM paradise. I'm gonna get some of Daugherty's upgrades.

  • Online zed9   us

    • Forum Supporter
    • Z900 God  ‐    4568
    • *
      #6

    Online zed9

    • Forum Supporter
    • Z900 God
    • *
    • Posts: 4568
    • Country: us
    • Bike: 2017 z900
    Re: Vague “news” about rear spring rates & sag.
    Reply #6 on: Mar 07, 2022, 12.43 am
    Mar 07, 2022, 12.43 am
    *Originally Posted by Its about speed [+]
    "When you take your suspension off try this..
    Place one end of your fork against a wooden floor then force it down to see the rebound rate. Then turn the clicker to adjust. You'll find that there is no perceivable difference no matter what you do. In other words, they don't do a thing."

    And all this time, I thought I was nestled down into OEM paradise. I'm gonna get some of Daugherty's upgrades.
    How much do you weigh?

     



    rockbound