Results 1 to 14 of 14
  1. #1
    I wonder why?
    Reputation: i1dry's Avatar
    Join Date
    Jan 2004
    Posts
    543

    Handling characteristics of specific frame/suspension designs...

    Okay Warp, your wish is my command, new topic.......

    In the Issues with the Motolite thread Issues with the Motolite there has been considerable debate regarding the performance pros and cons of various suspension designs.

    Warp thought that my response (below) might make an interesting topic of discussion.

    Frame and suspension design theory analysis is a complex subject with a large number of variables that are often not fully considered in this type of discussion. A definitive broad theory analysis is virtually impossible because of the many intangible variables involved.

    As Bikesilla states, each of us can only make “a BIKE SPECIFIC assessment...” I would go further and add that this assessment is also specific to the one making the assessment.

    From my point of view and experience, every frame has a sweet spot relative to body positioning on the bike (seated or standing) that greatly influences how the bike handles up, down, slow, or at speed. The sweet spot is also influenced by the riders body type and weight, frame size, suspension set-up, shock and fork type, and saddle height, stem length and height, etc.

    With some frames/suspension designs the sweet spot changes, sometimes subtly sometimes dramatically, with speed and terrain, i.e., up, down, etc. In addition, with some frames the sweet spot is easier to find and maintain while with others it’s more challenging.

    It would seem to me that similar sized Turners with a HL and TNT, with all other factors being the same, would have slightly different sweet spots. This would also apply to any other frame/suspension design for that matter. Therefore, the same rider would require some time on the bike to get the “feel” and fine tune the bike’s set up to optimize the handling characteristics. Furthermore, throughout this fine tuning process, an experienced rider on a specific frame will find that the sweet spot is often fluid or dynamic relative to terrain and over time naturally conditions or trains his body position to be “one” with the bike. Over time, body positioning becomes reflexive through conditioned neuromuscular feedback and muscle memory.

    Simply going from one bike to another doesn’t allow sufficient time to gain sufficient neuromuscular feedback from the “new” bike and retrain the appropriate muscle memory. The body will naturally (reflexively) position itself on the “new” bike like it did on the “old” bike, until it is retrained to do otherwise.

    Therefore, initially on a “new” frame/suspension one can get a general sense as to it’s characteristics, but to parlay that into a definitive on performance extremes is lacking is substance (experience) in my opinion.

    It would be interesting to hear how people of various body types maximized the handling characteristics of specific frame/suspension designs.

    i1dry?

  2. #2
    mtbr member
    Reputation:
    Join Date
    Nov 2005
    Posts
    220
    While I'm generally the type to launch into a spirited debate that's entirely pointless, and do so with reckless abandon.... this is just too much for me. The location of the pivots is, overall, more important than whether it's HL/VPP/Swingarm SP, unless you're concerned only with how something reacts to braking. The stiffness of the frame is probably more important than that, too; who cares how the suspension of the bike works if the frame flexes when you try to corner hard? How the bike fits and feels in terms of size and weight balance is more important than the rest. Some bikes are better for a particular riding style. This isn't something that can be quanitifed in a few sentences, because most people, when describing how they ride, are deluding themselves. It also definitely isn't something that can be ascribed solely to the bike being Horst Link, or whatever.

    We love our Moto-Lites, and the people who don't ride something else. I doubt any bike frame hits the market without at least one person behind the design believing that for the target market, that's going to be the best bike on the market.

    Let's not turn into the Turner forum here.

  3. #3
    "Its All Good"
    Reputation: Whafe's Avatar
    Join Date
    May 2004
    Posts
    10,715
    My two cents worth, if you remember, when it comes to the techy side of sus design, I am a plonka....

    My riding experiences are what counts.....

    I came off the Ellsworth Id, which I loved, then went onto the ExoGrid MotoLite..... I have been trying and trying to work out the differences and there are many. BUT it is very hard to put them into words. For example the ML has a Ti front triangle, this reacts and rides different to the alu Id frame, the I9 wheels are different to the CK, Bonty Mustang wheels I had on the Id....

    Point is I am trying to compare rides, when it is futile because of so many differing factors...

    I too put a lot of respect towards B Zilla's thoughts on the sus designs, he was able to side by side test both DT's rare ends, not literally but the frames.... Where I feel this gives him more reliability in the test....

    Another vital point, I think every design has as you say a sweet point, every designer, manufacturer feels their new design is the ducks nuts, because they more than likely suss out where the sweet spot is.................... I know the sweet spot on the Id, know where the ML shines.................... It is why I feel I can make the comment that a beginner rider will not really enjoy and feel good on an Id, where by they would on a 5 Spot or a MotoLite.................

    RIGHT, am now rambling, over and out.... These are my opinions, dont want people getting p i s s ed and taking it personal................... Its all good...
    The_Lecht_Rocks: whafe - cheeers - may i offer an official apology for the wagon wheeler "dis-belief"

  4. #4
    mtbr member
    Reputation:
    Join Date
    Oct 2005
    Posts
    54
    i am currently extending my suspension software to simulate the forces in various systems.

    in my calculations i consider center of gravity, frame geometry, specific pivot point placement, current travel, current gear setting, and the current torque applied at the bottom bracket.

    not included in the calculation are weight shifts performed by the rider while pedalling. while it would be very intersting to include that also, it also seems very complicated to get good numbers on what any specific rider would actually perform on his bike.

    my calcualtions are thus not giving absolute numbers about squat, but you can can still easily see forces parallel to the axle path changing periodically throughout the pedal stroke. so i can give a rough estimate wether the specific bike tends to rise or tends to squat under the periodically changing load from chain force.

    in the anmated gif images below (please take some time to load) i have illustrated two examples

    situation 1:



    you can see that, even though the chain force is periodically changing, the force parallel to the axle path remains constant. thus, that specific system in that specific gear does not require the rider to shift weight during pedalling (to counteract squat)

    situation 2:



    same system in different gear. now you can see the force at the axle changing periodically. with increasing load from the chain, the force at the axle will rise. thus the system tends to squat while pedalling. in the displayed example the difference between maximum and minimum force is ~80N. that difference will have to counteracted by the rider or the damper, otherwise the bike is going to squat.

    now it would be very interesting to know, up to which amount of force delta at the axle the rider will not notice any negative effects from suspension interaction. of course the specific damper will also play a big role and may compensate for a large amount of that suspension interaction.

    in the animations you can see that rider height (COG position) and frame geometry is at least as important as the specific pivot point locations or the specific suspension layout.

  5. #5
    "Its All Good"
    Reputation: Whafe's Avatar
    Join Date
    May 2004
    Posts
    10,715
    igorion, great post. I wish I was more up to speed on the specifics in the design and implementation of this stuff, but have never really concentrated on it. Very interesting. Very cool program to, could do some great assimilations I guess..

    Keep these posts coming, your knowledge etc is great...
    The_Lecht_Rocks: whafe - cheeers - may i offer an official apology for the wagon wheeler "dis-belief"

  6. #6
    mtbr member
    Reputation:
    Join Date
    Oct 2005
    Posts
    54
    ...no more posts for the next three weeks, i'm off for honeymoon tomorrow....


  7. #7
    "Its All Good"
    Reputation: Whafe's Avatar
    Join Date
    May 2004
    Posts
    10,715
    Quote Originally Posted by igorion
    ...no more posts for the next three weeks, i'm off for honeymoon tomorrow....
    Congratualtions, fantastic looking spot............ Go Hard....
    The_Lecht_Rocks: whafe - cheeers - may i offer an official apology for the wagon wheeler "dis-belief"

  8. #8
    "El Whatever"
    Reputation: Warp's Avatar
    Join Date
    May 2004
    Posts
    18,676
    I have noticed that Titus users generally have it easy to set up their suspension.

    All comments on first ride impressions are very positive regarding the suspension.... and this leads me (only my opinion) to believe Titus are not very affected in their suspension by set-up.

    This means it's easy to initially set-up a Titus for it to feel fine.... but what about when looking to get the "extra mm" out of your suspension?

    How hard has it been to you to get the bike "exactly where you want"?

    My Warp was very straightforwards too, but I feel it was too sensitive to geometry changes (at the suspension)... while the Blade is not.
    Check my Site

  9. #9
    Bike to the Bone...
    Reputation: rzozaya1969's Avatar
    Join Date
    Nov 2004
    Posts
    8,290
    Ok, my point of view is that I don't know squat about suspension.. ha ha ha

    I'm really not having much trouble finding how I like the suspension. I leave the rear travel at 5", and, usually, have the travel set around 120-130mm for general riding, and, when there is a climb and I rememeber, I lower it to 95-100mm (more or less). Sometimes I just forget to change it and like how the bike behaves.

    Now I'm going to have to test again when I get the DHX C, but I don't know how long to set it right. I hope it won't be long.

    What I feel somewhat more difficult is fitting. I had to change 2 stems to find the one I liked, although it was also handlebar width. I think that right now I have my ML set up just right for fit, and I'm happy with it.

  10. #10
    "El Whatever"
    Reputation: Warp's Avatar
    Join Date
    May 2004
    Posts
    18,676
    Quote Originally Posted by rzozaya1969
    Now I'm going to have to test again when I get the DHX C, but I don't know how long to set it right. I hope it won't be long.
    It'll take quite some rides or at least quite some runs, but follow Fox's instructions. They tell you what to adjust in sequence.

    First the sag, then rebound... and then all the parafernalia of knobs that darned thing has.
    I've had luck running most knobs fully open... but at your weight, maybe I'd pick the middle of all adjustments and work from there.

    man, that shock would be sweet!! (Too bad the Blade can't take a coil over).
    Check my Site

  11. #11
    "Its All Good"
    Reputation: Whafe's Avatar
    Join Date
    May 2004
    Posts
    10,715
    I have to agree, the susp was nto the hard thing to adjust, it was more the seat, too far back on the rails, too far forward... It is the little things. Now it goes like a cut cat, flat out like a lizard drinking mate.............

    Roll on the morning, heading to yet another new spot, have nto riddent the same area twice yet, fantastic.... Oh, if the baby comes tonight, no ride................. She is over due now, dam this waiting game. So any day, hour, minute, second..................

    I blew the front Magura braided hose last weekend. Have not been able to get one yet in Spain, so have a Goodridge on order.. So back to a standard black hose, will be interesting to see if I notice the difference, I used to, more fading, the braided hose so cools the oil down more.....................

    Yeah ha mate.......................
    The_Lecht_Rocks: whafe - cheeers - may i offer an official apology for the wagon wheeler "dis-belief"

  12. #12
    mtbr member
    Reputation: Braids's Avatar
    Join Date
    Jan 2004
    Posts
    811
    Quote Originally Posted by Warp
    I have noticed that Titus users generally have it easy to set up their suspension.
    I'm just easy to please.

    I have to be honest and say that I value the geometry and handling on my bike more than the suspension. Having said that I would pick a horst bike over any other design right now.
    Last edited by Braids; 07-28-2006 at 12:58 PM.

  13. #13
    "El Whatever"
    Reputation: Warp's Avatar
    Join Date
    May 2004
    Posts
    18,676
    Quote Originally Posted by Braids
    I have to be honest and say that I value the geometry and handling on my bike more than the suspension.
    Yeah... way to go. Suspension means squat if the bike can't go where you want the way it's intended to do.
    Check my Site

  14. #14
    "Its All Good"
    Reputation: Whafe's Avatar
    Join Date
    May 2004
    Posts
    10,715
    Quote Originally Posted by Warp
    Yeah... way to go. Suspension means squat if the bike can't go where you want the way it's intended to do.
    Yep, so much energy goes on suspension, when more people should concentrate on gettign a bike that fits, then worry about the suspension, with in reason, but you get my drift..
    The_Lecht_Rocks: whafe - cheeers - may i offer an official apology for the wagon wheeler "dis-belief"

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •