Page 1 of 2 12 LastLast
Results 1 to 50 of 63
  1. #1
    mtbr member
    Reputation: JoeC's Avatar
    Join Date
    Jan 2009
    Posts
    109

    Freedrive...single-pivot suspension?

    Hi, after taking close looks at the Freedrive suspension said by some to be similar to the GT's single-pivot I-Drive suspsension system, can anyone tell whether the the Freedrive is considered just a single-pivot suspension system? Which pivot exactly functions as the main pivot of the whole system then? Doesn' it look really like a kind of virtual-pivot system instead? Trying to see how the whole combination of linkgs work/moves is rather hard for me in this case....too many links!

    Regards,


  2. #2
    www.derbyrims.com
    Reputation: derby's Avatar
    Join Date
    Jan 2004
    Posts
    6,787
    In response to your PM inviting me to comment, I am happy to TRY to help. I have not ridden this design, so I would guess that it rides pretty well, but riding experience is the true test for any design to see if it works well for each rider's unique style and environment. As background, I am an avid trail rider of about 30 years, went to full suspension 15 years ago, fascinated by suspension dynamics, with a curiosity to ask questions where I don't understand. I have made some wrong statements in the past and will make more errors in the future. I've learned a lot about the physics and forces, but I am not formally educated in suspension, only a critical rider and tuner.

    I feel there are three major reactive conditions for full suspension, acceleration anti-squat, rider weight shift response, and handling balance or "feel".

    Isolating anti-squat in the Freedrive appears pretty simple initially as something like a high monopivot or URT, but is complicated and balanced with the rider weight-shift by the multi-links with the shock. I would generally categorize the design as a multi-linked URT-like (unified rear triangle) design, with some relation to GT’s Independent-Drive and Maverick suspension designs.

    I can only guess, this design is so complicated that a computer dynamic modeling would be needed to identify the force reactions, but it appear the acceleration force is focused though the upper swingarm pivot with the center frame, and would counter-act acceleration squat, and produce anti-squat much like a "sweet-spot" monpivot URT like the mid '90's Ibis Swabo. Similar to monopivot URT's, without corresponding downward force from rider pedaling input weight-shift, the suspension might "inchworm", extend, while pedaling more like an the later '90's Klien Mantra URT, but the rider's oscillating down force input while pedaling should keep the suspension stable. Rear only braking, like "sweet-spot" URT's might be stable but a little stiffening and loose traction easily over stutter bumps if the rider doesn't move their body weight rearward before braking.

    It appears to me that the linkage to the shock is just that, a complicated way to produce a rather linear leverage to a rising rate air sprung shock, producing a rising rate overall suspension, or "wheel rate", bringing nice small bump compliance, an big hit and bottomless feel plushness.

    Again I have not ridden this design, it is complicated by the multi-linked shock and floating BB, but it appears to be mainly URT-like in effect. I need to ride one to validate my semi-educated guesses. I hope this estimation isn't too far off.

    Ride it and see how it feels. Riding is the true test.

    Edit: "URT-like"
    Last edited by derby; 03-26-2010 at 08:46 PM.

  3. #3
    mtbr member
    Reputation: JoeC's Avatar
    Join Date
    Jan 2009
    Posts
    109

    Thank you, derby...

    Quote Originally Posted by derby
    In response to your PM inviting me to comment, I am happy to TRY to help. I have not ridden this design, so I would guess that it rides pretty well, but riding experience is the true test for any design to see if it works well for each rider's unique style and environment. As background, I am an avid trail rider of about 30 years, went to full suspension 15 years ago, fascinated by suspension dynamics, with a curiosity to ask questions where I don't understand. I have made some wrong statements in the past and will make more errors in the future. I've learned a lot about the physics and forces, but I am not formally educated in suspension, only a critical rider and tuner.

    I feel there are three major reactive conditions for full suspension, acceleration anti-squat, rider weight shift response, and handling balance or "feel".

    Isolating anti-squat in the Freedrive appears pretty simple initially as something like a high monopivot or URT, but is complicated and balanced with the rider weight-shift by the multi-links with the shock. I would generally categorize the design as a multi-linked URT (unified rear triangle) design, with some relation to GTs Independent-Drive and Maverick suspension designs.

    I can only guess, this design is so complicated that a computer dynamic modeling would be needed to identify the force reactions, but it appear the acceleration force is focused though the upper swingarm pivot with the center frame, and would counter-act acceleration squat, and produce anti-squat much like a "sweet-spot" monpivot URT like the mid '90's Ibis Swabo. Similar to monopivot URT's, without corresponding downward force from rider pedaling input weight-shift, the suspension might "inchworm", extend, while pedaling more like an the later '90's Klien Mantra URT, but the rider's oscillating down force input while pedaling should keep the suspension stable. Rear only braking, like "sweet-spot" URT's might be stable but a little stiffening and loose traction easily over stutter bumps if the rider doesn't move their body weight rearward before braking.

    It appears to me that the linkage to the shock is just that, a complicated way to produce a rather linear leverage to a rising rate air sprung shock, producing a rising rate overall suspension, or "wheel rate", bringing nice small bump compliance, an big hit and bottomless feel plushness.

    Again I have not ridden this design, it is complicated by the multi-linked shock and floating BB, but it appears to be mainly URT like in effect. I need to ride one to validate my semi-educated guesses. I hope this estimation isn't too far off.

    Ride it and see how it feels. Riding is the true test.
    and now I need to start some more study based on your explanation above. It is complicated to me. I hope I can understand this soon.

    Appreciate you time for this and hope you stay sharing your opinions about suspension whenever possible.

    Regards,

  4. #4
    locked - time out
    Reputation:
    Join Date
    Jan 2010
    Posts
    759
    Hahaha, you called Derby in as if he's an expert. Search through mtbr. He's been a joke for years here.

  5. #5
    mtbr member
    Reputation:
    Join Date
    Jan 2009
    Posts
    351
    Quote Originally Posted by glitz
    Hahaha, you called Derby in as if he's an expert. Search through mtbr. He's been a joke for years here.
    Was that really necessary? He's trying to be helpful and he seems to have a pretty good knowledge base about bike suspensions. I think everyone already knows to take what they read on the internet with a grain of salt . . . .

  6. #6
    locked - time out
    Reputation:
    Join Date
    Jan 2010
    Posts
    759
    Quote Originally Posted by Canaan
    Was that really necessary? He's trying to be helpful and he seems to have a pretty good knowledge base about bike suspensions. I think everyone already knows to take what they read on the internet with a grain of salt . . . .
    BWAHAHAHAHAHAHAA

    Did you even read his post?

    Why did you feel the need to post? You could have taken my post with a grain of salt, too...

    The knowledgeable people don't even post on mtbr anymore because of the degree of dilution of information and encouragement of agenda/adevertising driven nonsense.
    Last edited by glitz; 03-25-2010 at 11:04 AM.

  7. #7
    mtbr member
    Reputation:
    Join Date
    Jun 2006
    Posts
    7,734
    Quote Originally Posted by derby
    I would generally categorize the design as a multi-linked URT (unified rear triangle) design, with some relation to GTs Independent-Drive and Maverick suspension designs.
    It is nothing like a URT and doesn't possess a URT's defining characteristic. GT's i-drive and Mavericks' suspension aren't URTs either.

  8. #8
    mtbr member
    Reputation:
    Join Date
    Jan 2009
    Posts
    351
    Quote Originally Posted by glitz
    BWAHAHAHAHAHAHAA

    Did you even read his post?

    Why did you feel the need to post?
    1) Yes; and
    2) Because it seemed like you were going out of your way to be a prick.

  9. #9
    mtbr member
    Reputation: JoeC's Avatar
    Join Date
    Jan 2009
    Posts
    109

    Can it be?

    Quote Originally Posted by bad mechanic
    It is nothing like a URT and doesn't possess a URT's defining characteristic. GT's i-drive and Mavericks' suspension aren't URTs either.
    Based on a small link placed between the bb and the chainstay, can this Freedrive be chatacterized as a kind of virtual pivot suspension like that of VPP?

    Regards,

  10. #10
    mtbr member
    Reputation:
    Join Date
    Jan 2009
    Posts
    351
    Attached are excerpts from a NSMB review of a Mongoose Pinn'r and a link to a Mongoose video about the Freedrive design. Hope you find these useful.

    "FreeDrive shares patents with both GT and Maverick bikes and is basically a very high-point single pivot design. The single pivot is married to the rear triangle through a small pivot and to the frame through a massive link that is built around the bottom bracket. It also directly connects to and activates the shock, allowing the bottom bracket to float or move with the suspension."

    http://www.mongoose.com/usa/eng/mtn/newsDetail?id=617

  11. #11
    mtbr member
    Reputation: JoeC's Avatar
    Join Date
    Jan 2009
    Posts
    109

    From the video

    Quote Originally Posted by Canaan
    Attached are excerpts from a NSMB review of a Mongoose Pinn'r and a link to a Mongoose video about the Freedrive design. Hope you find these useful.

    "FreeDrive shares patents with both GT and Maverick bikes and is basically a very high-point single pivot design. The single pivot is married to the rear triangle through a small pivot and to the frame through a massive link that is built around the bottom bracket. It also directly connects to and activates the shock, allowing the bottom bracket to float or move with the suspension."

    http://www.mongoose.com/usa/eng/mtn/newsDetail?id=617
    Thanks a lot for that useful video link.

    From the video, I now know where the main pivot is located. However, I still wonder what practical function that black small link (bb and chainstay) is....

    There should be some significant function for this small link to be put there.

    Regards,

  12. #12
    mtbr member
    Reputation:
    Join Date
    Jan 2009
    Posts
    351
    I had a real hard time visualizing how that system works, too. I can tell you it does work though. I've got a 2008 Canaan Comp with a Fox Float R and I love the way it climbs and descends. Seems to have less pedal bob than the Stumpy FSR I rode on vacation, even without the ProPedal feature the Stumpy had.

  13. #13
    www.derbyrims.com
    Reputation: derby's Avatar
    Join Date
    Jan 2004
    Posts
    6,787
    Quote Originally Posted by JoeC
    Based on a small link placed between the bb and the chainstay, can this Freedrive be chatacterized as a kind of virtual pivot suspension like that of VPP?

    Regards,
    Hey JoeC, you are welcome, thanks for the invitation. I enjoy learning from mistakes and building on over a decade of knowledge from questioning other's theories and critique of my perspectives and interpretation. I question manufacturing marketing claims and sales hype, sometimes there is truth, but not much. The ride is the true test, and the best you know is only the best you've ridden.

    Obviously the Freedrive is not a standard monopivot, the BB floats not with the center frame but most directly with the rear swingarm like a URT to nearly eliminate any chain tension reactively, even more directly so in horizontal and vertical link angles than the similar floating BB designs of the i-drive and Maverick, so I call it a multi-linked-semi-URT-like design.

    There could be an effective virtual URT pivot. If you extend lines across a 4 pivots, 2 lines intersect, and the intersection from links off of a floating or isolated axle is typically called the IC (Instant Center). The IC is not a pivot when there is chain tension bringing another line of force, but does describe the angle of a virtual swingarm with the axle. In the case of the Freedrive, such as swingarm line would cross the BB constantly during travel. But the Freedrive is reported to have very little pedaling bob action unlike the massive pedaling bob a low angled swingarm would produce, so I think the pedaling dynamics are very similar to URT-like with the upper swingarm pivot.

    Watching the Mongoose video, Eric Carter describes a very active braking suspension. So it must be that the braking dynamics activate around the virtual pivot of the near BB location of the IC and produce a very active while braking suspension (to correct my first post above where I thought it might be stiffening like a high-monopivot URT). No one else has ever discussed the IC/Virtual pivot concept in any depth anywhere on the web that I seen when it related to floating BB designs.

    Hopefully, someone with greater knowledge can comment. I know there are many others on MTBR like me who what to learn more about suspension design theory.

    Edit: "...URT-like"
    Last edited by derby; 03-26-2010 at 08:48 PM.

  14. #14
    mtbr member
    Reputation:
    Join Date
    Jun 2006
    Posts
    7,734
    Could we please stop using the term "URT"? Is there a pivot between the rear axle and BB? Yes, therefore it's not a URT. There's no "semi-URT"; it's either a unified rear triangle, or it's not.

    EDIT: Goofed up wrote "No" when I meant "Yes".
    Last edited by bad mechanic; 03-26-2010 at 10:21 AM.

  15. #15
    What?
    Reputation: mullen119's Avatar
    Join Date
    Aug 2009
    Posts
    3,812
    Quote Originally Posted by bad mechanic
    Could we please stop using the term "URT"? Is there a pivot between the rear axle and BB? No, therefore it's not a URT. There's no "semi-URT"; it's either a unified rear triangle, or it's not.
    There are two pivot points between the rear axel and BB.

  16. #16
    mtbr member
    Reputation:
    Join Date
    Jun 2006
    Posts
    7,734
    Quote Originally Posted by mullen119
    There are two pivot points between the rear axel and BB.
    I goofed up my previous post and have fixed it. What I meant to write was if there are any pivots between the bb and rear axle, then it's not a URT.

  17. #17
    What?
    Reputation: mullen119's Avatar
    Join Date
    Aug 2009
    Posts
    3,812
    Quote Originally Posted by JoeC
    Hi, after taking close looks at the Freedrive suspension said by some to be similar to the GT's single-pivot I-Drive suspsension system, can anyone tell whether the the Freedrive is considered just a single-pivot suspension system? Which pivot exactly functions as the main pivot of the whole system then? Doesn' it look really like a kind of virtual-pivot system instead? Trying to see how the whole combination of linkgs work/moves is rather hard for me in this case....too many links!

    Regards,


    I took your picture and tried to explain it for you. I can tell you from experience that it works very well.


  18. #18
    mtbr member
    Reputation: Iridethedirt's Avatar
    Join Date
    Jan 2008
    Posts
    576
    I have an 08 khyber. I like the feel of the bike quite a bit. The rear suspension design works very well. I have an X-fusion 02Rl dual chamber rear shock that allows for ramp up adjustability, and the addition of the dual chamber ramp up controll adds to the bottomless feel of the suspension. It does remain active under braking, but I have not ridden the other designs that claim to be the best at keeping the suspension active under braking like giants VPP 2 or whatever the newest incarnation is called, or any of the other big names newest designs. However from what I have been told they are better... Now take that for what it is, because there is the whole mongoose stigma, and we are talking perception, something which is heavily influenced by what you want to see/feel and also the fact that everybody seems to think what they have is the best system. And hopefully it is the best system for them. Back to the point, I think the design and function has been explained well by previous posts, so all I will lend is that, it works. Plain and simple. Very little bob from pedaling, and good pedaling technique really helps this a lot, chain tension has no noticeable effect on the suspension, so if you can "pedal circles" rather than mash them, the design is just plain awesome. One of my favorite things is how easy it makes pedaling through rough rock gardens, it just feels so awesome to power through rough stuff, feel the suspension doing it's job. To elaborate, you don't feel the suspension moving as much as you feel a sense of seemingly uninterupted traction. And the folks who claim the freedrive climbs very well are telling the truth. I was impressed at the bikes ability to go uphill at such a portly weight. I can only imagine the teocali climbs even better since it is lighter.
    Go ride it, ride other stuff you are interested in, and buy what feels best to you and suits your riding style best. One thing about mongoose I like a lot is you will get more bang for your buck in the component spec. All those Wally world bikes that are sold help this cause... So everytime someone says "oh I have a mongoose too!" and it's a walgoose, thank them for helping your bike to be spec'd nicer than others in the same price range.
    Sorry for the long post!

  19. #19
    www.derbyrims.com
    Reputation: derby's Avatar
    Join Date
    Jan 2004
    Posts
    6,787
    Edited above in one place of each post to add "-like". This more accurately describes the similarity as I had intended to communicate, as acting much like a URT, possibly with some difference in braking action compared to a simple high pivot URT.

  20. #20
    locked - time out
    Reputation:
    Join Date
    Jan 2010
    Posts
    759
    Wow. Politician's answer. If you didn't know anything about the suspension, why a wordy, bloated, inconsistent answer that proves you're only answering for the sake of answering and sounding intelligent?
    Last edited by glitz; 03-27-2010 at 03:14 AM.

  21. #21
    mtbr member
    Reputation: Iridethedirt's Avatar
    Join Date
    Jan 2008
    Posts
    576
    A unified rear triangle is not very similar to an isolated drive train really, derby.
    The URT tries to accomplish the same desired effect but falls short in several catagories. Isolated drive trains like freedrive, allow for a linkage based movement of the drivetrain whch is far better at keeping the suspension active while standing, braking, etc. URTs fall short there. It's just not as similar as you'd think. The linkage is key in the function and in it's ability to remain so active while keeping chain tension a non issue. The urt also stiffens way more when standing as well. Some like it, I don't. Freedrive works very well... Try it out... You'll see!

  22. #22
    mtbr member
    Reputation: Iridethedirt's Avatar
    Join Date
    Jan 2008
    Posts
    576
    Quote Originally Posted by glitz
    Wow. Politician's answer. If you didn't know anything about the suspension, why a wordy, bloated, inconsistent answer that proves you're only answering for the sake of answering and sounding intelligent?
    Were you replying to me or derby? My answers show I obviously know SOMETHING about suspension systems, old and new. I am no pro for sure, but at least I offered helpful insight based on experiance riding the design! All you did was flame.
    So politicians answer.... Ok, you are less helpful than that, flamng troll answer helps nothing.

  23. #23
    locked - time out
    Reputation:
    Join Date
    Jan 2010
    Posts
    759
    Replying to derby, of course.

  24. #24
    CTB
    CTB is offline
    mtbr member
    Reputation: CTB's Avatar
    Join Date
    Feb 2008
    Posts
    1,156
    Here's a video of the Teocali (2008) moving through its rear travel. This shows how the links move, including the little black one at the BB. One thing I noticed is that the axle path of the Teocali is purely recessional, which would help with ride quality. Most bikes that aren't URT's have some form of precession (axle moves forward) after a period of recession (axle moves backward). Since bumps try to move the axle rearward, having recession helps with impact harshness over sharp inputs.

    Here's the video - make sure to choose the 480p option in the lower right of the play window.

    http://www.youtube.com/watch?v=w6VHDRAvlsc

    It's only 2.5 MB, so if anyone wants the actual AVI file, I can email it to you.

  25. #25
    mtbr member
    Reputation:
    Join Date
    Jan 2009
    Posts
    351
    Very cool -- thanks for posting.

  26. #26
    mtbr member
    Reputation: Iridethedirt's Avatar
    Join Date
    Jan 2008
    Posts
    576
    Awesome video. I knew it had a rearward axle path but wow... I can't help but think that has gotta help the isolated drivetrain in keeping pedaling forces separate from suspension activity. The DW link uses an extremely rearward initial movement to the axle path to keep pedaling forces from influencing suspension activity. I really enjoy seeing the bike industry innovate suspension design year after year, and to this point if I could have had any bike currently offered, I think I would have gone for the ibis mojo sl WTF. 23 lbs 5.5" of DW link suspension travel. Plus it is beautiful... It's also about 6500 bucks!
    Freedrive, as I see it, can compete against the offerings from giant, Gary fisher, specialized and trek. It can also compete with a lot of the DW link bikes. It does not beat them all out, but I know the bang for the buck catagory is dominated by mongoose's freedrive bikes. I hope to be able to throw my leg over at least a few more of these designs, and see how I feel they compare.
    Freedrive does exactly what it is supposed to do. I don't have a platform shock, and feel it does not even need one... That is good design. Mongoose freedrive is massivly underrated.

  27. #27
    CTB
    CTB is offline
    mtbr member
    Reputation: CTB's Avatar
    Join Date
    Feb 2008
    Posts
    1,156
    Quote Originally Posted by Iridethedirt
    The DW link uses an extremely rearward initial movement to the axle path to keep pedaling forces from influencing suspension activity.
    Wouldn't that have the opposite effect from what you are saying? If the axle path is extremely rearward and (and this is the key) has chain elongation from that rearward motion, then pedaling forces would work to constrain the suspension from moving. Pedaling force would work to pull the axle forward, against the motion that it wants to do. Am I all wet on this?

    To look at this further, I've put two more videos up to illustrate different cases. (Again, make sure to select 480p once Youtube finishes processing the videos.) One is the 2006 Ibis Mojo DW Link:

    http://www.youtube.com/watch?v=O09hJ6eZI-M

    Note how the pedal "kickback" is in the same direction as if you were pedaling. Thus, pedal forces promote suspension compression, or rather they don't fight it.

    Now look at the Turner 5-Spot DW Link:

    http://www.youtube.com/watch?v=eVQBu7ixhAg

    Note how the pedal "kickback" really is kickback - pedal forces work to stop the suspension from compressing. Also note that the axle paths are very similar.

    Thoughts?

  28. #28
    mtbr member
    Reputation: Iridethedirt's Avatar
    Join Date
    Jan 2008
    Posts
    576
    Quote Originally Posted by CTB
    Wouldn't that have the opposite effect from what you are saying? If the axle path is extremely rearward and (and this is the key) has chain elongation from that rearward motion, then pedaling forces would work to constrain the suspension from moving. Pedaling force would work to pull the axle forward, against the motion that it wants to do. Am I all wet on this?

    To look at this further, I've put two more videos up to illustrate different cases. (Again, make sure to select 480p once Youtube finishes processing the videos.) One is the 2006 Ibis Mojo DW Link:

    http://www.youtube.com/watch?v=O09hJ6eZI-M

    Note how the pedal "kickback" is in the same direction as if you were pedaling. Thus, pedal forces promote suspension compression, or rather they don't fight it.

    Now look at the Turner 5-Spot DW Link:

    http://www.youtube.com/watch?v=eVQBu7ixhAg

    Note how the pedal "kickback" really is kickback - pedal forces work to stop the suspension from compressing. Also note that the axle paths are very similar.

    Thoughts?
    Very interesting. So, if you notice the initial movement of the suspension is rearward, but less than i thought it was, less than the linkage makes it look like. these videos of suspension linkage motion are awesome, thank you for posting them! lets keep in mind, the true test of if it works or not, is the way it performs on the trail. that said, the axle path of the DW link does not funtion as i thought. the rearward initial axle path should in theory make pedaling forces unable to influence suspension motion. keep in mind, even the strongest pair of legs is no match for the amount of force impacts generate, so the idea of your pedaling causing chain tension to resist the initial movement of the suspension is kind of a non issue, combine that with suspension sag from rider weight and proper setup, and there isnt much rearward motion left... now, you see the axle path form a slight arc, moving the axle nearly verticle after the first small portion of rearward motion and then near the end of the axle path where it makes more of a significant arc forward, at this point in the travel most people are not pedaling. so pedaling forces influencing suspension activity would still be minimized with the DW link and the owners of the bike back up the claim. so to sum it up. the initial rearward motion will combat pedaling kickback for the majority of the time you are pedaling since the suspension is only mildly compressed under the proper amount of sag. the path is then mostly verticle, so again pedaling kickback is still fairly minimal, and the forward motion of the axle path is only most dramatic for the last third or so of the travel, a time when almost nobody is pedaling. There is a reason people RAVE about the DW link.
    I have never ridden it, i really would love to, and give it a true test instead of "bench racing" the designs based on diagrams and theory... even though that is fun too!
    I can't say if its better than the freedrive system, i haven't ridden the DW link. I can say that the freedrive system, again, is a major underdog, and isnt given the proper credit. I would love to go test ride all of the most popular, highly regarded suspension designs and compare them to one another. the DW link isnt quite as amazing as i thought when i see it in the animated schematic, but i would love to ride it! plus that mojo looks SOOO good!
    haha, great thread after the flaming stopped! keep it coming!

  29. #29
    CTB
    CTB is offline
    mtbr member
    Reputation: CTB's Avatar
    Join Date
    Feb 2008
    Posts
    1,156
    Quote Originally Posted by Iridethedirt
    keep in mind, even the strongest pair of legs is no match for the amount of force impacts generate, so the idea of your pedaling causing chain tension to resist the initial movement of the suspension is kind of a non issue
    Definitely not true. This wasn't my idea about pedaling forces - many discussions/articles about rear suspension design talk about this very thing being used in exactly the way I describe it. Pedaling forces are absolutely used to counteract suspension bob by providing some anti-squat forces in some designs, but certainly not all. Also, look at URT designs like John Castellano's (Schwinn Sweetspot, Klein Mantra, etc). The behavior of those suspensions is drastically altered by merely shifting rider weight from the seat to the pedals, so rider weight and pedal force definitely have enough magnitude to matter. I was merely pointing out that even the "same" design (in this case, DW Link) can behave very differently.

    I've never ridden a DW bike, either, but I'd love to try one. From what I've read, the Turners are much more firm and less plush than the Mojo, and this analysis may be one reason why. Turners are supposedly excellent for being immune to pedal bob, and the Mojo is supposedly excellent for absorbing trail inputs and still not bobbing much, if at all. These bikes just aren't available near me to try out, though.

    You're spot-on about "the proof is on the trail." On paper, my 4-Banger isn't all that great, but out on the trail it does exactly what I want it to do. You can't ride a spec sheet or a graph.

    Sidebar: Has anyone looked closely at the 2nd-gen Schwinn Rocket 88 and compared it to a DW Link design? It's not all that different. I'm curious how Rockets were for pedaling, as I've never ridden one of those, either. I'm attaching a photo of the Rocket, plus this diagram:



    but less than i thought it was
    That's the case with a lot of bikes. When one looks at VPP suspensions, the axle path is a lot less S-shaped than all the hype/press would lead you to believe. There's a lot of exaggeration out there for marketing reasons.

    If you have an interest in these types of analysis, get the Linkage bike software over at www.bikechecker.com. I have the $25 personal version, seeing no need to spend the $100 or $200 (whatever it was) on the professional version. There's a huge library of bikes in the web database, and it's a lot of fun to play with. You can also create you own models, as I have done with my own bike:

    http://www.youtube.com/watch?v=8Y-Oohpaa30

    Sicklines uses the software in many of their bike reviews.

    haha, great thread after the flaming stopped! keep it coming!
    Indeed!
    Attached Thumbnails Attached Thumbnails Freedrive...single-pivot suspension?-7.jpg  

    Last edited by CTB; 03-28-2010 at 11:29 AM.

  30. #30
    mtbr member
    Reputation: Iridethedirt's Avatar
    Join Date
    Jan 2008
    Posts
    576
    Well when I am wrong I am wrong! I wasn't saying though, that pedaling force cannot be used to help with anti squat qualities, more just maybe misunderstood what you meant. I was saying just that the DW link isn't going to stiffen significantly enough through pedaling at the top of the travel to cause it to become less compliant over bumps as a result of chain tension. Not that pedaling forces can exert no energy as to effect the suspension, obviously that's not true or we wouldn't have so many designs trying to counteract the negative qualities like pedal bob, etc. I should have been more clear. Either way, I am no expert.
    As a side note, I would also like to ride the other designs sharing the same patent as the freedrive, like the GT idrive. I remember the first incarnation of the idrive design back around 97 or maybe 98. I thought they were incredible at the time, with the BB rotating in the odd essentric linked through the "dog bone" to the rear triangle... I wanted one of those bikes badly! Were there earlier linkage based isolated drive train suspension designs?

  31. #31
    www.derbyrims.com
    Reputation: derby's Avatar
    Join Date
    Jan 2004
    Posts
    6,787
    Quote Originally Posted by Iridethedirt
    A unified rear triangle is not very similar to an isolated drive train really, derby.
    Freedrive works very well... Try it out... You'll see!
    I bet the Freedrive does ride very well if consistent with my analysis, better than a URT, better than most other well hyped suspension designs.

    Many Horst links especially the ICT and many of the FSR's have linked and so called "isolated" suspension, but pedal very similar and nearly identical to lower more active monopivots, however braking is usually much less stiffening than a monopivot, more active, grippy, and stable. I'm just pointing out that links don't make the action, what does is the rotation centers and paths, leverage rates, chain tension, and reaction to weight shift are the physical constraints no matter how it's linked up and "isolated" or not.

    It is as if the Freedrive has a high pivot URT-like design for pedaling, and a low pivot URT-like design for braking. I say it's "URT-like", but that label may be too "politically" charged. How else can we compare designs without labeling similar acting designs?

    I must ride one to confirm for myself it actually rides as well as I have analyzed it should.

    The ride is the true test of quality and performance.

  32. #32
    www.derbyrims.com
    Reputation: derby's Avatar
    Join Date
    Jan 2004
    Posts
    6,787

    nailed it

    Quote Originally Posted by Iridethedirt
    Were you replying to me or derby? My answers show I obviously know SOMETHING about suspension systems, old and new. I am no pro for sure, but at least I offered helpful insight based on experiance riding the design! All you did was flame.
    So politicians answer.... Ok, you are less helpful than that, flamng troll answer helps nothing.
    Iridethedirt nailed it.

    I wish I had some politician in me, some smooth talk and witty sales ability. Sorry, but I'm just a matter-of-fact, always honest participant, hoping for constructive critique and intelligent dialog to learn more about my favorite hobby.

  33. #33
    What?
    Reputation: mullen119's Avatar
    Join Date
    Aug 2009
    Posts
    3,812
    Quote Originally Posted by CTB
    Wouldn't that have the opposite effect from what you are saying? If the axle path is extremely rearward and (and this is the key) has chain elongation from that rearward motion, then pedaling forces would work to constrain the suspension from moving. Pedaling force would work to pull the axle forward, against the motion that it wants to do. Am I all wet on this?

    To look at this further, I've put two more videos up to illustrate different cases. (Again, make sure to select 480p once Youtube finishes processing the videos.) One is the 2006 Ibis Mojo DW Link:

    http://www.youtube.com/watch?v=O09hJ6eZI-M

    Note how the pedal "kickback" is in the same direction as if you were pedaling. Thus, pedal forces promote suspension compression, or rather they don't fight it.

    Now look at the Turner 5-Spot DW Link:

    http://www.youtube.com/watch?v=eVQBu7ixhAg

    Note how the pedal "kickback" really is kickback - pedal forces work to stop the suspension from compressing. Also note that the axle paths are very similar.

    Thoughts?

    Maybe I am misunderstanding what your saying, but the max chain growth on the free drive was 4mm while the other two designs had max chain length growths of 18mm and 23mm . Wouldnt that keep chain and pedal feed back to a minimum?

  34. #34
    CTB
    CTB is offline
    mtbr member
    Reputation: CTB's Avatar
    Join Date
    Feb 2008
    Posts
    1,156
    Yep, it would certainly help. I was forgetting that the BB moves on the Freedrive. Good call, Mullen.

  35. #35
    mtbr member
    Reputation: Iridethedirt's Avatar
    Join Date
    Jan 2008
    Posts
    576
    I will add that while at first i did notice a bit of movement at the BB on my Khyber, noticing that sensation went away within the first ride or two. I think I mentioned it before, but if not I will say it (again?) the freedrive system feels different than other designs in that you do not feel the suspension moving, you just notice bumps smoothed out and a sensation of traction and tire contact with the ground over rough stuff to the point of feeling almost strange, but in a good way. I am not super experiances with all the latest desgns, in fact I've not ridden many. But I have ridden several different types, unified rear triangles, high and low single pivots, 4 bar, and I even got to experiance an ibis bow-ti on mt tam back in the late 90s. The freedrive is different. I believe after seeing that awesome animated analysis of the the suspension movement, the reason it feels so different is the very rearward axle path with very little chain growth... Riding the design coupled with seeing the video posted earlier (again thank you for that!) just confirms what I already suspected... Mongoose freedrive is a underrated system that slips under the radar of most mtn bikers because of the walgoose stigma. I can't wait till my riding buddy gets his giant reign x so I can swap bikes and see if it is the holy Grail of suspension tech it is being hailed as. Who knows maybe it is. I will keep an open mind and post about it when the day finally comes.

  36. #36
    CTB
    CTB is offline
    mtbr member
    Reputation: CTB's Avatar
    Join Date
    Feb 2008
    Posts
    1,156
    I don't know that any suspension is considered the holy grail, but some are certainly held in higher regard than others. Maestro has gotten good press, and a friend of mine likes his quite a bit. Yet another brand I was hoping to sample on last year's massively rained-out demo day. Hopefully this year will be different. After this discussion, I wish 'Goose were going to be there so I could try a Freedrive.

  37. #37
    What?
    Reputation: mullen119's Avatar
    Join Date
    Aug 2009
    Posts
    3,812
    I wish I had something to compare free drive too, The only other FS bike I have ever had was a first generation I drive like 6 years ago. I don't even remember what it felt like to ride it. I would love to be able to test a bunch of designs back to back so I could compare them on a trail.

  38. #38
    CTB
    CTB is offline
    mtbr member
    Reputation: CTB's Avatar
    Join Date
    Feb 2008
    Posts
    1,156
    We have a demo day here in May that generally has Specialized, Giant, Trek, GT, Scott, and some others. I don't think Goose will be there, though. Last year it got rained out. This year I hope to make up for it. I only got to ride $17000-worth of bikes last year.

    A ha! Mongoose is listed (I figured with GT there, it might happen). Also Cannondale. For anyone who lives near the Detroit area, come on out. It's a great day when it doesn't rain, and sometimes you get swag. I got two nice bottles, a seat post bag, and a Cannondale beanie last year.

    http://mmba.org/forum/viewtopic.php?f=1&t=95333

  39. #39
    What?
    Reputation: mullen119's Avatar
    Join Date
    Aug 2009
    Posts
    3,812
    Quote Originally Posted by CTB
    We have a demo day here in May that generally has Specialized, Giant, Trek, GT, Scott, and some others. I don't think Goose will be there, though. Last year it got rained out. This year I hope to make up for it. I only got to ride $17000-worth of bikes last year.

    A ha! Mongoose is listed (I figured with GT there, it might happen). Also Cannondale. For anyone who lives near the Detroit area, come on out. It's a great day when it doesn't rain, and sometimes you get swag. I got two nice bottles, a seat post bag, and a Cannondale beanie last year.

    http://mmba.org/forum/viewtopic.php?f=1&t=95333

    I might go to that! I live just outside of cleveland so its not to far of a drive. Any address that I could put in my GPS?

  40. #40
    CTB
    CTB is offline
    mtbr member
    Reputation: CTB's Avatar
    Join Date
    Feb 2008
    Posts
    1,156
    Sure is! Go here and look for "Island Lake."

    http://mmba.org/trail-guide/#1

    12950 E. Grand River, Brighton, MI 48116

    You're looking at about 3.25 hours from Cleveland, pending traffic, etc. Cleveland is 2.5 hours from me, and Island Lake is a good half hour further northwest.

  41. #41
    What?
    Reputation: mullen119's Avatar
    Join Date
    Aug 2009
    Posts
    3,812
    Quote Originally Posted by CTB
    Sure is! Go here and look for "Island Lake."

    http://mmba.org/trail-guide/#1

    12950 E. Grand River, Brighton, MI 48116

    You're looking at about 3.25 hours from Cleveland, pending traffic, etc. Cleveland is 2.5 hours from me, and Island Lake is a good half hour further northwest.

    I think it would be worth the drive, never had a chance to ride a bunch of diffrent bikes in the same day before, I think I will be there as long as I have time.

  42. #42
    CTB
    CTB is offline
    mtbr member
    Reputation: CTB's Avatar
    Join Date
    Feb 2008
    Posts
    1,156
    If you see a 4-Banger there, that'll be me.

    I hope they do have Gooses there. I want to try one.

  43. #43
    Singletrack Slayer
    Reputation: Lastshot's Avatar
    Join Date
    Apr 2008
    Posts
    94
    Quote Originally Posted by CTB
    If you see a 4-Banger there, that'll be me.

    I hope they do have Gooses there. I want to try one.
    Definatly hop on one! I like mine very much, It has some very nice characteristics that I like compared to my friend Canon lefty

  44. #44
    CTB
    CTB is offline
    mtbr member
    Reputation: CTB's Avatar
    Join Date
    Feb 2008
    Posts
    1,156
    If they have a Teocali there, I'll certainly try it. The Otero isn't a Freedrive suspension, right?

  45. #45
    Singletrack Slayer
    Reputation: Lastshot's Avatar
    Join Date
    Apr 2008
    Posts
    94
    Quote Originally Posted by CTB
    If they have a Teocali there, I'll certainly try it. The Otero isn't a Freedrive suspension, right?
    Correct

  46. #46
    mtbr member
    Reputation:
    Join Date
    Jun 2005
    Posts
    42
    I have owned 2 freedrive bikes. An 8" ecd and a 4" ecx. I have owned dwlink bikes and tried alot of other suspension systems as well. The mongoose bikes were by far the best pedaling designs I've ever tried. The low amount of chain growth with the high pivot is an amazing combo for pedaling and was a big eye opener for me. These bikes cornered well and were active under braking. The negative of these bikes for me was the flickability/ jumping factor. I wouldn't say it was bad.... but it is different. It isn't your normal pull up on your handlebars and pop the bike feeling. This feeling is dampened with the rear shock between the handlebars and the bottom bracket ( the hand/ feet connection ). unlike a normal suspension bike where there is no damper interference between your feet and hands. But if flickability isn't a priority, these bikes are tough to beat and should be considered as a top contender for pedaling performance. better than dwlink ithink. Thats my opinion as an suspension hobbyist.

  47. #47
    mtbr member
    Reputation: Iridethedirt's Avatar
    Join Date
    Jan 2008
    Posts
    576
    my 08 khyber bb link pivot bearings are destroyed. so, for those of you riding the freedrive, if you hear a slight creaking sounding a lot like a loose BB and feeling pretty similar too, you should check the bb link pivot bearings, mine came out in pieces and the outer race of two of them in stuck in the frame! pay attention to your BB link pivots.. they aparently will get destroyed easily. good luck!
    btw: if anybody has bearing sizes, or part #s it would be SUPER helpful, my LBS is not a mongoose dealer.

  48. #48
    mtbr member
    Reputation:
    Join Date
    Jun 2006
    Posts
    7,734
    Get the bearing number off the bearing's rubber seal. It will most likely be a 4 digit number starting with a "6", and then go to www.mcmaster.com and buy replacement bearings of the same number.

  49. #49
    What?
    Reputation: mullen119's Avatar
    Join Date
    Aug 2009
    Posts
    3,812
    Quote Originally Posted by Iridethedirt
    my 08 khyber bb link pivot bearings are destroyed. so, for those of you riding the freedrive, if you hear a slight creaking sounding a lot like a loose BB and feeling pretty similar too, you should check the bb link pivot bearings, mine came out in pieces and the outer race of two of them in stuck in the frame! pay attention to your BB link pivots.. they aparently will get destroyed easily. good luck!
    btw: if anybody has bearing sizes, or part #s it would be SUPER helpful, my LBS is not a mongoose dealer.
    I dont know if the bearings are the same for the kyber as they are for the teocali, but from what I can find, This is a link to the bearings for the teocali. http://www.vxb.com/page/bearings/PROD/Kit8622

  50. #50
    mtbr member
    Reputation: Iridethedirt's Avatar
    Join Date
    Jan 2008
    Posts
    576
    Quote Originally Posted by mullen119
    I dont know if the bearings are the same for the kyber as they are for the teocali, but from what I can find, This is a link to the bearings for the teocali. http://www.vxb.com/page/bearings/PROD/Kit8622
    12x16x10 needle bearing????

    what pivot is this for on the teocali, and what year?

    The bearing size for the Bottom Bracket link pivot on an 08 khyber is 8x16x5 it requires 4 bearings. and it seems the right crank arm must be pulled in order to access one bearing. i removed the chain rings to get access to the bolt and remove it, but i believe in order to pull it from the frame and press a new one, the crank arms must be removed.


    here is a link to what i feel is the best option short of buying 65 dollar (each!) ceramic abec 7 bearings.
    http://www.ride-this.com/index.php/a...ource=googleps

    The enduro max bearings are using twice the number of balls in the bearing rather than a ball within cage design. they claim (and it makes sense) this allows the bearings to withstand a larger load, and hold up for longer. a few things i learned about bearings while researching which ones to buy;
    ABEC is a rating system, I would steer clear of anything less than ABEC 5 (goes up to 9) for high stress pivot bearings. ZZ means it is a cartridge bearing with metal "dust covers" RS or 2RS means they use rubber dust covers ie: Rubber Seal, the 2 means that they are on both sides. there are a lot of inline speed skaters using "mini bearings" which are the 688 bearings, the larger 608 bearings are the typical and standard skate bearing size, for both skateboard wheels and inline skate wheels, lots of these bearings come in big multipacks, and are also designed to spin freely and fast, not what we want in a pivot they are also often times not packed with grease as fully as a pivot bearing should be. a mtb pivot bearing should be fully packed with heavier grease than what you'd find in a skate bearing, or machine bearing. often times machine bearings (what you'd get from VXB, or mcmaster carr) are designed to go into electric motors, so they are minimally greased so that they do not contaminate the motors the are installed into. eduro bearings were the ones i chose for 3 reasons: the enduro max series makes a claim of increased load bearing capacity due to twice the number of balls/no cage. and they are designed for purposes other than use in machines with high rpm duties. The last reason is that i heard good things about them, and it was reccomended i look into them. If you want to get bearings from mcmaster carr, pop the dust caps and pack those suckers with grease. all i know is that this is my first go-round with pivot bearings, and i plan to update with how my home methods for pressing and removing bearings goes. i got the stuck bearing race out no probelm with a flathead and stubby hammer. i was super careful not to gouge the mounting surface, and did very well. however, i wouldnt reccomend this method to others because of how risky it is. What i would reccomend is lots of attention to your pivot bearings. any noise at all should be located, and fixed asap, this problem didnt show itself slowly, it came up pretty quick went from occasional creaking to full noise, and not untill i removed the rear shock and moved the swing arm through the travel did i notice ANYTHING binding in the slightest. like i said earlier, it felt and sounded like a loose bottom bracket... so freedrive owners, pay attention to your bottom bracket link pivot, it is undersized and as a result the bearings life span is maybe 1/4 of the other 3 pivots.
    I will add pictures soon. hopefully this helps someone else in a similar spot to me.

Page 1 of 2 12 LastLast

Posting Permissions

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