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  1. #51
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    Quote Originally Posted by iheartbicycles
    This would be fun to do - but honestly it's getting tiresome. Like you, I am always skeptical and I think this would be a good exercise. It's not going to happen today, though..
    Agreed the anaylsis is not something that can be completed at a key stroke. I have 2+ years into some of my job related anaylsis. First, you would have to have all the critical measurements of all the frames which would require a NDA from all the frame manufactures. Or you get a tape measure that is +/-.001

    Quote Originally Posted by iheartbicycles
    BTW - do you know what software sherwood used to design the suspension of the ventana?
    I have no idea. I will let him answer that if he chooses.

    Quote Originally Posted by iheartbicycles
    When I worked in the industry only about 1/2 the company's used any software, relying on physical models instead. I've worked with many an engineer that weren't degree'd.Charlie Cunningham, Steve Potts, Mark Slate, Erik Koski, etc. Have spent a good amount of time talking with Brent Foes as well.

    None of these guys use FEA. They just break ****. Then before they put it into production, they make it stronger.
    I use to work with a lot of smart "older timers" at Lockheed that were not degreed engineers. A degree doesn't make someone smart it gives them a good tool box to work with. But someone has to have a good amount of smarts to get an engineering degree. I think the difference boils down to common sense.

    If you don't have an engineering degree you really are not an engineer. And in the State of California if you do not have a Professional Engineering License then you can't sell your services as an engineer.

    http://www.pels.ca.gov/licensees/pe_act.pdf

    Quote Originally Posted by iheartbicycles
    I can't tell you who - but a very prominent bike company actually builds its suspension models starting with cardboard cut outs! These guys just have mechanical instincts and don't rely on computer models. I don't think that in any way discounts their capabilities.
    I don't think so either as long as their product doesn't fail leaving folks dead. And it works. I remember the glamour of the 1990's the cottage industry were pumping out pretty CNC'd parts......with little or no analysis. I had a college buddy that was the test engineer for RS when they were in San Jose......Ohhhh the stories. The difference being Optimization or build not to fail

    Quote Originally Posted by iheartbicycles
    Would you require of them a CAD/CAM drawing with kinematic analysis?

    Software is only a tool used to speed up the process - it is not a process in and of itself.
    Santa Cruz bikes have been in numerous engineering industry publications for their design analysis. It's very cool to see bike companies using high tech engineering tools. It's one link in the design process that has to be validated. But the beauty is once you spend the time to input all the data it's very easy to "save as" and start on a new frame design.

    I became an engineering right at the start of parametric solid modeling.....Pro/E was the first to go main stream. I remember a seat costing $25K not including the UNIX workstation to run the software that was an additional $50K. So small companies were locked out of this market until 1998 when SolidWorks came to market with a $5K solid modeling software package that ran on a PC which made it affordable for a lot of smaller companies.

    http://www.ptc.com/products/proengin...-pro/index.htm

  2. #52
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    Is there just one single factor to having satisfaction in a frame one rides. Guess the Jet9 owners are satisfied having a recall as they have less anti-squat. DW Turner riders are satisfied having to break down their fames and add grease every month. Let alone only able to run certain crankests as not to hit the chain-stay because they may have less anti-squat. I admit I'm not a suspension guru! But what effect in this anti squat debate does running a coil versa air shock?

    Now I'm heavier than most around here and run my Pushed RP23 in PP mode. I noticed very little bob when pedaling as I do move to the front of the saddle. I also get full travel from my El Rey with 5 inch rocker. I don't doubt there could be frames that pedal better than a Ventana. But I'm just trying to understand why this is the sole reason one would choose one frame or another! For me there are frames out there that would flex all over the place as the Intense 5.5 EVP I had. I hated that frame yet it was a VPP and it should have less anti-squt than my El Rey.
    Currently at Mayo Clinic being tested for a kidney transplant. Donors welcome.

  3. #53
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    Iheartbycles, I just want to say good job bringing out real data, and sticking to your guns in the face of this much fandom, it is pretty obvious to any outside reader that most of the posters here are completely biased and unwilling to consider any negative traits of their bike. I personally can list off half a dozen things about each of my bikes that I don't like, or think could be better, but that doesn't mean they are still not the best bikes I've ever ridden, but if I find a new bike that fixes the problems of the old, then that is what I will be riding, I wont keep my head in the sand blind to other options, and other bike's strengths over mine.

  4. #54
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    Quote Originally Posted by Flystagg
    Iheartbycles, I just want to say good job bringing out real data, and sticking to your guns in the face of this much fandom, it is pretty obvious to any outside reader that most of the posters here are completely biased and unwilling to consider any negative traits of their bike. I personally can list off half a dozen things about each of my bikes that I don't like, or think could be better, but that doesn't mean they are still not the best bikes I've ever ridden, but if I find a new bike that fixes the problems of the old, then that is what I will be riding, I wont keep my head in the sand blind to other options, and other bike's strengths over mine.
    I think iheart did a great first swag at the analysis but like I stated in my posts it needs to be substantiate with mainstream analysis software coupled with hand calculations.....not forgetting a viable engineering test plan. Anything less is a SWAG with pretty pictures.

    I like my Ventana with the good, bad and ugly. I like Sherwood....he's a great chap. Like most posters here they may or may not understand all the physics behind FS bikes. That doesn't discount their opinion on the fit, feel or performance of any FS bike. It's an opinion.

    Since we're offering up design challenges here list up your half dozen things.......can you hand out hard calculations what you don't like or could better about your bikes? I don't think anybody here has their head in the sand....they are riding what they like for reasons told and untold. I personally would like to own a Turner if they did semi-custom front triangle changes like Ventana offers but they only offer color changes. So that puts Turner off of my list.

    It's been my experience as an engineer that it's very easy to criticize someone elses design when you're staring at hardware but a lot harder to come up viable ideas when you're starring at a white sheet of paper or blank computer screen.

  5. #55
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    Right on!

    Quote Originally Posted by mtnbiker4life

    It's been my experience as an engineer that it's very easy to criticize someone elses design when you're staring at hardware but a lot harder to come up viable ideas when you're starring at a white sheet of paper or blank computer screen.
    Very true. Since this is the internet, I'll throw in my 2 cents: I like the motivation of Iheart to try and quantify a feeling on the bike. How far off the numbers are...who knows.

    Though I am curious about Iheart referring to inertia and then talking about F=ma. Those two aren't the same. I'd think if you are talking about leverage ratios and antisquat, you have to be talking about moments of inertia. Which, now that I think about it...that probably is what he was talking about when he (or someone) referred to being about the bike's center of gravity.

    I also wonder if that software package is doing a static or dynamic analysis. Yes, a static analysis should give you a fair indication as to a frames ability to resist "bob." However, I'd argue that bob is a dynamic characteristic and doing a dynamic analysis...you need to consider the effect of rider weight shifts as well.

    Anyway, I'd say the qualitative sense of the analysis he did though does seem to mach my experience (though I guess limited). Last summer I rented a Heckler with an RP23 in Downieville when I had issues with the ring drive on my CK hub that couldn't be fixed while there. I have a pushed RP23 on my 07 X-5. The heckler with unmodified RP23 felt a lot stiffer under pedaling than my X-5. However, I liked riding my X-5 better, for whatever reason. Also, (I haven't asked Push this myself), but someone on here once had issues with their pushed RP23...felt it was too soft and bobing too much. They reported that after talking to Push...the usually tune down the platform on the RP23 for the Ventanas. So, that may explain why the heckler felt stiffer under pedaling. But again, I liked the ride of my X-5 (same fork on both bikes) much better than the heckler.

    And, FWIW, I just finished up my MSME and I've often thought about drawing up a frame in SOLIDWORKS and running an Analysis in ANSYS (which for me...modeling the rider input to the bike would be the biggest challenge). But, I'd rather ride my bike with my free time.

  6. #56
    change is good
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    Uhhh. I have a Pivot and a El Cap and a El Rey. Engineering analysis aside, which I'm not qualified to perform, I have come to the conclusion that both designs have weaknesses and strengths. My PUSHed Ventanas feel better in the techy stuff. The Ventanas have better mud clearance. The Pivot and my old Blur packed up like crazy. Stiffness of the El Cap is unparalleled (I think). The El Rey and the Pivot are about equal as far as stiffness. The Pivot is a better pedaler. Not outstandingly so, but it is noticeable to me. I can tweak the Rey to be just as efficient, but then I lose the plushness. That being said, my Ventanas still put a smile on my face. I liked my Weyless XP either in AM or XC trim much more than the Blur I had at the time. The way a bike performs for a specific rider is much more important than graphs to me. That being said if the techno stuff turns you on, so be it.

  7. #57
    Shot Down in Flames...
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    W[SIZE="1"]here[/SIZE]TF is uktrailmonster? And why hasn't he responded to this thread? That guy could shed some light on this pissing match.


    D.

  8. #58
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    + / -

    Does the selection of pivot location always involve compromises? If so, a good designer picks one which maximizes the positive aspects of that trade-off. I believe this to be true of all suspension designs, not just Ventana's. If he ends up with something satisfying the majority of users most of the time has he not chosen well?

  9. #59
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    I like my squatty ventana. I don't have extended fireroad climbs, I have ledgy, rocky, rooty climbs and I like a stiff rear end that is active.

    Is it less pedal-efficient? Sure.
    Is it more efficient to not have to use body english to get over everything? Sure!

    Hey, Iheartarguingaboutbicycles...you have your work cut out for you. You can throw as many scienticians at this as you can hire, but you aren't going to change too many minds that like their Ventanas...and that is the majority of the people on this very quiet board. Good luck with that. You held out pretty well, and starting a new thread was good (note that I haven't really chimed in due to the tone), but you digress again in insulting people. Not going to get sucked into that.

  10. #60
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    squat on climbs is well documented.

    Just another reference to it that I posted a long time ago:
    Quote Originally Posted by CharacterZero
    Saturday: 16ish mile ride. Good first leg to stretch out the legs and then lots of up/down/technical riding with a few creek crossings and steep switchbacks, followed by a sweeping descent that begs for little braking.

    The bike felt great! The TM is a stronger climber than the X-6 was (with the fork at any length). The front end was easier to keep on the ground, especially around uphill switchbacks. On the way down, the rear end felt very smooth, this was running both 5 clicks of compression and 0 clicks compression on the PUSH'd shock. (FWIW, PUSH removes the PP functionality - it is hard-wired based on rider weight/style. The PP lever then becomes a straight compression dampening function.). The performance of the shock is in line with what you expect from PUSH - it felt snappy on acceleration on the flats with minimal compression dampening, but wallowed a bit on the steeper stuff. Then again, I wouldn't sacrifice an active rear suspension for anything, so the bit of wallow is completely acceptable. The geometry is definitely a bit more drop-friendly; it took almost no body english to get the front end up while approaching ledges, just a slight tug. I didn't notice the longer wheelbase. Standover was fine (although close - but the wife says that it can only save us money on a vasectomy). BB height was noticeably lower (both in feeling just a bit lower and a couple pedal strikes in sections that I hadn't had before). .

  11. #61
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    Quote Originally Posted by CharacterZero
    I like my squatty ventana. I don't have extended fireroad climbs, I have ledgy, rocky, rooty climbs and I like a stiff rear end that is active.

    Is it less pedal-efficient? Sure.
    Is it more efficient to not have to use body english to get over everything? Sure!

    Hey, Iheartarguingaboutbicycles...you have your work cut out for you. You can throw as many scienticians at this as you can hire, but you aren't going to change too many minds that like their Ventanas...and that is the majority of the people on this very quiet board. Good luck with that. You held out pretty well, and starting a new thread was good (note that I haven't really chimed in due to the tone), but you digress again in insulting people. Not going to get sucked into that.
    I can't tell if people simply don't understand what I am saying or are reading into what I am saying - but I am absolutely NOT arguing against ventana bikes as a whole. I am explaining with a level of exactitude the reasons why the bikes squat. This thread is a response to many, many threads posted on the subject wherein several users try to ascertain what the problem is. The problem is very specific.

    With regard to technical climbs - you're absolutely right - my 6" travel bike is much better than either my 4" travel bike or even my hardtail - no question about it. I would even go so far as to say an active single pivot (in my case I have a Foes FXR, but it would probably hold true for the Ciclon and Terremoto as well) would climb better than a DW link!

    BETTER THAN A DW LINK!

    Because DW's stiffen noticably when pedalling, they do stiffen up and will skip a little over rocks.

    I have owned the DW's and can make this comparison directly. It's one of the reasons I dropped the DW for my "all mountain" bike.

    But with regard to a specific problem/question - the squatting that is so noticable with my Salty is directly due to the main pivot placement and lack of antisquat. So many other single pivots do not have this problem and that information is easy to come by.

    With regard to "digressing into insulting people" (sic) go back and read the thread - I've only used the term "fanboi" and suggested people keep their heads in the sand - meanwhile I am called several names and no one seems to think anything of those.
    Last edited by iheartbicycles; 09-23-2009 at 08:53 AM.
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  12. #62
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    Quote Originally Posted by iheartbicycles
    With regard to "digressing into insulting people" (sic) go back and read the thread - I've only used the term "fanboi" and suggested people keep their heads in the sang - meanwhile I am called several names and no one seems to think anything of those.
    Sorry, you are correct, you don't insult anyone in this thread.
    No doubt there are some real fanbois around here.

  13. #63
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    Quote Originally Posted by mtnbiker4life
    I think iheart did a great first swag at the analysis but like I stated in my posts it needs to be substantiate with mainstream analysis software coupled with hand calculations.....not forgetting a viable engineering test plan. Anything less is a SWAG with pretty pictures.

    I like my Ventana with the good, bad and ugly. I like Sherwood....he's a great chap. Like most posters here they may or may not understand all the physics behind FS bikes. That doesn't discount their opinion on the fit, feel or performance of any FS bike. It's an opinion.

    Since we're offering up design challenges here list up your half dozen things.......can you hand out hard calculations what you don't like or could better about your bikes? I don't think anybody here has their head in the sand....they are riding what they like for reasons told and untold. I personally would like to own a Turner if they did semi-custom front triangle changes like Ventana offers but they only offer color changes. So that puts Turner off of my list.

    It's been my experience as an engineer that it's very easy to criticize someone elses design when you're staring at hardware but a lot harder to come up viable ideas when you're starring at a white sheet of paper or blank computer screen.
    I haven't forgotten about this and I still intend to check all measurements myself. My guess is you will once again raise the bar or change the level of proof required.

    That's ok. People who read this thread will make up their own minds. For me, I am always learning and you have actually caused me to think beyond what most people do.
    Stupid, but sometimes witty. Occasionally brilliant. Slow and fat though.

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  14. #64
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    Quote Originally Posted by iheartbicycles
    I haven't forgotten about this and I still intend to check all measurements myself. My guess is you will once again raise the bar or change the level of proof required.
    The level of proof required is totally governed by how much creditability you wish to gain from the results you have put forth. Since, this topic is related to physics and engineering, I have mealy stated what you need to provide to be taken seriously in the engineering community. I am not saying your results are wrong and some on mtbr may blindly take them as absolute truth. But as an engineer, I have to ask for some test methodology if I am to take these results as reliable analysis.


    Quote Originally Posted by iheartbicycles
    That's ok. People who read this thread will make up their own minds. For me, I am always learning and you have actually caused me to think beyond what most people do.
    Iím a little confused about this statement. Because you have stated there are folks on this forum that do not understand the physics regarding this type of analysis so they really canít make up their own minds, can they? I am sure there is a way to present this data so the lay-person can understand your methodology.

    -

  15. #65
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    Quote Originally Posted by mtnbiker4life



    Iím a little confused about this statement. Because you have stated there are folks on this forum that do not understand the physics regarding this type of analysis so they really canít make up their own minds, can they? I am sure there is a way to present this data so the lay-person can understand your methodology.

    -
    Ventana fanboi's aren't the only people who read this forum. Those with an open mind and a little technical knowledge will see the thread for what it is.
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  16. #66
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    Quote Originally Posted by iheartbicycles
    Ventana fanboi's aren't the only people who read this forum. Those with an open mind and a little technical knowledge will see the thread for what it is.

    Arm-chair engineer strikes head with hammer. Repeats. ?
    Since when did Need have anything to do with this?

  17. #67
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    Truthfully, I'm disappointed with the armchair engineer. He hasn't done the anti-squat profiles of all hardtails in existance yet.

    Quote Originally Posted by icegeek
    Arm-chair engineer strikes head with hammer. Repeats. ?
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  18. #68
    tl1
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    Pro squat and proud

    ...of it.
    Attached Images Attached Images

  19. #69
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    I hear the new Squatnleavit Constipation is the ultimate anti squat.

  20. #70
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    Quote Originally Posted by tl1
    ...of it.
    tl1

    Brilliant! You have validated with undisputed scientific evidence the old adage that " a picture is worth a thousand words."

  21. #71
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    On the salty is there a difference when using 5" rockers over 4", with the correct fork travel up front?

  22. #72
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    So...Does this program really cost $199?
    I only ride bikes to fill the time when I'm not skiing.

  23. #73
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    Quote Originally Posted by OldHouseMan
    So...Does this program really cost $199?
    you can download trial software for free - but the full blown version ain't cheap.
    Stupid, but sometimes witty. Occasionally brilliant. Slow and fat though.

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  24. #74
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    There is no magic bullet. Even if you have 100 pivots., ther is no getting around axle path/chain growth relative to the bottom bracket.(chain tension induced "anti squat") etc. Suspension performance is relative to the rider/style of riding. There are many types that have different charecteristics. Pick your poison. 1st gen VPP's have a lot of chain growth (chain tension induced "lockout"). So much so, that if set your chain up too short, compressing the suspension will rip the rear derailure off. Any suspension design can have a lot or little chain growth. The only thing unique I see about DW, is the chain growth has been tuned to be chainring dependant (or at least more so than other designs). That's why the man himself says the hammerschmidt will not work well with his design. Although I'll bet it works just fine for some people. The terrain on this planet as well as riding styles are too diverse for any single design to be "better" than another. This doesn't even take execution of the design in to account, which is a huge factor in performance.

    my .02

  25. #75
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    This is very well put. Each rider will have preferences and a riding style that is met better by one design over another.

    Your $0.02 is in reality, the gold standard.
    My presence would be the equivalent of painting lamb's blood on your frame, causing the "angel of crash" to nail me instead.

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