Page 3 of 5 FirstFirst 1 2 3 4 5 LastLast
Results 51 to 75 of 120
  1. #51
    Join Date
    Aug 2020
    Posts
    130
    There are now 1239 skis from 2021-22 in the comparator...

  2. #52
    Join Date
    Aug 2020
    Posts
    130
    Quote Originally Posted by J. Barron DeJong View Post
    Is there a reason those raw measurement graphs can’t be your ‘something better’?
    We added the raw measurements of bending and torsional stiffnesses in the comparator (i.e., full stiffness profile) along with 5 points flex/torsional stiffnesses in the table. It is like the Ski Flex Index, but normalized by a fixed number for all skis.

    Let us know what you think of that.

  3. #53
    Join Date
    Jun 2020
    Posts
    5,529
    Quote Originally Posted by alude View Post
    We added the raw measurements of bending and torsional stiffnesses in the comparator (i.e., full stiffness profile) along with 5 points flex/torsional stiffnesses in the table. It is like the Ski Flex Index, but normalized by a fixed number for all skis.

    Let us know what you think of that.
    Looks good. Much better than just the single number for both flexes.

    Could I suggest two additional numbers to consider adding in the charts?

    1) measured ski length, instead of just nominal, since not all companies measure the same way, and companies themselves aren’t always consistent (eg. a 177 Mantra measures a bit longer than nominal, a 184 a bit shorter)

    2) running length of the ski base (like effective edge length, but for the base)

  4. #54
    Join Date
    Aug 2020
    Posts
    130
    Quote Originally Posted by J. Barron DeJong View Post

    Could I suggest two additional numbers to consider adding in the charts?

    1) measured ski length, instead of just nominal, since not all companies measure the same way, and companies themselves aren’t always consistent (eg. a 177 Mantra measures a bit longer than nominal, a 184 a bit shorter)

    2) running length of the ski base (like effective edge length, but for the base)
    We are now showing the nominal length, the actual measured length, the running length (base contact point when the ski is flat) and the sidecut length (length from widest points of tip and tail). Note that you won't get good values for skis before 2020-21, as we were not measuring the full length back then.

    You can also now click on any points on the graph to add a ski to the current comparison.

    Enjoy!

  5. #55
    Join Date
    Aug 2020
    Posts
    130
    We recently looked at the scaling of a few different models. We found that a many skis, but not all, are basically not scaling up the full camber profile but just "extending" the tip/tail. That means that the running length is the same and that just the tip/tail are getting a bit longer. Sometime the flex is also perfectly identical to the shorter size.

    You can find an example here of the Mantra M6. The 177, 184 and 191 all have the same running length. The sidecut length however still increases with length, so more of the edge should engage when the ski is inclined. The 184 and 191 also have the exact same stiffness profiles, both in bending and torsion (the 177 is only a tiny bit softer). I would suspect that the 184/191 would feel almost identical on hard snow (but mass and sidecut radius are different).

    Has anyone skied them and could comment on how the different lengths feel? Do you feel that the differences between lengths are more subtle than for other models?

    In general, do you feel that the running length should also scale up with length? If not, why do you think it makes sense to keep it constant?

  6. #56
    Join Date
    Sep 2006
    Location
    North Van
    Posts
    3,757
    This is really cool, and helps explain differences between skis I expected to be similar. For example, 188 QST 106s were powerful carvers whereas 181 QST 99s felt vague on edge. I was wondering if the 99s were softer, but the tests show flex to be similar. Other than length, the 99s have substantially more taper and a shorter sidecut length for a given overall length, which I think is a big part of what I was feeling.

  7. #57
    Join Date
    Jul 2004
    Location
    NorCal
    Posts
    2,285
    Hi alude,

    Your DB includes a ski labelled as "2010 Line While Blister 182cm". I've never heard of it.

    Is it merely fake data inserted for software testing? Or maybe a rare early prototype of the Line Supernatural 108? Or what?

    See it is the top row highlighted in Section2 at https://compareskis.shinyapps.io/com...b=%22Select%22

    .
    - TRADE your heavy PROTESTS for my lightweight version at this thread

    "My biggest goal in life has always been to pursue passion and to make dreams a reality. I love my daughter, but if I had to quit my passions for her, then I would be setting the wrong example for her, and I would not be myself anymore. " -Shane

    "I'm gonna go SO OFF that NO ONE's ever gonna see what I'm gonna do!" -Saucerboy

  8. #58
    Join Date
    Aug 2020
    Posts
    130
    Quote Originally Posted by D(C) View Post
    This is really cool, and helps explain differences between skis I expected to be similar. For example, 188 QST 106s were powerful carvers whereas 181 QST 99s felt vague on edge. I was wondering if the 99s were softer, but the tests show flex to be similar. Other than length, the 99s have substantially more taper and a shorter sidecut length for a given overall length, which I think is a big part of what I was feeling.
    Yeah, what is scaled is quite different between models/companies. I think it would be great to identify which properties makes a ski feel longer/shorter and what scaling level is "standard". We could then have a better sense if the next length up/down will feel significantly different or not. What should be on the list of things to check? Running length, mass, flex, torsional stiffness, other things?

  9. #59
    Join Date
    Aug 2020
    Posts
    130
    Quote Originally Posted by Vitamin I View Post
    Hi alude,

    Your DB includes a ski labelled as "2010 Line While Blister 182cm". I've never heard of it.

    Is it merely fake data inserted for software testing? Or maybe a rare early prototype of the Line Supernatural 108? Or what?
    That is a bad label, but good guess! :-)

    It was the prototype of the Line Supernatural 108, as documented here: https://blisterreview.com/gear-revie...pernatural-108. We should probably remove it. I don't think it is a good practice to have "prototype" skis in the database.

  10. #60
    Join Date
    Jul 2004
    Location
    NorCal
    Posts
    2,285
    Quote Originally Posted by alude View Post
    ...It was the prototype of the Line Supernatural 108, as documented here: https://blisterreview.com/gear-revie...pernatural-108...
    Found it. Blister called this prototype the "Mystery Ski" by Line in 2014.


    .
    Attached Images Attached Images  
    - TRADE your heavy PROTESTS for my lightweight version at this thread

    "My biggest goal in life has always been to pursue passion and to make dreams a reality. I love my daughter, but if I had to quit my passions for her, then I would be setting the wrong example for her, and I would not be myself anymore. " -Shane

    "I'm gonna go SO OFF that NO ONE's ever gonna see what I'm gonna do!" -Saucerboy

  11. #61
    Join Date
    Jul 2004
    Location
    NorCal
    Posts
    2,285
    PM sent, to alude.

    Basically, I want to go VERY DEEP into this with alude or with anyone at SoothSki willing to give me the time, which will make me come across as a "stalker" here on TGR. So...alude can advise me if he wants me to spew everything here publicly, or via email/PM's, or what.

    .
    - TRADE your heavy PROTESTS for my lightweight version at this thread

    "My biggest goal in life has always been to pursue passion and to make dreams a reality. I love my daughter, but if I had to quit my passions for her, then I would be setting the wrong example for her, and I would not be myself anymore. " -Shane

    "I'm gonna go SO OFF that NO ONE's ever gonna see what I'm gonna do!" -Saucerboy

  12. #62
    Join Date
    Nov 2018
    Posts
    1,298
    Vitamin I - if you could somehow get all the skis from your collection into the DB, I would be immensely grateful!

  13. #63
    Join Date
    Mar 2006
    Posts
    109
    very funny how some armada ski's seem to be on the stiffer side of the spectrum given their reputation. Whitewalker seems an outlier ski , very light, very stiff. the declivity's seem to be stiffer than comparable ski's as well (the TI108's )
    i was looking at the black crows anima 182. i think the numbers on this one are wrong (waist width, tail width, profile,..)

  14. #64
    Join Date
    Aug 2020
    Posts
    130
    Quote Originally Posted by slashy View Post
    very funny how some armada ski's seem to be on the stiffer side of the spectrum given their reputation. Whitewalker seems an outlier ski , very light, very stiff. the declivity's seem to be stiffer than comparable ski's as well (the TI108's )
    That is one of the first thing that surprised me while using the comparator to find skis. I didn't know very much about Armada's skis, but when I searched for skis by specs, one of their ski would almost always come up. I didn't look in detail, but they seems to have a more varied lineup than just freestyle skis.

    Quote Originally Posted by slashy View Post
    i was looking at the black crows anima 182. i think the numbers on this one are wrong (waist width, tail width, profile,..)
    The 2020-21 seems OK, but there seem to be something wrong with the 2021-22. I will look into it. Thanks!

  15. #65
    Join Date
    Jul 2004
    Location
    NorCal
    Posts
    2,285
    Quote Originally Posted by slashy View Post
    ...i was looking at the black crows anima 182. i think the numbers on this one are wrong (waist width, tail width, profile,..)
    This link shows that the record for "Anima" seems to be polluted with many values found in the "Corvus Freebird" record.
    https://compareskis.shinyapps.io/com...=%22Compare%22

    .
    - TRADE your heavy PROTESTS for my lightweight version at this thread

    "My biggest goal in life has always been to pursue passion and to make dreams a reality. I love my daughter, but if I had to quit my passions for her, then I would be setting the wrong example for her, and I would not be myself anymore. " -Shane

    "I'm gonna go SO OFF that NO ONE's ever gonna see what I'm gonna do!" -Saucerboy

  16. #66
    Join Date
    Aug 2020
    Posts
    130
    Quote Originally Posted by Vitamin I View Post
    This link shows that the record for "Anima" seems to be polluted with many values found in the "Corvus Freebird" record.
    https://compareskis.shinyapps.io/com...=%22Compare%22

    .
    Thanks for the catch! We will correct that asap.

  17. #67
    Join Date
    Jul 2004
    Location
    NorCal
    Posts
    2,285
    I sent a couple emails to alude, hoping to kick off extensive discussions with him.

    For now, I might as well begin writing here...until maggots and/or alude tell me to shut up and take my excessive rantings to PM's/emails.

    DISCLAIMER: I have a "hidden agenda", to hopefully influence SoothSki to make improvements/choices that would also help serve my own maggot-based project, which might or might not make money someday (but likely just hobby/passion without any profits). Of course, I believe that whatever's good for my project is also good for the maggot community.

    So, I am VERY BIASED to be SoothSki's "biggest fan", and am willing to spend much effort to support their success---but to that end, I will also be focusing on many "negatives" to be considered as ways for SoothSki to positively improve their services. So I hope I won't come across as negative or rude.

    - - - - - - - - -

    HUGE THANKS to SoothSki for many things, but especially for:

    - Recent improvement of their measuring procedures to include the very ends of the tips and tails (new for the 21/22 ski models). So important!

    - Impressive response time to deliver the new RunningLength feature within 4 days of the feature request! (Also, only ~5 weeks for the requests for stiffness profile graphs, 5-point Stiffness Index, etc. ! )

    - 2 minutes per ski for the measurements. WOW! Such a KEY breakthrough towards ANY data-driven ski projects!

    - - - - - - -

    MY FIRST FEW IDEAS TO IMPROVE SOOTHSKI:
    (I apologize in advance if my many assumptions and guesses are wrong.)
    (I apologize if these ideas are already known issues.)

    1.) PREVENT "INCONSISTENT" AND "NOT LONG ENOUGH" LENGTH OF MEASUREMENT SWEEPS:
    From what I'm seeing, I think maybe this is the biggest source of error so far. Some skis (even some for 21/22) display graphs of profiles, where the measurements stop WAY too far away from the end of the tip/tail. I think maybe this single source of error is resulting in many bad consequences, including what I think is a significant inflation of the values for AVG bending and AVG torsion, which in turn invalidates 3 of the scatter plots displayed for comparing skis.

    alude, Is this an "incomplete measurement sweep" of the sensor caused by careless operator error? If yes, then maybe consider improving Operating Procedures and/or automated validation to ensure an adequate length is always measured. And if somehow TOO MUCH LENGTH is measured, then post-production logic can extract the appropriate subset of data from that.

    I think that the record for 16/17 Mantra was removed within the past 24 hours. That record seemed to have a significantly inflated AVG torsion value, because the very tip and tail were not "there" to bring the average down.
    Does this removal of 16/17 Mantra mean you are already addressing my issue above? What is your chosen method to address this issue? Just delete affected records? Or improve operating procedures? Or what?

    Similarly, this link below shows "incomplete horizontal sweep" of the sensor for the region at the end of the tail, even for a 2022 ski. This "sweep without any load" omitted the tail width point, and so results in bad consequences for many other reported values.
    https://compareskis.shinyapps.io/com...=%22Compare%22

    2.) MULTIPLE INSTANCES OF THE APP:
    Consider a 2nd instance of the app, which I hope would require mostly just an easy copy/paste in shinyapps---but make both instances "powered by" only ONE instance of the DB. Then declare one instance to be "for normal users" or consider it "production version" or whatever. And the 2nd instance to be "for R&D"...for the community of users/researchers/academics willing to tolerate inconvenient clutter and experimental features that might just fail in the end. This approach allows easy "divergent evolution" for possible separate user types, and later you could easily create a 3rd divergent branch if your work ends up revealing a way to target "non-nerd skiers" or whatever. Low cost (zero cost?) to increase number of instances on shiny apps.

    For example, when that user in the Newschoolers thread wrote that he'd like to try "Rotational Inertia" analyses, you can first implement that feature in the "for R&D" instance of the app, without annoying the "for normal users" instance until after that new feature is perfected first. Also, for example, I could try many of my ideas for new metrics (which require your data as inputs) and determine if any might turn out to be useful for "normal users".

    NEXT: IF YOU LIKE "MULTIPLE INSTANCES" IDEA, THEN MIGHT AS WELL FIX SOME STUFF BEFORE BRANCHING. But could continue to display "bad" data in the "R&D instance", to provide transparency for the community to see and help you identify possible reasons for the "bad" data.

    3.) REVERSE CAMBER VALUES WARRANT A DISCUSSION:
    Notice the "help text" for "Camber" displays a figure of a ski with straight line drawn from very end of tip to very end of tail.
    Notice the "help text" for "Camber" also displays the following words:
    "Negative camber, or reverse camber skis, have no gap under the binding when the ski is laid on a flat surface. Reverse camber skis usually offer more float in powder and effortless turn initiation. In these cases, the camber value is the distance between the boot center and an imaginary line drawn between the tip and the tail points."

    Notice the values displayed for negative camber ARE WAY INACCURATE.
    SOLUTION: I suspect the values are "by design", and I suspect the help text and figure are WRONG. I think the values are using a method which considers ONLY the segment from TipWidth to TailWidth. If yes, then easy to just fix the help text and figure.

    4.) SETBACK VALUES FROM PRE-"ACTUAL LENGTH" ERA WARRANT A DISCUSSION:
    The errors for Setback are just too big for skis without "Actual Length" values (so is that all the skis for 20/21 and earlier?). Those bad values cause more harm than good. With discussion, I think I can convince you to just stop displaying those values in a "normal users" instance of the app (but feel free to continue to display that "bad" data in an "R&D" instance of the app). I suspect those bad values cannot be salvaged by any post-production adjustment (other than re-measurement).

    5.) CAMBER VALUES WARRANT A DISCUSSION:
    I don't have conclusive proof yet for my hunch here...but my hunch is that your method for "base-up" measurement of camber might be inflating your values in a way that "normal users" are not accustomed to interpret properly. We could discuss your confidence about this, or instead you can challenge me to prove my hunch first. If I am correct about this "flaw", at least the good news is I suspect those values PERHAPS CAN INDEED be salvaged by a post-production adjustment. Requires discussion.

    More to come later...

    .
    Last edited by Vitamin I; 12-15-2021 at 05:16 PM.
    - TRADE your heavy PROTESTS for my lightweight version at this thread

    "My biggest goal in life has always been to pursue passion and to make dreams a reality. I love my daughter, but if I had to quit my passions for her, then I would be setting the wrong example for her, and I would not be myself anymore. " -Shane

    "I'm gonna go SO OFF that NO ONE's ever gonna see what I'm gonna do!" -Saucerboy

  18. #68
    Join Date
    Aug 2020
    Posts
    130

    Post

    Quote Originally Posted by Vitamin I View Post
    I sent a couple emails to alude, hoping to kick off extensive discussions with him.
    Well, I will never have time to reply to all your emails with comments here also! :-)

    Joking aside, we are a small team that work on this in a very part time way. We love it, but our bandwidth is somewhat limited. But we are listening.

    Quote Originally Posted by Vitamin I View Post
    So, I am VERY BIASED to be SoothSki's "biggest fan", and am willing to spend much effort to support their success---but to that end, I will also be focusing on many "negatives" to be considered as ways for SoothSki to positively improve their services. So I hope I won't come across as negative or rude.
    That is awesome. We very much appreciate all the comments!


    Quote Originally Posted by Vitamin I View Post

    1.) PREVENT "INCONSISTENT" AND "NOT LONG ENOUGH" LENGTH OF MEASUREMENT SWEEPS:
    From what I'm seeing, I think maybe this is the biggest source of error so far. Some skis (even some for 21/22) display graphs of profiles, where the measurements stop WAY too far away from the end of the tip/tail. I think maybe this single source of error is resulting in many bad consequences, including what I think is a significant inflation of the values for AVG bending and AVG torsion, which in turn invalidates 3 of the scatter plots displayed for comparing skis.

    alude, Is this an "incomplete measurement sweep" of the sensor caused by careless operator error? If yes, then maybe consider improving Operating Procedures and/or automated validation to ensure an adequate length is always measured. And if somehow TOO MUCH LENGTH is measured, then post-production logic can extract the appropriate subset of data from that.
    Many of these recents "not long enough" are due to convex bases. Our sensor used to measure the width/sidecut jump of the edge of convex bases and we have to remove this part of the data. Height/camber and full length should still be OK. We will improve the machine for next year, but there isn't much we can do with the data we already took.

    We are working on removing all calculated values that depends on this though (and also on full length measurement when we don't have them). I agree that it can be missleading right now. You will see some changes in the next few days/weeks.

    Quote Originally Posted by Vitamin I View Post
    I think that the record for 16/17 Mantra was removed within the past 24 hours. That record seemed to have a significantly inflated AVG torsion value, because the very tip and tail were not "there" to bring the average down.
    Does this removal of 16/17 Mantra mean you are already addressing my issue above? What is your chosen method to address this issue? Just delete affected records? Or improve operating procedures? Or what?
    Different issue. Full details here. Sorry about this. Our process is now much more robust.

    Quote Originally Posted by Vitamin I View Post
    Similarly, this link below shows "incomplete horizontal sweep" of the sensor for the region at the end of the tail, even for a 2022 ski. This "sweep without any load" omitted the tail width point, and so results in bad consequences for many other reported values.
    https://compareskis.shinyapps.io/com...=%22Compare%22
    As much as I like skiing the Sakana, they are a b**** to measure. The measuring head fall off the swallow tail before we can complete the width measurement (similar problem as with convex bases). I think one year we patched the hole with tape so that we could get better measurements (2021).

    I am realizing that the interpolation of height/camber doesn't work here though. Usually we do it only for the last 5 cm so it creates very little error. But in this case, interpolating over 20 cm just doesn't work. Any suggestions on what to do instead of interpolating to still show where the end of the ski is?

    Quote Originally Posted by Vitamin I View Post

    2.) MULTIPLE INSTANCES OF THE APP:
    Consider a 2nd instance of the app, which I hope would require mostly just an easy copy/paste in shinyapps---but make both instances "powered by" only ONE instance of the DB. Then declare one instance to be "for normal users" or consider it "production version" or whatever. And the 2nd instance to be "for R&D"...for the community of users/researchers/academics willing to tolerate inconvenient clutter and experimental features that might just fail in the end. This approach allows easy "divergent evolution" for possible separate user types, and later you could easily create a 3rd divergent branch if your work ends up revealing a way to target "non-nerd skiers" or whatever. Low cost (zero cost?) to increase number of instances on shiny apps.
    That would be great. We are thinking about it (and also adding many other "app" that would use the data in different ways). Shiny apps is not free and doing a 2nd instance of the app would make us bust our current hours. We would need to go up the next plan, which is 3x more expensive. Still not crazy expensive, but the only way we are supporting the app and the measurement right now is by using the sales of the machine. Not very sustainable, not the best business plan!

    Quote Originally Posted by Vitamin I View Post

    Also, for example, I could try many of my ideas for new metrics (which require your data as inputs) and determine if any might turn out to be useful for "normal users".
    If you are OK with sharing your metrics idea, please do. I feel that the best way to come up with something useful is to discuss it together. We could easily add an "experimental" section to the table and the graphs. No one "normal" would notice! :-)

    Quote Originally Posted by Vitamin I View Post

    NEXT: IF YOU LIKE "MULTIPLE INSTANCES" IDEA, THEN MIGHT AS WELL FIX SOME STUFF BEFORE BRANCHING. But could continue to display "bad" data in the "R&D instance", to provide transparency for the community to see and help you identify possible reasons for the "bad" data.
    We need to get better at revision control stuff and using community inputs to flag weird data. For now the best way is to contact us here, by PM on by email.

    [QUOTE=Vitamin I;6485199]

  19. #69
    Join Date
    Aug 2020
    Posts
    130
    Well, too many character for a single reply! Ahaah!

    Quote Originally Posted by Vitamin I View Post
    3.) REVERSE CAMBER VALUES WARRANT A DISCUSSION:
    Notice the "help text" for "Camber" displays a figure of a ski with straight line drawn from very end of tip to very end of tail.
    Notice the "help text" for "Camber" also displays the following words:
    "Negative camber, or reverse camber skis, have no gap under the binding when the ski is laid on a flat surface. Reverse camber skis usually offer more float in powder and effortless turn initiation. In these cases, the camber value is the distance between the boot center and an imaginary line drawn between the tip and the tail points."

    Notice the values displayed for negative camber ARE WAY INACCURATE.
    SOLUTION: I suspect the values are "by design", and I suspect the help text and figure are WRONG. I think the values are using a method which considers ONLY the segment from TipWidth to TailWidth. If yes, then easy to just fix the help text and figure.
    Yes, giving a number for reverse camber is hard. Any suggestions for a better number? We thought about camber radius...

    I am pretty sure we are now calculating the height from a line that pass through MaxTipWidthLocation and MaxTailWidthLocation. We will update the description and figure.

    Quote Originally Posted by Vitamin I View Post
    4.) SETBACK VALUES FROM PRE-"ACTUAL LENGTH" ERA WARRANT A DISCUSSION:
    The errors for Setback are just too big for skis without "Actual Length" values (so is that all the skis for 20/21 and earlier?). Those bad values cause more harm than good. With discussion, I think I can convince you to just stop displaying those values in a "normal users" instance of the app (but feel free to continue to display that "bad" data in an "R&D" instance of the app). I suspect those bad values cannot be salvaged by any post-production adjustment (other than re-measurement).
    Correct. We are working to correct that by displaying N/A for all values that depends on the full length measurement. Should be up shortly.

    No way to salvage these unfortunately.

    Quote Originally Posted by Vitamin I View Post
    5.) CAMBER VALUES WARRANT A DISCUSSION:
    I don't have conclusive proof yet for my hunch here...but my hunch is that your method for "base-up" measurement of camber might be inflating your values in a way that "normal users" are not accustomed to interpret properly. We could discuss your confidence about this, or instead you can challenge me to prove my hunch first. If I am correct about this "flaw", at least the good news is I suspect those values PERHAPS CAN INDEED be salvaged by a post-production adjustment. Requires discussion.
    There is no standard on how to measure camber. Some do with the ski laying on a surface, some do with the ski being positioned sideways, some do with both ski bases touching each other, so do with the ski standing up on a wall, etc. No measurement will be the same. We do it upside down because is it quicker/easier with the machine. When we put the ski upside down, its own weight actually slightly increases the camber (just guessing here, but let say 1-2 mm). The exact amount depends on the weight, the stiffness of the ski and the position of the supports. Before putting the reading head in contact with the ski, we raise the jack to support the ski in the middle. This is automated and applies just a tiny force. The nice thing is that it is super consistent. Once the jack is in place, the reading head will deform the ski by less than 0.5mm while taking the measurements.

    So we have very consistent results. Can skiers get use to that new "standard"?

    We could use the support positions, weight and bending stiffness of the ski to calculate the exact camber that would be measured using any other way. Would it be useful? You tell me!

    However, remember that camber can changes with temperature if the construction is not balanced and that 1-2 mm won't make a big difference on the pressure distribution on the snow as it requires very little force to fully flatten a ski...

    The beauty of EI/GJ measurements (vs deformed shape or distance) is that we could calculate the deformed shape of the ski under any given load! Interested?

  20. #70
    Join Date
    Aug 2020
    Posts
    130
    There is an interesting thread here comparing the Rustler 11 to the Mindbender 116C.

    You can look at them in the Sooth's Comparator. It is a fairly easy comparison as the shapes are almost identical.

    The MB116C is the same length, but has a bit longer tip and shorter tail. It has very similar running length (and same snow contact points wrt the mountpoint) and sidecut length/radius. It has a bit more tip/tail taper. It is about 200g lighter in the 186ish lengths. The recommended mount point is also 2 cm further back. Torsional stiffness profiles are pretty much identical. Bending stiffness is about 15-20% softer.

    Reviews on TGR say that the MB116C floats better. That is because of the mountpoint is further back (which means more front area vs back area). The softer flex probably also makes it bend and float more in powder.

    Reviews also say that the Rustler is more composed at speed (less tip flapping). That could be explained by the higher flex and shorter tip. The added mass probably also helps.

    There are more little differences in the 180ish lengths, but the same general observations apply. You can compare them here.

  21. #71
    Join Date
    Aug 2020
    Posts
    130
    Some of you have asked for it, so here is a little bit more about the history of Sooth Ski. Maybe one day we will be able to do automated recommendations like Netflix, but for now we just see the measurements as being part of the conversion between skiers, reviewers, reps, sale staff, manufacturers, etc. Getting feedback from someone you trust or skiing the skis yourself is still the best. It is just not always available.

    As for the "business model", to be honest, I have no idea what it will be or if we will be able find one. We had many idea and tried many things over the last few years (e.g., having a machine in each shop to measure the wear of skis... but turn out that stiffness doesn't change with use so that was out, offering ski fitting sessions, etc.). Right now the sales of the machine are going all to support the measurement efforts, the data processing and the online comparator. We are a little stupid that way, but we think that is the right thing to do for skiers and the community. We hope that we can continue to provide these measurements long term as we think they are useful for skiers. There is a slight hope that with traffic could come some small monetization opportunities (like everything on the internet) so that we can continue supporting this ... We will see!

    In the meantime, the online comparator is quite useful for post-Christmas shopping, so enjoy it or not!

  22. #72
    Join Date
    Jul 2004
    Location
    NorCal
    Posts
    2,285
    Quote Originally Posted by alude View Post
    ...For bending and torsional stiffness, it is more complex. We measure everything in between the supports of the machine, which we typically place at the points where the tip/tail start to rapidly curve up (not at the point of early-rise or at the start of the rocker, that would be too short in most case). Right now, the comparator displays the average value between that. Having a little variation about where you put the support is not critical. Take for example a ski that has an average value of 250 Nm^2 over a length of 150 cm. If we are missing 10 cm in the tip/tail @ 50 Nm^2, that means that we should have had (250*150 + 50*10)/(150+10) = 238 Nm^2, which is only 5% off.
    I've been examining the Sooth data to scrutinize those claims by alude.
    CONCLUSION: Great job at measuring stiffness, Sooth!

    Although I found (in general) that Sooth's stiffness measurements often extend for a "disappointingly incomplete" portion of the total length of each ski, NEVERTHELESS I believe alude is 100% right that they are "complete enough"---any possible "problems" from that incompleteness can be adjusted by post-measurement calculations/estimates in ways that will be "accurate enough" for even the wackiest deformation scenarios we want to simulate in the future. So, during measurement, I agree that "incomplete" sweeps of the rolling sensor (for bending and torsion) will not hurt much at all.

    Two example cases: I agree it won't hurt much that 29% of the length is unmeasured for the Renegade stiffness graphs, and also that 20% of the length is unmeasured for the more traditional Rossi Hero Master. For simulations, it would be "adequately accurate" for alude to just "fill in" the missing portions with smartly estimated imaginary data values. (FYI, those 2 skis are at https://compareskis.shinyapps.io/com...=%22Compare%22 )

    Quote Originally Posted by abraham View Post
    I wonder what you'd get by measuring where the ski crosses +0.5/1/1.5/2 cm vertically from the contact points? That might give you some interesting information about how the ski does in various 3d conditions...
    Ha! That's my idea too! But I would want to start that analysis on skis in a WhileDecamberedToAFlatSurface deformed shape, and I'd likely skip the 1.5cm elevation...I'd just try 0 / 0.5 / 1 / 2cm. Yes, alude is INDEED capable of calculating how his measured skis would deform to a WhileDecamberedToAFlatSurface shape, and I am willing to drive that effort forward with alude....but alude is a busy guy, so I don't know what priority he can give to "what if?" research ideas like this.

    Quote Originally Posted by alude View Post
    ...One exemple is the directional stability (https://www.mdpi.com/2504-3900/2/6/315). ...However, you can use a simpler equation to describe what is going on. It is still "complex" with 5 variables, but all the variable are currently available in the comparator (i.e., camber, ski length, bending stiffness, sidecut radius and edge angle)...
    alude, yes please start reporting experimental metrics like that 5-variable metric for "directional stability". If you think it is too confusing for most users, then you could report it all the way down at the bottom of the webpage---I am willing scroll all the way down to view experimental stuff like this !

    Quote Originally Posted by Marshal Olson View Post
    Vitamin I - if you could somehow get all the skis from your collection into the DB, I would be immensely grateful!
    Might happen someday. Most of my collection is in Truckee, so Sooth could bring their machine for one trip to measure:
    - my skis,
    - Moment factory
    - Praxis factory,
    - Mountain Mike's shop at Olympic Valley carries a bunch of maggot-worthy lengths of Palisades-worthy models (at least last time I checked, before COVID era)

    First, we would need to help alude figure out:
    - what time of year is best for the most inventory at Moment factory, Praxis factory, etc.?
    - how to confidently subtract the "binding effect" from measurements of my skis, and from the demo-mounted skis at Mountain Mikes, etc. (because I ain't willing to unmount all my skis for this project).

    .
    - TRADE your heavy PROTESTS for my lightweight version at this thread

    "My biggest goal in life has always been to pursue passion and to make dreams a reality. I love my daughter, but if I had to quit my passions for her, then I would be setting the wrong example for her, and I would not be myself anymore. " -Shane

    "I'm gonna go SO OFF that NO ONE's ever gonna see what I'm gonna do!" -Saucerboy

  23. #73
    Join Date
    Aug 2020
    Posts
    130
    In response to this. A few people have told us that the side profile looks weird. Our graphs are stretched vertically so that we can more easily compare the differences between skis. Some think it is too much, some think it is too little. I think also that part of the "doubting" comes from the line thickness that we are using (including the horizontal line), the fact that we just put a single ski on the image (vs two skis touching on their bases), and maybe just the habit of seeing pictures of tip/tail. Anyways, doubting is good.

    So I fired Powerpoint to compare the photo from SkiEssentials and from our measurements (we could do more complex things if you guys feel like it is necessary, but that would be possible only on the limited number of skis that we have). I am using this picture of the Bash 86 from SE. I am using this ski in our database. What I did is put the SE image in the background and then overlay the image from our comparator, choosing the white color of the graph as a transparency color. I then scaled our measurements to align the ends of the tip/tail and the contact points with the photo. Note that for the tip/tail, I put them where I think they should be given the 3D perspective. It is not perfect, but I am mostly just trying to see if it is way off or not. It is easier to compare when you can turn on and off the measured curve, but here are a few screenshots of what I get :

    Click image for larger version. 

Name:	Screen Shot 2022-01-04 at 9.18.07 AM.jpg 
Views:	330 
Size:	327.0 KB 
ID:	399681

    Click image for larger version. 

Name:	Screen Shot 2022-01-04 at 9.18.21 AM.jpg 
Views:	350 
Size:	330.0 KB 
ID:	399682

    Click image for larger version. 

Name:	Screen Shot 2022-01-04 at 9.18.33 AM.jpg 
Views:	350 
Size:	323.0 KB 
ID:	399683

    I think the fit is surprisingly good. I wasn't sure how well the comparison would work. Obviously, I trust our measurement, but this is a long and relatively heavy ski with very soft tips which could probably show the worst deformation we could get. There is also often lens distorsion in photos (think wide lens), and it is unlikely that we measured the exact same ski that is in the photo. I would say the overly is pretty good from the 80 cm mark at the tip all the way to 70-75 cm down the tail (for everything below 10 mm). It gets harder at the ends (distorsion due to variable ski width? lens distorsion? who knows...). Even the camber in the center seems to be good, even if we measure the camber upside down in our machine and here in the picture it is right side up.

    Of course, everything can look good when you look at a pixelated image!!!

    Hopefully that brings a bit more trust/understanding in our measurements (and/or improvements). Let us know if something else look weird and if you think we should display things differently.

  24. #74
    Join Date
    Aug 2020
    Posts
    130
    Been looking at this thread on the QST Blank, and found this:

    Originally Posted by D(C)
    My bet is that 194 QST Blank = 188 QST 106. The Blanks look to have longer tip and tail taper and rocker than the 106s.

    My bet as well. There is a lot of taper in those rockered sections.

    It's been a few years since I have been on the 188 106, but the 186 Blank felt like a tad less ski/is easier to manage and I kept thinking that the 188 106/194 Blank would be a fairer comparison.
    It is a quick check. Measurement are here. You can easily compare their shapes. For both Blanks, you have roughly the same running length (rocker starting points) and camber. It is just that the tip/tail are a bit longer for the 194. That will give it more float, but otherwise they would behave similarly in many conditions. There is more tip/tail taper on both Blanks when compared to the 106. The QST 106 188 has a longer running length than both of the Blanks. Its sidecut radius (21) is closer to the Blank 194 (19).

    The main difference between the 186/194 is the stiffnesses. The 194 is 15-30% stiffer than the 186 depending on where you look on the ski. The QST 106 in 188 is almost the same stiffness as the Blank 194 (just a bit torsionally softer underfoot).

    So yeah, that is a good bet!

  25. #75
    Join Date
    Sep 2006
    Location
    North Van
    Posts
    3,757
    Quote Originally Posted by alude View Post
    Been looking at this thread on the QST Blank, and found this:



    It is a quick check. Measurement are here. You can easily compare their shapes. For both Blanks, you have roughly the same running length (rocker starting points) and camber. It is just that the tip/tail are a bit longer for the 194. That will give it more float, but otherwise they would behave similarly in many conditions. There is more tip/tail taper on both Blanks when compared to the 106. The QST 106 188 has a longer running length than both of the Blanks. Its sidecut radius (21) is closer to the Blank 194 (19).

    The main difference between the 186/194 is the stiffnesses. The 194 is 15-30% stiffer than the 186 depending on where you look on the ski. The QST 106 in 188 is almost the same stiffness as the Blank 194 (just a bit torsionally softer underfoot).

    So yeah, that is a good bet!
    Nice! That's quite helpful.

    Having these ski measurement comparisons available will be helpful for picking ski models and lengths to try, similar to how looking at geometry charts and suspension kinematics curves for bikes can be used. But I have found with bikes that what’s on paper can give a starting point, and there are certain elements that can turn out differently when actually riding (some of that could come down to the accuracy of the available information). I will be interested to test how on-snow feel compares with what I would expect from the ski measurements.

Posting Permissions

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