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Fair Wheel Crank test #4

Viewing 15 posts - 1 through 15 (of 24 total)
  • #93181
    Keymaster

    Welcome back to the 4th installment of the crank shootout.

    New cranks that have been added for this round are Ax Lightness Morpheus, Extralite QRC2 and Rotor 3d.  The next round will include the new Tune Smartfoot, Thm M3 and hopefully a production version of EE.

    Note. There are several changes to the review.

    Change 1.  First and foremost, errors were corrected.  I must have been drunk when I wrote the last review, as there were a lot of typos in the numbers, they were all quite minor and don’t really effect the overall picture, but still there were a lot of them, so for that I’m sorry and hope to get them all straight this time.

    Change 2.  Average deflection will be carried out to 3 decimal places.  Previously I only used 2 decimal places in the review so some cranks appeared to be equal when in reality there were small differences.  The actual testing was carried out to 3 decimal places so it seems ideal to take advantage of those small differences.

    Change 3.  We wanted to go to a more universal stiffness to weight ratio so we are once again changing it.  I ran the numbers and it doesn’t change the order that cranks finished in previously nor does it really change the margins between them but it might be a bit more universal.  ((1/average deflection)/weight)x100

    So on to the review.  These are the cranks we’ll be looking at for part 4 of this review, in alphabetical order.
    1. Ax Lightness Morpheus
    2. Campag Record UT
    3. Easton EC90
    4. EE
    5. Extralite QRC
    6. Extralite QRC2
    7. FSA K-Force Light
    8. FSA SLK-Light
    9. Kcnc Ktype
    10. Lightning SL
    11. Lightning HD
    12. PMP MicroII
    13. Rotor 3d
    14. Shimano Dura Ace
    15. Sram Red
    16. Storck Powerarm SL
    17. Stronglight Fission
    18. Stronglight X-wing
    19. Thm Clavicula
    20. Tune Fast Foot 6pack
    21. Zipp Vuma quad

    A couple of notes on how the deflection testing was done.  Each arm was preloaded with 50lbs.  From there another 200 lbs was added and the difference was measured in inches.  Each arm was tested twice and an average of those two measurements is what I will post.  A lower number represents a stiffer crank.  These will be labeled as Deflection-D(Drive side deflection) and Deflection-ND(non-drive side deflection)

    NOTE #2 We have now added a corrected weight to even the comparison in weight of sets.  All corrected weights are complete with BB and using TA rings.  In some cases we mounted a set of TA rings, in other cases we weighed the stock rings and corrected the total to represent  the TA set of rings.  We feel this gives a more even comparison of differences in the cranks and less of that in the rings.  TA rings are available for almost every crank in this test with the exception of 2(XWing and Zipp)

    Now on to the test.
    ———————————–

    Ax Lightness Morpheus
    Claimed Weight: 380grams
    Actual Weight: 389grams
    Corrected Weight: 513grams
    Q-factor: 151mm
    Spindle: 30mm
    Deflection-D: 0.192
    Deflection-ND: 0.345
    Average Deflection: 0.268
    S/W:0.704

    Likes:  Weight.  Aesthetics.  This is a nice looking crank as a complete unit, however the finish at a detail level does harken to the function over fashion ideal.  I particularly like the molded Ax logo which is in a color that’s sure to match any bike.   Superlight with a good stiffness to weight ratio.  Adjustable crank lengths (170, 172.5 and 175 inserts are all included with the crank.)  Easy installation and it includes a nicely made tool.   Oh, and did I mention that it’s light.

    Dislikes:  151mm Qfactor, I’d like to see it narrower.  Price.  Like some of the other superlights this one too has a weight limit.

    Neither like nor dislike:  Durability.  Obviously this crank is light and Ax is known for pushing the limits of what could or should be done.  It will be interesting to see what kind of long term durability a crank this light has.  I also wonder if the pedal inserts will become a source for creaking noises.   We’ll update this review as more long term use reports come in.
    ———————————–


    Campagnolo Record Ultra Torque
    Claimed Weight: 690grams w/bb
    Actual Weight: 702grams w/bb
    Corrected Weight: 694grams
    Q-factor: 145mm
    Spindle: 25mm
    Deflection-D: 0.163
    Deflection-ND: 0.279
    Average Deflection: 0.221
    S/W:0.644

    Likes:  Aesthetics, it’s a very simple and clean looking crank.  Looks good on almost any bike.   Q-factor is 2nd narrowest in the test which is great for most people.   The rings shift quality and durability is also near the top of the charts.

    Dislikes:  Setup.  The design requires tight frame tolerances, it’s often not a plug and play kind of crank and is known to have issues with creaking noises.  Also the proprietary bcd on the compact seems a bit annoying, however I’m giving them the benefit of the doubt in thinking that the compact gained something from the odd length 5th arm.  The chainring bolts that are ridiculously priced are well beyond explanation(it’s just plain gouging).  Also since a very high torque is required to attach the two arms it would be nice if it were a bit easier to find the proper torque wrench attachment(for the price of these cranks the tool should be included.)

    ——————————-


    Easton EC90
    Claimed Weight: 663grams
    Actual Weight: 671grams complete
    Corrected Weight: 681grams
    Q-factor: 146mm
    Spindle: 24mm
    Deflection-D: 0.200
    Deflection-ND: 0.352
    Average Deflection: 0.276
    S/W: 0.539

    Likes:  A nice all around crank.  Very easy installation.  Shifts well and has a decent q-factor.  I also liked that the chainring bolts used were allen key backed on a torx front.  I like that the non-drive arm obscures the bearing cup by fairing it.  I also like the raw functional look of the UD carbon.  Ceramic bb option is reasonably priced.

    Dislikes:  The graphics and pedal insert.  For some reason those two aspects give the crank a cheapish look.   I also can’t understand why someone taking this long to get into the crank market would go with the 24mm spindle rather than a larger spindle.   The only reason I can think of for this is that they choose to target the oem module market over building a better crank.

    ——————————-


    EE Proto
    Actual Weight: 669grams
    Corrected Weight: 629
    Q-factor: 142mm
    Spindle: 30mm
    Deflection-D: 0.144
    Deflection-ND: 0.225
    Average Deflection: 0.185
    S/W: 0.803

    Note:  I didn’t plan on including this in the test as I only wanted cranks that I could put miles on and have some real world feedback on.  It turns out that this is an older prototype and there is already a version after this one, that meant that this one was available for me to use for testing.  Please note this crank will not be available for sale I’m including it just for fun.

    Likes:  In terms of technical function, this is the best balance I’ve seen yet in a crank.  Low weight, high stiffness, very narrow q-factor, fantastic shifting(with DA rings).  Having this has only made me hope that they decide to one day put a crank into production again.  I also liked how the bearings were retained in the cups with clips making a bearing change much easier than on all the other outboard setups.

    Dislikes:  Gold, though I suspect there are alternate hardcoats that can be used in other colors.  The other complaint I’d have with this as a production crank is that the left and right bearings have different IDs.  This is accomplished by a very thin ti shim between a bearing and spindle.   Similar to how THM has done it, but in this case it’s not bonded to the spindle.  It’s possible this could lead to creaking issues, but I don’t know  that is true, nor did I have any noise issues.
    ——————————-


    Extralite QRC
    Claimed weight: 485grams no rings
    Actual weight: 484grams no rings
    Corrected weight: 615grams
    Q-factor:138mm
    Spindle: 22mm
    Deflection-D: 0.206
    Deflection-ND: 0.513
    Average Deflection: 0.359
    S/W: 0.452

    Likes:  Weight.  A really good weight particularly for an alloy crank.  I absolutely love the 138mm Q-factor.  This is one of very few integrated cranks that give you the ability to adjust the preload on the bearings, another great feature. Far narrower than any other crank.  Looks are good, setup is quite easy and the bearings run smooth and long.  All in all the ideas and execution are top notch.

    Dislikes:  I don’t like that it is only available in compact.  I also would love to see it a bit stiffer.  I’d gladly trade a few grams to increase the bb diameter which should stiffen the crank a bit.

    ——————————


    Extralite QRC2
    Claimed weight: 485grams no rings
    Actual weight: 479grams no rings
    Corrected weight: 603grams
    Q-factor:138mm
    Spindle: 27mm
    Deflection-D: 0.222
    Deflection-ND: 0.439
    Average Deflection: 0.331
    S/W: 0.501

    Likes: This is a lot like the original and has all the same likes(weight, q-factor, looks, bearings, setup).  Add in the new lighter weight, stiffer design and it’s an improvement over an already nice crank.  I also really appreciate the self extracting mounting bolt as a nice upgrade over the previous.

    Dislikes:  Again I don’t like that it is only available in compact.  I would still like to see it gain a little more stiffness. There also seems to be an issue with the hidden bolt tab needing to be filed with some rings but not others in order to ensure they run true.
    ——————————


    FSA K-force Light
    Claimed weight: 660grams
    Actual Weight: 721grams w/bb
    Corrected Weight: 711grams
    Q-factor: 147mm
    Spindle: 24mm
    Deflection-D: 0.164
    Deflection-ND: 0.309
    Average Deflection: 0.236
    S/W: 0.587

    Likes: I like that the QFactor has gone narrower with these cranks than the SLK and I like the lower weight.  The finish is nice and the cranks look good on most bikes.  One detail I did appreciate was the carbon plug that covers the hollow spindle on the drive arm.  Although it’s a minor detail it does show that they are focusing on improving their line with each generation.  Another plus are the ceramic bearings.  As I understand it, the bearings are sourced from Ceramic Speed which is known for high quality ceramics.

    Dislikes:  Maybe I’m being a bit picky here, but why do ceramic cups have to be red?  When spending over $500 on a crankset it seems like one should be afforded a neutral color choice.  The only other thing I can find to complain about the set we received is that they are only available in compact and a 53t is not available.

    ——————————


    FSA SL-K Light
    Claimed Weight: 780grams w/bb
    Stock Weight: 766grams w/bb
    Corrected Weight: 732grams
    Q-factor:150mm
    Spindle: 24mm
    Deflection-D: 0.149
    Deflection-ND: 0.278
    Average Deflection: 0.213
    S/W: 0.612
    Lateral-D: 0.005

    Likes:  The best thing I can say about this crank is that it is stiff.  Right on par with DA and Campag.  It’s a nice looking crank and typically has a price that makes it quite a deal for a carbon crank.

    Dislikes:  Previous versions of their carbon cranks have been unpredictable.    The cranks vary in weight by as much as 40-50 grams per set.  Often spiders and rings were not true.(however after sampling a a group of the SL-K Light, that does seem to be vastly improved).  Rings also could use some improvement in their shifting quality and a reduction in q-factor would be nice.

    ——————————-


    Kcnc Ktype
    Claimed Weight: 740grams
    Actual Weight: 706grams
    Corrected Weight: 674grams
    Q-factor: 145mm
    Spindle: 24mm
    Deflection-D: 0.223
    Deflection-ND: 0.407
    Average Deflection: 0.315
    S/W: 0.450

    Likes:  Price, this is the least expensive crank we tested.  Shift quality is quite high.  Bearing quality is good and installation is very easy.   Definitely a great bargin in terms of 700gram cranks.

    Dislikes:  I’d like to see a version with a bit more stiffness, perhaps with a 30mm spindle.

    ——————————-


    Lightning SL
    Claimed weight: 445grams no rings
    Actual Weight: 448grams no rings
    Corrected Weight: 572grams
    Q-factor:144mm
    Spindle: 30mm
    Deflection-D: 0.260
    Deflection-ND: 0.355
    Average Deflection: 0.307
    S/W: 0.542

    Lightning HD
    Actual Weight: 592grams w/bb
    Q-factor: 144mm
    Spindle: 30mm
    Deflection-D: 0.264
    Deflection-ND: 0.361
    Average Deflection: 0.313
    S/W: 0.519

    Likes: I had a very early version of this crank several years ago, and while functionally it was great, the carbon work left alot to be desired in the aesthetics.  The change in the appearance was the most striking difference to me.  This new version is well built with no real visible flaws in the carbon.  I also like that they seem to have aimed at a balanced crank.  It hits the middle of the field in almost every category.  It’s light.  It’s reasonably priced compared to it’s carbon competition.  Like the Extralite crank the Lightning has a bb that is preload adjustable, a big plus in my book.  Setup is easy and performance is good.

    Dislikes:   The recessed pedal insert may cause problems of heal rub for some riders, the fix for that is a spacer which could possibly cause problems with not getting enough contact with the pedal threads.  I was going to complain about the graphics, but the cranks can be ordered without them.   Has a weight limit, a high weight limit but does still carry one.  (220lbs SL and 280lbs HD)

    The long term reports are coming back now and overall durability seems to be very good.  There have been some QC issues which seem to be decreasing in frequency over time, and Lightning has been pretty good about addressing them in the past as they had arisen.

    ——————————


    PMP MicroII
    Claimed Weight: 825grams
    Stock Weight: 845grams
    Corrected Weight: 814grams
    Q-factor: 147mm
    Spindle: 17mm
    Deflection-D: 0.204
    Deflection-ND: 0.683
    Average Deflection: 0.44
    S/W: 0.256

    Likes:  It’s different.  I really like that they went a bit off the beaten path to try something different with this crank.  The crank looks nice and all the parts fit together well.  The setup is very time consuming though it works quite well when done.  The chainrings were my favorite part, the machining is great and they function quite well.  I like the overall look of the crank as a unit, especially the black one.  I also like how the crank arms fit over the outboard cups making for a clean transition.

    Dislikes:  Stiffness, or lack thereof.  This is the least stiff crank we tested as well as also being the heaviest, not a good combination for me.  I can’t see any reason to use such a small diameter spindle, especially when it’s ti.  Making that larger could improve the stiffness a bit.

    ——————————


    Rotor 3d Steel spindle
    Actual weight: 724grams
    Corrected weight: 724grams
    Q-factor:145mm
    Spindle: 24mm
    Deflection-D: 0.176
    Deflection-ND: 0.309
    Average Deflection: 0.243
    S/W: 0.563

    Likes:  Looks (this refers to the shape not to the graphics.)  Removable spider that can take a power meter.  Stiffness.  Saab bottom bracket.  Separate preload/pinch bolt design that has proven as a concept to be very trouble free.

    Dislikes:  Stiffness/Weight ratio.  Being so incredibly similar in design to the EE prototypes I had expected a lot more from this crank in terms of S/W.  The main dislike for me is the graphic package, graphics like these were only half way cool on a trapper keeper back in the 80′s and for me lack any retro appeal.  But if my biggest complaint about your crank is the graphics package, that can’t be a bad crank.

    ——————————


    Shimano Dura-Ace
    Claimed Weight: 740grams
    Stock Weight: 772grams w/bb
    Corrected Weight: 746grams
    Q-factor: 147mm
    Spindle: 24mm
    Deflection-D: 0.140
    Deflection-ND: 0.295
    Average Deflection: 0.217
    S/W: 0.597

    Likes:  Stiffness and shift quality.  The shift quality of the DA rings is unmatched by any other crank I’ve ever tried.  Installation is easy and quick and generally without problem.  While being heavier than most of the lightweights it’s very much a bolt and forget kind of crank.  In terms of pure performance, this is the current benchmark for others to aim for.

    Dislikes:  I’d like to see the weight come down a bit.  The looks.   Like most, I thought this was the ugliest crank when it came out, however now it seems I’ve desensitized a bit and only find it somewhat offensive.  I guess I found some beauty in function.

    ——————————


    Sram Red
    Claimed Weight: 760grams
    Actual Weight: 755grams
    Corrected Weight: 754grams
    Q-factor: 150mm
    Spindle: 24mm
    Deflection-D: 0.150
    Deflection-ND: 0.278
    Average Deflection: 0.214
    S/W:0.619

    Likes:  It’s a good looking, stiff crank at a good price.  The Red crank had one of the lowest average deflections of all cranks we tested.  When you add price into the equation it becomes a very balanced crank set.  I’d call this crank the sleeper of the test.  It was the one that surprised me the most.

    Dislikes:  Rings.  While the rings shift ok, they could definitely stand for some improvements.  I’d also like to see the q-factor reduced by at least a few mm, but preferably more.  It was also one of the heaviest cranks in the test, only 2 of the 21 cranks weighed more when corrected.

    ——————————–


    Storck Power Arm SL
    Claimed weight: 440grams no rings
    Actual Weight: 442grams no rings
    Corrected Weight: 581grams
    Q-factor: 152mm
    Spindle: 30mm
    Deflection-D: 0.193
    Deflection-ND: 0.314
    Average Deflection: 0.253
    S/W: 0.663

    Likes:  I like that they addressed what I felt were several problems with the Clavicula.  The end cap does not crack, the insert does not come loose nor do the bearing races.  Other than the spindle material being different the cranks seem virtually the same.  Functionally it’s a great crank.  Stiff and lightweight and a triumph of carbon manufacturing(I don’t know if this credit should go to Storck for thinking of the changes, or to THM for implementing them for Storck)

    Dislikes:  The 152mm q-factor and the price tag are two to start.  One detail that really bothers me is that the end cap has been redesigned from what THM used.  In doing this they have created a new standard that is not an allen key nor is it the shimano end cap tool.   It is it’s own design with it’s own tool.  However it seems that their is no specific tool for this.  The handle of the bb cup tool works nice or a quarter can work.  Support from Storck has been virtually non-existent in the U.S. for a quite a while.

    ——————————-


    Stronglight Fission Ti
    Claimed weight: 795grams
    Actual Weight: 754grams w/bb
    Corrected Weight: 759grams
    Q-factor: 154mm
    Spindle: 22mm
    Deflection-D: 0.195
    Deflection-ND: 0.396
    Average Deflection: 0.295
    S/W: 0.449

    Likes:  Looks over the Pulsion are greatly improved.   The CT2 rings are some of the best rings.  I also like that the pedal fitting is reversible to create arms that are either 172.5 or 175.  The adjustable fitting also looks like it won’t be subject to de-bonding as the Pulsion did.  Muted graphics match any bike.

    Dislikes:  The very small bearings.  By keeping the bearing inside the frame they have used an Isis bearing that has questionable durability and is difficult to find as a replacement, a bad combination.  For a ti spindled carbon crank, I’d have expected it to be lighter.

    ——————————–


    Stronglight X-wing
    Claimed Weight: 650
    Actual Weight:  737grams
    Corrected Weight: 737grams
    Q-factor: 146mm
    Spindle: 22mm
    Deflection-D: 0.181
    Deflection-ND: 0.379
    Average Deflection: 0.280
    S/W: 0.484

    Likes:  I can’t quite put my finger on it, but something about this crank appeals to me.  It probably has to do with the shape, aesthetically speaking.  I also like the 146/110bcd bolt pattern.  This should make for a stiffer ring(both compact and std) which could be an important characteristic when moving to Di2, as well as giving the owners the option of switching back and forth between compact and std without changing cranks.  The UD finish is nicely done too.

    Dislikes:  graphics, especially on the ring, there is just too much writing on the crank/ring.  The ugly plastic plugs that cover the multiple chainring bolt sets.  I dislike the very thin not easily replaced bb bearings.  Wearing out a bearing on a Stronglight crank in the U.S. is not a good thing since the distributor does not usually stock bearings.  Standard sized outboard bearings with a larger spindle would be a big improvement in my opinion.

    ——————————


    Thm Clavicula
    Claimed Weight: 420grams no rings
    Stock Weight: 406grams no rings
    Corrected Weight:  530grams
    Q-factor: 151mm
    Spindle: 30mm
    Deflection-D: 0.169
    Deflection-ND: 0.315
    Average Deflection: 0.242
    S/W: 0.728

    Likes:  What’s not to like about this crank.?  Looks, stiffness, weight, S/W, exclusivity etc… It has it all.  It’s the pinnacle of what carbon constructed cranks can be.  The attention to detail is fantastic.  Not many people know this, but there is a built in wear indicator in these cranks.  Under the outer layer of carbon is a layer of yellow carbon fiber.  If you have heel rub and eventually wear through the outer layer you’ll begin to notice the carbon turns yellow indicating it’s time to replace your cranks.

    Dislikes:  What’s not to like about this crank?  Ok, so perhaps there are a few things.  The price, the 151 q-factor, and the availability.  The big one for me is the q-factor, they are just a bit too wide for me.  And while this is one of the stiffest cranks in the test it’s also one of the ones that does have a weight limit.

    NOTE: In the past we had some dislikes about bearing sleeves coming loose on the spindles and the same with preload inserts.  There were changes in production a while back and we’ve not seen any of those issues in the last couple of year, taking a great crank and making it even better.

    ——————————-


    Tune Fast Foot + 6 pack ti
    Corrected Weight: 687grams
    Q-factor: 154mm
    Spindle: 19mm
    Deflection-D: 0.292
    Deflection-ND: 0.488
    Average Deflection: 0.390
    S/W: 0.373

    Likes:  The non-tapered bb means arms don’t get stuck easily.  Also it has a minimalistic clean look to it and is available in a wide range of colors.

    Dislikes:  The Q-factor is large, 154.  The setup is a complete pain in the… and the stiffness is certainly lacking.  I’d love to see Tune take a stab at redesigning and improving on a design they have had for quite a long time.  I think the arms could be stiffer as could the bb.

    —————————–


    Zipp Vuma Quad
    Claimed Weight: 580grams
    Actual Weight: 586grams
    Corrected Weight: 586grams
    Q-factor: 146mm
    Spindle: 30mm
    Deflection-D: 0.209
    Deflection-ND: 0.308
    Average Deflection: 0.258
    S/W: 0.661

    Likes:  Weight, stiffness, q-factor, and looks.  Again with muted graphics it matches any bike.  A solid S/W number being the highest production crank produced outside of Germany.

    Dislikes:  Rings.  The rings could certainly use some work on their shifting ramps and pins.  That wouldn’t be much of a dislike if I could put TA or Stronglight rings on it, but since I can’t it becomes much more of an issue to me.  We’ve also seen what I’d consider a higher number of warranty issues with these than with some of the other super-lights.

    —————————–

     

     

    This one shows just the average deflection of all the cranks.  Lower numbers are better.

     

     

     

     

    Here’s a ranking of the cranks in order of lightest to heaviest as a complete system with corrected weights:

     

     

     

     

    This one shows S/W.  Higher being better stiffness to weight ratio.

     

     

    Here’s a few pictures of the testing:

    So that’s it in a nutshell.  Some facts, some opinions and some pictures.

    Keep an eye out for test 5 which we hope won’t be too far off.

     

    #93182
    CJ

    How come you included a Dura Ace 7800 crank in this test and not a 7900? Would be interested in seeing the 7900 included in the next up date. Still a very interesting test/article. Thank you.

    #93183
    Participant

    You say you carried out measurements to 3 decimal places. So does that mean that a given instrument read “x.xxx”? If so, that least digit isn’t reliable. More precisely measurements should indicate the measurement error in the system, i.e. x.xxx ± 0.xxx or summat. It may seem like nitpicking, but the reader needs to be sure that printed measurements are accurate and precise.

    #93184
    William Cameron

    I’m impressed with your due dilligance in such an apparently daunting endeavour. Would you consider including examples of now out dated cranks, but still quite prevalent on pro bikes around hear.{ shimano dura ace 7700 for example]. Many of your readers in these trying economic times could justify a purchase,or not.

    #93185
    David

    Excellent test, though the DA 7900 seems to be a glaring omission. Keep up the great work.

    #93186
    Participant

    Excellent data points, hope you can include the Rotor 3D+ (with the 30mm axle) next round.

    #93187
    Mark

    Note that Zipp has discontinued the VumaQuad: http://www.zipp.com/cranks/vumaquad/

    The Easton EC90 crankset has a problem with spindle coming loose in the spider: http://waywardcyclist.wordpress.com/2010/04/21/warranty-shootout-part-1-which-company-has-the-best-customer-service/

    The same thing happened to me. They are issuing RMAs and have apparently discontinued selling the cranks.

    #93188
    tyler

    Can you tell me exactly how you go about measuring the q-factor?

    Thanks!

    #93189
    Matt Spohn

    I’d like to see the Cannondale Hollowgram tested here!

    #93190
    Jordan

    I would also like to see the Hollowgram tested!

    #93191
    Vincent

    Well done!
    I would love to see if you put the DA 7900 crankset into this test!

    #93192
    mepe3

    [One detail that really bothers me is that the end cap has been redesigned from what THM used. In doing this they have created a new standard that is not an allen key nor is it the shimano end cap tool. It is it’s own design with it’s own tool. However it seems that their is no specific tool for this. The handle of the bb cup tool works nice or a quarter can work.]

    Also works with a coin of 50 cents. euro.

    #93193
    Dominic

    I 3rd the Cannondale Hollowgram crank.
    It’s a pretty bad mama-jamma at 575 grams.

    #93194
    Phil Wardman

    I would have liked to see how the new Tune smartfoot cranks compare as i am considering them for my cross bike.

    #93195
    Len

    One observation: you are wrapping too much chain around the crank. i.e. the test is not as close to “real life usage” as it could be. Why not wrap the chain from 6 o’clock to 12 o’clock as normal(course, depending on BB drop vs rear axle height and rear cog size)?
    In fact, if I explain this well, you might improve readings by using standard chain wrap. My thought is that by wrapping the chain 75% around the big ring, you could be over-bracing the big ring and reducing meaningful readings. Why? If your measurement point is 6 o’clock then you’re looking for flex about the axle in the vertical plan. But to me the extra chain wrap from 12 to 3 o’clock is bracing the crank in this same vertical plane. Hope that makes sense.
    Also, why not measure the crank arm deflection? To me, your measurement point is only looking at spider and BB flex. Why not put a gauge right under the pedal hole of the crank? That would measure straight vertical flex.
    While you’re at it, why not add 2 gauges pointing at the side of the crankarm by the pedal hole lying horizontally? This would give a concept of the crank arm twisting as it was loaded up.

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