Road Bike Crank Test

As a lot of you tuning in already know, we’ve been working on our in-house road crank tests for the last 7 years, with our updates posted alongside all the previously tested cranks. One thing we’ve come to realize is that while some cranks have obvious changes over the years, others have quietly evolved behind the scenes. Because of this and a desire to build a new testing fixture, particularly one that would handle BB30 cranks as well, we decided it was time to retire the old tests and start again with a clean slate. Please note that because of the new fixture and testing loads, results from this and future tests are not comparable to results from previous tests. Being that only 2 of the first 12 cranks tested in the last round carry over from previous tests we felt this was a good time to make the change.

Luckily, Jason Krantz is back as our resident data-cruncher (Jason is an experienced mechanical engineer with a strong background in both finite element analysis and composite materials.) We’re always happy to have him work with us on our tests and place a high value on his contributions.

Disclaimer: A lot of typing and numbers have gone into this article and we apologize in advance for any typos, but would warn that the possibility of mistakes is present.

About the testing method: Each arm was preloaded with 50 lbs of weight, then all calipers and load cells were zeroed out. Another 150 lbs was added and the difference was measured in mm. Each arm was tested three times and an average of those measurements is the result. A lower number represents a stiffer crank. These will be labeled as Deflection-D(Drive side deflection) and Deflection-ND(non-drive side deflection) . This method uses a total load of 200 pounds, in comparison to the old test which used a total load of 250 pounds. Further more in previous tests a large solid rod was used to simulate the pedal and load was applied 60mm from crank arm. With the new fixture, we’ve switched to using actual steel pedal spindles removed from a set of production pedals. The loading has also been moved slightly inward toward the crank arm.

Stiffness/Weight: Is determined by: (1/average deflection)/weight)x10000

Notes about stiffness: According to conventional wisdom, the more pedaling stiffness the better. Stiffness implies efficiency, along with the notion of a stiffer bike inspiring confident and responsive handling. As desirable as those traits are, and even after a crank’s stiffness is proven empirically, the outcome still seems subjective—we are simply going by how many people feel more efficient on a bike with a stiff drivetrain. But it’s far from clear whether that tactile, from-my-quads-directly-to-the-road sensation is actually faster. This is the question: is a stiffer drivetrain actually more efficient, or does it just feel that way? Looking at the numbers, we can see that average deflections range from roughly 0.20 inches to 0.30 inches. From this, we can generalize and say that the most flexible crank is about 50% more flexible than the stiffest crank. It’s easy to imagine that the stiffer cranks feel better, or have better “power transfer,” which is a particularly vague and ill-defined concept.

So how can we move beyond “feel” and attempt to quantify whether a stiffer crank is better? The answer is, strain energy. Strain energy is simply the energy stored by an object as it is loaded. Quantifying how much energy stored by a given spring under a particular load is a basic problem that works perfectly well for understanding whether a stiff bicycle crank is better than a slightly less stiff crank. That is, you can think of a bicycle crank as a very stiff, oddly-shaped spring. The equations for calculating stored energy in a beam under bending are fairly simple. The following figure is taken from a Creative Commons-licensed engineering textbook by Piaras Kelly at the University of Auckland:

In the equation above, U is strain energy, M is applied moment (torque), L is beam length, E is the Young’s modulus (stiffness) of the beam material, and I is the moment of inertia of the beam cross-section. A crank is somewhat beam-like, but it’s not really a beam. And we’re not applying a pure moment but rather a force at a distance that creates a moment. This bending example is somewhat close, but it’s still not a very good approximation of a crank on a bicycle. We can get a very good approximation of a crank on a bicycle by using finite element analysis (FEA). To find out how much strain energy a typical crank stores, we can solve an FEA model to find the strain energy of each of the constituent elements. We can then add up all of those strain energies to get the strain energy of the whole crank. This strain energy can then be converted into absorbed power by assuming a cadence; we used 100 RPM for this example. In this way, we can determine exactly how much power goes into crank flex, which can then tell us how much crank flex matters to total power output. We used ANSYS, a well-regarded FEA program, to model a generic aluminum left crankarm (172.5mm) and half an attached 24mm steel bottom bracket spindle.The remote force works out to 250 pounds of force (lbf), and it is applied 60mm to the outside of the center of the pedal threads. This simulates applying the force through a pedal.

Most of the action is happening on the inside of the crank; the interior elements report a higher strain energy value than the external ones do. But things get a lot more interesting when we dump the strain energy values for each of the elements to a spreadsheet. By summing the elements’ strain energy values, we can get the total strain energy for the entire crank and half BB spindle. The total strain energy of this crank under a 250-lb pedaling load is 4.604 Joules. As a unit, Joules don’t do much for most cyclists. We can convert them to a more useful unit by assuming a cadence of 100 RPM. At that cadence, this half-crank soaks up 7.67 Watts. The right-hand crank is usually stiffer than its left-hand counterpart, so it stores correspondingly less strain energy. So rather than doubling the left-hand figure, we’ll round down a bit to 14 Watts for the entire crank/BB axle system. 14 Watts might sound like a lot, and it is. But let’s keep in mind that this is a 250-lb force applied 1.67 times per second. A rider applying this force over 160 degrees of crank rotation produces an average power of 880 Watts, which few of us can sustain for long. And 14 Watts out of 880 is 1.6% To put this in perspective, if you were pedaling along at a steady 300 Watts, your crank would be absorbing 4.8 Watts of your effort. But those 4.8 Watts go into winding up your crank “spring,” which will spring back with nearly all the energy that was spent winding it up. Some of that spring-back energy probably helps turn the drivetrain while some of it may behave in a negative manner. However, there’s a fair amount of debate about how much energy is returned. The answer to the energy-return question involves kinematic analysis far outside the scope of this article. For now, we’ll assume that all of those 4.8 Watts spring back in a way that doesn’t help turn the drivetrain nor hinder it. As mentioned before, the most flexible crank in this review shows about 50% more deflection than the stiffest crank. Our FEA crank is quite flexible, and it absorbs 4.8 Watts of a 300-watt effort. Strain energy, roughly speaking, is inversely proportional to stiffness. We can use these relationships to calculate that at 300 Watts, our flexible crank absorbs 4.8 Watts, or 1.6% of total power output. Meanwhile, a 50% stiffer crank absorbs 3.2 Watts, or 1.07%, in strain energy (technically, strain power). That’s a difference of 1.6 Watts (or 4.7 watts at our tested 880 Watts). And remember, this assumes that no strain energy is returned to the drivetrain. That’s not to say that crank stiffness is irrelevant, there is a measurable difference. It also provides all the psychological and “feel” benefits described at the beginning of this section. A stiff crank also incrementally improves efficiency by keeping bearings aligned, keeping the pedals more directly beneath your feet, etc. Keep in mind that this 1.6% calculated strain energy absorption represents an upper bound of energy dissipation—that is, the maximum possible energy loss due to crank flexure. Real cranks are much stiffer than our modeled crank and therefore store less strain energy. Moreover, a great deal of that stored strain energy is likely returned to the drivetrain. The real-world losses to crank flexure are, in all likelihood, a fraction of that number.

Things get slightly more complicated for carbon cranks. Composite materials really do damp vibrations better than most metals, and cyclists treasure this property to ease their stinging hands as they hammer over Belgian cobbles and hop curbs on their way to the local coffee shop. But damping is just another word for energy absorption, and a carbon crank certainly absorbs and dissipates more energy than a metallic crank. Modeling that dissipation requires, among other things, intimate knowledge of the crank’s construction (“laminate schedule,” in the argot of composites engineering) But even if we can’t quantify carbon crank losses due to damping, are they worth worrying about? Almost certainly not. They are a tiny addition to the already-small losses in a metallic crank.

Notes about Crank Length: Over the years a lot of different arguments have been made about the benefits of longer/shorter cranks. None of which has really been thoroughly tested until Jim Martins study. Martin showed that length didn’t statistically matter when it came to power, once power was averaged around the entire pedal circle and not just in the forward position, it turns out that shorter cranks (down to 145mm) produced more average power than a longer crank. This conclusion however considers only average power and not other factors which definitely have a bearing on real world use. Damon Rinard followed up the Martin study with some of his own testing comparing the aerodynamic differences in crank length. In almost every case there was an aerodynamic improvement with the shorter crank and without a loss in power. So the power advantage and aerodynamic advantage, combined with shorter cranks generally allowing for a more aggressive or more comfortable position on the bike and less chance of repetitive motion injury we feel that shorter cranks are something most people should consider. We’re not saying they’re right for everyone, but if you’re on the fence as to which size is best for you, we suggest that you go for the shorter. If you’re interested in more on crank length we suggest reading the above articles as well as this article written by Frank Day for USA Cycling.

Notes about weight: Some cranks claimed weights include rings and bb in their complete weights while others do not. To have a level and fair comparison all cranks in this test will be tested and weighed with their stock bsa bottom brackets, and any crank that does not include rings will use our Praxis rings and KCNC alloy chainring bolts.

Notes on prices: Prices are MSRP for the U.S. and include rings and bottom bracket.

We do plan on adding more cranks to the review as they are released and as testing is completed. In choosing the cranks to start the new review with we listened to feedback from previous tests. We went with the most popular cranks as well as some of the lightest options. One suggestion that kept coming up in past tests was that people wanted to see how an older square taper crank did, so in this test we’ve included one.

Note that in comparison to square taper all the external-cup type cranks are worlds stiffer.

Now Onto the Results

*You’re viewing a truncated table since we can’t fit all the data on a cell phone screen. To see all nine columns and eight data points we collected on every crank please re-visit our site on a desktop or laptop.

Manufacturer Model Weight (g) Price (USD) Spindle (mm) Deflection-D (mm) Deflection-ND (mm) Average Deflection (mm) S/W Ax-Lightness Pelton (2016) 742.5 $550 30 4.97 7.04 6.00 2.245 Campagnolo Record (2006) 894.7 Not current model Square Taper 5.60 8.82 7.21 1.550 Campagnolo Comp Ultra (2015) 669.8 1050 30 4.15 6.66 5.40 2.764 Campagnolo Record UT Carbon (2014) 674.8 756 25 4.3 7.04 5.67 2.615 Campagnolo Super Record (2015) 678.3 1165 25 4.1 6.9 5.5 2.680 Cannondale SISL2** (2014) 609.4 1185 30 4.25 6.91 5.58 2.943 FSA K-Force Light (2015) 672.3 699 30 4.24 6.56 5.42 2.747 FSA K-Force Light (2017) 658.8 649 30 4.20 6.49 5.34 2.84 FSA SL-K Light (2015) 651.6 649 30 4.33 6.7 5.51 2.784 Lightning Lightning Carbon (2015) 548.2 860 30 5.5 7.22 6.36 2.870 OMC Italia V-Strong One (2015) 644.7 600 30 4.74 7.34 6.05 2.56 Praxis Zayante (2015) 828.8 349 30 3.96 6.17 5.06 2.383 Shimano Dura Ace 9000 (2014) 698.0 640 24 3.98 7.67 5.83 2.460 Specialized SWorks** (2015) 663.2 665 30 4.26 5.75 5.01 3.013 Sram Force22 (2014) 782.3 390 24 4.32 6.99 5.65 2.261 Sram Red22 (2014) 667.4 490 24 4.08 6.8 5.44 2.754 Thm Clavicula Classic (2014) 540.8 1450 30 4.39 6.46 5.42 3.410 Thm Clavicula M3 (2014) 579.9 1150 30 4.65 6.96 5.80 2.972 Thm Clavicula SE (2016) 494.8 1450 30 4.41 6.99 5.70 3.55 Vision Metron (2016) 874.8 950 30 4.96 6.90 5.93 1.93

** Fits only BB30/PF30 frames.

Graphs? Yeah, sure, why not?

Thoughts on Each Crankset

Ax-Lightness Pelton (2016) Complete Weight: 742.5 Grams

742.5 Grams Price: $550

$550 Spindle: 30 mm

30 mm Deflection-D: 4.97 mm

4.97 mm Deflection-ND: 7.04 mm

7.04 mm Average Deflection: 6.00 mm

6.00 mm S/W: 2.245 The Ax crank is a beam style machined arm which has it’s drawbacks in our testing. The crank ranks 16th of 20 in weight. 17th of 20 in deflection which puts it’s stiffness to weight near the bottom of the tested cranks at 18th out of 20. However this is a very modular crank with lots of bottom bracket options and in our opinion a very nice look. It also has a reasonable price tag. Campagnolo Record (2006) Square Taper Alloy Complete Weight: 894.7 Grams

894.7 Grams Price: Not current model

Not current model Spindle: Square Taper

Square Taper Deflection-D: 8.18 mm

8.18 mm Deflection-ND: 12.60 mm

12.60 mm Average Deflection: 10.39 mm

10.39 mm S/W: 1.076 The Campagnolo Record square taper crank was considered to be one of the top cranksets for many years. We’ve included it in this test just for comparison’s sake. The results were pretty dramatic, revealing the differences between this crank and all the other tested cranks. It was significantly heavier than all the other cranks and at the same time not nearly as stiff. This of course resulted in it having the worst stiffness to weight of any crank in the test. Campagnolo Record UT Carbon (2014) Complete Weight: 674.8 Grams

674.8 Grams Price: $756

$756 Spindle: 25 mm

25 mm Deflection-D: 4.3 mm

4.3 mm Deflection-ND: 7.04 mm

7.04 mm Average Deflection: 5.67 mm

5.67 mm S/W: 2.615 The Campagnolo Record UT crank ranks slightly lower than mid-field pretty much across the board. 13th out of 20 in terms of weight. 12th in deflection and 13th out of 20 in stiffness to weight. A nice looking crank with good shift qualities. BB variations in the past left something to be desired with the PF30 BB version having migration problems, but with the introduction of the Overtorque model this is no longer as big of a concern. My opinion of the non-standard bcd of the 5th bolt still hasn’t changed and I find it quite annoying, as it does seem to be more about removing compatibility with aftermarket rings than improving performance. Overall though this is still a nice crank. Campagnolo Comp Ultra (2015) Complete Weight: 669.8 Grams

669.8 Grams Price: $1050

$1050 Spindle: 30 mm

30 mm Deflection-D: 4.15 mm

4.15 mm Deflection-ND: 6.66 mm

6.66 mm Average Deflection: 5.4 mm

5.4 mm S/W: 2.764 The Comp Ultra is Campagnolo’s foray into a 30mm spindle crank and was done quite successfully. They opted to go with a universal 386 design rather than a restricted BB30. The Comp finished mid field in weight, 11th of 20, slightly lighter than the other tested Campag cranks. In terms of deflection it was 4th out of 20 which landed its stiffness to weight at 9th overall. The Comp Ultra has a wide range of bb options including bsa. The biggest drawback to it is that it doesn’t have the same simple installation as the UT cranks and does require special tools for installation and removal. Campagnolo Super Record (2015) Complete Weight: 678.3 Grams

678.3 Grams Price: 1165

1165 Spindle: 25 mm

25 mm Deflection-D: 4.1 mm

4.1 mm Deflection-ND: 6.9 mm

6.9 mm Average Deflection: 5.5 mm

5.5 mm S/W: 2.680 We had hoped to see a bigger change with the new Super Record from the previous Record UT, but it just wasn’t the case. Weight, deflection and stiffness to weight were all almost identical to the results from the UT Record crank. This crank has a more polarizing look, for most people it’s either love it or hate it. The new spider and chainrings do however seem to make a difference in shift quality. So all things being equal this crank is an improvement. Weight 14th out of 20. Deflection 8th and stiffness to weight 12th. Cannondale SISL2 (2015) Complete Weight: 609.4 Grams

609.4 Grams Price: $1185

$1185 Spindle: 30 mm

30 mm Deflection-D: 4.25 mm

4.25 mm Deflection-ND: 6.91 mm

6.91 mm Average Deflection: 5.58 mm

5.58 mm S/W: 2.943 The SISL has been the most requested crank for us to test so needless to say we were excited to see how it would do. Of course we already knew the crank was light, at 609 grams it was the 5th lightest crank in the test. It was also on the top end of price spectrum, and by far the most expensive alloy crank. In terms of deflection it ended up in the middle at 10th out of 20 which put its stiffness to weight at 5th. Having a shorter spindle than most other cranks in the test should have improved its weight, which it clearly did. The shorter spindle should also have resulted in better than standard non-drive deflection but in this case we didn’t notice that. The SISL2 is in our opinion one of the nicest looking cranks in the test, particularly with the tested spiderweb chainrings. However being that it is a true bb30 crank its use is restricted to frames with bb30 and pf30 shells only. We’d still love to see them do a 386 version and improve the shift quality of the rings. FSA K-Force Light (2015) Complete Weight: 672.3 Grams

672.3 Grams Price: $699

$699 Spindle: 30 mm

30 mm Deflection-D: 4.24 mm

4.24 mm Deflection-ND: 6.6 mm

6.6 mm Average Deflection: 5.42 mm

5.42 mm S/W: 2.747 For the K-force Light we tested the 386 Evo version with a threaded bsa cup set. 386 has compatibility with every bb standard we can think of except for bb90. Overall the finish on the crank is very nice. In terms of weight it was 12th out of 20. However this extra weight translated to extra stiffness. In deflection testing it finished 5th out of 20. That stiffness helped to lift its stiffness to weight ratio to 11th overall. Shift quality has definitely improved over the years. Finish and build quality both remain high. Considering its $600 price tag ($699 with ceramic bb) and that it is also available in a Campag specific version, it’s a well rounded crank. FSA K-Force Light (2017) Complete Weight: 658.8 Grams

658.8 Grams Price: $699

$699 Spindle: 30 mm

30 mm Deflection-D: 4.20 mm

4.20 mm Deflection-ND: 6.49 mm

6.49 mm Average Deflection: 5.34 mm

5.34 mm S/W: 2.84 The latest version of the K-Force Light improved on the previous version we tested. It shaved 14 grams moving the total weight to 8th. Stiffness also improved over the already stiff previous version, moving this one to the 3rd stiffest crank in the test. That puts it stiffness to weight at 7th out of 20. Those results put this as the best tested all around crank from the major manufacturers and one of the widest selections of bottom bracket standards. FSA SL-K Light (2015) Complete Weight: 651.6 Grams

651.6 Grams Price: $649

$649 Spindle: 30 mm

30 mm Deflection-D: 4.32 mm

4.32 mm Deflection-ND: 6.70 mm

6.70 mm Average Deflection: 5.51 mm

5.51 mm S/W: 2.784 The SL-K comes in as the lightest of the major manufacturers. 7th out of 20 in weight. Deflection came in at 9th out of 20. Overall stiffness to weight ratio was up to 8th overall again beating all the major manufacturers. Same nice build quality, good selection of lengths (165+) and good looks as the K-force and with rings that shift well. Also like the K-force this SL-K is a 386 Evo standard which gives it compatibility with just about every bottom bracket standard on the market. Lightning Cycle Dynamics (2015) Complete Weight: 548.2 Grams

548.2 Grams Price: $860

$860 Spindle: 30 mm

30 mm Deflection-D: 5.5 mm

5.5 mm Deflection-ND: 7.22 mm

7.22 mm Average Deflection: 6.36 mm

6.36 mm S/W: 2.870 While this current (2015) Lightning crank may look the same as past versions there are definitely some differences with it. This was one of the lightest cranks in the test being 3rd out of 20. The weight savings does come at the cost of stiffness though, with the Lighting being the least stiff (with exception of the square taper Campag) but not by a large margin. The crank is quite light though which gives it the 6th best stiffness to weight ratio of all tested cranks (though two that finished ahead of it are BB30 only). BB options are as wide as a 24mm crank: BSA, Italian, BB86, PF30, BB30, Bbright, BB386, and even BB90. Crank options are also the most plentiful of all tested cranks. Matte or gloss, with or without logos and a variety of arm lengths from 160 up to 190. OMC Italia V-Strong One (2015) Complete Weight: 644.7 Grams

644.7 Grams Price: $600

$600 Spindle: 30 mm

30 mm Deflection-D: 4.74 mm

4.74 mm Deflection-ND: 7.34 mm

7.34 mm Average Deflection: 6.05 mm

6.05 mm S/W: 2.56 It’s always nice to see a new entry into the crank market. Though OMC is not brand new, as they’ve been working on the crank for a number of years. The OMC is a lighter than average crank, being 6th out of 20 in weight. However like many lightweight cranks that savings translates to an increase in deflection with the OMC being 18th in terms of stiffness. That puts it’s stiffness to weight ratio at 14th of 20. Nice looking and with proprietary rings that shift well. However the OMC does have some overly complicated installation procedures (requires multiple installations) We look forward to seeing this crank refined over time. Praxis / Turn Zayante (2015) Complete Weight: 828.8 Grams

828.8 Grams Price: $285

$285 Spindle: 30 mm

30 mm Deflection-D: 3.96 mm

3.96 mm Deflection-ND: 6.17 mm

6.17 mm Average Deflection: 5.06 mm

5.06 mm S/W: 2.383 The Turn Zayante crank finished the test as the 3rd heaviest of all current cranks, but also as the stiffest of all current cranks (with universal fit) 2nd overall out of 20 and 16th in SxW. Part of the added weight comes from the substantial BB which promises to be extremely durable using an expanding collet design. Overall this is a very well thought out crank at a great price and one that we’d definitely consider as a top choice for training/daily rider crank. Good looks, great shift quality and solid function at a very respectable price. The crank is also available in mirco drive 32/48 which is a nice option to have available. Shimano Dura Ace 9000 (2014) Complete Weight: 698.0 Grams

698.0 Grams Price: $640

$640 Spindle: 24 mm

24 mm Deflection-D: 3.98 mm

3.98 mm Deflection-ND: 7.67 mm

7.67 mm Average Deflection: 5.83 mm

5.83 mm S/W: 2.46 For many years Dura Ace cranks have been considered the pinnacle of cranks. That may still be the case when it comes to installation, reliability, finish and shift quality. However in the metrics we were measuring in this test the DA 9000 crank fell short of mid field. 15th of 20 in total weight, 15th of 20 in deflection and 15th in terms of stiffness to weight. The best thing the DA crank has going for it is unrivaled shift quality, which is arguably quite important in a crankset. However it does suffer by adhering to the (now quickly disappearing) 24mm spindle size, and the lack of stock BB options (though aftermarket options are plentiful.) We’d love to see a future update of this crank with a 30mm spindle. The spindle diameter shouldn’t be underestimated. If you look at the drive side test, this crank is the 2nd stiffest of all tested. However when you look at the non-drive side it’s the worst of all the current cranks we’ve tested (excepting the 2006 square taper.) Specialized SWorks (2015) Complete Weight: 663.2 Grams

663.2 Grams Price: $805

$805 Spindle: 30 mm

30 mm Deflection-D: 4.26 mm

4.26 mm Deflection-ND: 5.75 mm

5.75 mm Average Deflection: 5.01 mm

5.01 mm S/W: 3.013 The Sworks crank has done very well in testing. Like the SISL2 the shorter spindle of this crank should help to keep the weight down as well as improve the non-drive side stiffness. In terms of total weight it hits 9th out of 20. Its real quality though is in its stiffness with the best total deflection of any crank we’ve tested to date (as expected it did very well with nds deflection being the only crank to drop below 6mm). Mix those two attributes and the stiffness to weight ratio is great coming in 3rd out of 20. Shift quality is not the best of all the tested cranks but is certainly more than adequate. Finish is very nice as is installation and its unique preload adjuster. The biggest drawback with this crank is the restricted use to only bb30 and pf30 frames. It could be a pretty popular aftermarket crank if it were available in a 386 version. SRAM Force22 (2014) Complete Weight: 782.3 Grams

782.3 Grams Price: $390

$390 Spindle: 24 mm

24 mm Deflection-D: 4.32 mm

4.32 mm Deflection-ND: 6.99 mm

6.99 mm Average Deflection: 5.65 mm

5.65 mm S/W: 2.261 The Force 22 crank is more than 100 grams heavier than Red22 and we expected that to translate into increased stiffness

but in fact it ended up less stiff than the lighter Red22. 11th out of 20 in stiffness and 17th in terms of weight put the

stiffness to weight near the lowest (17th out of 20) of all the current modern cranks in the test so far. That said, it is still

significantly better in every category than the traditional square taper. It is a good looking crank, better than Red22 in our opinion, but with it being only slightly less expensive we feel the Red22 would be a better choice for most riders looking for a SRAM crank. SRAM Red22 (2014) Complete Weight: 667.4 Grams

667.4 Grams Price: $490

$490 Spindle: 24 mm

24 mm Deflection-D: 4.08 mm

4.08 mm Deflection-ND: 6.8 mm

6.8 mm Average Deflection: 5.44 mm

5.44 mm S/W: 2.754 SRAM’s flagship universal fit crank Red22 comes in as one of the lighter cranks from major manufacturers in the test, 10th of 20 overall and 7th in

deflection which puts its stiffness to weight right in the middle at 10th of 20. Good shift quality, light weight,

reasonable stiffness, wide selection of stock and aftermarket BBs, and the best price of any flagship model in the

test–to us that means that this could be one of the most well rounded cranks available and a good fit for many

riders. The hidden bolt design does restrict some aftermarket chainring compatibility, but overall SRAM has to be

considered as a serious contender with this crank. THM Clavicula Classic (2014) Complete Weight: 540.8 Grams

540.8 Grams Price: $1450

$1450 Spindle: 30 mm

30 mm Deflection-D: 4.39 mm

4.39 mm Deflection-ND: 6.46 mm

6.46 mm Average Deflection: 5.42 mm

5.42 mm S/W: 3.410 THM’s Clavicula is now in its 10th year of development and refinement, and it shows. 2nd in weight, 6th in stiffness

and 2nd in stiffness to weight. Of course that performance comes at a cost, and in this case that cost is not

insignificant. Great aesthetic qualities and a wide range of BB choices (everything except BB90). It does lack in

length options being available only in 170, 172.5 and 175 but given that those are the sizes most people ride it

definitely covers the largest percentage of users. In recent years the weight limit has been increased to 231 pounds

which should cover most riders. Thm Clavicula M3 (2014) Complete Weight: 579.9 Grams

579.9 Grams Price: $1250

$1250 Spindle: 30 mm

30 mm Deflection-D: 4.65 mm

4.65 mm Deflection-ND: 6.96 mm

6.96 mm Average Deflection: 5.80 mm

5.80 mm S/W: 2.972 The Clavicula M3 is a newer model than the Classic, designed to be a little heavier and a bit more modular in its

design. 4th in total weight, 14th in deflection just ahead of Dura Ace 9000 and 4th in stiffness to weight puts this up with the

best cranks. Unlike the Classic, the M3 uses a removable spider that can be swapped from standard to compact as well as

SRM Powermeters. It has a narrower q-factor than the Classic and a higher weight limit (242 pounds). Its alloy

spindle also gives it more flexibility in BB choices including direct fit plus a lower price, though the M3 is still one of the

most expensive cranks available. Thm Clavicula SE (2016) Complete Weight: 494.8 Grams

494.8 Grams Price: $1450

$1450 Spindle: 30 mm

30 mm Deflection-D: 4.41 mm

4.41 mm Deflection-ND: 6.99 mm

6.99 mm Average Deflection: 5.70 mm

5.70 mm S/W: 3.55 The SE is Thm’s newest and lightest crank. The flagship SE comes in 1st in weight, by a significant margin. 13th of 20 in stiffness and 1st in stiffness to weight. New carbon spindle without the bonded bearing races improves on it’s longevity and a taper in the spindle makes installation much easier. Still continue to have a wide range of bb options but only 3 arm length options. The Q-factor is improved (narrowed) compared to the classic Clavicula and the finish is still top shelf. Though it is the most expensive crank in the test. Vision Metron (2016) Complete Weight: 874.8 Grams

874.8 Grams Price: $950

$950 Spindle: 30 mm

30 mm Deflection-D: 4.96 mm

4.96 mm Deflection-ND: 6.90 mm

6.90 mm Average Deflection: 5.93 mm

5.93 mm S/W: 1.93 Vision Metron crank is the only aero crank in the test so comparison against the others isn’t really on a level playing field, but we included it for variety. We were pleasantly surprised that the flat/aero arms were as stiff as they were, though that came at added weight. 19th of 20 in total weight. 16th in terms of stiffness and 19th in terms of stiffness to weight. However even without wind tunnel testing, it would probably be a safe bet to say this is certainly the most aero crank in the test.

Final Thoughts

Now that you’ve gotten through the entire test, or skipped to the end, we suppose you’re looking for a summary. Well, we aren’t really going to offer much other than to say that when it comes to cycling there really isn’t a universal best. There is a best for a given set of circumstances. Each rider has to decide the aspects that are important for them and their needs, be it weight, aesthetics, price, size, BB compatibility etc… Hopefully we’ve provided enough information to help each rider determine which crank is best for them.