The Bike List

Rotor 3DF / 3D30 Compact Road cranks (£269) & Rotor NoQ Round chainrings Pro-Compact 110mm BCD (£114) - £383 combined

Tested by Oliver Laverack, tester for The Bike List

Like many good ideas the original Rotor crank began life as student project back in 1995 at the Engineering School of Madrid. Three years later and the project had become a business venture with cranks available for the public to buy, but early systems had limited compatibility and couldn't be used with conventional bottom brackets as they needed a specific frame. Fast forward to 2001 and this had changed, with Rotor offering cranks to fit any bicycle, but it wasn't until four years later that Rotor's most talked about product was first released: ovalized chainrings a.k.a. 'Q-rings'. Since then the company has grown from strength to strength and today offers a wide range of cranksets, bottom brackets, chainrings and a power meter to suit most cycling disciplines.

The Rotor road range is based around three cranks, the 3D, 3DF and 3D+. Each of which can be adapted for different disciplines including cyclocross, triathlon, track and mountain bikes. For mountain bikes the top of the range single chainring REX 1.1 is already available to buy and, Rotor told us, the rest of the Rex range has already hit production and will be available very soon.

Rotor Power (including 3D+ crankset) power meter

Rotor also offers an ANT+ compatible crank-based power meter featuring their top end 3D+ crankset which weighs only 81g more than their standard 3D+ cransket and only 51g more than the 3D+ MAS crankset, which offers additional adjustment options for those using Q-rings. It does however cost an additional £1,110 so it remains the reserve of the serious enthusiast and pros. It is worth noting though that Rotor's power cranks include two power meter sensors, one for the left and one for the right side which provides output readings for both sides yet retails for less than Garmin vector pedals (£1,350). Arguably it is much easier to swap pedals from one bike to another (providing you are happy to use Look Keo compatible pedals) but if you also ride off- road (specifically cyclocross during the winter) then a crank-based power meter gives you more flexibility, providing you don't mind swapping cranks over now and again and that both frames will accept the same crankset.

Rotor 3DF

The 3DF we've had on test is Rotor's middle option at £270, costing £70 more than the 3D and £70 less than the 3D+. The differences between the cranks are subtle but worth knowing. The 3D crankset is CNC machined, comes with a 24mm steel axle and weighs in at 546g (175mm length crank arms). The 24mm axle means that it is compatible with standard bottom brackets from Shimano, FSA etc - see below for the full compatibility list.

Crankset deflection / axle twisting

Most of the deflection (undesired movement such as twisting or flexing) comes from the axle twisting whilst pedalling. By using a 30mm spindle, Rotor and other manufacturers are able to use aluminium alloy, which because of the larger diameter tube is stronger and lighter. The result is less undesired twisting and therefore deflection and ultimately more power transferred to the wheels. Realistically these gains are unlikely to be noticeable unless you are a world class sprinter putting down huge watts in the final few hundred meters of a stage finish but if you have the option to have a more efficient bottom bracket / crankset combination then why wouldn't you?

Both the 3DF and the 3D+ use a stiffer 30mm aluminium axle but are still compatible with a wide range of bottom bracket systems - see below for the full compatibility list. The aluminium axle also means that the 3DF and the 3D+ are lighter, weighing in at 532g (175mm length crank arms) and 475g (170mm length crank arms) respectively. The main difference between the 3DF and 3D+ is that the 3DF crank arms are cold forged with some CNC machining and the 3D+ crank arms are purely CNC machined which has enabled Rotor to remove even more material and make the 3D+ crankset 57g lighter.

All three cranksets feature what Rotor call their 'Trinity Drilling System' which is a process that involves hollowing the cranks out by drilling three cylinders along each crank arm all the way from the axle to the pedal. The process results in a weight reduction of approximately 43% for a single arm and gives you an idea of how much material in grams is removed. Rotor claim that by removing the material in this way, the stiffness to weight ratio stays about the same. On the right you can see one of the round billets of aluminium alloy that Rotor start with on their CNC machined cranks and what it looks like after it has been machined.

So, with this detailed, yet worthwhile introduction out of the way, it's time to talk about the product in hand. Having used a number of high end cranks / groupsets in the past few years including SRAM Red, Force 22, Shimano mechanical Dura-Ace, Ultegra and electronic Ultegra Di2 we thought it was about time we give one of Rotor's products a go to see how they shape up against the competition. We've certainly noticed an increasing number of high end bikes from manufacturers such as Cervelo, Focus, Fuji, Giant, Time and Ridley starting to feature them as standard rather than more common cranks from the likes of Shimano, SRAM, Campagnolo and FSA.

We paired our 3DF test crank up with Cervelo's aero S5 frame and opted for their NoQ round Pro-Compact 110mm BCD 52/36 chainring combination. Unfortunately their 36 tooth small ring was out of stock so we ended up with an interesting 52/34 combination. Unlike most crankset manufacturers, Rotor sell most of their cranks and chainrings separately. This is good in the sense that you can choose the chain ring combination that best suits your style or type of riding, assuming you know what that is of course. The guys at Velotech Services tell us that the semi-compact 52/36 Qrings by far outsell all other chainrings including the common compact combination of 50/34 NoQ round rings. They do however now offer a 52/36 NoQ round option similar to the setup we have for those that don't want ovalized chainrings. There is however a £50 premium for Qrings which would bring the crankset on test up to a wallet denting £433 for the complete crankset and chainrings combo.

The other key thing to note here is that you'll need to opt for either a 110mm or 130mm BCD (Bolt Circle Diameter). This is significant as each BCD places restrictions on the maximum or minimum size of the small chainring. The small chainring must have 38 teeth or less on the 110mm BCD crankset and must have 38 teeth or more (usually 39) on the 130mm BCD crankset. This means you'll need a 130mm BCD if you want to run a 52/39 or 53/39 or 54/42 racing / triathlon / time trial specific chainring combination and if you want to run a 52/36, 53/38 or 50/34 etc you'll need to opt for the 110mm BCD crankset.

What is BCD and why is it important?

BCD stands for Bolt Circle Diameter and is the diameter of the circle created by, in this case, the five holes at the end of the arms on the spider - the multi armed piece that connects the chainrings to the crankset.

The BCD number must be the same for both the crankset and the chainrings otherwise they won't be compatible.

The main reason to pay attention to the BCD is that if you're time trialling, racing, wanting to get into racing or averaging higher speeds you'll probably want a 53/39, 52/39 or 52/42 chainring ratio, also known as a 'standard road double' chainring combination. As mentioned you'll need a 130mm BCD crankset for this.

Alternatively if you're a recreational rider and mostly ride with your local club and the odd sportive you'll probably be beter served by a smaller 50/34 or 50/36 chainring ratio also known as a 'compact' chainring ratio. For this you'll need a 110mm BCD crankset as covered earlier.

There is a middle ground 'semi-compact' chainring combination of 52/36 or 52/38 which has started to appear on more bikes. On this setup the smaller chainring has just two more teeth than the small ring on a compact chainset yet the larger chainring only has one tooth less than the big chainring on a standard or double setup.

Interestingly on Shimano's latest 22 speed Dura-Ace FC-9000 chainset the BCD is the same on all cranks allowing you to run either a double or compact chainring combination. With an online price of around £300 this has to be one of the most practical high-end options around.

For most, the 52/36 chainring combination using the 110mm BCD crankset will offer a best of both worlds. The larger 52-toothed ring is big enough for keeping pace with the peloton if you're racing, yet the 36-toothed (34 in our case) smaller ring allows for higher cadence riding when on medium to steep climbs. Thanks to the mild winter we've had so far this year I've managed to get around 900 miles in using this crankset on the Cervelo S5 over the last 10-11 weeks using the 52/34 chainring combination. This has included a few high tempo training rides where I've averaged 25-35mph during high intensity bursts as part of a group of four, taking it in turns on the front. This simulated race pace was the perfect test for my 22-speed SRAM Force setup with a 11-26 tooth cassette (see Cadence at Speed table on right for more details) and I was pleased to find that I had more than enough gears to cope with any speed increases that the others threw at me. The racing I do early in 2014 will be the true test but I felt happy enough knowing that I still had a few gears left to call on. The smaller 34-toothed chainring has at times felt like a big step down in terms of pedalling and it's been hard to adjust my cadence smoothly in some situations when switching from the big ring to the small or vice versa. A 36-toothed small ring would make this gap easier to bridge and will also offer more usable gears on the generally flatter terrain that makes up most of my riding. Arguably I'd be better off with 53/39 ratio chain ring combination but personally I'd rather have the 36 toothed smaller ring so that I can take my bike to the Lake District or even the Alps (and make the relatively easy change to a 11-28 cassette) and be comfortable on long climbs or really sharp inclines. A 34-toothed small chainring might even be a better option on seriously hilly terrain, particularly on long alpine ascents where you need to maintain a steady cadence uphill for an hour or more.

With top end groupsets mostly being 22-speed it's good to know that the Rotor range of chainrings is compatible with these. The Rotor NoQ round Pro-Compact chainrings on our crankset features five lifting pins with machined ramping patterns to help move the chain smoothly and quickly. Shifting on my SRAM Force 22 setup has been at least as good as comparable chainsets from the likes of SRAM and Shimano. In fact I can't tell the difference between the shifting on the Cervelo S5 and my cyclocross bike which also runs on SRAM Force 22 but with a SRAM Force 22 cyclocross specific (46/36 chainrings) chainset.

With a complete weight of 687g (729g claimed) on the Bike List scales (including 52/34 chainrings, single spacer) our 3DF test chainset hits the scales only 4g heavier than Shimano's Dura-Ace 9000 series chainset which sits at 683g. If you're looking for the lightest chainset on the block, then SRAM's Red 22 complete chainset (BB30 172.5mm 53x39 BB not included) with carbon fibre arms is still the mainstream crankset to beat at 557g. That's a full 172g lighter than our test chainset and although the RRP for SRAM's Red 22 chainset is £460 you can buy one for around the same RRP as our Rotor 3DF chainset on test if you shop around. To compare the Rotor 3DF to other cranks see the table below for comparable statistics.

Quick guide to the Press Fit 30 bottom bracket standard.

Bottom bracket and crankset compatibility for the Cervelo S5

Working out bottom bracket and crankset compatibility can give you a headache but Rotor's system is straightforward once you've got your head round their naming convention. To the right is a table that helps you work out what system you need for your bike based on what frame you have and whether it accepts threaded or non-threaded bottom brackets. From there you simply need to know the diameter and width of your bottom bracket shell (which you can measure with a ruler) and whether you want or need a 24 or 30mm axle. The Cervelo S5's bottom bracket is unique in that it uses Cervelo's proprietary bottom bracket standard 'BBright Press Fit 30' with a 46mm diameter and 79mm width. The very wide 79mm bottom bracket shell is unique to Cervelo BBright bottom brackets and means that a longer axle is required to reach through the frame. The reason for the extra width is that it allows Cervelo frame designers to incorporate oversized frame tubes (up to 16% wider than standard bottom brackets) which save weight and increase stiffness.

Click here to read our quick guide to the press fit bottom brackets.

Currently Rotor are the only company that make a 30mm axle crankset with a long enough axle to fit Cervelo's BBright PF-30 bottom bracket standard. This is no coincidence as Cervelo and Rotor collaborated to create the original 3D crankset back in 2009 with products being tested by team riders and deemed fit for the sprinting demands of Thor Hushovd yet light enough for climbers such as Carlos Sastre.

For the Cervelo S5 and other Cervelo frames that use the BBright PF-30 bottom bracket standard the choice of 30mm cranksets is limited to Rotor's 3DF or 3D+ products. 24mm cranksets from other companies such as Shimano are compatible when using a Press fit 4624mm BBright converter bearing (£39.50) that compensates for the smaller axle width.

Given that the S5 will accept a 30mm axle, most will want to take advantage of the stiffer axle and lighter overall weights offered by both the 3DF or 3D+ cranksets. On the Cervelo S5 this would require a Press Fit 30 4630 bottom bracket (£45), from Rotor however we've combined our test crank with SRAM's BB30 Press Fit 30 bottom bracket as supplied by the Cervelo factory.

Compatibility with other bottom bracket standards

If you're also considering a power meter from Rotor then the flexibility of swapping the crankset to other road / cyclocross bikes would appeal to me as Rotor cranks are compatible with large range of bottom bracket standards. Here is the exhaustive list as of Jan 2014.

UBB30 (3DF, 3D+ & 3D+ MAS) cranks are 100% compatible with BSA (68 & 73), ITA, BB86, BBB89, BB92, BB30, BB386 evo and BBRight frames (not with BB90 & BB94).

UBB24 (3D) cranks are 100% compatible with BSA (68 and 73), ITA, BB86, 89, 90, 92, 94, BB30 and BBRight frames (except for BB386 evo, because it's not in demand).

For cyclists that also ride cyclocross for example this is a great option as one crank with two sets of chainrings can be swapped from one bike to another whilst not being restricted by pedal options such as with Garmin Vectors which can only be used with Look road specific KEO compatible pedals.

In terms of stiffness it is very difficult to comment with any degree of accuracy as to how stiff these cranks are compared to others at similar price points that I have tried. I would say however that the performance from the Rotor 3DF cranks was consistent, reliable, and at no stage was there any sign of noticeable flex in any of the parts. Sadly I doubt I could put enough power through the cranks even on a sprint to notice any kind of deflection. Interestingly Rotor told us that the 3DF is a bit stiffer than the more expensive 3D+ but it is of course 57g heavier. This might make the 3DF a better option for bigger riders who are more likely to put serious power through the cranks.

It is worth noting that all Rotor cranks are fatigue tested, with their road cranks being tested with a load of 1800N (180kg or just over 28 stone) which is applied one hundred thousand times on each pedal. To pass there must be no deflection increase or visible damage to the crank arms after the test has been performed.

Looks-wise I personally think Rotor's cranks are some of the most aesthetically pleasing out there and with a very reasonable weight of 687g for the crankset and chainrings combined on test I wouldn't hesitate to recommend them for anything from recreational to competitive use. Those looking for a high quality component with the option to upgrade to a power meter and the flexibility to swap their crankset plus powermeter to other bikes throughout the year should definitely put Rotor cranks on their list. If you own a Cervelo with a BBright PF-30 bottom bracket then Rotor's 3DF or 3D+ cranksets are the most obvious option to make the most of the bottom bracket technology on your frame. If you're keen to reduce the overall weight of your bike and you think you might want to upgrade to Rotor's own power meter then the 3D+ is the obvious option but personally I'm not sure I'd stump up the extra £70 for the Rotor 3D+ as the 3DF is in fact stiffer and I'm not elite enough to warrant paying over a pound per gram (£1.23 /grams to be exact) to reduce the weight further.

As well as Rotor's own power meter, the 3DF and 3D+ cranks are also compatible with the German-made Power2max power meter. The power meter unit alone, without cranks, retails for €740 (approximately £620) which makes this a more affordable option than Rotor's own power cranks. To read our long term review of the Power2Max power meter click here. The major downside to the Power2max sensor is that it weighs 229g for the 3DF crankset and 234g for the 3D+ crankset (110 BCD), which is considerably more than Rotor's own power meter unit. If you can live with the extra 150 or so grams (over the Rotor Power 3D+ Cranks at 556g) then you'll save yourself £490 over Rotor's power meter.

Fitting the Rotor 3DF to our Cervelo S5

Once you've established which crank and bottom bracket combination to plump for you may decide to fit the parts yourself. If you have a reasonable amount of mechanical knowledge and the right tools there's no reason you shouldn't have a go but our guide below will help you through the steps should you get stuck.

  1. If you haven't already, press your press fit bottom bracket into the frame using a bottom bracket press tool. Three bottom bracket options for the Cervelo S5 include Rotor's Press Fit 30 4630 bottom bracket, SRAM's BB30 Press Fit 30 bottom bracket or Wheel Manufacturing Inc PressFit 30 Bottom Bracket.
  2. Line the areas where the bottom bracket bearings will touch the axle with a thin layer of grease.
  3. Adjust the pre-load adjustment nut so that it sits as close as possible to the non-drive crank arm (the one on the other side to the chain)..
  4. Place the seal that came with the bottom bracket on the non-drive side axle shaft and slide the axle through the bottom bracket.
  5. Once the axle is through, slide the other bottom bracket seal on the drive side of the axle and then slide on one of the 11.5mm spacers so it sits against the bottom bracket seal.
  6. Grease the cone of the axle. [do you mean axle here? If yes use axle throughout. Try to use same words throughout when giving instructions, makes it less confusing.]
  7. Slide the drive side of the crank on to the cone of axle that you have just greased.
  8. Tighten the drive-side alloy bolt to 35Nm using an 8mm allen torque wrench.
  9. Turn the pre-load adjustment nut clockwise by hand the on the non drive side to eliminate lateral movement whilst leaving enough movement to allow the cranks to rotate freely.
  10. Lock the pre-load nut by tightening the pinch bolt clockwise with a 2mm allen key.
  11. Get on your bike and go for a ride!

Note: None of the supplied plastic washers were needed for our setup.

This video will help with the removal and re-installtion of your Rotor cranks should you need to replace the chainrings or bottom bracket etc.

Additionally PDF's of all the instructions manuals you might need can be found here.

In Summary...

The Rotor 3DF crankset has offered solid, reliable performance and we wouldn't hesitate to recommend this product to others. The versatility of Rotor's cranksets is excellent and with the correct bottom bracket it can be fitted to most modern framesets. It's worth noting that the 3DF crankset will soon be re-named to become the 3D30 crankset but will not alter in any other way, except the graphics of course.

The design, engineering and manufacturing of this product is to a very high standard and the sleek, solid black sand-blasted finish of the 3DF are matched by excellent performance. Personally I think the crankset would look better without the graphics but that's just a matter of taste. The total cost of the 3DF (crankset and chainrings) on test comes to £383 which is a significant chunk on cash for a single component but the price is in line with the level of design, engineering and quality you can expect at this price point, if not better.

Images taken at Greenwheel Cycles Peterborough

At a glance

Verdict A versatile, good looking, stiff, well engineered performance crankset that will efficiently transfer every last ounce of power and offers multiple power meter upgrade options.
Value
Performance

Rotor says:

The newer version of ROTOR 30mm axle cranks, these forged cranks are the cranks of choice for many brands including, FOCUS, TIME, RIDLEY, FUJI and LOOK. 3DF can be fitted to any 30mm BB system including BBright using the selection of Bottom brackets from the rotor range. Also compatible with BSA threaded frames using ROTOR BSA30mm BB Cups.

Black Anodised finish with Laser etched graphics, these cranks have all the features of 3D+ but are part forged, this process leaves more material on the cranks than CNC machining.

Innovations include a high precision bearing Pre-load adjustability through a fine thread compression lockring. 3D+ BB30 Axle is compatible with:
-Cervelo BBRight specification, -BB30 frames 68mm width, -Classic threaded frames (using the NEW ROTOR BSA threaded 30mm bearing cups),

Weight without rings 532 grms (175mm)

Super-compatible UBB30 technology

The 3D30 uses ROTOR's ultra-rigid and super-compatible UBB30 technology (developed for the 3D+), offering an "indestructible" upgrade opportunity for almost all bikes on the market - whether they were designed for 30mm cranks or not.

Cold forged, trinity drilled

The 3D30's cold forged, trinity drilled arms and aluminium UBB30 axle ensure serious rigidity and performance to face anything you can throw at it, while saving weight in regards to the majority of 30mm cranksets.

Groundbreaking concept, 100% compatible

The 3D30's axle technology comes from our UBB concept, which encompasses all bottom bracket standards on the market. This allows for surprising and unexpected new options for upgrading bikes of any BB type: our groundbreaking UBB30 axle concept is 100% compatible with BSA (68 & 73), ITA, BB86, BBB89, BB92, BB30, BB386 evo and BBRight bikes.

Bombproof design and reliability

ROTOR's bombproof trinity drilled crank arms resist bending and twisting forces better than classic hollow tube crank designs can. ROTOR's crank arms are stiffer than the competitions forged products due to our Trinity Drilling System. This process drills three full-depth holes from axle to pedal, leaving behind a boxtrellised structure (similar to box bridges). This gives our crank arms superior rigidity and an exceptional stiffness-to-weight ratio.

It works with everything!

The UBB (Universal Bottom Brackets) system is not a standard; It's all standards. It allows installation of almost any 30 or 24mm axle crank from ROTOR on the bike you have, regardless of its BB type. ROTOR's "UBB" super-standard encompasses all BB standards.

Solutions. That's probably the best word to describe ROTOR's design philosophy. We identify performance problems and set out to solve them, resulting in improved & optimized products.

Supplier: Velotech Services, +44 (0)845 475 5339, velotechservices.co.uk