inventos ciclistas /Rotor Q-Rings – a guide to oval chainrings

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Triatlón - Series ITU. Campeonato del mundo
25 abr 2013 Series ITU. Campeonato del Mundo de Triatlón. Prueba de San Diego (Estados Unidos).

http://www.rtve.es/alacarta/videos/triatlon/triatlon-series-itu-campeonato-del-mundo/1787340/

TRI-STAGE RENAIXEMENT
Los próximos 19-20-21 de Julio tendrá lugar el TRI-STAGE RENAIXEMENT. El primer clínico de triatlón en la ciudad medieval de Tortosa , para los que habeis estado por aqui conocereis los circuitos del Doble Olimpico Terres de l'Ebre y tambien muy cerca el circuito del Ironcat.

Contaremos con la presencia del mismísimo CLEMENTE ALONSO. Es una buena oportunidad para conocerle en persona rodar, correr y nadar con él.Y como no sólo de triatlón vive el hombre y su familia, os podreis sumergir en el ambiente medieval que viste la ciudad en esas fechas. Recomendable para turismo familiar.

Si estáis interesados podéis enviar un email a: info@es-sport.org, o bien visitar la web:
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la falsa seguridad del carril bici urbano
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Rotor Q-Rings – a guide to oval chainrings
Triathlon Plus | Bike Gear | Gear | 25/04/2013 12:27pm
1 Comment and 0 Reactions
Should you use oval chainrings? Decide with our step-by-step guide to Rotor’s Q-Rings.


Elliptical chainrings such as Rotor’s Q-Rings fascinate many triathletes with their promise of smoother pedalling, more power and less lactates, but there’s also a definite sense of apprehension for most when considering leaving behind the world of circular chainrings.
Why use oval chainrings? Do I need new cranks? How do you adjust them? What’s the shifting like? Should I train and race on them? These are all concerns that frequently arise from those worried about the jump to oval chainrings, but fear not, we’ve got the answers. Here’s our Q-Rings guide to help you decide if they’re for you.

WHY USE OVAL CHAINRINGS?

The principles behind oval chainrings are simple. You push a larger gear during the downstroke, making this phase of the pedalling motion longer to get the most from your muscles. You then push a smaller gear in the dead spot, where less power is generated, to get you back to the downstroke faster. This smooths out the flow of power and also helps recycle lactates faster at threshold intensity.
Rotor concedes that the benefits of increased power and lower lactates are most pronounced during hard efforts, but research conducted into oval rings shows there’s no biomechanical disadvantage.
As weight is comparable to other rings and compatibility near universal, the only other considerations then are the price and installing them at a sensible time of year to allow fine-tuning of the Q-Rings’ position well before your big races.
Triathletes will also be glad of the reduction in hamstring and knee load, making the prospect of a tough run more appealing after a hard bike.
Though professional cyclists such as David Millar and Bradley Wiggins have been using Q-Rings for a while, more triathletes are now adopting them too, with the whole of Team TBB signed up in a addition to the many athletes buying the gear themselves to try and eke out that marginal gain.
The rings are available for both standard (130 BCD) and compact (110 BCD) cranks in various sizes. All the rings, including the company’s most popular setup – 52/36 – equate to the same sizes as regular round chainrings so there’s no complicated conversion equation needed when selecting your rings.
Rotor has also launched QXL rings, which offer an even larger oval shape. Available in a more limited range of sizes – the company are currently working on expanding their range – you can add a QXL inner ring to a normal outer Q-Ring for a more pronounced feeling while climbing.

DO I NEED NEW CRANKS FOR OVAL CHAINRINGS?

Q-Rings fit on all cranksets although a few – such as Shimano Ultegra 6700 compact and new SRAM Red BB30 (the GXP version is fully compatible) aren’t currently fully adjustable, but look out for specially adapted rings soon as Rotor strives to provide new designs to fit more unique crankset types or contact your Rotor dealer if you’re curious about compatibility.
If you’re in the market for a new crankset anyway, Rotor offers a model to suit every type of bottom bracket standard on the market thanks to the plethora of bottom brackets and adaptors the company makes to enable compatibility. Even BB90 is catered for thanks to Rotor’s 24mm 3D crank.
Once the bottom bracket in installed, crank setup is a five-minute job that needs only an 8mm allen key while removing the cranks is also simple thanks to a self-extracting system, requiring an 8mm allen and a Shimano cassette removal tool.
Rotor makes variations on two types of cranks – a regular five-bolt spider and their MAS (Micro Adjust System) models. The former works like any other crank, but benefits from being both very light and very stiff, while the MAS option allows additional fine-tuning of the chainring setup.

HOW DO YOU ADJUST Q-RINGS?

Rotor’s Q-Rings are as easy to install as any other chainring, with five simple bolts securing the chainrings in place.
On standard (non-MAS) cranks, there are five choices of orientation at 5˚ offsets and this is often what puts people off, but getting your perfect setup isn’t a daunting proposition.
Rotor suggests starting with position three, as marked by three dots on the rings, which is an angle of 108˚. Get the bolt holes lined up, tighten the bolts to the correct torque and all that’s left to do is adjust the height of the front derailleur to put it clear of the outer ring’s teeth at its tallest position. Then you’re ready to ride.
Despite it sometimes taking a while mentally to get used to non-circular chainrings, Rotor says your muscles will be at home with the motion almost instantly. This certainly chimes with our first ride on them; while the feeling of the oval rings remained, it wasn’t hard to get used to when first taking them out on the road.
We did however get some additional muscle soreness on the lower quads during our first few rides, though during a couple of weeks’ riding, this sensation lessened and then stopped completely. Even so, we wouldn’t recommend making the jump to oval rings just before a big ride or race.
From this first setup, it’s just a case of fine-tuning your position. This is done by feel and Rotor offers an easy guide to some common issues, suggesting alternative ring positions to alleviate these problems.
Rotating the chainrings from one position to another simply makes that power-producing part of the pedal stroke come sooner or later. So, if you’re riding in a TT position where the body is further forward in relation to the bottom bracket – as many triathletes do – position 4 will mean the downstroke comes later in the pedal cycle, making the most of this riding style.
Rotor suggests trying at least one other position before settling, even if the neutral number 3 setup feels fine from the start.
Listening to feedback from pro cyclists who felt they sat between two positions, Rotor created the MAS spider to cater for those who wanted more adjustment. The process for setup on the MAS is exactly the same as above, but these cranks uniquely offer half-measures of adjustment, giving 10 possible options at 2.5˚ intervals.

WHAT’S THE SHIFTING LIKE WITH Q-RINGS?

One of the biggest worries people have with switching to oval rings is whether they’ll be constantly fishing their chain from around their bottom bracket after dodgy down-shifts from the large to small chainrings.
Having ridden for several hundred miles without a single occurrence of this, we can say it’s probably more of a derailleur setup issue that causes problems. That doesn’t mean it won’t ever happen – any chainset can drop a chain – so we’ve now fitted a chain catcher as an insurance policy to avoid race day catastrophes.
As for shifting up, we’ve found this to be as clean as with any other setup, though a fair bit of tension in the cable is needed to keep it spot on.

SHOULD I TRAIN AND RACE ON OVAL CHAINRINGS?

The simple answer to this is yes. Unlike riding a heavier bike or set of wheels during the winter to beef up your legs, keeping on elliptical chainrings throughout the year is the best way of maintaining adaptation.

ARE OVAL CHAINRINGS WORTH IT?

Q-Rings offer an interesting concept and in testing, they’ve proved as practical in use as any other chainring system.
At £159 a pair, Q-Rings are expensive compared to some regular chainrings – though Shimano’s Ultegra outer rings are now £80 and Dura Ace £150 – but if you’ve got the money and you’re curious, you can give Q-Rings a go with Rotor’s 30-day money back guarantee.
The feeling of using Q-Rings was instantly comfortable and the additional muscle soreness we experienced initially actually had a positive mental effect in that we felt as if we were utilising more of our legs’ power on the bike. Much like the confidence that comes from a proper bike fit, being able to tailor the rings exactly to get a perfect personal setup gives a real boost during riding that you’re getting as much from yourself as you can.
Even if the effects aren’t huge without going flat out, being comfier and feeling efficient helps to create a really positive mindset. We’ve also found running off them easier – of course, this could be psychological rather then physiological – but it’s a welcome result of the oval rings nonetheless.
Overall, if it’s an idea you’ve been toying with, we’d definitely recommend giving Q-Rings a go.


Read more: Rotor Q-Rings - a guide to oval chainrings | TriRadar.com http://www.triradar.com/gear/rotor-q-rings-a-guide-to-oval-chainrings/#ixzz2RYzfFRkj