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Пробитые подвески прямиком из Val di Sole 2013 года / World events 41

Можно подробнее про технику поворотов и управления на трамваях?

24 апреля 2020, 16:56

Виды крепления Direct Mount звёзд и почему их так много? / Велоиндустрия 93

Hi Anatolii,

My name is Pablo Carrasco, co-Founder of ROTOR.
In the bike industry we do really have a problem if we talk about standards… It happens everywhere along the complete bicycle: BB’s, head-sets, hub’s lengths and their axles, disc brakes rotor attachments…
Taking just about your question, about Direct-Mount “cranks”, I understand your are talking about the Direct-Mount attachment, normally intended for spare spiders, spider based power-meters, or of course for just one-by chainrings:
Yes there are too many. Probably each crank manufacturer has got its proprietary one.
A main reason is that right now there are so many “shit”-patents about every small and even silly detail in the bike, that to copy something which one of the biggest is using is a big risk. This is one of the reasons for sure… And make sense for them trying to protect their own attachment: imagine to avoid the competitors to sell power-meters for your crankset when you are one of the big sellers… That is not our case.
In ROTOR we have been using our own spline interface for many years, but having different solutions for 24mm and 30 mm axles, and their designs were based on the integrity and specifically fatigue resistance of our lightened crank-arms, at that time all of them made of aluminum: using other manufacturer options would have result in a heavier product at that time… That spline attachment was not patented, and some power-meter manufacturer as well as chainring manufacturers have been selling products for our crank-arms for years.
But in the recent years we have adopted a new “standard” which is close to perfection in terms of fatigue resistance, small enough in dimensions, very neutral about interfering power-meter calibration values, and reproducible because for this interface attachment we just use a 45 teeth DIN standard. Why?:
Apart of all the advantages I have already mentioned, for us, the use of oval rings is a real advantage in which we have been pioneers, and the main reason for which we are world-wide known. Nowadays there are many manufacturers of oval chainrings, but only 2 of them (first ROTOR and then OSYMETRICS as well) have been recruiting a big list of professional victories including Golds at the Olympics and World Championships as well as Tour de France or other ProTour races… we have been always investing in Road cycling, MTB and Triathlon, with a 20 years history of racing success. Having said that, what make sense to this number of 45 is what we call OCP (patented), which is all about the option to adjust the orientation of the OVAL for the best biomechanics performance you can obtain when ovalizing your pedal stroke:
Having 45 teeth result in 180º/45 = 4 degree increments for each OCP value.
Furthermore combining a Direct-Mount with 45 teeth with an axle-to-arm spline connection with 8 groves, we result in 360 different combinations which means that we can adjust the orientation of the OVAL every 1 degree (as an example, it is like when you can adjust your seat-post height every 1mm), when other manufacturers using our oval shape just can say that they have designed the perfect clocking (orientation) for each chainring size… but it is never a possibility for each cyclist.
Anatolii, I hope all this explanation can help you, but I am open for you to come back with whichever question at my e-mail address.
Remember that for whatever technical question about cycling and bicycles you can contact me… And hopefully we will meet somehow in whichever Bike Show in the future. I know that you there in Russia have a much better situation than here in Spain, but take care.

Best regards,
Pablo

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