Author Topic: are rohloffs slower than derraileurs?  (Read 10613 times)

Beave

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Re: are rohloffs slower than derraileurs?
« Reply #45 on: August 12, 2010, 03:01:14 AM »
Here is a basic rundown of Gear 11 as I understand it.

-Sprocket drives Ring Gear 1 (nothing special here, same as all gears)
-Ring Gear 1 is locked to Sun Gear 1-1 via a ratcheting clutch ring (now two planetary elements are locked together, so the third (twin planet carrier) is forced to rotate along with Ring Gear 1 and Sun Gear 1-1/Sun Gear 1-2)
-The Twin Planet Carrier is locked to Ring Gear 2 (output) via the same effect listed above, only it's another clutch ring that locks Sun Gear 2-2 to Ring Gear 2.
-Ring Gear 2 is always (permanently, in any gear) connected to Sun Gear 3
-Sun Gear 3 is locked to Ring Gear 3 in the same fashion, with a ratcheting clutch ring. (This is the same effect for all gears 8 thru 14).
-Now with Sun Gear 3 and Ring Gear 3 locked together, Planet Carrier 2 (which outputs to the hub shell and makes the wheel go around) is forced to spin 1:1 with those components.

Long story a little bit shorter:
-Sun Gears 1-1, 1-2, 2-1, 2-2 and 3 are all spinning around the central axle, all at the same speed as the drive sprocket
-The Twin Planet Carrier and Planet Carrier 2 are both locked to the Sun Gears and spin with them, at the same speed
-All Planet Gears are locked and do not spin within their respective carriers
-Ring Gears 1, 2 and 3 are all locked to their respective Planet Carriers and spin at the same RPM as the Planet Carriers and the Sun Gears

Really short?
Every possible gear is spinning, all at the same RPM of the drive sprocket, all in unison. (The planet gears would spin if they could, but they are locked by the other planetary members.) Since none of the gears are actively multiplying or reducing ratios, even though they are spinning, they are considered "not active". Sprocket, Ring Gears, Sun Gears, Planet Carriers, the Hub Shell and your Bike Tire are all spinning at the same RPM.
« Last Edit: August 12, 2010, 03:27:05 AM by Beave »
 

MilitantGraham

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Re: are rohloffs slower than derraileurs?
« Reply #46 on: April 22, 2011, 02:45:52 PM »
Both these links appear to be dead.
http://www.bhpc.org.uk/HParchive/PDF/hp52-2001.pdf
http://www.ihpva.eu/HParchive/PDF/hp55/hp55p11-15.pdf

I should have downloaded the .pdfs at the time.  ::)
Has anyone got a working link to any similar research ?

alcyst

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Re: are rohloffs slower than derraileurs?
« Reply #47 on: April 22, 2011, 07:59:11 PM »
I have a specialised roubaix s-works & a rohloff drop bar bike. On both I can happily stay with the club Saturday training run, average speeds 25km/h to 30km/h for a 3-4 hour run (& on both I can outpace some & be out-paced by others). The rohloff bike is heavier by approx 3kg, but I weigh 83kg. I recently rented a bike with schwalbe marathons @ an upright position; that was a slow bike with any gearing system.

The snow + life meant that I was off my bike for a month around December & January, the loss of fitness was very clear, it took 6 weeks of bicycle commuting and weekly rides to get back to previous speed & endurance.