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cdevil

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  • Province
    Western Cape
  • Location
    Stellenbosch
  1. Not a complaint, just a comment. These berms are terribly shaped, they should have a bowl shape not compacted flat at 30 degrees.
  2. Slightly off topic, but did you have any issues with the single rear cog cutting into the freehub body?
  3. Not sure if these are the jumps you referring to? They nowhere "near vertical" tho
  4. Yeah, and you know its BS when someone makes claims like this without anything to back it up:
  5. I tried searching but didn't find much. If you have some links could you please post them?
  6. You had me at "the real world of organic machines" Any studies to back up these claims?
  7. https://www.researchgate.net/publication/21157829_Physiological_and_biochemical_factors_associated_with_elite_endurance_cycling_performance Abstract: In this study we evaluated the physiological and biomechanical responses of 'elite-national class' (i.e., group 1; N = 9) and 'good-state class' (i.e., group 2; N = 6) cyclists while they simulated a 40 km time-trial in the laboratory by cycling on an ergometer for 1 h at their highest power output. Actual road racing 40 km time-trial performance was highly correlated with average absolute power during the 1 h laboratory performance test (r = -0.88; P < 0.001). In turn, 1 h power output was related to each cyclists' V̇O2 at the blood lactate threshold (r = 0.93; P < 0.001). Group 1 was not different from group 2 regarding V̇O(2max) (approximately 70 ml·kg-1·min-1 and 5.01 l·min-1) or lean body weight. However, group 1 bicycled 40 km on the road 10% faster than group 2 (P < 0.05; 54 vs 60 min). Additionally, group 1 was able to generate 11% more power during the 1 h performance test than group 2 (P < 0.05), and they averaged 90 ± 1% V̇O(2max) compared with 86 ± 2% V̇O(2max) in group 2 (P = 0.06). The higher performance power output of group 1 was produced primarily by generating higher peak torques about the center of the crank by applying larger vertical forces to the crank arm during the cycling downstroke. Compared with group 2, group 1 also produced higher peak torques and vertical forces during the downstroke even when cycling at the same absolute work rate as group 2. Factors possibly contributing to the ability of group 1 to produce higher 'downstroke power' are a greater percentage of Type I muscle fibers (P < 0.05) and a 23% greater (P < 0.05) muscle capillary density compared with group 2. We have also observed a strong relationship between years of endurance training and percent Type I muscle fibers (r = 0.75; P < 0.001). It appears that 'elite-national class' cyclists have the ability to generate higher 'downstroke power', possibly as a result of muscular adaptations stimulated by more years of endurance training. It is clear that the work gets done on the downstroke. "However, an active pulling-up action on the pedal during upstroke increased the pedalling effectiveness, while reducing net mechanical efficiency." "...while torque during the upstroke did reduce the total positive work required during the downstroke, it did not contribute significantly to the external work done because 98.6% and 96.3% of the total work done at the low and high workloads, respectively, was done during the downstroke."
  8. Read a couple of scientific studies: http://www.radlabor.de/fileadmin/PDF/PowerForce/Mornieux___Stapelfeldt_Artikel_Feedback_Pedalkraefte_2008.pdf Abstract: The aim of this study was to determine the influence of different shoe-pedal interfaces and of an active pulling-up action during the upstroke phase on the pedalling technique. Eight elite cyclists © and seven non-cyclists (NC) performed three different bouts at 90 rev•min–1 and 60% of their maximal aerobic power. They pedalled with single pedals (PED), with clipless pedals (CLIP) and with a pedal force feedback (CLIPFBACK) where subjects were asked to pull up on the pedal during the upstroke. There was no significant difference for pedalling effectiveness, net mechanical efficiency (NE) and muscular activity between PED and CLIP. When compared to CLIP, CLIPFBACK resulted in a significant increase in pedalling effectiveness during upstroke (86% for C and 57% NC, respectively), as well as higher biceps femoris and tibialis anterior muscle activity (p < 0.001). However, NE was significantly reduced (p < 0.008) with 9% and 3.3% reduction for C and NC, respectively. Consequently, shoe-pedal interface (PED vs. CLIP) did not significantly influence cycling technique during submaximal exercise. However, an active pulling-up action on the pedal during upstroke increased the pedalling effectiveness, while reducing net mechanical efficiency. http://www.fitworkscycling.com/uploads/4/5/3/8/4538224/pedalingtechnique.pdf "...while torque during the upstroke did reduce the total positive work required during the downstroke, it did not contribute significantly to the external work done because 98.6% and 96.3% of the total work done at the low and high workloads, respectively, was done during the downstroke." https://www.researchgate.net/publication/21157829_Physiological_and_biochemical_factors_associated_with_elite_endurance_cycling_performance Then why do most people still ride clips? It's more convenient being attached to the bike, feet stay locked in position and can't slip off. Are clips more efficient than flats? No
  9. Read the original post, I only said that both will result in exactly the same amount of energy being used to pedal to the top. With regards to which one is faster, have a look at Sam Hill's race wins over the years: https://en.wikipedia.org/wiki/Sam_Hill_(cyclist)#Results Quite impressive for someone riding on flats which according to you is slower than clipless.
  10. The same rider on the same bike riding up the same hill (assuming flats and clipless pedals weigh the same) will burn exactly the same amount of energy when using either flats or clipless. Clipless is advantageous in XC/Road/TT as the rider can divide the leg work (quads/hamstrings) more evenly. For DH its obviously more convenient being attached to the bike through the rough sections, but Sam Hill has had plenty of podium finishes on flats over the years. Ride what you want, I personally have more fun on flats.
  11. Thanks for the explanation, but it takes the same amount of energy (kilojoules) to pedal to the top.
  12. I've tried both, there's no difference between the two on climbs. In technical single track climbs flats require a bit more skill, but both require the same effort to get to the top.
  13. They have gold in stock! Check the colour selector
  14. Why don't you just DHL two of these: http://www.jensonusa.com/SRAM-X-Sync-Eagle-3mm-Ofst-Chainring?cu=USD
  15. Here you go OP: https://www.instagram.com/p/BTeZm7XgezB/
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