Ride faster (section 2)
- 1. By Morten Pedersen January 2015 (v1) March 2017 (v2) WANT TO RIDE FASTER ? A Layman’s comprehensive decomposition with actionable items
- 2. F A S T ? F A S T E R ? Something about the aero position… Team Sky Team TT! Sir Bradley Wiggins Fastest of them all = knighthood 2x disc wheels!!! (J. Kenny)
- 3. Objective: Ride Faster A decomposition into actionable items 3 RIDE FASTER Increase your Watts to Weight ratio Reduce Resistance+ Increase your Power (Watts) Reduce Total weight Improve your Aero- dynamics Improve the Bike Mechanics Let’s look closer at SECTION 2 Objective Level1 Level2 Improve race day Execution Prepare for Race Day with B-races and by race simulation Train by following a training plan + SECTION 1 SECTION 2 SECTION 3
- 4. Reduce Resistance Improve your aerodynamics – body, bike and gear n Majority of drag is caused by your body position on the bike (see the hotter colors below) 4 Improve your Aerodynamics Improve your Riding (body) Aerodynamics Improve your Bike & Gear aerodynamics Stay in Aero-position Tri-bike for triathlons. Aero- road or road bike for peloton races Level2 Level3Level4 Improve your Flexibility On road bikes: Use drops. Learn to descend Upgrade gear that reduce drag the most Draft whenever allowed Bike Fit to optimize your position
- 5. Resistance Aero drag (wind resistance) is the biggest factor at 65%+ 5 Source: Cervelo.com Source: Ryan Miller. CEB555 “The Aerodynamics of Bicycles” Percentages come out different in various test settings. Left bar chart is based on 4km pursuit, where right list is more general.
- 6. Improve your riding aerodynamics Smaller frontal area is better – requiring less power n Aero-position minimizes your frontal area by ‘hiding’ your large chest area n Sitting up (hands on the ‘tops’) while riding is dramatically slowing you down or requiring much higher power to keep the same velocity 6 Source: (Above) Ryan Miller, CEB555 The Aerodynamics of Bicycles. (Left)
- 7. Upgrade gear to reduce drag Skin suit then TT helmet deliver biggest time savings 7Source: POC Sports … and shaved legs. Wind tunnel proven to shave off 50 sec on 40k TT... Based on new evidence from Specialized’s wind tunnel (still limited sample of 6 test athletes)
- 8. Bike Aero Shape matters.Think airplanes. Hence tri-bike frames n Cervelo, Felt and Guru tri-bikes have similar frame shaping, using a wing (airfoil or droplet) like shape to further reduce drag on the frame. n The shape of the head tube matters most as it is the first point to break the air flow 8 Cervelo P3 Felt B2 Guru cr901 Drag coefficient for different shapes (lower number is better)
- 9. Bike Aero (cont’d) Take it to the next level with the Falco V n Eliminating the conventional seat tube reduces frame drag even further - is it worth it? n Keep in mind you can shave you legs, get an aero-helmet and wear a skin suit – all of which yield better improvements 9 Above wind tunnel graphics: Notice the yellow and red areas behind the rider.
- 10. Bike Aero (cont’d) Pushing the boundaries: 1 hour records n Did I mention that AERODYNAMICS MATTERS!? 91.5 km/h in an airplane like bicycle vs. 51.8 km/h on a ‘regular’ triathlon bike in an indoor velodrome 10 Current hour record for IHPVA bicycles (International Human Powered Vehicles Association) sits at 91.556 km – that’s 50-60 km/h faster than your 40k TT! ICU approved Hour Record set September 18th 2014 by Jens Voigt at 51.110 km (under the new UCI unified rules). Later beat by Matthias Brandle, Oct 30th 2014 at 51.852km.
- 11. Power Transfer: Frame Stiffness Marginal importance unless you are a sprinter n Your bike’s power transfer only matters for Crit racing and sprint events. Stiffness often comes by sacrificing comfort! n Top end models from Cannondale, Giant, Cervelo, Specialized, Canyon, Scott,Trek and Felt score well… other brands were likely not part of Giant’s test (e.g. Colnago, Guru, Pinarello,…) 11 Improve the Bike Mechanics Pick a frame with Good Pedaling stiffness* Level2Level3 Pedaling stiffness As published by Giant Sep-2012. Frame testing * Also known as Bottom Bracket stiffness Ensure Right Gearing Use race tires with Low Rolling Resistance Ensure your bike is Well Maintained Highest frame stiffness
- 12. Rolling Resistance (~5-10% of energy) Tires come with different rolling resistances n Choosing the right race tires can help you further reduce rolling resistance and free up 2-6 Watts for speed instead of friction loss 12 1 1 2 2 In general a slick tire will have lower resistance. Low rolling resistance often comes at the compromise of less durability. Hence race wheels with race tires is a good idea.
- 13. Rolling Resistance Tire pressure is also key to reduce rolling resistance Individualized tire pressure n Determine tire pressure based on: n Tire rating - Tire Pressure Indicator (60,150,220 or 320 tpi) n Weight of you + your bike n E.g. male with bike weight >95kg using 150tpi rated tires results in 115 psi on front, 120 psi on rear tire Tire Width together with Pressure determine rolling resistance – not tire width in isolation. In general a wider tire will reduce the rolling resistance but a narrower tire can often sustain higher pressure and will have better aerodynamics. Google “AFM Tire Testing Rev9” for a comprehensive list of rolling resistance. Only limited data is shared on www. 13 Source:Vittoria Tyre Guide
- 14. Right Gearing Avoid running out of high gears on descents or low on hills n Standard or compact crank set? 12-25 or 11-27 Cassette? n Changing a 12-25 cassette to 11-25 teeth adds 4 km/h of potential cruising speed – e.g. on a -3% descend (47.3 to 51.6 km/h. see below table) 14 Source: bicycles.stackexchange.com
- 15. Maintenance A well maintained bike rides smoother with less friction Get your bike race ready with a tune-up at your local shop… 2-4 weeks before your race Ensure that: n Rotating components are clean n Rusty components are changed n Brakes aren’t rubbing n Chain & drive train are lubed and gears run and shift smoothly 15 Source: Bycycology.org.uk: A Guide to … You can learn how to adjust brakes a n d g e a r s yourself… it is handy to know, but don’t r isk this leading up to your A-race.
- 16. Wrap-up Overview for part 1 and 2 16 RIDE FASTER Reduce Resistance+ Increase your Watts to Weight ratio Improve your Aero- dynamics Improve the Bike Mechanics Improve A-race Execution+ Increase your Watts Reduce total Weight Increase the Cadence Your body: Lose Weight Your bike: Shed off gear weight Train & race with a Power Meter Polarized training program Nutrition Pick a frame with Good frame stiffness* Ensure Right Gearing Use race tires with Low Rolling Resistance Objective Improve your Riding (body) Aerodynamics Improve your Bike & Gear aerodynamics Stay in Aero-position Tri-bike for triathlons. Aero-road or road bike for peloton races Improve your Flexibility On road bikes: Use drops. Learn to descend Upgrade gear that reduce drag the most Draft whenever allowed Train by following a training plan Prepare for Race Day with B-races and by simulating race day Ensure a well Maintained bike Bike Fit! SECTION 3