The following applies to time trialing, a friend of mine has taken up doing ITTs and I wrote her a summary of a study that was conducted by Specialized in July 2008, I thing the findings are interested, if of limited value to typical roadies.
In plain English, one gets the best performance (least aerodynamic drag), as you might expect from a TT bike with a TT helmet and the worst performance (most aerodynamic drag) from a regular road bike with a conventional road helmet. But also notice, on a modern road bike the boost from just throwing on clip-on aerobars represents more than a 10% reduction in energy output to achieve the same speed.
Also notice that our roadie with clip on bars and an aero helmet actually outperforms, slightly, the TT bike with a regular road helmet, but another huge gain (about 6%) is made by giving the time trialist a proper TT Helmet.
These findings appear to be backed by the wind tunnel tests:
In the Wind tunnel it does appear that a TT bike with a road helmet outperforms the road bike with clip-on aerobars and a TT helmet, but again the delta is modest.
In short conclusion, I am drawing from this is:
1. To get the biggest gain in Time Trials, go aero, use either clip-on aero-bars or if you are getting a new bike, get a TT bike.
2. No matter what, get a TT helmet, clearly given the comparative low cost (a TT bike is at least $2000, a TT helmet is probably no more than $200) a TT helmet will give the biggest bang for the buck, unless of course you are sticking with just a road bike, then get some aero bars too.
I should note, in terms of point 1. this advice is if and only if you are looking to win in an ITT or triathalon, for regular club rides, don't get a TT bike.
Most people associate the lust for the cutting edge with roadies, triathletes and lycra-clad XC racers with a weight fetish. But the "All-Mountain" MTB crowd are fully capable of opening their wallets in the pursuit of bragging rights while riding bikes that take the big drops.
This year, SCOTT has decided to throw it's hat into the "most tricked out, price-is-no-object bike" ring with the 2011 Genius LT:
It's a 32 pound, full carbon all-mountain bike with 185 mm of travel, remote suspension control for adjusting the ride without stopping the ride, and a price tag that will get your local bicycle shop offering you espresso and valet parking.
Okay weight weenies, Interbike is on from September 22 to the 24'th and I suspect this bike will appeal to Thi, it weighs even less than he does (6lbs). It is safe for riding but too light for UCI regulations. It was a one off build and costs a modest (as compared with a Ferrari F-430) $45,000 (US).
Of course the pedals on that 6 pounder won't work with your regular Shimano cleats, but the good news, Shimano has carbon dura-ace pedals.
Back in the day I recall that the biggest weight weenies were the Ride Across AMerica people, the royalty of fully-supported Ultramarathon racing. The rules didn't have any weight restrictions, so the top racers would use ultralight bikes for climbing. When they reach the top of the hill, they would change bikes and their team would re-true the wheels, fix anything cracked, and so on.
Now if you'll excuse me, I'm going to go jump my bike off some concrete blocks at the Cloud Park. If i'm going to ride something that weighs as much as six of those bikes, I might as well do something far beyond their capabilities...
Crr is a measure of rolling resistance. Bigger number means more power is required to roll the tire.
If you download the CSV file, the watts per tire is also reported.
Interesting that the Watts range from approx 12W to 16W.
I expect that the numbers will be proportional to load on the tire (bike plus rider weight).
The tester is 185 lb with 15 lb bike = 200lb
So for a lighter rider, say 130 lb + 15 = 150lb then the power numbers should be 150/200 x 12 to 16 = 9 to 12 W
Riding on the flats for me at 30 kph is probably 200W on Michelin pro3 = 13.9W,
Savings for best tire 13.9 - 12 = 1.9 W, times 2 tires = 3.8W or approximately 1.9 percent easier
Losses for worst tire 16-13.9 = 2.1, times 2 = 4.2 or approximately 2.1 percent harder
A couple of percent may be important on race day, but probably other factors, like tire cost, durability, and availability are more important for everyday riding or training.
Any thoughts on 'aging' tires?
Seems like some believe and some don't.
But one thing that you allude to, a Vredestein Fortezza needs about 19.5w whereas for example a Hutchinson Fusion seems to need about 16.3 watts. Assuming price was the same, I'd still buy the Fortezza's. Anyone who's ever used a Hutchinson knows the delight that is chainging an inner tube road side every half hour.
Even in a race, a DNF is a lot worse than last place. Just personal experience here, but the Fortezza's are really good at protecting the tube, so are Vittoria Diamante Pro's.
Are tubulars no longer in vogue for road riding? I have clinchers on my tandem but ran tubeless on my cyclocross bike and I'm loving tubeless on my mountain bike. Inner tubes are for emergencies only :-)
Which brings up a relevant point: I have read that running tubeless lowers rolling resistance, because the tube itself has some resistance to deforming as the tire rolls. Eliminate the tube and you eliminate its resistance. This appears to be noticeable on mountain bike tires. Is that true for road tires, and if so, is the effect noticeable/measurable?
Doesn't seem that tubeless road tires have caught on yet. Shimano is offereing tubeless in Dura-Ace and Ultegra wheels, I think that Hutchinson may be only choice for tires. I haven't seen any rolling data comparing the tubeless to wheels with tubes.
Cycling in the summer can be about casual riding, sprinting, spinning, big-ring hammerfests or what ever your chosen type of riding is. The BCC was founded for the sole purpose to network cyclists. It has grown into a successful club which accommodates Riders at almost all skill/fitness levels. Everyone should be able to participate and have fun at their respective levels.
Start time is 8:00am early season, 7:00am as days get longer. Route distances vary from 55-120km and several pace groups are available. Saturday morning rides focus on a social vibe.
Rides will start around sunrise. Rotating routes will focus on distances from 55-160km. Remote start rides outside the GTA.
Advanced Turbo Tuesdays
For this ride, advanced group riding and bike handling skills are required. You must also be aware of your limitations. Riding speed is 35kph+.
Starts at 5:40am. This ride includes Bayview, pottery rd, redway other local hills.