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Road tubeless has arrived!!!

Friday, April 30, 2010

The Optima Baron that folds, very quickly.

This is the best folding recumbent I have ever seen, period!
A share from Becky's blog:

Wednesday, April 28, 2010

Anatomy of a failed breakaway.

I did this a few weeks ago, before my camera was being reliable, and before my new mic showed up. Crank the volume to hear me. I shot video at 4 or 5 other crits, but the camera shut down. Sad, as I would have been able to show you the best save after slamming the inside pedal into the pavement that I have ever seen a DF rider do.

I am starting to learn, always have the camera on. Never know what your going to catch....

So why do some breakaways fail, even with very strong riders? Watch:

Anatomy of a failed breakaway. from Jim Verheul on Vimeo.
Filmed with GoPro HD camera at 720p, 60fps. Edited and narrated with VideoPad free version. I need a better mic, you might have to really crank the sound to hear me talking. Vimeo reports the video at 28 minutes but its only a shade over 10.

Cheers, JV

Descending Decker Canyon (ATOC Stage 8) with Bruce and Matt.

Here is my second narrated road riding video. This is the same descent that will be featured on the last stage of this years Amgen Tour of California, 4 times. Bruce and Matt skillfully lead the way down. As I make these its occurring to me that they have some instructional value.

Bruce, Matt and I on Amgen Tour of California Stage 8 (Decker Canyon Descent) from Jim Verheul on Vimeo.
GoPro HD on Flashpoint bar mount, 1280x720p, 60fps, wide angle.

Oh, this is embarrassing: I refer to Bruce as Kurt a few time in the video. Yeeeeesh!!!

Here is a map:


Tuesday, April 27, 2010

High speed passing etiquette

Most cyclist agree that its a good idea to warn someone that you are about to pass them. You yell "on your left" or ring a bell. I like the bell myself. It seems more polite and cheerful, and saves my throat.

Keep in mind I speak as a rider who is commonly passed on the climbs, but does a lot of passing everywhere else. Its the bike.

Skilled racers in higher categories rarely do this amongst themselves, because most racers ride predictably enough that notifying them will not change a thing. Also most racers are not startled by being passed. Most race packs involve constant passing and being passed.

There are however a few riders that you do NOT want to notify. They will either move into your path or turn their shoulders to look at you, causing them to move into your path. Unless you know the rider, it can be hard to tell. But, some riders do not respond well to notification of a pass. Please don't be one of them.

Here is a video of this very thing happening tonight. One ding of a bell and the rider looks behind him, moving 3 feet to his left in the process.

CVC Tuesday Night Rock Store Ride (Also ATOC stage 8), passing etiquette from Jim Verheul on Vimeo.
GoPro HD on flashpoint bar mount, 1280x720p, 60fps, wide angle.


Wednesday, April 7, 2010

The latest tire rolling resistance data is out!!

Al Morrison puts all his data together once every year or 2. Al does a big service to the racing community with this.

If you put it into Excel or an other spreadsheet application, you can sort by only new tires, width, clinchers.....

Interesting observations from the data:
  • 25c Pro3 Race are indeed faster than the same tire in 23c, at the same pressure! 
  • Used tires are faster than new. Some get faster than others, depending on how much rubber hey had when new. I always thought that 4000Ss had a bit much rubber on them, and you can see how much they benefit from some miles.
  • Knowing how durable a lot of these tires are, I am still stuck riding Pro3 Race, and 4000Ss, but now have an interest in trying the Bontrager/Trek tires, and maybe the Pro3 Light. 
  • Urethane tubes roll just about as fast as latex without the air loss.
  • There are slower tires that he has not tested, but you can send him some. The fattest one is 27mm. 
If you read his test set up at the top of the document, its done on a smooth 79mm roller, corrected for temperature, and pretty repeatable.  Look at the standard deviations. There is a 12W per wheel difference between his fastest and slowest clinchers at the test speed, 30mph. That's 24W or lost power if you have 2 wheels on the ground. Since rolling resistance is linear with speed, that's 12W of lost power at 15mph. He says real world differences will be 50-100% greater. I am not sure how he got that, as the contact patch is very short and deep in his test set up.

Here is some data he took on a bumpy roller.
More air is almost always faster on smooth pavement, but not when its bumpy.

There has also been some work done by the esteemed Dr. Andrew Coggan correlating Al Morrison's roller data with rolling resistance on the road:

For the test methodology, see this article:

In brief, this is why we believe data taken on rollers is very useful indeed, as it accurately ranks tires in the right order, so you can choose intelligently, not based on marketing hype, or feel.

Anyway, if you want efficient tires, this is very useful data indeed.

Tuesday, April 6, 2010

Pictures of a 5' rider on Bacchetta Corsa 24

These are from my GoPro HD camera, but screen shots from QuickTime. Note the relaxed arms. In the future I'd like to recline her a bit more than 25 degrees and get rid of a bit of elbow bend. Ideally the bike would have a shorter boom, and the BB would be a bit higher, and the rear wheel a bit closer to her. The only solution I know to this is a custom bike, like a Carbent.

You can see the Rans stem here as the stem up to the bar is straight, not curved like the Bacchetta stems. The curve on the Rans takes place lower. Note the Gel flask within easy reach. BTW, we are on a 12% grade here.

A few months ago she told me to stop modifying the bike and let her start adapting to it as it was. This was good timing, as I had her pretty dialed in. She is quite comfortable on the bike.