July 4

June 4, 2006

A speed and watts test with the Critical Power Streetliner, my 400 km training ride, and a new HPV hour record!

I got a chance to get out to my standard highway 22 out and back run for a speed and watts test with the Critical Power Streetliner. It is a steady uphill grade for about 3 km (it's really the flatest road around here), and I did average watts of 152.1 and averaged 31.05 kph. The plan, as per typical protocol, is to maintain 150 watts on the return leg, then average out the speed for both legs. However, I only managed to average 88 watts on the return leg because of some sudden side wind gusts combined with large trucks and motorhomes zooming by within inches of my right shoulder. These created quite a scary feeling as the wind and vacuum from the trucks pushed and pulled the fairing to the right and left. Handling it was OK though, so again, perhaps my biggest problem is simply getting used to it. If I had maintained my 150 watts average on the down leg run, I would have averaged over 60 kph. I do have the gearing for that, but I'm not confident enough yet to manage the wind issues with speed.

So, total average watts were 120.2 and average speed was 38.165 kph. I calculated a CdA of .95 with a Crr of .0050. This seems really poor to me, so I think I'm going to have to try it again, but attempt to average the same watts back as out. I don't think I can average the two out and back runs if the power input for each is as different as it was in this case - does anyone have any input on that?

Actually, hang on a sec.... I think I know the right way to figure this out. Because of the wind direction and grade of the road, I think I need to compare both runs using the SAME power input (like I said). Since the power is less on the return leg, I think what I can do is to calculate the CdA of that leg only assuming that there was ZERO wind and ZERO grade. 88 watts and 45.3 kph gave me a CdA of .2. Using the drag coefficient of .2 , I took a look at what speed 'would have' resulted if my power was 150 watts instead of only 88 watts. It worked out to 62 kph. So, now I have two out and back runs, each with 150 watts of power. I averaged the two speeds, and it works out to 46 kph and 150 watts which is a much more realistic CdA of .67. Nothing to write home about, but certainly better than .95.

I am trying to estimate how fast I could do 100 miles in the CriticalPower Streetliner. A CdA of .67 should get me an average of 55 kph at 200 watts which would result in a sub-three hour century. Adding a disc wheel to the rear, and taping up the seems and holes better, and I could probably drop that CdA to .6.

I ran some tests using the SRM meter to determine exactly how many watts it is costing me just to turn the two chains and 3 sets of gears around on the mid drive. It came out to only 2 watts and that compares to 1 watt to turn the standard long direct chain on the M5. Not bad. However, to turn cranks and chain and free hub of a road bike takes far less than 1 watt.


I painted the mid drive hanger to protect it from rust. The round tube that is protruding from the rectangular tube is an adjustable chain guide. I was having problems with the chain that goes from the largest ring at the back of the mid drive to the rear wheel coming off the mid drive cog. The reason is that when I am in the easiest gear, the chain angle pulls the chain off the mid drive cog. It is very sensitive, so I made an adjustable guide. It's a strip of UHMV (Ultra High Molecular Volume) plastic with a position screw in the round tube. I turn the screw to push the plastic guide out or in to get the perfect amount of pressure on the chain when it is in it's most 'coming-off' position.


This is the route from a super nifty little web application called RouteSlip. At RouteSlip.com you can create a ride by plotting a path on a map from Google Maps, then it will calculate your distance and plot an elevation profile. Very handy! Then you can share your route for others to suffer - I mean follow.

I was out the door at 5:15 am, about 15 minutes after the official sun rise here in Calgary. The ride was cold for the first hour, but quickly warmed up and I started to shed most of my layers. It was a perfect day for a 400 km (250 miles) ride - cloudless, calm winds and temperatures that reached a high of 29 degrees C.

The trip was non-eventful for the most part. Bow pass (the first big bump on the elevation profile) was tough - about 2800 feet of climbing with no break from the heat at the top. Sunwapta pass was MAJOR tough!!! A super steep grade that climbs almost 2000 feet without any breaks. It was so steep that I couldn't stop because I would have a REALLY tough time getting the M5 going again. And to boot, this monster climb happened 260 km INTO my ride!

After reaching the top of Sunwapta pass, the elevation change becomes a bit friendlier with a gradual 100 km down slope all the way into Jasper.

Helen picked me up 30 km from Jasper because it was getting close to 10:00 pm, so I only made 370 km. I think it would have stayed light enough to cover an additional 20 km in 45 minutes which would have still put me 10 km short of Jasper and it would have been totally dark. 370 was good enough and I was ready to call it a day. Whew!

We spent the night at the Jasper Park Lodge, then went on hike where we climbed 3000 feet up to the Jasper Tram.

The 370 km Jasper ride was my final ultra distance training ride. Now I start my taper by decreasing my training volume by 20% per week until the 24 record attempt on July 19th.


Fast Freddie Markham has just set a new HPV hour record of 53.4 miles on the Nissan Test track in Arizona. Rob English has a full report of the event at his site. Dave Balfour's write-up with some photos is here.


The record attempt is less than 3 weeks away!!!


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