Friday, November 16, 2007

It's all about the bike

We all know that in Ironman, it's all about the bike.

Interesting...Coeur d'Alene's bike course is anywhere from 6,600 ft of climbing to 8,800 ft of climbing (and just as much descending) from the different sources I've come up with (Motionbased Garmin reads...funny how the same course can come up with such varying Garmin data...). It would be nice if it's "only" 6.6k, but lets just use 8,000 ft of climbing as our assumption.

Now, lets assume that there is just as much descending as there is climbing. So, if that were true, then for 56 miles you are climbing and 56 you are descending. 56 miles, climbing 8,000 ft makes the average slope 2.7%. I've used this power calculator to figure out what kind of watts are required for different speeds and different weights. Check it out:

Now I don't have a power meter, so what does this mean in numbers I can understand? Well, I did the calculations with weight and power on flat roads, so that I could use my speedometer to get a gauge of my watts - after all, most of my training is on flat roads. So that's the last number on the chart. As this winter progresses, and I get my bike mileage in, I can gauge my expectations at CdA based on flatland speeds and the weight I lose.

Take the Florida Challenge as an example - at the bottom of the chart. 2700 feet of elevation in 58 miles at 250 lbs at an average speed of 18.1 - the average slope was 1.76%, to do it, required 212 watts on average. It's fairly accurate, 'cause I know I can ride fairly hard on a flat course at 20.5 mph for 60 miles.

So, 2 things have to happen - of course...first I need to be able to push more watts, which I'll be able to do, but to save some for a marathon, I think staying in that 210 watt range will be appropriate. In training, however, I'd like to get my century rides up there in the 21 mph average speed range. Second, again obviously, I need to lose weight. Look at the difference between a 170lb person on the hilly course and a 230lb person. Pushing the same watts, the 170lb'er gets done with the bike an HOUR earlier. That's huge. 230lbs would be my minimum weight goal...220lbs would be "OMG" outstanding.

Does all this math sound logical to you "Watt Hounds" out there?


SWTrigal said...

Does all this mean I have to train hard and lose weight?

Rainmaker said...

Cool link - did you put together that Excel sheet, or is there a link for it? Neat stuff though.

supalinds said...

Huh? That all want over my head. But I think I caught the basics, less poundage equals speedy gonzalez...or something close to that.

Mister P. said...

I'm mostly trying to wrap my head around the idea of 170lbs being a "skinny person". (155 soaking wet here.)

I don't have a power meter so I have no reference point for the numbers, but as a math geek I LOVE the analysis. Even if the way it's worded sounds kind of scary ("56 miles of climbing".) But I understand the comparison.

Fe-lady said...

All those numbers make my brain hurt...I am better off going into things blind, with no number knowledge...except maybe the distance covered..