Thursday, August 11, 2011

FNF - Drafting Revisited

You kind of expect to hear that bad 70's porn music right about now - bow chicka wow wow...


Generally speaking I don't find that new hampshire has much to offer a socialist liberal atheist like myself. However, they do two things very well - they maintain the national forest land, and they keep their roads in great shape. One of the sections of road I have to travel to get to my job now is a 4 mile stretch of route 111 where it crosses route 3 and heads west ( yes, in new hampshire, just in case you aren't aware). I actually take route 111 from Windham near the route 93 interchange to quite near the Mass border for my commute, but for the purposes of this blog entry, we'll stick with the western terminus.

This section of road is - much like the rest of route 111 all the way to the seacoast - in great shape. Smooth, wide shoulders, very few patches or any other non-asphalt items to break up the tarmac. Add to that very gentle sweeping corners, very flat terrain, no stop signs or stop lights, and nothing but residential side roads, and you have a good road for driving and riding...and drafting.

Wednesday morning I crossed the highway and saw a large box truck waiting at the last stop light for the next 4 miles. It popped it into the big ring, passed a few cars and tucked in behind the truck. I had no idea how far he was going. He could very well have pulled off at the next side road.

But he didn't.

He kept going...and going....and going.

He kept a smooth steady pace of about 40 for most of it, but as he crossed the town line from nashua to hollis, he pushed the speed up to about 45. My computer registered a maximum speed of 46.8. That's a drafting record for me, my previous some years ago being 46.

Now, I know what you're thinking...."47 mph on flat ground? something is wrong with your computer".

Well, no. You can see from the downloaded data above my cadence was in the high 120s.

Do the math.

A 700c wheel with a 23C tire has a circumference of 6.67 feet. I have a 53x11 on this bike which is a ratio of 4.81, so one turn of the cranks moves the bike 32 feet (4.81*6.67 = 32.13).

47 mph is 4136 feet per minute. Therefore, if you divide the speed by the distance for each pedal revolution, you get you cadence in revolutions per minute. 4136/32.13 = 128.7 rpm. Check the max cadence in the data above, you get...128 RPM.

You can also see from the data I wasn't working very hard. My heart rate actually dropped as my speed increased. Aside from the initial effort to catch the draft (peaked at 650 watts), it was pretty easy going.

But, I know you didn't come here today for a math lesson, so here is what you _did_ come for, Fully Naked Friday, Gotta luv a woman that can accessorize.......


Thursday, August 4, 2011

FnF - on the precipice of a cataclysm

Sometimes the irony of life really makes you stop and wonder. Regular readers of this blog probably know that I do rather stupid things on a regular basis, generally involving going very fast on bicycles behind large vehicles on public roadways. You need to have a bike you can trust for that, as well as be very trusting of the the condition of the road and the driver of the vehicle you're drafting.

Some of you may remember last winters' project - the Quasi-Kellog built up as fixed-gear (39x14). I rode the bike to a cookout last weekend, 22+ miles, relatively flat with a few short steep hills that require getting out of the saddle in the drops and muscling the bike over the pitch. Less than a mile from my destination, I hopped into a truck draft while it cruised through danvers at 30 mph.

It only lasted about a 1/4 mile, but spinning a 39x14 at 30 mph in 95 degree heat takes a bit out of you (that's a cadence of about 140 for you non-math majors)

So I get to the event, ride up to the hosts and my wife (she drove down) to let them know I'm there. We chat for a minute, and I get my car keys to go load my bike in the car and get my clothes. I step back into the pedals, and with the first stroke I hear this sickening slow crack. The handle bar snapped.

The initial crack.

This is after I ripped it apart.

Less than a mile earlier, I was drafting a truck at 30 mph.

Gotta luv the irony of life.

Here it is, Your Fully Naked Friday