Monday, August 3, 2015

53x13

Bike nerd post.

On my three nicest bicycles I ride Chorus 10 speed.  This means Campagnolo Chorus components with a 10 speed gear cassette and 10 speed rear derailer.  I ride a double chain ring in front, a 53-39.  The cassette has cogs with the following number of teeth:  13-14-15-16-17-18-19-21-23 and26.  This gives me 20 gears to choose from.  I mostly ride in the middle cogs of the cassette.  For one thing, that is where shifting between the two front rings is the easiest and most efficient.  When I have a tailwind and/or am feeling strong I am most often in the 53x17.  When I have a headwind or when I am not feeling very strong or when I start up a hill I most often shift the front ring to the 39 and ride the 39x17.  I live in a location featuring glacial terrain, hilly to be sure, but people who live near mountains would scoff and call it flat.  I sort of agree, the hills around here are always short, I do most of my basic uphill in the 39x19 and occasionally if the uphill and the headwind are combined I use the 39x21.  Once this year all three of the factors which put me on the small ring conspired to occur simultaneously and I shifted down to the 39x23, the second lowest gear available to me.  I haven't been in 39x26 since either the last time I climbed the Myrtle Street Hill in Stillwater or the last time I climbed Ramsey Hill.  Just a comment here, the Myrtle Street Hill is extremely difficult to begin with but also the bottom of the hill is located approximately 25 miles from my garage, meaning that any climb of the Myrtle Street Hill is the beginning of the second half of a 50 mile ride.

I occasionally get a tailwind and a downhill which can find me moving up the the cassette even while in the big ring.  I can ride easily over 22 mph in the 53x15.

But the truth is my most common riding gear now is the 39x17.  In this combination I do still have to turn the pedals to make the bicycle move forward but I do so with a mechanical advantage of 39 divided by 17 or approximately 2.3.

I felt good today, good legs.  Shortly after starting out I turned onto the slightly downhill eastbound Larpenteur Avenue.  I had a decent tailwind and I was lucky enough to make the light at Fairview.  I started clicking up the cassette and eventually ended up for I believe the first time ever, certainly the first time in a very long time, in the highest gear the 53x13.  A mechanical advantage of approximately 4.1.

I wasn't even trying very hard as I obtained a maximum rate of speed of 27.2 mph.  That's slow for Cav but it is very fast for me.

Enough about gears.

The neighbor across the street has a tree which again this year has given the second harbinger of things to come.
They are both maples, the one on frame left is, I believe, a Schwedler maple (a cultivar of the Norway maple).

The one on frame right is a huge disappointment to us all, its leaves having begun to turn before August 3.  It comes soon enough anyway, the dang fauna could at least hold on until actual fall.

The first harbinger of things to come was, of course, the beginning of the shortening of the length of days.

3 comments:

Santini said...

Just so you know, I read the entire first paragraph word for word and understood it all, including the math. I felt obligated to do so, somehow. Though there are other bike nerds who read your blog.

I have noticed, just yesterday driving along a street near here, a similar looking tree. It just seemed wrong.

Emily M said...

That tree is a quitter. But at least Tom hasn't managed to kill it (yet?).

BDE said...

Just so you know, I skimmed the first paragraph and clearly understood the last few sentences. 50 miles and that uphill would require some serious training.

Still some summer left--we haven't even been to Michigan yet.