Monday, November 15, 2010

Bike Speed

I spent a little time thinking about bike speed this week.  My last two triathlons had 20 and 24 mile bike legs and I averaged 20.2 and 19.8 mph respectively (very flat courses).  I'm not unhappy with that, but would like to get a little faster in short races, like 22-23 mph.  So what can be done about it?  It comes down to four five things.  Power, weight, aero dynamics, and rolling resistance, oops money is number 5.

Power - I don't have a power meter so I don't know how many watts I'm cranking out, but more is always better.  I won't be buying one anytime soon since they start at over $500.  I will increase my power over the winter following my plan.

Weight - I have an entry level road bike with clip on aero bars. 

My bike
 I'm comfortable on it and until I save $3k for a tri bike, I'm gonna live with it. Maybe if I sign up for a full triathlon, I'll get one of these.  It just looks fast.

I've already dropped almost three grand on gear, nutrition, and race fees.  New Orleans is already up to $750 just with the race fee and hotel.  Add travel and food and that one race will be over a grand.  Man this sport is expensive!  Anyway, back to weight.  I could lose about another 10 pounds and that would help but I love steak, bacon, and beer too much.  We'll see.

Aerodynamics - I already have aero bars which help.  Next up is an aero helmet.  They can increase your speed between 0.5 and 1.5 mph for about $100-150 bucks.  That is cheap speed.  Aero wheels provide about the same increase in speed but they are over 10x the cost.  I'm not sure if I consider myself fast enough to wear one yet.

Rolling Resistance -  I've always thought my tires looked wide.  I checked them a little closer this week and my Kenda Kriterium's are 25 mm wide!  Looking at racing tires, they vary between 19 and 24 mm.  Here is a really cool chart where some guy tested a whole bunch of tires.   Based on some reviews and forum searches I decided I'm going to buy some Continental GP4000s' for training next year and maybe some Specialized Mondo Open Tubular's for racing.

I just looked up my tire. Here is the quote "This tire can do it all, from training to racing. Also available in a 700Cx25 size for touring and commuting."  So I've been racing on a touring tire!  Why didn't the bike store tell me?  These tires are now my trainer tires until they pop.

Kriterium's - 255g - ~$30 each - 20 Watts per wheel? 
GP4000s' -  198g ~$50 each - 14 Watts per wheel
Mondo's   - 225g - ~$70 each - 11.5 Watts per wheel

So I could gain ~12 Watts for ~$100.  Assuming I'm pushing 200-250 Watts, that's a 5% gain.  That could equal in the neighborhood of 1 mph.

So adding up the gains from my increased training, aero helmet and tire upgrade, I could be pushing close to 23 mph in a flat Olympic distance race next year.  That would be sweet.

Bike training this week has been good.  I did three workout's almost per plan.  The first was supposed to be a lactate threshold test.  After a warm up you go all out for 30 minutes and see what heart rate you can sustain.  It is as painful as it sounds.  So I was all primed to do the workout when I got home and we got a last minute invite from one of the neighbors for a chili dinner.  I love chili.  I figured if I skipped the beer, I could probably still do my work out.  Nope.  I got on the bike and was burping chili and got heart burn whenever I got in aero position.  It turned in to an easy zone 2 ride just to keep dinner down.  For my two hour ride yesterday I combined the 3rd and 4th workout in the plan.  So after about an hour and 20 minutes I did 14 30 second sprints pretty much all out.  Yep, it was painful. 

Running wasn't so good.  I was lazy and slept in so no running in the morning.  I planned an hour run on Sunday but tweaked my back Saturday.  My plan starts in two weeks, so not much more slack time.

This week

Swim 0 hours
Bike 4 hours
Run 0 hours

1 comment:

kizzy said...

great them...

"Running is the greatest metaphor for life, because you get out of it what you put into it."
-Oprah Winfrey ~mountain hardwear