Saturday, May 30, 2009

Waterville Valley Time Trial

An individual time trial is often referred to as a "race of truth." It is called such because team tactics and drafting are removed. Each rider must fend for themselves. This truth is not an absolute, however. A flat TT clearly favors bigger guys that put out raw Watts. A climbing TT will favor small guys that put out high Watts per kilogram. What flavor of "truth" would you like? Both climber and flat TT specialists might do poorly on a technical course with tight turns, so riders with handling skills might come out ahead. Perhaps an honest race of truth somehow mixes all of these elements into one course.

But what about equipment? Pro's pretty much all have the same stuff, get wind tunnel testing, the works. In the amateur ranks, there is wide variation in equipment and how well the rider is fit to his or her rig. I do not have a TT bike. I refuse to go part way by clipping on aero bars. It is an all or nothing deal for me. Unfortunately, equipment makes a huge difference in a fast time trial. There's no way to be competitive with your peer group if you lack the equipment they are riding. To some degree, I resent this barrier to entry. A decent TT setup (bike, wheels, helmet) can easily cost thousands. I can see putting this into a light weight hillclimb bike, as it can be used for road races and everyday riding. A TT bike has very limited utility in my book.

I did the WVTT last year, so my goal was to beat last year's time. The course was extended slightly this year. I used the same bike but with slightly less aero wheels, modest section aluminum Rolf's. I did use my IBC skinsuit for the first time. So all that was pretty much the same. The weather was different, however. It was cooler (cold air is denser, thus slower), and it was windier. There was virtually no wind last year. By 10:07am, my start time, the gusts were picking up pretty good.

My bib number was 3. This meant I was third fastest guy from last year that registered this year and was third to last guy to go off. The two guys behind me were much faster than me last year and would surely pass me early with their TT equipment. One was Patrick Ruane (Sunapee/S&W). Brad Ek (NHCC) was #4 from last, my 30 second man. This was perfect, as I beat him by 8 seconds last year. I figured I would pass him on the climb out, then he'd steamroll by me on the descent back. Whether he'd take back those 30 seconds and beat me in the end was up in the air. Or so I thought.

The WVTT profile. Little ripples at lower elevations are not really there.

I push off, and it didn't take long before I realized I was going too hard. A diagonal head wind had something to do with this. It was taking my speed down and I was over-compensating. The road is quite open and I could see Brad almost continuously. The deal was, he wasn't getting any bigger in my field of vision. I pass my one minute guy, but Brad still looked like he was 30 seconds out. I think it was Patrick that passed me just before the steepest part approaching the Waterville Valley village. He passed me decisively. Then the speeds drop to less than 15mph and all the aero goodies lose their effectiveness. I'm pretty sure I took a few seconds back from Patrick since I gained on him on a constant grade. But once we topped out near the village into a gusty headwind, Patrick and Brad were both gone.

Like last year, riders that were near me beginning the descent put incredible time on me during the descent. Of course, they all have aero equipment. The speeds on the return trip are very high. I saw a max of 43.1mph. Aero is hugely important at these speeds. Unlike last year, nobody passed me on the return. The only two staged behind me passed me heading out, and only one rider I passed was well behind me. Initially, there was nice tail wind heading back out of the village. Much of the course dealt with crosswind. But due to how mountains shape wind flow, we had some more headwind coming the last few km's into the finish too.

I finished with a 49:27.15, almost a minute slower than last year. The course was extended a claimed 600m this year, making it an even 20.0mi (32.2km), so times should be slightly slower on average. But the wind was the biggest factor. Here's some stat's:

19.7mi (31.7km)
70F, calm winds
24.35mph avg
20.0mi (32.2km)
63F, moderate NW wind
24.27mph avg

So very nearly same average speed on cooler, windier day. I'll take it. Very good chance I averaged higher power and had a better race this year than last year despite not placing as well. It is interesting to note that I averaged 19.7mph heading out to exact half-way point (right at taking left to loop through village), and I averaged 31.7mph coming back. Combination of gradient and wind was behind this. Last year I had max speed of 38mph, this year 43mph. The average speed is pretty impressive I think considering I rode cannibal, it was breezy and there's about 1100ft of climbing on the course. Don't think I got girled either.

Doing a little "research" on the web, I could expect a full TT setup to boost my average speed by at least 2mph on this course. A boost of just 1mph could have netted me a win in my age category. Does this bug me? Just a little. Does it bug me enough to drop some serious nickle on a TT rig? Probably not. The so called race of truth is more like a race of best setups in the amateur ranks. There are some stage races I'd like to participate in sometime. No TT bike = not competitive in the GC. I keep threatening to make the plunge. Maybe this year will be the year.


James Scott said...

Nice meeting you today, Doug. I agree that if you mostly do road races, dropping a lot of money on a TT rig doesn't make a whole lot of sense. I understand not wanting to go halfway, too, but I think it's possible to get a good setup without breaking the bank.

My choice for a budget setup: The Cervelo P2/P2K/P2SL (now known as the P1) represents a very good value as the basis for a TT rig, and they're plentiful in the second-hand market. Throw on a set of Profile or Vision aluminum pursuit bars + aero extensions. Add a set of deep-section clincher wheels - you can share these with your road bike - and put on a rear wheel cover for a "ghetto disc." The rest is pretty standard.

I'll say that position matters as much (if not more) than the equipment, and finding the right tradeoff between power output and drag (CdA) can take some fiddling.

As for today's race, despite the fact that I had my full-aero kit, you beat me by about 20 secs (I didn't hang out for the official results, that may be off a bit). I figured I would have lost that time to you on the outbound leg. But if you say you averaged 19.7 M/h to the halfway point, 16.1 Km, and 31.7 coming back...I averaged 20 M/h to the halfway point, and only 30.1 on the back half (with a max around 40.5), so looks like you did the return significantly faster than I did. I must have really blown the pacing. I was working pretty hard going out, and my average power dropped by about 15% on the return leg.

Hill Junkie said...

James - good meeting you too. Fit is a really big deal. The WVTT is the only real TT I've done, twice now, where aero is allowed. I found in my futile attempts to get "aero" on my regular road bike, my hip angle is all wrong. I end up with some unbelievably sore glutes after the ride. This no doubt robs me of power if things are stretching that tight back there. I had to keep changing body position to less aero postions due to fatigue in weird places. I've never been on a TT bike. I can only assume a good TT fit eliminates these problems.

James Scott said...

Yes, for the position to work you have to be able to hold it for the duration of the race! So comfort is a component of a good TT fit. Getting your trunk as close to horizontal without compromising power output (too much) is another important component. But the best TT position is not necessarily the one where you can put out the most power. Accepting a lower power output might be the right thing to do if the improved aerodynamics more than compensate for the lost power.

I associate the sore glutes with different muscle recruitment patterns due to different position, not necessarily flexibility issues per se. Training in TT position will help that quite a bit. My main issue from yesterday is a sore neck from ducking my head.

Bill Thompson said...

Doug - you missed a great stage race in CT this weekend. I enjoyed catching up with Brett. I bought an older used Cannondale TT frame and assembled it with various used parts and Paul Curley did a nice job putting the shrink wrap cover on my wheel for $50 - he does good work. Bike was relatively inexpensive. But, as usual, now I want a nicer bike!

Kerry said...

The most important factor in determining your optimal aerodynamic position on the bike is a reduced frontal area, which is achieved by reducing trunk angle. Trunk angle is the single most important variable in determining frontal area, more so than aerodynamic tubing, frame geometry, or body mass.

If you're going to take the plunge for a TT bike, you want the model that enables you to optimize your aerodynamics (by reducing frontal area) without compromising power output.
Things to consider in terms of power output are
1.) Seat Tube angle - you want a steeper (>76º) STA in order to reduce potential compression of the hip angle that might reduce power output. A slacker STA won't allow you to get the lower frontal area without compression of the hip angle, which will inhibit power output.

2.) Aerobar drop - the drop between nose of the saddle and your arm rests is key to reducing frontal area. I see way too many people with TT bikes/aero bars and the bars are sitting up too high. This is especially a problem with clip on aero bars - if you add them to standard road bars without dropping the road bars down, you end up perched higher than if you simply opted for no aerobars and rode in the drops.

Contrary to popular belief, the key to an optimized TT position is not bringing the elbows close together (which is what clip on aero bars essentially do). The key is a reduced trunk angle, and that can only be achieved when STA is steepened and the appropriate drop is established to the aerobars (there is an equation for this if you are interested in determining optimal drop).

The Cervelo is nice, but so is a Felt (B2 or similar model). Every brand makes a TT bike, but the key is getting one that has variability in saddle position/STA (ex: Trek Equinox does not offer such variability) and an adjustable stem/stem position variability, which allows you to get the appropriate drop.

Sure, aerodynamic tubing is nice, but rider position is most important. You can get a very aero position on the right frame without dropping $3-5k on a high end TT bike, you just need to know what to look for.

For a very cheap price you could buy a Leader TT frame; it has a 78º STA and the lower end TT frame ($139 msrp) has a standard round 27.2 seat post. Combine it with a zero set back seat post, Look ergostem and Vision tech bars, you could get a very aero set up.

Hill Junkie said...

Great feedback everybody. What I think I'll do is take a pragmatic approach in acquiring new hardware, then get myself down to Fit Werx for a professional fitting. I've never been fitted even for my regular riding position. Who knows, maybe even something as basic as my current cleat position is sub-optimal.

solobreak said...

Jeez Doug, for a guy with a bike collection like yours this sounds pretty whiney to me. Anyhow, this discussion would not be complete without noting that USCF 1Je still states that UCI regs (ie 5cm seat setback) will be enforced at Nationals, even for Masters. Not sure about the CDA race but you never know. You can get to 5cm setback with a normal seat on just about any frame. If you want to go further forward or run a stubby seat, the Trek Equinox has a reversible 20mm offset seatpost, so I'm not sure what Kerry is referring to. Flipped forward you'd be way ahead of the BB. Getting the bars low enough remains the challenge with nearly every bike on the market these days.

Having been there and done that with the cheapo frame route, buyer beware. Don't assume that a $200 frame is going to have two wheels tracking in the same plane, parallel dropout faces, a BB centerline that is square to the seat tube, or an accurate seatpost ream.

I'd fix your body before getting a custom fit too. Why get all set up for an inflexible back?

zencycle said...

I bought a used Cube Aerium frame for $50 from the mavic van at one of those pedros sales they used to have in wilmington. Aerotubes all the way around, including the chainstays (ostensibly to reduce drag from rear wheel turbulence).

I bought a 54 since i knew I was going to need to get low low low (I ride a 56 road frame), and still needed to use a 12 deg stem upside down to get low enough, but my form looks pretty pro. I also feel good on the bike, It's a very comfortable ride even with my elbows below my knees.

I set a PR average speed for a TT on the bike at the WMSR a couple of years ago. Not that the TT frame was the key, it certainly wasn't. It was the extra time I put into setting the bike up. (Ignore my results at the rye duathlon last week, when I left the transition are my seat dropped 30 mm from a clumsy attempt at a cyclocross mount wearing road shoes, that fucked me all up)

As an anecdote, Solo laid down a serious ass smacking at the bob beal SR a few years ago riding a 20 year old takara(?) road frame with a mishmash of parts from his basement. He had done the same thing I did with my TT frame, spent extra time dialing in his position.

The point is that a cheap frame is certainly a viable option if you pay very close attention to positioning, and it doesn't need to be a TT frame. I personally think all this business about aero tubes is highly over rated unless you are planning to ride consistently over 30 MPH against other guys that are riding consistently over 30 mph. I only bought mine because it looked cool.