Wednesday, 2 September 2009

Of pointy hats and small cogs

After a summer of trying out a few informal "club 10" time trials, I finally managed to complete something bigger on Monday: an open 50 mile TT on one of the fastest courses in the country. Over 100 riders took part, with the winner riding finishing in 1:40:50 (that's nearly 30mph!). I managed a respectable 2:05:43, which is 23.86mph or 38.4km/h, but still finished more than eight minutes behind the women's winner and only 6th out of the women's field. Still, I was satisfied with my performance as I managed to pace it fairly evenly (more about that below), with 1:02:57 for the first 25 miles and 24:42 for the last 10 miles. I'm hoping these numbers bode well for my open 10 mile TT in two weeks and 25 mile TT at the end of September. Not only are these TTs good training for Kona, but they'll give me good baseline times to improve next year, not to mention a shot at some trophies at the Kingston Wheelers awards dinner at the end of the year!

The data and discussion of my ride are below, but before I get into that, I thought I'd provide a newbie's point of view of time trialling in the UK. According to Wikipedia, it's quite an old sport, first beginning in 1895 and historically being held on the fastest roads available. Supposedly, races were held illicitly for many years as the highway code didn't allow any racing at all. Now it's a sport with a devoted following of early-risers (TTs often start at 6am) who squeeze every conceivable ounce of speed and aerodynamic advantage out of their equipment possible; I thought triathletes were bad, but TTers put them to shame! When I arrived at HQ, I was shocked at the number of bling frames, frighteningly low handlebars, disc wheels, aero helmets, tiny gear cogs and skinsuits all in one place. In fact, I felt rather out of place in my regular bike jersey and shorts (albeit the tightest-fitting I own), triathlon shoes, and a mere 60mm deep rear wheel with *gasp!* my everyday cassette on it. At least I had picked up an aero helmet at the last minute, so from far away I didn't look too out of place. But it's funny how a sport as old school and grassroots as time trialling -- where sleeveless shirts are not permitted but helmets are optional -- has at the same time the most flashy equipment and slick-looking riders. I didn't see anything like BBAR champ Nik Bowdler's bike (pictured below), but there were certainly a lot of huge chainrings and tiny cogs around!

That's a 73 tooth chainring on the front!

My start time was 7:43am, but given the convoluted course instructions I figured I'd better get there early to drive it and make sure I knew where all the turns were. I needn't have worried, as the organisers had signed everything very well and placed marshals at every junction. Not a fun job to stand on the side of a divided highway and point an endless stream of cyclists in the right direction for hours on end -- at least in a road race you get to watch the attacks and breaks! -- but the volunteers were great, even cheering me on each time I passed their grim position. The weather turned out better than expected, as the chilly wind from the previous few days had died down considerably, leaving only a misty drizzly and warm morning. Later on the mist lifted and the roads dried up, and nearly all the top times were owned by vets, who started long after 8am and enjoyed extremely fast course conditions compared to the early starters.

I didn't really have a goal time in mind, but figured somewhere around 2 hours 5 minutes would be a good time for me in my first go at the 50 mile distance. After Googling around to try and figure out a good wattage number to aim for, I finally decided on ~215 watts, or ~95% of my test FTP on the TT bike: much harder than the 80-85% I'd target for a 56-mile half-Ironman bike leg, but not as all-out as a Richmond Park three-lap challenge. In fact, I had read that a good perceived effort for a 50 mile TT was more or less that of an Olympic triathlon (which lasts roughly the same amount of time), so I kept that in mind while I was out there.

According to Joe Friel, the third quarter of a TT is always the hardest, even if you hold back in the first half. Paced properly, the last quarter can be quite strong; paced badly, I would imagine it to be a complete sufferfest. Below is my power graph for the entire event, divided roughly into four quarters (and slightly smoothed for ease of viewing). Even though my VI is 1.01 -- nearly perfect for a more or less flat time trial -- it's apparent I didn't pace anywhere near perfectly.

50mileTT_graphHeart rate is red, power is yellow, elevation is orange.

First quarter:
Duration:   30:59
Work: 392 kJ
TSS: 42.6 (intensity factor 0.908)
Norm Power: 213
VI: 1.01
Pw:HR: 5.18%
Pa:HR: -4.93%

I managed to go out a bit hard for the first 15 minutes or so. In fact, after the first five minutes when I realised that I forgot to switch my cassette from the hilly IMLP 12-25 to a more appropriate 11-23 for a flat time trial, I decided I'd better try and compensate the loss of speed and power on the downhills by going a tiny bit harder on the uphills (bad idea, next time just make sure to start with the proper cassette!)

Second quarter:

Duration: 32:02
Work: 400 kJ
TSS: 42.9 (intensity factor 0.897)
Norm Power: 211
VI: 1.01
Pw:HR: 4.71%
Pa:HR: -1.44%

I was expecting a headwind at any moment once I turned south again, 20 miles into the event, but it never seemed to come. In fact, the section between 20 and 25 miles felt the best of the whole day. Riding past the turn-off for the finish line, I started the second lap feeling pretty good.

Third quarter:
Duration:   31:48
Work: 387 kJ
TSS: 40.9 (intensity factor 0.878)
Norm Power: 206
VI: 1.02
Pw:HR: 4.46%
Pa:HR: -18.3%

Somewhere between 30 and 40 miles, I started to suffer, as my legs were really starting to hurt and I wondered how I could possibly do another 30 minutes at my current pace. It felt like my watts were really dropping (though it probably just seemed that way as I glanced at my powermeter probably at moments where I knew I was slacking off). I also started to lose focus a bit. Spending 90 minutes by myself, riding at the same pace, in the same position, on a boring straight highway with traffic roaring by was taking its toll mentally. In reality, I was only down a handful of watts, but at the time it felt like I was pedalling in molasses.

Fourth quarter:

Duration: 30:56
Work: 397 kJ
TSS: 43.4 (intensity factor 0.918)
Norm Power: 216
VI: 1.01
Pw:HR: -2.9%
Pa:HR: -5.96%

Thankfully in TTs the last 10 miles are counted down one by one; whether that's for added pacing assistance or just to motivate the riders to finish, I was overjoyed to see those markers. The final 5 miles seemed to go by more quickly than expected, so I guess I had more left in the tank than I thought. The final mile was downhill and with one eye on the clock, I was pretty sure I'd break 2:06 and I did. You're supposed to yell out your number to the timing official but I really had nothing left as I passed him. No doubt about it, I left nothing on the course and in fact had to pull over to eat something before I started the 15-minute easy ride back up the hill to HQ. A rider who finished just after me rode by and I couldn't even bring myself to make conversation, let alone join him. I was simply too spent.

Overall, I managed 1:02:57 for the first half and 1:02:46 for the second half, with 212 NP for each. Next time I'll make more an effort to hold back a little bit at the start, and be more mentally prepared for the draggy third quarter so my watts don't drop so much. Between that and some very needed aero improvements (as can be seen from the photo below!) I should be able to get a lot closer to 2 hours for 50 miles on a good day.

a3cgr_50_cropCopyright Charles Whitton Photography


Anonymous said...

You are, in the best sense possible, a complete animal.

I'd be happy these days with a ten mile ride any speed. But then, I haven't done any biking, swimming or running for 10 weeks now.

Looking forward to hearing about your exploits in Hawaii.

Marc Scudamore

Mum said...

So with a time trial you don't get to see any other riders on the track? I understand that you leave x number of minutes apart but is it the loneliness of not trying to beat anyone but the clock - the chases, attacks and breaks that you missed?? Would it be that way if it were more hilly or not on a highway? Sounds as if you need to put in earphones and listen to music as you ride!!

leona said...

i can't believe your thinking of doing it again!!!