Dirty Kanza Power Data Analysis & File from 2018's race!

Fellow #Groaders - we talked about Pacing on last week’s podcast if you recall, using the tortoise and the hare analogy .

Podcast listener and FasCat Coalition member James Walsh was kind enough to share his power file with us here: http://home.trainingpeaks.com/athlete/workout/KYQUO4IUMRMHB3T25WTH4DFQFI

First off, James finished 21st overall !! Plus 3rd in the 40-44 category so we know he’s a total beast. Let’s get into what Jame’s power data tells us:

#1 1st off a TSS of 810 is really high, like too good to be true high. So
#2 I checked his peak 60 minute normalized power output per our March 14th podcast, on how to measure your FTP from your race and training data.

James’s Peak 60 min normalized power output is 317watts to his 277 average watts. Given that this 317 watts is his normalized power and it the first hour of a 12 hour 200 mile race, I’m inclined to say a) James went out way too hard and b) his FTP is roughly 300 watts. which is what he had it set at soooo

#3 be able to ride a TSS of 800 to finish the DK (ouch!).

The conundrum on the tortoise and the hare is that James was riding in the lead group for the 1st 93 miles. That’s quite the time savings compared to checking your ego and pacing the start at say 280-290 watts for the first hour.

How much time did James gain in those first 93 miles - that is a BIG question.

Because… ! ! ! ! James hit a rock at mile 93 not having a line of sight and then rode for the next 2.5 hours to mile 140-ish at 223 watts (high zone 2). Then the wheels feel off even more where his power & heart rate went down even more to 200 watts which is low zone 2 (.67 IF).

So the million dollar pacing question IS: did the times savings from riding in the lead group for the first 93 miles[282 watts @ .94 IF] outweigh the time loses for the final 67 miles [200 watts @ .67 IF] ??

Its tough to answer, that’s why this is a :moneybag::money_with_wings::money_mouth_face: :money_mouth_face::money_with_wings::moneybag: question!

Overall, its important to remember James finished 21st so that’s a whole lot of ‘did it right’ in that effort. On the other hand James is going back this year to try and win his age group , go James!

Had he not of flatted at mile 93 I think he’d have gotten a much better result. So it will require some luck. On the other hand he didn’t flat for 93 miles riding in the group without a line of sight so he was really lucky in that regard. Beefy’er tires? More 4 lead clovers? :four_leaf_clover: Dunno.

I’d be curious to see if anyone out there has an example power file from the Dirty Kanza where they felt they paced the race well and didn’t go out too hard. What’s the power differential between the first and last hours and then relate that to how much one can expect their power to decrease towards the end of the race.

Its like @Jackson said in this podcast, its all about how much you don’t slow down, not how fast you go initially.


Thanks for taking the time to analyze my file. I for sure burned some matches in the first 93 miles staying with lead group but that was my plan… I just wanted to see if at 40 years old I could hang with those hammers… and I was pretty successful until I cracked my wheel (photo below). The time savings was huge too… i stood on the side of (gravel) road fixing my tire/rim for at least 5 minutes and not a single rider passed me. I got back on and rode slowly for another 3-5 minutes before another rider and then another group short after.

I rolled into the mile 103 checkpoint and had to take another few minutes to swap my front wheel (luckily I brought a spare wheelset). I think my big mistake was then chasing out of that checkpoint to eventually catch the group i rolled in with. I burned way too many matches that late into the race and paid the price from miles 140-162… at the mile 162 checkpoint I ate half a sandwich and slammed a beer… that brought me back to life and I rallied to the finish passing a handful of riders in the process.

live and learn. stoked to get back this year for another go.


Good stuff! Funny, I was planning on asking a question about pacing in long gravel events. This year I did the Croatan Buck Fifty and the entire time I kept thinking am I going too fast or too slow? If I run my HR over a certain BPM will I pop before the finish? What should I be eating? When should I be eating? etc… etc… Anyway, I survived which was the only goal, however I felt I could have done much better if I was better prepared.

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Great topic. I’m doing the Truckee dirt fondo in early June. Did lost and found 2 years ago. Don’t think I have data on that. It’s at altitude so from a power perspective I’m not sure what too hard or easy will look like since my FTP is from sea level. Any advice on how to pace this? Detail: elevation 6-8k, elevation gain I think about 6k. Total mileage about 70.

Let’s have a look at the elevation profile for starters (for pacing) and can you post?

Link to Strava route

Image of profile

I would ride within yourself at sweet spot and tempo watts until the bottom of that climb and then let ‘er rip - that looks to be the decisive crux of the race

Thanks. Wondering how to think about watts at altitude if I’m a sea level guy but racing at 6 to 8k. I’ve seen anecdotal commentary that FTP watts will likely be about 10-15% less. Seems like that in conjunction with HR might be a good way to keep things in check

Coach @Jake has got a great altitude training tip I’ll let him share and elaborate on per your race :wink:

@Jake would be great to get your insights on altitude on race day.