Dirty Kitten '25: 5th

My official AARP invitation arrived just 2 days after this race. I'm feeling it.

Dirty Kitten is a 2-day affair. Saturday is for the hitters: the folks who want to race 60 or 80 miles. It has also seen worse weather almost every year. Sunday usually has a more casual vibe, with race options of 40 or 20 miles. Saturday's fields are typically packed; Sunday's rarely exceed 45 riders in any given field.

This year was weird.

The men's 40-mile Sunday race had 93 registrants, almost equal to the *entire* grouping of men's entries for Saturday's fields combined. The women's 40 was close to 30 registrants, putting the Sunday 40 firmly into "biggest race of the weekend". 101 people started. Crazy.

Saturday, though, was even more hampered by weather than usual. The forecast called for crushing heat, as it did 2 years ago. In 2023, the Saturday races saw temps hovering right around 100F. With a similar forecast for this year, organizers sent out a last-minute race reduction that pulled a lap off of everyone's registered distance for Saturday. 80 became 60, and 60 became 40. But then it also rained. Like biblically. The opening climb was marked with deep ruts, the grassy section was underwater, big puddles everywhere, and most worryingly: the descent from the Crusher was purportedly rutted. Lap times were way off from previous years, and folks were reaching out to me Saturday night to warn me about the conditions.

And, of course, it also rained Saturday night after the race.

But I had a brand new rear tire that should be extra grippy, and suddenly that 36T ring up front felt extra validated by the slower lap speeds. And at the starting line, I asked the organizer about the day's conditions, and he said the course had dried out nicely overnight, and that the worst of the ruts were clearly marked.

Alastair and I had a plan to start at the front, punch over the opening climb, form a rotation with any other survivors, leave a cooler in an elevated chair so we could swap bottles after lap 1, and keep things neutral until the 2nd ascent of the Crusher, after which it would be an open race to the end.

Things did not go to plan.

We knew the biggest risk of the day was heat. The race started in fog at 80 degrees, and was forecasted to finish at about 90 degrees with a real-feel well over 100. Alastair struggles mightily in those conditions, so that bottle-swap was the pivotal element of the day's plan.

Unfortunately, while the first half of the plan went great, one rider punched over the first ascent of the Crusher, leaving 5 or 6 of us to chase. We were not a confident group of descenders, either, so by the time we were back on open roads, the guy was way up the road, just barely visible. Instead of a neutral rotation, we were a chase group. Alastair and I were on our limits for the next 3 miles, and I'd already spent entirely too much time in the wind just establishing the group's separation.

When we got to the pit to swap bottles, he was empty. I was able to continue without stopping, but tried to gum up the group a little to buy him time to catch back up. The group was not impressed nor impeded, and suddenly I was also in chase mode, but this time starting to feel chills in the sunshine. I let the 2 attackers from our group go, catching them again briefly for a moment before my body screamed to stop, and then settled into limp-mode with one other rider from our group.

The leader was long gone, the 2 chasers were gone, and this was now a trudge to finish in the top 5.

I never saw Alastair again (until after the race, obvs).

I managed to hold on for dear life with one other guy until after the 2nd Crusher, which--for the first time ever--I successfully climbed twice (woohoo gearing choices!). Once we got into the final sunshine-exposed climb by the farmhouse, the chills came back, and I basically just stopped pedalling. I watched my final companion ride away and just limped to the finish line in 5th place.

It was my slowest ever DK40 at 2:26:58, with my worst finishing position of 5th.

Alastair incredibly did not buckle in the heat, but kept a steady rhythm and came across the line just a few minutes after me for his fastest ever at 2:34:47, and his best finishing position of 6th!

https://www.bikesignup.com/Race/Results/79259#resultSetId-569185

Gearing

I spent the previous posts opining about gearing options, and used this space as a place to openly explore the idea of making the least-expensive change possible on the bike to produce the biggest improvement: a 36T chainring to replace my usual 40T.

I pulled charts of gear-usage from previous editions of Dirty Kitten and Monstercross to examine the amount of time spent at either end of the cassette, along with power distribution across the gears showing that even when I got to the fastest gears, it wasn't really meaningful for keeping power.

My theory was that moving from the 40T to the 36T would roughly adjust the time distribution chart by 1 gear toward the top end, but should reduce the bias at the extremes from 4:26 in the 44 and 0:54 in the 10. I ruled out a 38T chainring as being insufficiently different to make a meaningful change, and could potentially throw me into oddball cadences at the typical cruising speeds on this course.

I'm incredibly happy to say it worked out exactly as I'd hoped. Even with slightly odd course conditions and PR's on some of the flatter segments, the gears got me over the Crusher both laps, and I never had any chain drops. In fact this was the first year I've made it through the entire race without putting a foot down.

The following images show gear usage by time and power. The left side are 2025's race, the right are 2024.

Note the more even distribution of power across the cassette with the 36T chainring, as well, with no dips in the 38 or 11. Power was very low in the 10 this year, but even with the smaller 3.6:1 max gearing, it was really only useful on gentle descents.

What this year's gearing did not do was make the Crusher easy. With ramps reaching 23%, nothing will ever make that thing easy. But it did make it manageable, without taking away from the rest of my race. The heat did that on its own.

https://www.strava.com/activities/15255288036

Want to see the Crusher rip our little grupetto apart? Start at 48 minutes: https://youtu.be/r0Wf1c4B2TY

Horses for courses

Well, I did it. Ordered that 36T chainring and let it sit on the bench for a few days, nervous I'd made the wrong choice, in spite of the maths. But Monday I put it on and also mounted up a brand new rear tire, and...

It's hideous.

The 40 was never a big ring, but it looked "right" on a gravel bike. The 36, with that big 10-44 cassette out back, looks like it can't decide if it wants to be a mullet or a wayward mountain bike.

That bar tape I put on the top tube--initially as a joke, but left on when I realized how horrible shouldering that skinny tube was in CX races--doesn't win any style points, either. Nor does the pannier mounting brick on the seatpost. This bike has become a mockery of itself, and...

It's perfect.

I was worried I'd have to take a couple of chain links out, but while the derailleur folds up almost to its limit, the chain is taut in the 10. Biggest surprise of the change was having to adjust the B-screw. I don't think I'd ever had to do that for any previous chainring changes, but it absolutely would not get up onto the 44 until I made a couple of full rotations.

And the ride feels exactly the same, except now I can easily spin up some climbs at Pocahontas that used to have me grunting a little. Nothing that quite replicates the savagery of the Kitten Crusher I'll face next weekend, but sufficient to get my hardened teenage son to notice how high my cadence was while he was grinding away.

For giggles, I dug up the AXS report from 2024's MonsterCross to compare gear usage to Dirty Kitten. In that 3-hour race, I spend only a few seconds in the bail-out 44T cog, and only half a minute in the "big dog" 10T. The 40T chainring remains, in my mind, the ideal solution for that event. So this change becomes a "horses for courses" event-to-event change based on elevation profiles.

For the rear tire I stuck with the tried & tested WTB Resolute in 700x42. On the cheap-but-indestructible Sun Duroc G30 wheels, it sets up wider than a 44, and fresh rubber should help keep power delivered to the ground at the steepest parts of the climbs and when my son attacks me in the final sprint.

Dirty Kitten Gravel Race - still hunting for the perfect setup

What has become my favorite annual summer gravel race has somehow not yet warranted a post, which is bananas because I've had some decent results over my 5 attempts.

I first heard of Dirty Kitten during the pandemic, and that year it wasn't a race, so much as an isolation fondo. There were timed segments, and riders rolled out at intervals. You were allowed to ride with folks who came with you, and I brought Alastair. Though he holds no love for gravel, this one got into his heart, and we haven't missed an edition since. We always do the Sunday races, which are 40 and 20 miles, as neither of us enjoy gravel quite enough to want a 60 or 80 mile race.

I've been on the podium in the 40-miler every year since 2021, and last year was the closest I've come to victory at 2nd place.

With just over 6 weeks until the 2025 event, I'm beginning my annual panic over training and equipment for an event most folks do just for fun.

The course is just a tick under 20 miles, with no pavement anywhere. Conditions change year-to-year, but generally the gravel is stable and well worn-in, so speeds are pretty high over most of the course. It's absolutely normal to see 20mph+ on the flatter sections, even with my middle-age legs. There are 2 significant climbs that will test gearing limits. The first, Cedar Mountain, is just a deep-gear slog. It comes less than a mile into the course and generally determines who's there to compete. Usually fewer than 10 people make it over the top at the front, and fewer still get a clean run through the off-camber crumble to the screaming fast descent. Last year I nearly ate it--the trail gods demanded a bottle sacrifice.

After that, you're rewarded with 10 miles of flattish gravel. A few sharp turns, a couple bits of soupy gravel, and one section that's best described as "forest road" where the ruts and conditions are unpredictable year-to-year (but I imagine this would be MISERABLE when wet).

Then you get to the signature element of the course: the lollipop of death and the kitten crusher. This 4.3 mile portion of the course is mostly exposed to unabating July sunshine and can be broken down into a few critical elements:

• the 1.4 mile approach road that pitches upward at anywhere from 3 - 11%. This thing just sucks the life out of you before you even get to the real climb, and every year somebody decides to make this road hurt even more than necessary. But I've never seen a move succeed here, and there's more than enough pain coming.
• The Kitten Crusher. "Is this the climb?" Oh you sweet summer child... The approach is 8%. The first ramp is 15%. Each blind left turn holds an even-steeper grade, but just wait until it turns right. The Strava segment shows 154.5% and goddamn it feels like it. Whatever little group you've been riding with will be shattered here. Most will walk, but that doesn't really make it easier. Fortunately (?) there's an aid station at the top, and a dude with a sprayer to cool you down. If you stop, your race is done. I've made it over 2 times in 5 years / 10 efforts.
• The Crusher Descent is quite honestly one of the scariest descents I've ever undertaken on a bicycle. It doesn't help that your heart rate is still sky-high from the climb, but the first turn is loose and steep, and while you're in blessed shade for the first time, that just makes it hard to see. Average gradient -11.4% with peaks close to -20%...in a turn. Hang your ass off the back of the saddle, squeeze those brakes as much as you dare, and just pray for the bottom--you'll get there one way or the other.
• Though there's no segment for it, the rest of the lollipop sees you climb back up to the approach road and run it in reverse. If you got dropped on the crusher, this is where the work starts. A half-mile climb at 5% back to the road, a quick breather, a 10% punch, and then a screaming 1 mile descent in 2-way traffic of yelling at folks to stay on their side. It ends with a braking zone that would make a F1 driver weep before tackling a sharp right back onto a public gravel road.

The rest of the course is far less dramatic. At about 3 miles, it's 1 mile of flat recovery (or chasing, depending on your crusher results), 1.5 miles of undulating rollers in sunshine, and 0.5 miles of sharp rollers in the shade with an uphill kick to the finish line.

Then you get to do it all again. Yay!

I've spent years trying to get the "perfect" setup for this race. My first forays saw me on a 1x mechanical SRAM setup, always with a 40T chainring, but with various cassettes from 11-36 to one miserable effort with a 11-4(x?) and a WolfTooth goat-link intended to extend the supported cassette size for the derailleur. It didn't work well at all--the chain jumped all over the place and ghost-shifted on every climb. it was awful. Awful awful awful.

2 years ago I upgraded the gravel bike to electronic shifting, settling on a 10-44 cassette and keeping that same 40T ring up front. I was still dropping chains, but on the 2nd lap I finally made it over the crusher for the first time ever.

Last year I picked up a derailleur hanger alignment tool and corrected a massive mis-alignment, which made shifting so much smoother, but the chain *still* fell into the wheel on the way up. I ended up panicking on the 2nd lap and just got off the bike before it could fail again, costing me the potential to sprint for the win.

The only constant over the years has been at the front of the drivetrain: that 40T ring. While the gearing of the past 2 years has gone deeper than 1:1, I've still only gotten over the crusher 50% of the time, and lost the chain into the wheel 4 times. At the opposite end of the spectrum, the SRAM AXS app shows I only used the 10T cog for 54 seconds of the entire race.

That 54 seconds had an average power of 133W, as well. By contrast, the 44T cog saw 4:26 of use at an average power of 304W, with the steepest 2 ramps of the crusher at over 400W. 

So this year I'm thinking of trying something different. I cannot affix a SRAM XDR-compatible cassette deeper than 10-44 (if such a thing even exists), and even if I could, through some sort of updated Goat-link equivalent, I would never want to re-invite the issues I had with the bike 3 and 4 years ago. Going XD (SRAM's mountain-bike drivetrain popular in "mullet" gravel bikes) would add tons of cost. But I can move to a smaller chain-ring for $20.

I've resisted this option for years for a few reasons. The first is, honestly, it feels wimpy to go smaller up front. I'm a Big Strong Man(TM)! I don't need a smaller ring for MonsterCross or any other gravel/CX racing I do, and the idea of constantly swapping equipment is not even close to appealing. But aside from that, there's chain-line efficiency: the 15T (4th from smallest) gets almost 45 minutes of use--far and away the most used gear on this course, followed distantly by the 17T at just over 30 minutes. Using a smaller chain-ring would put that use farther outboard, creating a less optimized chain-line, which increases drive-line resistance, even if only slightly. Then there's the compound issue of more chain movement and slap--even with a clutched derailleur--as the chain moves farther outboard. I run a chain-keeper on this bike, but when the chain comes off, it always gets tangled in the keeper, which makes it just that much harder to re-seat when you're already on the limit. I don't want to create another situation where I panic and just get off the bike.

So what size ring? I went through this exercise when setting up the old crit bike as a purpose-built climber, and ironically ended up at 40T on that bike, too, though that was driven by wildly different goals and maths.

The power-meter crankset on this bike has a 5-bolt 110BCD interface, so I could go down as far as 34T, but that would see me spun-out for almost 15 minutes of the race. The gear-ratios of 40:15 and 34:13 are nearly identical, so that 45-minutes in 15T would become 45 in 13T, and it would come with a ridiculously deep gear on the climbs.

A 36T chain ring would offer one deeper gear for the climbs while only cutting off the top gear on the flats, making me spun-out for only about a minute. A 38T ring is honestly insignificantly different from a 40T--changes at the front need to be more substantial than changes at the back.

Since I'm trying to solve for about half of 4:26 of the race, I don't want to make a change that will impact the faster bits, so I've settled on trying the 36T.

According to my calculations, that will reduce the top speed at 90RPM to 26.9mph, which will only affect the two main descents--but let's be honest: I wasn't doing much pedalling on those anyway.