I went tubeless this season by trolling the internets for a tubeless wheelset and quick selling one of my tubular wheelsets — pretty much a direct swap. It’s a nice wheelset — American Classic hubs and Stan’s ZTR 355 rims — and chose Clement PDX Crusade tires because I had used them for training last season and was impressed with their performance. I also understood them to work well in tubeless applications even though they are not rated as tubeless tires. I decided to make the switch because tubular tires are really expensive. I was fine with gluing my own tires and really appreciated the performance of tubular. But my tires were wearing and I needed new rubber.
Three races and a few vigorous weekly world sessions later and I have had no issues with the setup and am pleased with the performance. I am absolutely sold on the technology. However, I’ve been reading about racers that have had lots of trouble with their tubeless installations which aroused my curiosity. The conundrum is that there are many people racing successfully with tubeless but there are still a significant number of people unable to do it without catastrophic burping events (CBEs).
I used the local race email list to troll for user experiences and got quite a few, about half of them bad. That’s not surprising since failures elicit an emotional response and thus people are more likely to report poor experiences than good ones. A sampling:
“Raced clinchers before tubeless, and currently racing tubular. Of the 3 systems, tubeless were by far the least reliable for me in race conditions. Burped tires seriously affected my results in at least 4 races, so I lost all confidence in them for racing.”
“The ride quality is awesome but I have burped my front wheel one too many times. Last time it happened the front tire completely blew out.”
“I would discourage going to tubeless. Maybe I didn’t find the right tire/rim combination but there have been several of my teammates with similar experiences. When running tubeless in cross, the pressure has to be so high in order not to burp air that it doesn’t really give you any advantage over standard tubes. In addition, it is more annoying to set up than standard tubes.”
These disgruntled voices are a marketing liability for manufacturers of tubeless products because they will inhibit acceptance within the cyclocross community. Tubeless for mountain bike is well established and it’s increasing on the road too. And just as road tubeless has a different set of rules than mountain tubeless, cyclocross has enough differences from either that people need to understand the complexities to have success. Here are some of the rules as I’ve been able to ascertain:Burps are the bane of cyclocross and it’s worthwhile to understand how they happen. The tire deforms in such a way as to allow a (temporary) gap between the rim and tire allowing air to escape. Since CX tires don’t have lots of volume, a single burp can make a tire unrideable. The most common pattern is for the wheel to encounter an obstruction that completely deforms the tire to the rim — bottoming out. Depending on sidewall construction and bead security, the sidewall folding can pucker the bead in such a way as to form a gap. Once pressure drops, the tire will bottom out more and probably burp more. A second and rarer method is for lateral forces to pop the bead. This usually results in a CBE and may be paired with a previous bottom out burp.
- Just because you can seal up a tire on a rim doesn’t mean you can race on it. There are a lot of variables that determine a viable tubeless racing setup and they go above and beyond holding air.
- The bead has to fit tightly. Tubeless specific tires have special beads that don’t stretch and provide a secure connection to rims with adequate bead retention mechanisms. Let me elaborate:
- The rim needs a sufficient hook to retain the bead. Since CX requires low pressure, virtually all clincher rims have an adequate hook. However, it also requires a shoulder to prevent the bead from being pushed down into the rim channel when the sidewall deforms. When tubeless conversions cite building up the channel with tape, what this really accomplishes is creating that shoulder on which the bead will rest. You want a really tight fit for the bead between the hook and shoulder.
- If the bead stretches, it will be easier to deform and may have enough play to slip over the hook. Using tires that aren’t tubeless specific is a gamble. Mud2 and PDX Crusades set up well and appear to have a bead that resists stretch — for some period of time. The older a non-tubeless tire is, the more the bead stretches. I recommend using those tires for a single season only. And don’t take them off the rim unless absolutely necessary since removal stretches the bead. Double-and never use a tire that blows off the rim for tubeless again — the bead is stretched too much.Note: Every time I’ve heard of a Clement PDX Crusade tire mounted to a Stan’s ZTR burping, the tire was well used.
- Tubeless tires on tubeless rims are your best bet for ease of setup and confidence for reliability.
- Wider rims appear to be more secure. Since the rim is wider, the tire profile is not quite as high. Perhaps this reduces the pressure sidewall deformation exerts on the bead. Aside: A wider rim will make your tire wider. If you are worried about UCI width requirements, this might concern you. I compared my PDX on the ZTR 355 (wide rim) side by side with a tubular PDX. Mine was 3-4mm wider.
- Rider weight, tire pressure, and riding style make a difference. People should be riding a pressure where they are on the cusp of bottoming out on the rough stuff. If you are light and know how to float, you can run ridiculously low pressure. If the opposite is true, then run some more pressure. Sometimes I get the impression that tire pressure is a “how low can you go” pissing match. Experiment and find a pressure that works for you. If you are rattling around on the rim and/or folding over your tires in the corners, it’s too low. If you don’t bottom out ever, it’s too high.
And that’s about it. CXMag already published a three-part series on tubeless how-to and the third installment is really important to take to heart. After trying out my tubeless solution, I divested my wheel collection of the last of my tubular wheels. I’m all in and have no misgivings. Failures can happen with any tubular, tubed clincher or tubeless setup. If tubeless isn’t working well for you, you are doing it wrong — and it’s likely from lack of information rather than poor technical savvy.
At a recent race, one of my teammates commented that he had to run his tubeless solution at a higher PSI than when he used tubes. He then went on to say that he had burped them repeatedly and had even blown one off the rim. He was using Clement PDX on Mavic Ks. I gave him my two minute spiel on tubeless and how I was confident that he could make it work at reasonable (read low) pressures. He seemed weary of the effort and resigned to tubeless not quite living up the hype. I can only hope that he revisited his setup in light of some of my suggestions and you can be sure I’ll follow up.
Since I’ve gotten email from them, I know there are plenty of racers out there like my teammate. I’m not sure what it’s going to take to change minds as quickly as the technology warrants. Maybe companies that make tubeless products should sponsor some ambassadors who dispense their expertise for free at big events. Or they can just wait a few years while best practices emerge piecemeal and the stigma of CBE fades. Personally, I’d want to sell more product now.
Winter Cross at the Washougal Motocross Park was my last race of the season — a bittersweet proposition. It will be nice to be able to go for bike rides without worrying about being ready for race day. But I’ll miss the competition, routine, and companionship that race day brings. The weather was cool and partly sunny but the course retained some mud from the soaking the week previous. Perfect for the final race.
The promoters used this venue previously in the year for Nincrossi and the course was a climbers dream — it was set on the side of a hill where the moto dudes warm up. For this installment, they used a bunch of access roads in and around the motocross courses and linked them up with some grass and small bits of the motocross course. There was a short run up and a single barrier for two dismounts per lap. Otherwise the climbs were short and there were plenty of tricky corners. I understand that things were pretty slippery early in the day but some stuff had dried out and lines formed by my end of the day start.
The single speed field had a decent turnout for a non-Crusade race. Twenty eight of us lined up and some of the fast dudes were gunning for the series overall. I was hoping to beat Scott Barker with whom I was tied for series points. I lost that race within the first half lap where Scott proved far superior through the technical stuff. And the hills weren’t quite long enough for me to be able to use that advantage over him.
Instead, I ended up racing Martin Baker from start to finish. Martin was faster in the technical stuff too but I was able to stay close enough to pass him on other parts of the course. That made him pass me through the tech and kept us closer together. Unfortunately, just past the midway point, he got a decent gap and I could do no better than get near him on the places I was faster. I made a big effort on the final lap and was about 2 seconds behind him at the finish. Still, Martin is a pretty strong masters rider so it was cool staying with him all race. I did have the advantage of having raced SS all season (and I’ve been riding SS on the road too).
The course was outstanding and lots of fun. I pulled off an 11th which wasn’t bad given the competition. I have a grocery list of things to work on for next season and one of them is getting faster though the tech sections. So I want to hit the trails once a week through the winter so I can get comfortable riding in slippery conditions.
I had been waffling about which race to do this weekend — Edgefield or Salem. Since my brother and his wife were coming into town on Saturday and would be arriving a little before my race time, I decided the closer race would be the best choice. While I heard great things about the conflicting race in Salem, Edgefield presented a classic hard CX course. It had everything you could have hoped for except a sand pit. If you want to pick nits, the start could have been better but it worked out fine given the field sizes.
There is a lot of topography and varied surfaces to play with out at Edgefield. We hit cart paths, pavement, grass (groomed and bumpy field) and even some bark chips. The weather even worked out well because it rained all Friday evening and over night but didn’t do more than spit on Saturday. So we had all the benefits of some mud without the detriments of rain during pre-ride and warm ups.
The start was on some pavement and dumped into an uphill cart path pretty quick. Soon that hair pinned and went back down cart path to some vinyard service road (2-track). Back to cart path heading up hill which ended in a steep grass run up to cart path again (keep running or try to remount) which quickly turned more uphill over a ditch (long jump or you might lose a shoe). Now you might think being on the top of the course would be great. Except it dove back down on some gravel (sketchy) and just when you could get some speed on a flat bit, it turned back up hill on grass (run). Okay, now you are on top. Gravel 2-track for a bit (into the wind) which curved down hill for lots of speed before …
A super greasy off camber right hand turn into the field. The field bent down hill slightly over very bumpy stuff. At the bottom of the field were double planks just before a tight left hand turn. The question was to run the turn or remount (I remounted and it worked better than those who ran I think). Back up the bumpy field and briefly onto some pavement which curved to the left and went over a nasty curb and a plank so you had to dismount anyway.
Then we went around the correctional facility which looked like an asterisk from the top. We went into and out of three of the alcoves (greasy turns each time) right into the wall. It was a short run but I swear the pitch was steeper than 45 degrees. The only way to get up was to use the “steps” kicked into the face. It was perhaps 12 feet tall.
Then back around on pavement for a brief respite and continuing on some packed gravel. The honeymoon ends with a bumpy, crappy transition to the field and greasy left hand turn. That briefly bumps you down hill to a greasy off camber sweeping right hander bordered by blackberry brambles. Bump along the field some more (relatively flat for a change) to a greasy left hand turn that goes down a sort of steep hill featuring a bump that could get you airborne if you wanted/weren’t careful. At the bottom of the hill was another greasy left hander and a flat almost not bumpy section of field.
All that ended with a little jog up and over a paved path (nasty lip) and then onto some grass/mud. That section was pretty short but featured a heavily rutted dip and ended in a sketchy turn into the bark chips. The chips sapped speed as it went gently up hill to pavement and a short sharp climb. That turned right and continued on pavement briefly and then went through a short grass section with a few gentle bends and undulations to make it interesting. Then pavement and a left hander to the start/finish.
That course kept you on your toes 100% of the time.
So my actual race? I toed the line with 14 other single speed riders and took the whistle. I got fourth wheel off the line behind the eventual top three finishers. I kept them in spitting distance for about half a lap. At which time, Scott Barker (remember last week?) came around me and lead through to the start of lap two. I distanced him on the hill and run ups and spent the rest of the lap feeling him get closer. I thought I had put him away on the third lap but he was clawing his way back on the bell lap and I nailed the whole second half of the course to hold him off by a good margin.
It was almost a carbon copy of the previous week. I took fourth and Scott got fifth.
At Ryan Storfa’s suggestion, I did a linear regression on the average lap times by age. I only looked at the A, A+, 50+ and 60+ data. I took average lap times excluding the first lap. Here’s the picture.
Okay, what’s up with the 35+A and the A field? I think you have to go to the histograms a few posts down to figure out what’s going on with the data.
All those histograms were nice but here is the picture I really wanted. This allows a pretty rich comparison of all the men’s fields (women coming soon in their own plot). A brief explanation:
- Line in the box represents median
- Maroon diamond is mean
- The box represents the second and third quartiles (meat) of the field.
The A, A+ and B fields have really good compositions. The second and third quartiles are compact and the bottom whiskers are relatively short. B+ isn’t bad. SS and beginner show a wide range of ability levels within the fields. The SS field has the largest difference between median and mean — which indicates a lot of pretty fast guys with a fairly thick tail of slower racers. The juniors men have a similar profile which isn’t too surprising.
Click on the image to see a larger version …
I’m not going to provide a lot of commentary right now since I’m tired of working on this at the moment. But here are the histograms. Lots to mull over here. I took some liberties with the data to make the pictures work out “better.” I’ll discuss that later.
After my race last week, my legs were feeling rather leaden. Following Saturday races I’ve been taking Sunday off the bike then riding through the week. Some weeks that means a little intensity on Monday, Bridge Club on Wednesday, and a moderate ride on Friday. And easy going on Tuesday and Thursday. Last week, I went easy on Monday and Tuesday, Bridge Club on Wednesday, off the bike on Thursday and an easy ride on Friday. Even with that my legs had no punch racing on Saturday.
The course was pretty flat except for a canyon the course dropped into and out of twice per lap. There were a number of features in the flat sections to keep things interesting and the rain overnight spiced up all the corners. My legs felt like crap in pre-rides and I wasn’t sure whether it was just regular feeling like crap before all my races or actual crap feelings. So hard to tell. Compounding all this was the fact that the Cross Crusade had decamped to Bend for the weekend and a lot of the big names would be racing there. Consequently I had a better chance for a good result based on who actually showed to race.
I second guessed myself and changed out the 18t cog for a 20t. But while I was warming up right before my race I changed my mind again and put the 18t back on the bike. There were a few more than a dozen of us at the line and I felt pretty confident that there were at least three guys faster than me — Sam Nicoletti, (who did the A race too), John Lin, and a Portobello dude. I figured I could take the rest except for Scott Barker. Scott might make a race of it.
The whistle blew and right away Sam, John, and Portobello guy were in front with Scott and I right behind them. Within the first quarter of the course, the five of us had separation on the rest of the field. Scott and I were hanging close to the front three going into the off camber section. I was fifth wheel and everyone but me made it through clean. I had a line from pre-ride but I stubbornly refused to use it all race long. So going into the canyon I was gapped.
I rode the first half of the hill out of the canyon and then ran the rest. I made it through the pocket park in good order and dropped back into the canyon using due caution. I wished I felt more comfortable on the swoopy trails and then made the turn to climb back out. The climb back out was all run and I saw Scott almost walking up ahead. I’m no speedster on my feet but I was faster than Scott. I was on him again at the top and passed him just past the finish line.
By that time, the three leaders were gone and Scott and I battled the rest of the race for fourth place. I was faster in some places and Scott was faster in others. I tried to push harder in the places I was faster and kept hoping that the string would break and he would drop off the pace. But he was having none of it. The good news for me was that he was *slow* on the run up and I was consistently passing the finish line (less than a minute from the top of the run) with a gap.
When I took the bell I had a good gap. I wanted to keep it and head into the canyon first since Scott was faster on the singletrack. Though I flubbed the off camber in spectacular fashion, I made it into the canyon first with Scott right behind. I put a small gap on him when we got off to run. Then I pushed it harder as we continued up to the top of the pocket park. In front of me was a B rider and I immediately formulated a plan to get that guy between me and Scott before the final long section of singletrack. After exiting the playground wood chips, I hit the pedals hard and made a sweet pass as we rode up a little side hill.
Mission accomplished. Entering the canyon, and I had a slower racer between Scott and me. I rode along the canyon bottom as well as I had any lap and smoothly turned to start the run. I worked the run as best I could and remounted at the top with legs nearly dead. As I approached the final barrier, and I glanced back and saw I had a huge gap on Scott and soft pedaled it to the line. Fourth place out of 15 riders.
I plan to take three days off the bike this week and I’m also considering skipping Bridge Club. I want to feel rested for the next race.
Team leader Bill puts on a Wednesday workout. Lately it’s been happening during lunch time at a park conveniently close to work so I have been attending each week. He has each workout scripted on his Garmin unit so we move from one activity to the next in a crisp, regimented fashion. The script keeps things moving well. The basic format is pretty much the same from week to week with occasional tweaks:
- Take a couple of laps around the “course” to learn it. There is nothing terribly technical since it’s supposed to be a workout, not skills training.
- A dozen minutes of tempo around the course. Cutting the course is encouraged if you fall behind.
- Starts x 5. Roughly 60 seconds on and 2 minutes off.
- Barrier drills. The point is to get clipped and up to speed. Two barriers spaced enough to remount, hit the pedals a few times and dismount again. I usually do tempo (or just recover from starts) during this rather than the barrier drills.
- Intervals. We mix this up. This week we did (2 minutes + 4 minutes) x 3 with rest commensurate with work. We’ve done pyramids. Or all 3 minutes x 5. Again, cutting the course is encouraged. I’ll often start at the back (or near the back) to work on passing.
- Cone patrol.
- Barrel races. Put two big cones about 20 yards apart. Three people at a time race between the cones. The point is to try to make a pass. One minute on, one minute off. The distance is enough to get some speed but not so much as to be “dangerous.” I love this drill.
Afterwards, I feel about as spent as if I had done a race. We usually have 4-7 people each week and it definitely makes the mid-week workout a lot more fun.
The course on the banks of scenic Vancouver (WA) Lake was flat. There were a few mounds which were used to their fullest potential. And there was the beach. Getting on was a grass to soft sand transition which a volunteer raked periodically throughout the races to prevent a worn groove from forming. Then it was a balls out packed section at the water’s edge for a hundred yards or so. Then soft sand to get off — so soft that no one came close to riding it back to the hard pack. And to top it off, there was a long (like quarter mile or more) section of crushed gravel that was *fast*. So I decided on the 18t.
I felt crappy before the race but that’s nothing new. It’s all psychological and it generally disappears when the whistle blows. I got a call up and slotted in the second row behind one of the big engines. I was hoping to hang on for the drag race by getting all the help I could in the draft. Single speeds went before B’s this week which meant no slower traffic for a while, maybe the whole race. The whistle blew and we were off. The first couple hundred yards went okay but after that, I started losing ground, unable to keep pace with the big guns. The good news was that a small group coalesced around me and we were able to hang together through the first bit.
By the turn onto the grass, our little group was 10-20 yards behind the lead bunch. And that was that. Scott Barker, John Lin, some guy I don’t know because he was always in the back, and I formed a compact group that stayed together for a little over two laps. John and Scott drove the pace early on. Every time I would stick my nose in the wind, it seemed like one of them would come around me to push things a little harder. i think it was less about me dropping pace at the front and more about the way they race — they feed off of the wheel in front and always want to get around it.
A few laps in, maybe three, Scott was starting to fade a little bit and the fourth dude was having trouble staying too. John and I got a small gap coming off the beach and I drilled it on the road to keep the gap up. Pretty soon John came around me and we flew down the straight. Scott was permanently adrift. John and I were by ourselves.
Just before three to go, the B leader passed us on the straight and John and I jumped on his wheel. We took the ride all the way through the speedway sections and past the finish. Just hanging on to the wheel was putting the hurt on me and once we started the twisties, I got gapped. It was just a little but I could not quite get back on.I stayed 10-20 yards behind John and the B leader for the rest of the lap. Back on the straight, John and I both passed the B leader. I was rather surprised about that since he had gears and we didn’t. He should have been hauling ass relative to us. He didn’t pass us again and no other B racers made up the 30 second stagger to pass us.
I spent the penultimate lap maintaining. The gap to John didn’t grow and the two of us picked off a couple of single speeders who blew from the initial pace. Coming around the speedway before the bell, it looked like I made up a few seconds on John so I made it my mission to pass him before the finish. When we took the bell, he was still 5-6 seconds ahead. I hit the beach perfectly and made up some time there and I drilled it along the shore. When we remounted after the sand, we were close. I rode the final mound better than him all race and the last time through was no different. I hit the speedway 2-3 seconds behind him and went as hard as I could to make the catch.
When I tucked in behind, I hoped to catch a breather in his draft and make another push on the super bumpy grass to get around him. Unfortunately John had other ideas. He saw me on his wheel and upped the pace. I’d spent all my matches making the catch and had nothing left to hang on. I drifted back. And then a little more. By the line, he had pushed his advantage back to 5-6 seconds. I still got 9th in a field with more than a couple fast guys at the front.