Corbin's Treehouse - Corbin Dunn, Santa Cruz, CA
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26″ Mountain Unicycle Tires

I have had my geared 26″ mountain unicycle since about 2009. It is a Kris Holm 26″ frame (KH26), the Schlumpf 2-speed hub, and a custom handlebar I made. I’ve gone through a few tires in the past years, so here is my recent experience and research on them.


Tires I’ve Used (in order):

1. WTB Stout 26×2.3″: Cost: ??. Weight ??. My first tire that I got on the unicycle in 2009. I wanted something very light weight for racing and cross country. Unfortunately it is too light, and definitely not wide enough. I felt like uni was a little too unwieldy to ride, or too “squirrly”, wanting to wander about. It also would kick me off on bumps, as I had to ride it with a bit higher pressure (at this point, I forget what I used). I still have this tire hanging in my basement. I also recall that this tire was *very* hard to get on and off the KH rim.

2. Maxxis Ardent Wire Bead Downhill Tire 26 X 2.6: Cost: $35 (plus shipping). Weight ??. Part #: TB74306200.  In November 2011 I decided to go for a wider tire to get more stability. It definitely worked; the unicycle felt more stable, and I was pretty happy with this tire. The Ardent is also a good “all round” tire and seemed to perform well for muni. Unfortunately the 2.6″ width isn’t available anymore from Maxxis. The widest Ardent that they make is now 2.4″. But that is okay, because in February of 2015 I started having trouble with the tire: it kept popping off the rim! This is probably because I had a heck of a time changing a flat one day on a ride. I could not get the tire off. I broke a plastic tire iron off, and it was still fighting me. Eventually I got it off and patched the tube (which didn’t hold!). Putting it back on was even worse: I couldn’t get it back on. I eventually got it on, but I’m sure I blew out the wire bead in the process. On the next ride I did (very wet and muddy out with my friend Roland), the tire kept popping off the rim about 3/4 the way through the ride. Oh well; the tire tread was getting a little low, so it was time to replace it.

3. Maxxis High Roller II: (26×2.40), Cost: $65. Weight: 840-855 grams. What I’m currently using. I’m using a light weight tube, and the tire is pretty light, so it has really good low rolling weight for hill climbing abilities. It also feels pretty good on the street, with low resistance (not like a Gazzoladi at all!). It fit the rim pretty well (not too tight, not too loose). It corners really well — great tread. I am using a light tube — which means I have to have higher pressure (32psi), so it is a bit bouncy. A regular or heavy weight tube would add up to a pound more in rolling weight, but I could run lower pressure (25-28psi), and would be able to avoid pinch flats and potentially roll faster on bumpy ground. Overall, I think I really want a little wider tire, but it works really well, and should be good for my upcoming Nepal unicycle tour.

Tire Research

I did quite a bit of tire research before settling on one (actually, two!). I wanted a tire that was good for off road use; particularly fast high-gear unicycling on flowing trails, but with enough stability to roll down rough trails and a high pace and not get too thrown off. I also wanted it to be as light as possible, as I’m going to use this tire on the next big unicycle tour in Nepal over the Annapurna Pass (coming up in April 2015). The tour will have lots of climbing, so I want it to lower the rolling weight. I decided to stick with Maxxis; they are a pretty good tire, and have too many options to choose from. Adding another manufacture or two would make it even more difficult to decide. For tire wide, I was ideally shooting for 2.5″ or higher, and 2.7″ was ideal. However, the 2.7″ tires were nearly twice as heavy as 2.5″, so I cut them from my choices. I also decided to throw in a 2.4 in the mix. I wasn’t picky about tread compound: EXO, 3C, TR, or whatever — they don’t mean too much to me, except one will wear faster because it is stickier. I’m not doing fast road cornering, so stickiness isn’t too important on a unicycle — weight is, so I picked whatever compound was lightest (when there was a choice).

1. Maxxis High Roller II: 26×2.4, 840 grams. Web: Maxxis High Roller II.$65 on Amazon. Light weight (for muni) at less than 900 grams, but only 2.4″ width — I really wanted 2.5″ or wider!

Maxxis High Roller II.png

2. Maxxis Minion DHF: 26×2.5, 860 grams. Web: Minion DHF . $? on Amazon. Also pretty light, and 2.5″ width! The DHF stands for “Downhill Front”, but that doesn’t matter for unicycling. I ordered this tire too, but the High Roller II came first, so it is the one I’m running. This might be a great tire, and the uses show the same as the High Roller. But the high roller might be better for less rolling resistance on hard packed dirt

Maxxis DHF.png

Tires that seem less good to me:

3. Maxxis Minon DHR: Web: Minon DHR : $?. Seems good, but 2.35″ width just isn’t wide enough for me. DHR stands for Downhill Rear.

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4. Maxxis High Roller: Web: High Roller. 26×2.5: 1180grams. 26×2.70: 1320 grams. Too heavy. At least for me, for now. This might be a great tire — and it is offered in a 2.7″ width — but at 1320 grams it is a pound heavier than the 2.4″ High Roller II. The tread looks not as good for wet ground.

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5. Maxxis Ardent: Web: Ardent. 26×2.40: 685 grams. I already know this is a good tire, but I figured it was time to try something new. It is lighter than the High Roller II and the same width.

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6. Other’s considered: Griffin (26×2.4 – too heavy at ~1130 grams), and Aspen (not wide enough).

I also looked at some of the wider downhill tires, but they were all way over 1000 grams — great for pure downhill muni, but horrible for climbing.

Downstairs Bathroom Remodel, shower pan, etc

This is mainly for myself to remember what I did.

I built this half wall, but it seemed flimsy. I didn’t want it to move *at all* as it might cause tile to crack:


I ended up adding in lots of other support members, and that stiffened it up. Ideally just some 45 braces from the top edge down might have helped more than anything else.

Doing the drywall by myself was challenging on the roof. I devised this T bracket to hold up one half of a sheet while I screwed the other half on (holding it up with my head at the same time):


Doing some typical copper brazing. The Kholer valve is basically flush on the 2×4 brace:


Notes to self: tighten the copper threads *really tight*. My first try leaked, and I had to cut it out and try again. Install the top piece (seen above vertical and not installed) after I get everything brazed on and set.

Drink beer while mudding drywall:


Wear a mask! <me at age 36>


Do a skim coat on the drywall for a really smooth walls:


Shower pan; I built it like the last one I did based on my eBook on the subject. It involves:

1. skim coat of thinset on the plywood floor. I accidentally waited for it to try; apparently I should have done that, but I don’t think it will matter too much.

2. Mortar mix: 3-4 parts sand (I used the regular sand from Home Depot, NOT the play sand) to one part portland cement. This means 4 shovels of sand to 1.5 shovels of cement. Mix the cement before adding water. Then add enough water till it is wet, but not too wet. I made it wetter than the first pan I did so I could screed it more easily (and it was a lot easier)

3. 1/4″ raise per foot to the edges, first coat about 1.5″ thick.

4. Add shower pan liner; weld corners w/ shower pan corners from home depot w/ shower pan cement.

5. Mark level edge, again make sure it is 1/4″ raise per foot from the drain. Put small rocks in weep holes. Add more mortar like before.


Curb is wire framed over it, held slightly off the bottom (about 1″) to avoid putting a hole in the pan liner.

WildFire v3 Arduino compatible Wifi enabled board

Wicked Device is making a cool little Arduino clone called the WildFire. Why is it cool? Because it includes the CC3000 Wifi chip built in, an SD card slot, and the ATmega1284p processor – which has tons more memory than the Arduino UNO! It is also a great price at $50. Consider the alternative of buying an UNO ($25 – Adafruit) and a CC3000 breakout board ($35) and you are now already at $60 before adding on an SD card. The board is also well thought out; you can easily breadboard it with the female headers, and then solder it into your project with the duplicated pin holes on the side. Great idea!


I’ve been needing a device for some internet enabled side projects that I want to do. Victor from Wicked Device ran across my post on CC3000 and offered to send me one to play with. So, I’m excited to play around with it!

Red Rocks climbing

Did some climbing in Red Rocks, Nevada last weekend. This is more of a record and reminder for myself. Last time I was there was in 2005 back when I was a strong 5.11 climber. I don’t climb very often right now, and I felt rather nervous about doing much of anything.


Costanza and her dog Douglas came with me. The first day we arrived around noon and stopped at the first pullout. I didn’t bring a guidebook (mistake) hoping I could piece it together from the Mountain Project website. I was targeting Panty Wall, but it was way too busy. We walked/hiked around a lot, which was a ton of fun in itself. We hiked towards the left (second pullout area) and saw some people climbing at Tsunami Wall:


A young guy was doing the 5.12s. I debated doing the 5.7 trad climb…but I was just too nervous and wanted to work with Costanza on lead belaying first. We headed back towards Panty Wall and stumbled upon Amusement Park; I didn’t know what it was at the time, since we lacked a book, but it didn’t look too hard and I could setup a top rope on one of the last routes on the right to give me confidence:


I set it up as a top and it was super easy for me. After Costanza gave it a good try I pulled the rope and led all of them for fun and practice.

The next day (Thanksgiving) it was again packed. We stopped at the first pullout again briefly; packed as usual at about 11am. We went to the second pullout and got out to hike around. I wanted to go to Magic Bus, as I recall doing routes there in 2005 with Jason. Unfortunately Douglass couldn’t make it up there, or the scrambling back behind it to check out other routes. No problem, so we went on to the Sandstone Quarry parking lot area. We hiked the short walk into the gap that I think is Front Corridor; it was packed, and two dogs where there off leash, so we looked for some more areas. The Wake Up Wall, which is to the left of the wash and a bit north west was recommended. We saw it from a short distance, and it looked packed. Plus, the easiest was 5.9..and I wasn’t sure I wanted to lead 9′s yet. We hiked in the wash “Turtlehead Peak” trail (according to the map) and found some routes on a wall. It clearly hasn’t been climbed in a while (or not much at all), and I setup a top rope pretty easily. The rope dragged over the edge because I forgot my webbing to extend it, but it was lots of fun! I’d say 10d to 11ish in rating. I can’t seem to find this area on the Mountain Project; I see the rock on the map, but nothing marked. I’d say it is the rock to the west and slightly south of Bull Market. Here’s a picture I took;


The day after Thanksgiving we got up early and got there about 10am. This was early enough to get any parking (although it got super busy again later in the day). Panty Wall was already busy, but The Hamlet was empty and seemed easy to top rope for the “Lower Tier”:


I don’t know what routes we really did; they were all 5.7 to 5.8, although I picked out some 5.10 variation moves that were pretty fun on the flat face like portion seem in the middle of the above photo (to the left of the large crack).

After got busy, so we left and went to a later pullout by Willow Springs…TODO: look up the name of this area (I have it on my phone but can’t find it on Mountain Project):


I did the easy 5.7? trad lead. One bolt on the bottom, and some old slings on top tied off a rock for rappelling.

EV Page of Shame: Drax in a Lexus at the Aria Hotel in Vegas

UPDATE: Thank you Aria hotel! They are going to update their signage and start towing offenders. I just talked with someone from the security team and they are on top of this. They are also going to fix the broken charger. Excellent! They handled this very well, and I’d be happy to stay with them the next time I’m in Vegas.

(Still, I think Drax and others should not park in these spots, so I’m leaving the post up).


Aria Hotel in Las Vegas: You provided four EV charging spots but failed to enforce the rules, and allowed three non EV cars to park in them:


First and foremost I blame the people who ignorantly and rudely parked in these spots; especially the Lexus with the California license plate “IM DRAX“:


That Lexus belongs to this wonderful person, Drax:
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Lots of awesome tattoos and guns:

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His instagram account shows pictures of him at the casinos as he moved to Vegas about four months ago to become a professional poker player. Drax is even hip enough to have a reddit account, and lets us know that he weighs 190lbs (follow the link for some sexy underwear pictures).

Drax, I’m glad you are making it big as a poker player in Sin City, but please walk a little distance and don’t take up an EV parking spot, unless that Lexus is actually plugged in. Also visit Drax on YouTube, and GooglePlus . Now, the fourth car in the green parking spots (not seen) is a Model S:

But the last Chargepoint station was broken, and the Model S couldn’t reach to the other working station that did work due to it being “ICE’ed”.

Drax, welcome to the EV Page of Shame!

For sale: 1940 Ford Deluxe

1940 Ford Deluxe

For Sale

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Custom built street rod in high gloss black. Drives and handles superb with a V8 Chevy 350 and Turbo 400 3 speed automatic transmission. Tons of chrome under the hood with Edlebrock carb, chrome valve covers, MSD coil and 6AL ignition system, Mallory distributor, chrome alternator, Billet aluminum pullies, Sanderson headers, dark heads, Lokar dipsticks. Scott’s Mustang II coil over front suspension. Ford 8″ rear end with a spare set of gears available (I think it has 2.78 on it, and a lower ratio in my basement). Ice cold Vintage A/C. Full gray leather interior with custom Ford lettering accents and Billet Aluminum handles and accents. Power front seats, CB radio, and AM/FM stereo with CD player. Saldana Racing Products aluminum radiator setup to automatically turn the fan on and off; runs cool. Power brakes and power steering makes it easy to handle. Includes a custom made leather bra (not installed at the moment). 16,580 miles. I drove this car across the country and it was comfy!

Location: Santa Cruz mountains / Los Gatos, California.

Asking: $43,000, or best offer. I’m willing to consider offers, so send them my way!

Contact me: corbin at corbinstreehouse DOT com, or: 831-359-6189

Electric Bug: Running Again!

So, I got my new rebuilt transmission from MOFOCO. I put it back in the car and buttoned up the rear end entirely. I then attached the shifter…but, it wasn’t shifting! So, I posted on and the guys there said something might be wrong w/the nosecone setup. I had to drop the transmission/motor combo again. This time I decided to make a better cradle for it:


These pictures are mainly for my future reference so i can remember how it goes. The strap holds it on pretty well.


I popped the nosecone off and it was definitely shifted into a gear. It didn’t seem like it was shifted into two gears at the same time…but it definitely wasn’t working before. I pulled the three things below so they were all aligned, and put the nosecone back on. I could then shift it by hand, as I should have been able to do in the first place. Excellent!


Then it went back in the bug…and it seemed to be doing okay. I put it all back together…and did a quick test drive. Success! Back to electric driving. I’ve been missing it.

Adafruit CC3000 + Webduino = Arduino Web Server over Wifi

Adafruit has a CC3000 breakpoint board for $35 on their site. Rather expensive, considering the chip should be $10, but it adds some nice features and they wrote a library for it.

Cut to the chase: for a rather full featured Arduino web server with the CC3000 chip, check out my port of Webduino CC3000 on my GitHub page. REQUIRES my forked version of Adafruit_CC3000


Longer story: I want to add Wifi support to my LED cyr wheel. My goal is to be able to wirelessly control it from an iOS device (iPhone or iPad). I also want to be able to update my LED Pattern Sequence files from my desktop Mac computer. Right now, I manually put them on an SD card, but it seems like I could skip that step and send it over wirelessly. Short range wireless connections on iOS are difficult; bluetooth would be ideal, but has stupid rules to be able to use the API/hardware. Bluetooth LE is newish and supported by the later iOS devices and computers, but my Mac doesn’t support it. Stupidly, my friend Jason gave me the solution for that: just by a dongle. Oh yeah… but anyways, I’m going to try Wifi first.

I now realize the CC3000 chip isn’t ideal because it can’t create an ad-hoc wifi network. It can only join one. That means I have to bring a wireless router with me for circus jobs and have the phone/wheel on the same network. Or setup internet sharing on my phone and connect to the iPhone wireless network from the wheel (that does work, and is okay for now). Bluetooth LE may have been better…but I’m not sure if I can control multiple wheels at the same time (another goal) and synchronize them, as I think bluetooth is a 1-to-1 connection (I could be wrong, I don’t know). I also heard the newer CC3100 chip(or 3200) might have more features; maybe ad-hoc. I should investigate if I ever make my own PCB board that has it on it.

So, using the CC3000 and wifi. I quickly realized I have to make a web server in the wheel. I came up to speed on some new(hah) “protocols” like REST, which seem to be all the rage today. I like stateless, so it seems good. I found a few REST solutions, including aREST (Arduino-REST) that uses CC3000, but it isn’t very flexible.

I then ran across Webduino; it is a few years old, but looks awesome. You can plug in your own handlers for URLs, which is a very simple way to implement REST. So, I ported it over to use Adafruit’s CC3000 breakout board. Check it out: Webduino CC3000

UPDATE: I have been constantly working on this and made Webduino and CC3000 work together better by having a simple state machine. REQUIRES my forked version of Adafruit_CC3000

LED Cyr Wheel v2: Custom PCB

I finished designing a custom PCB for my LED cyr wheel. It simply combines all the chips I use into one board. Ideally I would eliminate all of the other boards except the Teensy, but I’m not so good at SMD soldering yet.

I designed it in Eagle:

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And I’ll be printing it with OSH Park based on advice from my friend Spencer.

This things should be awesome! It’ll be my first PCB, so i’m crossing my fingers that I did everything right.

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SD Card errors with Arduino / Teensy 3.0

With my LED cyr wheel I kept getting random errors in reading data from my SD card with Ardunio code. Sometimes init would fail, even at half speed. Most often I would get corrupted data, or not be able to read the filenames. Worse, it would start to read and then fail. Searching around, I found it could be one of the following problems:

* Bad SD card (I tried a few of them)
* Improperly formatted SD Card (I used the official SD Card Formatter from SD: and it still failed)
* Floating CS (Chip Select / Slave Select) pin. I made sure I had the Chip Select pin was correct, and it was. This can be set to anything you want as long as it is wired properly and passed to the initializers.
* Incorrect voltage for the SD Card; it needs 3.3v. Now…long story short: this was the problem, but I thought it wasn’t because the SD Card Adapter from PJRC has an onboard voltage regulator.

I poked through the SdFat library quite a bit adding in debug logs and couldn’t figure it out.

Finally, I poked at the voltage that the SD Card Adapter was reading; it had a 5v input and the regulator was outputting about about 3.0something volts. I thought this was okay…but later I came back to it, and wired the 3.3v directly from the teensy output to it. Then stuff started working!

So: be warned. The PJRC Teensy SD Card Adapter needs a separate 3.3v input (and solder together the 3v joint). The onboard regulator doesn’t work well enough!

UPDATE: I’m not 100% confident this was the problem. Dealing with the SD card has been a nightmare due to read errors and inconsistency. I could reproduce the corrupt data problem on my breadboard and with my physical hardware, which is why I felt like the voltage was the problem. However, in my LED wheel I still had issues, and it seemed to be due to wire length and size. I’m now using 22 gauge wires with shielding, and slightly shorter. It seems to work so far.

UPDATE 2: Maybe I am just an idiot; after re-wiring a bunch, I realized what CS pin I thought I was using may not have been right! That may have been my problem all along..

(c) 2008-2012 Corbin Dunn

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