Sunday, October 25, 2015

First Impressions: Yuba Spicy Curry Review

My Cetma cargo bike was recently damaged when a dump truck backed into it while the bike was parked. After reviewing a few replacement options for electric assisted cargo bikes (mostly the Yuba and the Larry vs. Harry Bullitt), we opted for the Yuba as it is easier to learn to ride and comes pre-equipped with a mid-drive assist instead of having to retrofit one. I will miss the box on the front, but I should still be able to carry all the crazy stuff I need to while having a bike that is easier to manage at low speeds and while walking.

With an aluminum frame and no giant wooden box, this bike is less than half the weight of my previous bike. It is light enough I don't use the assist nearly as much, saving it for hills. With the mid-drive system, the power is supplied through the cranks, instead of through the hubs. The cranks and the chainring can move separately, meaning the motor doesn't drive the pedals, only the chain (unlike a Stokemonkey mid-drive). This makes the motor engaging and disengaging a lot smoother.

Motor

The motor uses magnetic sensors on the rear wheel and cranks to detect motion, as well as a torque sensor on the cranks to determine when and how much to engage. The system is pretty seamless when up to speed, though there are situations when the motor kicks in when it shouldn't. When slowing to a stop and still pedaling, the motor will sometimes engage momentarily. Also, I have had it engage when walking next to the bike if the pedals start turning, as when going up a curb where the pedals get caught on the curb.



There are 4 levels of assist, with the lowest level being hardly noticeable and the highest level only appropriate for going up steep hills or going 20+mph on level ground. I usually leave it on 0 or 1 on level ground and 2 when going up regular hills. The motor helps most when pedaling slowly, around 50-60 rpms. The power drops as you pedal faster, with the assist not helping much when pedaling more than 80-90 rpms. For me, riding with the motor requires a slightly different riding style than without. The power of the motor drops as the battery gets drained. Level 1 on a full battery is the same as level 2 or 3 when the battery is at 40% charge.

The addition of the motor and the ability of the pedals and chain to move independently means the pedals are very far apart. About 5/8" wider (190mm total) than on a commuter or mountain bike (150-165mm). Personally, this is acceptable in exchange for having the motor in the cranks. The Cetma had the pedals about 1/4" wider than a mountain bike without a motor because of the wide chainstays.


I have noticed a little noise coming from the motor cover when pedaling. It isn't clear whether it is the two covers rubbing against each other or the cover rubbing on the frame. I will have to investigate as the creaking noise is annoying because the rest of the bike is so quiet.

Components
The components were very well chosen on this bike for good durability, value, and low maintenance. It uses Tektro hydraulic disc brakes with large rotors for fantastic stopping power. It is easy to slow the bike going downhill with one hand while signaling with the other hand. These brakes use mineral oil like Shimano instead of the DOT fluid used by other manufactures. Having bled other brakes before, I prefer to work with mineral oil, despite the higher cost.

The drivetrain is 8 speed with an 11-32 cassette, which I would consider changing to 11-34 when it comes time to replace it. Xtracycle and Bullitt mostly use 9 and 10 speed drivetrains, which seems unnecessary for cargo/commuter bike use. Replacing the chain and cassette when they wear out will cost 20% more for 9 speed and 100% more for 10 speed.

The wheels and tires are heavy duty, the rear wheel is 48 spokes and the front is 36, with both using extra thick 13 gauge spokes. Tires are Schwalbe Big Apple Plus front and rear, which is my personal favorite for cargo bike use. The wheels are a little easier to remove than on my previous bike, so I could probably use the regular Big Apple tires and change an extra flat now and again. The wheels come with a quick release. I would have expected axles with nuts on them for heavy duty use and for the extra security. I replaced the quick releases with security skewers. After I installed running boards in the back, I noticed that the quick release skewers wouldn't be able to open with the running boards on. This wouldn't be too much of an issue with the Yuba's running boards because they can be removed without tools. Mine are installed more permanently, so using the security skewers is good as the tool to loosen them just fits without removing the running boards.
Not much clearance between running boards and hub skewer.


Accessories
The bike comes equipped with front and rear lights as well as front and rear fenders. This is pretty unique, even among cargo bikes. The front fender was an inexpensive Planet Bike fender, which I replaced with the better supported (two sets of stays instead of one) and longer Planet Bike Cascadia fender.

The lights are Spanninga lights for use with ebikes. The front is a Spanninga Corona Xe, it has 3 leds that put out 20 lux that provide good indirect light to avoid blinding oncoming traffic. The mirror reflector and the lens used to direct the beam make it a little too diffuse and irregular (dappled might be the right word). It doesn't provide the uniformly bright light pattern of the B&M lights I use on my other bikes and (which vary from 50-90 lux). But the ability to mount the light in front of the basket instead of the handlebars means better lighting angle and stuff in the basket doesn't block the light.


The rear light is a Spanninga Lineo. It has a large central reflector with leds along the lower edge.

The lights are controlled via the buttons on the handlebar. The only indication that the lights are on is the presence of the backlight on the display, which is hard to see in sunlight. It would be nice to have a more distinctive indication the lights are on or have the lights come on automatically when the battery is on. I like to have the lights on all the time, even during the day. It is perhaps the easiest thing you can do to prevent collisions due to driver inattention, especially the left hook. There is a ambient light sensor on the display which will turn the headlight on automatically at night. I found it nearly worthless as it will turn the headlight off if you are directly under a streetlamp. I'm not sure if it just poorly calibrated or the fact that the sensor faces up is the problem. In any case, I just covered the sensor with tape and now the headlight comes on automatically every time, just like I wanted.

I opted for the double leg kickstand since Oscar will be climbing up from both sides and doing who knows what else on the bike once he gets comfortable. The wide kickstand and the low deck, mean the bike is very stable. I haven't gone through the trouble of trying to tip it, but it should be noticeably more stable than the Yuba El Mundo which starts to get tippy if more than one kid tries to climb up the same side of the rear deck.

Frame
The frame is aluminum with lots of points for mounting accessories. Many of the small mounting points are rivnuts, which are just held in place by pressure. This is ok for non weight bearing points. In places where there will be weight bearing accessories (front Bread Basket and the rear deck), they use solid aluminum rods that are threaded or unthreaded as needed. 

Some rivnuts visible above the running board, not sure what you would use them for.

Front Bread Basket mounts nicely to hollow tube running all the way through the frame.
Headset is heavy duty 1.5" instead of normal 1.125"

The entire frame is very well braced and stiff. The balloon tires at moderate pressure (35 psi) make the ride pretty smooth.

The bike is a lot of fun to ride for both driver and passengers. All the parts are relatively easy to use and should give a lot of worry free use. I can't wait to take on some longer rides, maybe another camping trip up the canal, or a day trip to Silver Spring. I'm looking forward to taking it to the Mid-Atlantic Cargo Bike Championships at Hains Point next weekend.

Saturday, October 10, 2015

15 Miles (Part II)

We finally followed through with the canal camping and made it out to Swain's Lock for an overnight excursion.

It's at least a two hour trip with a fully loaded cargo bike. We don't have much lightweight/small camping gear so there was barely room for Oscar to fall asleep on the way out.


Once we made it to the campsite and got set up, Oscar was in charge of meeting the neighbors. There were two bike-based campers and one hiker.

This is Maurice, a biker who was headed west. The other cyclist was headed back to DC.
video

We cooked a few hot dogs at the neighbor's fire (he had brought hot dogs for dinner too), while discussing the exploits of Admiral Farragut during the Civil War. We had just gotten one hot dog each before the forecasted rain came on suddenly.
 We played "Captain America" in the tent while waiting it out until a wayward thrown shield forced me to take a break from the action. Afterwards, we made a fire that lasted just long enough to cook two marshmallows before it died due to wet wood. We made the remainder of the hot dogs on the stove.

The next day we stopped at Great Falls on the way back and did some exploring.





We had just enough energy to make it back to Georgetown before we needed to refuel. Luckily, there is a conveniently located coffeeshop, Malmaison, to fulfill your pain au chocolat and macchiato needs.


Sunday, May 31, 2015

Gratuitously Inconsiderate

Time for another predawn wake-up. This time for 95 mile loop headed north from Rockville, at the end of the Red Line.

I switched to eating peanuts, orange juice, and gatorade instead of clif bars. It seemed to work much better. Less sugar energy spikes (clif bars are mostly rice syrup, aka sugar).
Quadratic Drive?

Albuagh Rd. The gravel of Old West Falls Rd a few miles back was better 'cause it was shady.
I stopped for lunch in Mt. Airy when the weather was starting to get very hot. At least it seems that way when you've been riding for hours and there isn't much shade to be had. Luckily, I started packing 3 water bottles instead of two. I used a whole bottle just dumping water on my head and back.

It was hot enough by mile 85, I had to stop and dip my feet in a roadside stream and spotted this wild strawberry. That's how you know it's been hot the last few weeks.
Wild strawberries...
Had some encounters with gratuitously inconsiderate Maryland drivers. Apparently, asking them to wait the 1 second for oncoming traffic to clear is too much to ask.

Monday, May 25, 2015

Georgeous Prince George's

That's the PG County motto, and I hardly thought it applied given what I previously knew about PG county, mostly their car-centric Metro station design (stations surrounded by acres of parking, with poor pedestrian accessibility and no businesses).

After numerous trips out the C&O canal and surrounding areas west of DC I thought it was time to give the east side a try. I found a 200K route through the area. It doubled back on itself which can be boring if ridden frequently, but was ok this time. I shortened it to 80 miles so I could be back in time for an afternoon appointment.

Fridays are my day off and the metro starts running at 5am (instead of 7am on the weekends), so I can reach the start of the ride by 6am, perfect for warmer weather and it allows me to get things done later in the day. All I have to do is wake up at 4:45am, no problem, right?

Watching the sun rise over West Hyattsville.
This is why it's worth it to wake up that early... I remember now.
The USDA Beltsville Agricultural Research Facility
Beaver Dam Road
But, you are still in Maryland. People love their trucks...and littering on the side of the road.

I ran into this a few hundred yards before I was supposed to cross the Patuxent River. I was really hoping it didn't turn into this. The closest crossing was many miles away and was on a major highway. I decided to investigate further. The small bridge was fine for bikes. But perhaps it had been damaged enough to prevent it from carrying car traffic. I saw 2 other walkers using the closed off road as well. Closing a road to cars sure makes it pleasant for walking and biking, and no more potholes, infrastructure problems: SOLVED.


I made it all the way to Deale, MD before turning back.

Made it back the metro at exactly noon for six hours of riding, including 15 minutes of breaks. I had some trouble eating enough food while riding, Clif Bars are not cutting it anymore (too much simple sugars). Time to do some more research on Glycemic Index, maybe I will switch back to using peanuts and orange juice like I did in France.

Saturday, May 23, 2015

Party Time!!!



Loaded up with all the party supplies. Perhaps we should retain this bike-based tradition so our parties don't get out of hand (sorry, no bounce houses in our future).

A pinata in the front basket.


Doing what Oscar does best, getting everyone's attention. In this case yelling "It's CAKE time!!!"


Ghost cake pops. Oscar led the charge and finished off at least 6, falling asleep and eating one on the way home.

Sunday, May 10, 2015

Happy Mother's Day

We had a great mother's day. Rebecca's friend+daughter came over for a visit.

First, Oscar and Co. had to go pick up some plants from our friend in Mt. Pleasant. Don't bother going to Mt. Pleasant without instruments, you'll be run out of the neighborhood.


There were wonderful covers of Erie Canal as well as original songs such as "Ukelele Dukelele No. 3"

Then we went to a restaurant, where there was grilled cheese and peek-a-boo.


Then describing the chef's tasting menu (more gouda on the grilled cheese) on the chalkboard...



Hope your mother's day was special...

Friday, April 24, 2015

Velo Orange 50.4 BCD Cranks Mk II

While looking for lower gearing I was searching for a crank that would take smaller chainrings than my current 110 BCD compact double. Compact doubles usually take 34 teeth for the smallest ring. There are some mountain bike doubles available that go smaller, but they come stock with much smaller rings and I did not feel like replacing rings. The other option is to use a triple crank, but only use two of the spots, with the third left unused.

At the time, I only knew of Sugino, TA, Rene Herse, White Industries and Velo Orange cranks that would fulfill my criteria. Pricewise, the choice was clear: Velo Orange (VO) was at least $150 less than the others. Especially since when I was choosing them, I had access to them at wholesale prices. That access was unavailable when it came time to purchase because the company I work for is disorganized and incompetent, so I ended up paying retail. Afterwards, I also found the IRD Defiant Wide Compact cranks which are similar in price and features to the VO cranks. They use the more commonly available 94 BCD rings, instead of the less common VO/TA chainrings. See the bottom of the post for more comparisons.

Upon installation (greasing the bottom bracket spindle) it quickly became clear that one of the chainring bolt spacers was missing. The bolt that it was supposed to be on was still tightened, causing the inner ring to dive too close to the outer ring for one portion of the rotation. In this state, it was unusable as the chain would get jammed against the big ring.

The spacer in question, missing from another position on the crank.
My temporary solution: 4 small spacers to replace one large one.
I contacted the seller and they contacted VO and got me a replacement spacer and chainring bolt. The extra chainring bolt may come in handy since these aren't the same size as standard chainring bolts.

Standard chainring bolt on left, 50.4 BCD bolt on right
They also include very nice aluminum bolt covers (on right in photo below). Unfortunately, one of the crank bolts had a built in flange that was slightly off-center. With the tight fit of the cover over the bolt, I decided not to install it and risk damaging the extractor threads, I also decided not to go through the trouble of filing off the offending part of the crank bolt. I had an extra bolt cover from some very old cranks (on left in photo), but decided not to use it since I only had one. In any case, I didn't see any reason to put a cover over the bolt, it would just require one more tool for removal.


Cranks, minus crank bolt cover.
The recommended bottom bracket length is 118mm to give a chainline of 43.5, the standard for road doubles. I decided to go with a 115mm bottom bracket to keep the q-factor low (143mm w/ 115mm BB). The inside of the arms are 120mm apart at the ends, you can use that info to measure your chainstays to see if you need a longer bottom bracket for clearance reasons. I also figured since I wanted to use the entire cassette with the large 46 tooth ring (42 to 92 gear inches), putting the large ring a little closer to the frame would minimize the chain angle when using the large cogs on the cassette.

With a 115mm bottom bracket the measured chainline is 42.5mm (measured at the midpoint between the two rings) and rear cassette has a chainline of 42mm on a 130mm hub. When using the small 30 tooth ring, the chain starts to catch on the ramps and pins of the large ring when using the smallest cogs on the cassette. This can lead to severe chain suck and a broken derailer, so I need make sure I don't use those combinations. I may make a little indent on my barend shifter so I know when to stop downshifting in the small ring. This is a problem that is possible on other compact doubles, though it is a non-issue with an unramped large ring like I was using previously.

The gear range is what I was looking for, and it that respect, it gets the job done. My gear range is 27-93 gear inches using a 13-30 cassette, enough for everything I'm using it for, unless I start doing camping trips with it. The chart below (created using a wheel size 4 mm smaller than mine, so not perfect) shows the useable gears, good range in the big ring with a two gear overlap in the small ring.



The smallest chainrings available are 26 teeth. The 50.4 BCD designation is misleading, since the small ring mounts to the large ring, not to the crank arm spider. The small chainrings use a 6 bolt 80mm BCD pattern. To compare, the Rene Herse cranks use a larger BCD spider (70mm) but can mount smaller rings (24 teeth) because both rings are mounting to the same crank arm spider.

I rode it for a while until finally replacing the missing spacer. There was some lateral oscillation on the big and small rings. After a little internet research (thanks Sheldon and Jan) I took the rings off to check the spider. The video below shows that two of the spider arms are closer to the frame than the others. They disturb the zip tie I attached to the frame as reference. They are about .5-.75mm out of alignment, which is magnified at the chainring.  It may take a few viewings to see the arms in question.


I was able to straighten the offending arms with a 12" adjustable wrench. I don't recommend doing this unless you have a very good feel for the elasticity of metal. You need to be able to feel juuuust when it starts to deform, not an easy task when you're using a 12" lever. After doing this, there was one arm still slightly out of alignment (perhaps .1-.25mm), but it was so difficult to adjust the zip tie to get it to hit only one arm I decided to leave them alone.

After reinstalling the chainrings, they were much better, within 1mm at the edge of the chainring.

Here's a table comparing the Velo Orange and IRD cranksets

Velo Orange Grand Cru 50.4IRD Defiant Wide Compact
Price
$200$199
Stock Chainrings
46/3046/30
BCD
50.4 outer/80 inner94
Smallest ring
2629
Bottom Bracket
118118
q-factor
149152
Notes
uses non-standard chainring bolts

Saturday, April 18, 2015

15 miles on the...


Oscar and I took a ride out the C&O Canal yesterday as a test run before trying to ride all the way out to Swain's Lock to go camping along the Potomac. We made it just past the Chain Bridge before we decided to do some exploring.



By exploring, we mean "getting so wet, he rode home naked."

On the way back we decided to listen to Erie Canal by Bruce Springsteen and Oscar made up appropriate hand gestures for the various parts of the song..."low bridge, we're coming to a town."




Part II
I took my bike on the towpath the next day for a fast-ish ride and explored a little of the other things available near the path. Like a kayak course...
 ...hidden down an innocuous sidepath...
 And some singletrack, which was fine on my bike...


and I had to remember to capture lots of insect specimens for Oscar. Luckily my hairy sunscreened arms were perfect bug transport.


Sunday, April 5, 2015

Velo Orange Grand Cru Zeste Brakes Review

I've been struggling to find cantilever brakes strong enough to satisfy my needs. The very rainy Severna Park 200k ride demonstrated that a few hours of rain, road oil and grit can turn adequate brakes into non-stoppers very quickly. After way more research than I thought possible on the subject of cantilever brakes, I got the Velo Orange Grand Cru Zeste brakes. I figured the longer arms plus the low profile should give me the most stopping power available from a cantilever brake.

While researching cantilever brakes, I relied mostly on this mechanical analysis from Circle A Cycles. I also read Sheldon Brown's article on cantilever geometry, but I found it oversimplified things and left out a lot of details. I did not completely verify the math in the Circle A Cycles article, but I will trust the resulting equations. Namely, the equation relating mechanical advantage (MA) to yoke height (footnote 8 on page 3, his equation uses degrees, mine uses radians).


For a given bike, PO is fixed at half the distance between the cantilever bosses, and DO is the vertical distance from the cantilever boss to the middle of the rim braking surface. The variables are PA, the distance between the cantilever post (P) and the cable anchor point (A), YO, the vertical distance from the cantilever boss to the yoke, and 'a', the cantilever angle, the angle from vertical of the line PA. This angle is measured differently than in Sheldon's analysis, where it is the included angle between the A, P, and the rim surface.

Circle A Cycles diagram. Cantilever Angle is APZ (not APR as in Sheldon's).


Sheldon's Diagram. Cantilever Angle is angle APS.
The equation is far from elegant, but it is easy to see that lengthening the arm of the cantilever brake will increase the mechanical advantage. And it doesn't take much, if DO=24, PO=44 (in mm), and a=.436 rads (25 degrees), then a 10% increase in the arm length (PA) leads to a 30% increase in MA. If your canti bosses are higher than normal and DO is smaller, so that the pads are in the lower end of the adjustment range, the MA can be increased 15-25% over pads at the upper end of the adjustment range.

For reference here is a list of a few cantilever brakes and their arm length (PA, pivot to cable anchor distance, measured 'as the crow flies'):


Brake NameArm Length (PA) in mm'a' angle (approx)
Velo Orange Zeste
7615
Paul touring
6820
Shimano Non-series
6720
IRD CAFAM I
6730
Avid Shorty Ult
6375 or 30
Tektro Oryx
6030
Paul Neo Retro
4774
Tektro 720
4875

There are threads started every day on how to adjust cantilever brakes, and given that I've used four different sets on my rear brake (Tektro CR720, Shimano non-series low profile, generic low profile, and VO Zeste), here's what you need to know.

  • lower yoke height=more power (but less modulation)
  • medium and wide profile brakes are less sensitive to yoke height, up to a point
  • low profile brakes are sensitive to yoke height throughout the range
This is relatively common knowledge, the part most people don't realize is there is tipping point for wide profile brakes (like Tektro CR720). Lowering the yoke height doesn't make them much more powerful, until you reach a certain point. Then the mechanical advantage skyrockets with each small lowering of the yoke. Perhaps all the people who are satisfied with the CR720's have sufficiently narrow tires or other frame distances that allow them to have a lower yoke height and thus higher than normal mechanical advantage. It's also possible that different levers have sufficiently different mechanical advantages (while still being 'short pull'), that the 720's can perform well. TRP makes two versions of the mini-V brakes with different length arms (and thus different mechanical advantages) for Shimano/Campy and SRAM brake levers, respectively.

Enough with the engineering, onto the review.

Comes with two brakesets, enough for one bike. All necessary hardware? Yes. Instructions? No, none at all. Tools necessary: 2, 2.5, 3, 4, 5 mm allen keys, 10 and 13mm wrenches, phillips screwdriver.

When installing the calipers, the 5mm allen key bolt should be facing out, and the 13mm nut should be behind the caliper. The 13mm nut has to be very tight to keep the brake pad holder from moving. It would be easy enough to label the bags of hardware 'front' and 'rear.' But they weren't.

There are so many adjustments that can be made it can be time consuming to go back and forth between various adjustments until the pads hit the rim squarely, at the same time, and all adjusting bolts  (spring tension, pad angle, cable barrel adjuster, etc.) are near the middle of their respective adjustment ranges.

These take more tools to install than are present on any multi tool I have ever used. It is a little bewildering that a brake that may be used for long distance events would require either a 13mm wrench or an adjustable wrench.

I certainly appreciate the long arms that provide more power than almost any other cantilever brakes, but the user interface (to borrow a software term) is not quite refined enough to be truly useable for non-mechanics. These brakes could really use a couple hundred more hours of engineering. I would have considered halting the project once a 13mm wrench was required. It is unfortunate that Velo Orange is such a small company they can't afford to make these more user friendly without making them prohibitively expensive. As a comparison, Compass Bicycles offers boutique centerpull brakes that are as powerful as possible with no performance compromises (they also directly copied a well established design, so they spent a lot of time on manufacturing, not as much on design). But they require specialized bosses that are so sensitive to alignment and spacing, they should only be installed by a framebuilder. They also cost $325 for one bike.

Update: In corresponding with smutpedaller about these brakes, they pointed out that they are available here under a different name, although the listed arm length is significantly different (66mm vs. 76mm) than the Velo Orange ones. After a careful analysis of the product photos with some calipers and using the length of the brake shoes as a constant (54.2mm actual, 26.5mm in the photos), it seems the product description is correct, they are indeed shorter than the Velo Orange Zeste brakes. Perhaps the only thing VO did was spec the arm length and the brake pads.





The brake pads sit far enough away from the frame that the entire arm swings out of the way for removal of fat tired wheels. It's a nice feature, and Grant can tell you all about it.

I swapped out the stock pads for Kool Stop Salmons. Once installed the brakes work great. Fantastic power with good modulation. The Compass 650Bx42mm tires have so much grip you are still unlikely to lock up the wheels. I could stop the bike with one or two fingers on the front brake. On a drop bar lever, that is pretty impressive. Pads run pretty close to the rim for cantilevers, about the same as V-brakes.

After using Kool Stop pads for about 8 months, they developed a horrible squeal in both brakes. I switched to the Velo Orange stock pads, which are supposed to be resistant to squealing. They were quieter, but also not nearly as powerful. I put up with it for two more months until they started squealing as well. The pad holders don't allow you to toe the pads in very much, so I wasn't able to eliminate the squealing that way. I finally gave up and switched to a linear pull V-brake with a Travel Agent in the rear. I couldn't do this in the front because of too little clearance between the front rack and the fender, so I am switching to the Tektro Oryx calipers. They won't be as powerful, but hopefully they will be silent.

So, after 1 year, I had to abandon both Velo Orange brakes due to squealing issues. It's possible it is partly an issue with the rim, but I don't have a spare wheel I can try I haven't been able to eliminate this cause.


Cable Pinch Bolt (Sturmey-Archer on left, Velo Orange on right)

There were only two reviews of these brakes I could find online. One mentioned that the pinch bolt was prone to cutting the straddle cable since the end of the bolt can be sharp. I checked out the bolt and it seemed fine. I have been using the Sturmey-Archer pinch bolt of a similar design for years on my drum brakes without problem. The S-A pinch bolt uses larger diameter threads, but is functionally identical. If you aren't used to these types of anchors, they actually deform the cable instead of the clamping it. You do not need to tighten as much as normal anchor points where the cable is clamped between a washer and the arm. If I had to guess, I would use 5Nm.

If you go the V-O webpage on these brakes, here. You will notice that the brake cable exits the pinch bolt on both sides at a strange angle. Whoever installed it didn't hold the anchor with a 10mm wrench while tightening the M4 bolt. Please do not follow their example.


By the numbers:
Power: 5/5; Ease of installation 3/5; Field Serviceable: 1/5