Monday, November 18, 2013

Custom headset caps

Ever since threadless headsets became standard on most new bikes (maybe 15 years ago), headset caps have become a popular way to customize bikes. A few years ago when I needed to replace a cap on my road bike (it broke due to overtightening), I considered some of the options from Purely Custom but eventually just got a plain one. I couldn't think of any text interesting enough to put on a cap, and none of the artwork options interested me much. Heather recently got a new road bike, and I was looking for something creative for her bike on her birthday when I discovered Kustomcaps, which will make a cap with completely custom artwork in addition to various text options. In trying to come up with designs that fit the circular area, I realized that Celtic knots are well suited to this, and Heather happens to be a fan of these type of designs, as she has several pieces of jewelry featuring them. So, I came up with a couple of designs:

These designs were created using Inkscape. The procedure for creating the weave pattern is very helpfully described in this tutorial. Eventually, I settled on the second design, which allowed a little more space to add some text. Here's the result (with a blue bolt to go with it).

I liked it so much I decided I needed one for my own bike. As it happened, we recently made a trip to Ireland, and inspired by the Celtic knot on Heather's bike and my own Irish heritage, I was on the lookout for interesting and unusual designs. I found what I was looking for in the floor tiles of St. Patrick's Cathedral in Dublin.

This was one of many very interesting patterns from that particular floor that we took pictures of. I had to stretch the proportions and add or remove parts in order to get the square pattern to fit a circle better, and I came up with two different candidate designs for a headset cap.

These designs were also created in Inkscape, in this case by importing the photo and using the "trace bitmap" feature to get an outline of the pattern, which then required considerable tweaking. I ultimately chose the second of the two designs. Here it is installed on my bike.

Now I don't think I can go back to a plain cap on my bike.

Tuesday, October 22, 2013

Short Cranks for Kids on Tandems

In my first post about my Bike Friday tandem from last year, I showed a picture of the Ride2 crank shorteners I first used for making the rear crankarms a more suitable length for riding with small kids on the back. Crank shorteners get the job done, but they are a bit expensive ($110 on Amazon right now), and they have the effect of spacing the pedals out further away from the bottom bracket (the so-called Q factor). I would assume this is more noticeable to riders with short legs, so I think it's a less than ideal solution. Since the Bike Friday was already set up with single side drive due to the DualDrive shifting, the rear cranks can be replaced with any standard crankset.

When we acquired another tandem last year, I put the crank shorteners on that bike and tried using a short crank on this one. The cranks pictured here are made by Sinz, who make parts for high-end BMX bikes. These cranks are available for both square taper and ISIS bottom brackets, in lengths from about 130 mm to 180 mm in 5 mm increments. They can be found online for about $60, and occasionally less. The ones in the picture are 145 mm ISIS cranks. (Note that the bike comes with square taper bottom brackets, but I found an unusually good price on an ISIS crank and happened to have an extra ISIS bottom bracket.) The cranks have a 110 mm bolt circle diameter, which matched the old cranks, so I just moved the original chainrings over to the new cranks.

I think this is a superior solution for tandem riding with kids. It's not adjustable in length like the crank shortener, which has three different lengths. However, it is possible to buy two Sinz cranksets in different lengths for not too much more than the cost of one pair of crank shorteners. If I did it again, I would do that, getting them in lengths of 145 and 155. Using this approach requires single side drive, but in this era of compact road cranksets and 11-speed gearing, one could theoretically convert even a standard double side drive tandem to use cranks like this without losing much in terms of gearing range.

Bike Friday Tandem Customizations

I already wrote previously about my Bike Friday Family Tandem. I used it for over 2 years in the configuration it came in: flat handlebars with Sachs (now SRAM) 3x7 Dual Drive shifting. I prefer drop handlebars, so last winter I decided to switch out the handlebars.

Switching to drop handlebars on this bike requires a few other changes. First of all, I needed a pair of 3x7 Shimano STI brake/shift levers, which various online sources claim are compatible with the older DualDrive hub/derailleur combinations. Shimano hasn't made a 7-speed shifter for a number of years, so these have to be bought on the secondhand market, but even then they are hard to find because Shimano had already gone to 8 speed on their high end drivetrains when they introduced STI in the 1990s. The one exception is the RSX shifter, which presumably was sold on some lower end road bikes in that era, and comes in a 3x7 configuration. I found these RSX shifters on eBay.

One problem these shifters had when I bought them was that the smaller levers (the ones that shift to a smaller chainring or rear cog) did not engage. This apparently is a fairly common problem with these shifters and it is caused by the old grease getting sticky. I can confirm the claims made by others on the internet that this problem can be fixed relatively easily by spraying degreaser into the shift mechanism a few times, followed by a light lubricant, which eventually frees up the mechanism.

The brakes on this bike (drum brake front, V-brake rear) expect a longer cable pull than STI shifters are capable of generating, so it is necessary to add the Problem Solvers Travel Agent. I've used them on another tandem already and they work great. They come in two varieties, one for V-brakes and one for disc brakes (or drum brakes), so I installed one of each type. Here's the rear V-brake with Travel Agent installed. It replaces the curved "noodle" normally installed between the cable housing and brake.

The disc brake version comes with a hole at the top so that it can be attached to the fork using a cantilever brake mount. This fork doesn't have cantilever mounts, so I attached it to the fork with zip ties and used a piece of inner tube around the fork blade to prevent scratching the paint and hold it in place. So far, braking performance both front and rear with the travel agents installed has been great.

The left shifter, which normally goes to the front derailleur, has worked fine operating the 3-speed internal hub. It takes some getting used to because when connected to this hub, its operation is backwards from a front derailleur: the large lever shifts to a lower gear rather than a higher gear. The combination of the right shifter and rear derailleur has been less than ideal so far. The cable pull for each click isn't quite enough for the derailleur. It's adjusted so that it works OK in the middle of the gearing range, but starts to miss shifts as I get out to the edges. It's possible the derailleur or shifter are just old, but the original grip shifter that came on the flat handlebars worked better.

DIY Winter Cycling Gear

Some time in the late 1980s, I bought this neoprene headband from the Performance Bike Shop in Boulder, Colorado. Since then, it's been used for countless miles of winter cycling, including two years of 12 mile commutes during college, and many other winter outdoor activities. It's been great for cycling in particular because it's quite thin and easily fits under a helmet while keeping my head and ears warm for any temperature above freezing. Colder than that usually requires additional headwear.

Its design is incredibly simple: a single peice of neoprene with a single seam at the back stitched together using a zigzag stitch.

As is evident from the first picture, it's starting to show its age a bit. Some of the foam material has started to break down so it doesn't feel quite as thick as it used to. I'd have bought a replacement years ago if I could find one, but have never seen anyone selling anything like it. Last year Heather and I started doing more winter rides and it became apparent that her fleece headbands were often not enough. It occurred to me that my headband should be quite easy to replicate. Neoprene fabric can be bought in small quantities online from various sources. I bought a 1 foot by 4 foot piece of it from an eBay seller for about $15. I estimated the thickness of the fabric used in the original to be about 2 mm thick, so I ordered the material in that thickness, but it appears to be a slightly thicker than the original. It's possible the original was actually 1.5 mm (I think the fabric is also available in that thickness), or that it's just thinner due to deterioration over time. In any case, 2 mm seems like about the right thickness for me, but others may prefer something in a different thickness.

I have a relatively large head, and Heather's is relatively small, so based on the original headband, I created two separate patterns, to fit large and small head sizes. In case this is useful to anyone, I created this PDF document with patterns for both sizes.

Note that the patterns reach relatively close to the edges of letter-sized paper, so check the print settings when printing it out. Some viewers by default will try to shrink it to add extra margin at the edges. In Chrome PDF viewer, uncheck the "fit to page" option. To make sure the printout is the right size, I've added measurements to the diagram so the size of the printed pattern can be checked before using it to cut fabric.

Here's the end result. It basically looks like the original, except that it's clear my pattern cutting skills weren't quite good enough to get the bottom of the seam to line up perfectly. Since I made them in two sizes, I stitched my initial into it in order to tell them apart coming out of the laundry. I made a total of 3 of these using about 1/3 of the neoprene fabric I bought, so for about $15 in materials (probably about what I paid for the original headband), someone could make 9 of these.

Sunday, January 13, 2013

Raleigh Tandem With Customizations

I wrote a couple of months ago about acquiring a second tandem. As I noted then, the Raleigh tandems look like a great option for riding with children because they are reasonably priced and can accommodate relatively short riders with just a few modifications.

Fit Customizations

The most important modifications are to get it to fit its riders. The goal was to be able to comfortably fit an 8-year-old on the back and a 5'4" rider on the front. It should be possible based on my measurements of the frame, but the suspension seatpost that came installed in the rear made it impossible to get the seat down as low as I needed. Furthermore, the oversized seat that came on the bike added some extra height of its own.

In the front, the seat went low enough, but the reach to the handlebars was a bit far for a shorter rider, so I wanted to reduce that by moving the front seat as far forward as possible and installing a shorter reach stem. The set back of the stock seatpost on the front limited how far forward the seat could move, so I moved that seatpost to the rear and installed a smaller saddle I happened to already have. The challenge, then, was to find a seatpost for the front with the right diameter and no set back that didn't cost a lot. The diameter turned out to be 29.2 mm, which appears to be common on tandems, but in general is a somewhat non-standard size.

This seatpost made by Origin8 comes in a huge variety of sizes, including the 29.2 mm that I needed. While it didn't matter in this case, it's also very long at 400 mm, so it would be easy to set up this tandem for a very tall rider using the same seatpost. The relatively relaxed seat tube angle of the frame means that putting the seat all the way forward like this will result in a position that will not feel unusual to a rider accustomed to typical road bikes.

The remaining fit-related customizations included the installation of this short reach stem. It's a Profile Design Boa with a 65mm extension and relatively steep angle (45 degrees if I recall correctly), which brought the handlebars in about 8 cm closer than the original stem did.

I also added Ride2 Crank Shorteners to the rear cranks. The pedals are currently installed in the outermost hole, which results in an equivalent crank length of 145 mm. These shorteners were transferred over from my other tandem.

With these customizations complete, the bike was basically ready to ride, but I wasn't done changing things yet.

Optional Customizations

The other customizations made to this bike were purely based on our preferences. I replaced the 26x1.95" tires with more touring-oriented 26x1.25" tires, which are better suited for the type of riding we do. I replaced the stock pedals in the front with different ones that would take toe clips. Heather and I are both used to road bikes with drop handlebars, so I also replicated that setup on this tandem. The existing drivetrain is a 24-speed Shimano setup, so I got a used pair of Shimano Sora 3x8 speed brake/shift levers, Tektro auxiliary brake levers, and a used road handlebar.

Because road and mountain bikes use different shaped cable ends inside the levers, I had to buy new cables as well. The extra cable lengths required for a tandem required that I do a lot of careful measuring before I bought anything so I could be sure everything was long enough. In the end, I concluded the least expensive option was a complete road cable kit plus an extra cable for the rear derailleur. I bought the Jagwire Racer XL kit, which had brake cables that turned out to be long enough for both front and rear brakes on this frame. The derailleur cables were not long enough, but the rear cable was long enough for the front derailleur on the tandem, and for the rear I bought a Jagwire stainless steel cable in a length of 3100 mm.

The linear-pull cantilever brakes (also known as V-brakes) that came on the bike require a longer cable pull than typical road brakes. In order to match the shorter pull of road brake levers with the longer pull required by the cantilevers, Problem Solvers makes this little pulley called the "Travel Agent". The cable wraps around the smaller disc and then jumps to the bigger disk, effectively doubling the distance traveled by the cable as it comes out. The second hole at the top is so that the effect can be reversed if someone wanted to use mountain-style brake levers with road-style caliper brakes. It works great. The Jagwire cables (except for the extra rear derailleur cable I bought) come with a black PTFE coating that makes them super slippery, and all of the braking and shifting on this bike is really solid.

The choice of red accents actually started with the water bottle cages. I was searching online for some inexpensive bottle cages to go on this bike and found something that came in black, gray, and red. We liked the idea of red and bought those, and subsequently got the cables and handlebar wrap in red. I think it looks great with the otherwise monochromatic black, white, and gray color scheme.

Completed Project

Here's the tandem with all of the customizations complete.

The tandem was bought for $200. The most expensive part of the fit customizations are the crank shorteners, which run around $90. Adding a seatpost, stem, and smaller saddle brought the size customizations to a total of around $150. The other customizations probably added more than $200 more, with the shifters being the most significant cost, even buying them secondhand, but the total cost of this tandem is still well below what I spent on my Bike Friday tandem, so I consider it money well spent.

Part Sources

We don't have many bike shops in Champaign, Illinois, and even a bigger city is unlikely to have a bike shop that stocks a lot of the items I've described here, so I do a lot of shopping online for parts. Given Shimano's constant gear inflation, finding shifters for older drivetrains is something that mostly has to be done on the second hand market, and eBay is an important source for that. For the other items, the one source that seems to consistently have almost everything I'm looking for, no matter how obscure, is Niagara Cycle Works, who I buy from through Amazon marketplace. They don't offer super fast shipping, but everything has always arrived by the date promised, the shipping charges are reasonable, and they usually have the lowest available price of the Amazon marketplace sellers, or are close enough to it not to bother buying from someone else.