Monday, May 4, 2015

MC286 component considerations

The logical choice for components for the MC286 is to install a road drivetrain and a set of mountain bike wheels because 142x12 rear wheels for mountain bikes are readily available for reasonable prices. It turns out one of the great challenges of making this frame work on a reasonable budget is the incompatibility between 11-speed road cassettes and mountain bike hubs.

When 11 speed was introduced to road components a couple of years ago, it required a slightly longer freehub body. (Note that this is all just from reading rather than experience; my road bike is still at 9 speed.) Mountain bike components didn't introduce 11 speed until more recently, and so far they have stuck with the old freehub body dimensions. This means that using a standard mountain bike wheel won't work with an 11 speed road group. There are very few road-specific wheels available with a 142x12 rear axle at this time, though I'm sure that's likely to change soon enough. The 142x12 standard is relatively new to cyclocross bikes and to my knowledge is not used anywhere (yet) on regular road frames. I suspect most cyclocross bikes being sold by the major brands that include 142x12 rear axles are using proprietary wheels. Because this standard is being introduced on higher end bikes, there aren't likely to be many budget-oriented options right now.

I did a lot of research and considered several options for wheels:
  • Use a mountain bike wheel with the new Shimano XTR 11 speed cassette and a road group. Aside from the high cost of XTR, this may not be workable because it's only available with a 40 tooth large cog, which likely exceeds the capacity of the road derailleurs. This could become viable in the future if Shimano were to offer more options (in price and gearing ranges).
  • Use a Campagnolo 11 speed cassette. According to this article by Lennard Zinn, the Campagnolo 11 speed freehub bodies can fit on most 10 speed road hubs. However, this requires finding a hub that has both 142x12 and a Campagnolo freehub body available as options. I don't know whether this exists, and if it did, it would be very expensive and also quite restrictive in the available gearing ranges.
  • Find a wheel specifically built for cyclocross and through axle wheels. Right now the only thing I can find off the shelf is the Stan's Iron Cross wheelset. The new DT Swiss 240S DB hub is also designed exactly for this purpose, but I don't know what the cost is, and haven't yet found any wheels for sale based on this hub. In both cases, however, I think the cost is higher than what I was hoping to spend.
  • Use a standard mountain bike wheel and install only 10 of 11 cogs from the road cassette.
As far as I can tell, only the last two options are even likely to work, but the last option has many more price options available because there are so many wheels available for 142x12 29er mountain bikes. I ultimately chose the Mavic Crossride wheelset because it looks like a good reliable set of wheels and is half the price of the Stan's wheels.

For components, I considered Shimano 105 and SRAM Rival and eventually settled on Shimano 105 because in part because I was able to get a great price on the complete group without brakes from Starbike.com in Germany. They were one of the few retailers I could find anywhere that offered their road groups with brakes optional, and they also had a great price on the Mavic wheelset I wanted. Starbike's prices are such that I'm sure they would have been competitive even a year ago with shipping from Germany to the US, but the strong US dollar vs. the Euro right now made the price even better. For two wheelsets, two component groups and several other miscellaneous parts, shipping was only an extra 10 Euro for what turned out to be two very large boxes. The parts arrived in less than two weeks.

This is the drive side of the Mavic rear wheel. The freehub came with the sticker on the right wrapped around it, warning against using cassettes that use individual cogs as opposed to a carrier. I got a 11-32 cassette with my Shimano 105 group, which uses individual cogs for the first 8 cogs and a carrier for the last 3 cogs. The reason for this warning is the aluminum construction of the freehub body. Individual cogs will eventually dig into the splines of the aluminum feehub body, where the carrier spreads out the load and avoids this. Using the cassette that I have chosen will therefore have a risk of damage to the freehub body over time, particularly in the middle cogs, which will be subjected to more torque than the smaller cogs. For now I'm going to accept the risk and try it for a while.

This is the complete 11 speed cassette set in place on the freehub without the lock ring. The last cog spins freely in place because the splines are not tall enough to engage it. In addition, the threads do not extend far enough to properly engage the lock ring. It's possible to get it on, but it will only catch about 1/4 turn worth of the thread. So, it's clear this won't quite work.

The excessive stack height of the 11 speed cassette is made clearer by attempting to install the wheel with the whole cassette on it in the frame. The picture on the left shows all 11 cogs in place, and the picture on the right shows only 10 cogs. With 11 cogs, the lock ring rubs against the dropout so that it would not be able to spin with the cassette, and the smallest cog is so close to the dropout that even without the lock ring problem, the chain would likely rub against the frame. On the right, there is enough space for everything to work properly, just with one fewer speeds. Because the first two positions each require special cogs, doing this properly requires buying both a 12 tooth first position cog and 13 tooth second position cog, and using them to replace cogs 11, 12 and 13. However, someone wishing to not buy the cogs could theoretically just remove the 13, leaving a 11, 12, 14 ... combination, which would leave an unusually big jump in gearing between the 12 and 14. The picture above shows the 12, 13, 14 combination, which added an extra $20 or so in costs, but made it possible to keep the total cost of the bike down by quite a bit.

The last important consideration for this bike is tires. The Miracle Bikes web page for this frame specified that the frame could handle a 38 mm tire. I went ahead and bought some 37 mm tires and installed them on the rims. I looked at a lot of tires trying to find a balance between smooth center for riding on pavement and some kind of tread on the sides for riding off pavement. I decided to try the Continental Contact, which is really more of an urban/commuting tire. Here it is installed in the frame.


My first reaction is that I wanted something wider than this and there appears to be a lot of room. By my measurement the tire is closer to 32 or 33 mm. I measure about 50mm between the stays, and similar clearance at the bottom bracket and top of the fork. This made me wonder if I could have gone wider and knobbier, so I'm going to try a set of 40 mm tires instead.

Sunday, May 3, 2015

Arrival of the MC286 frames from Miracle Bikes

The MC286 frames arrived earlier this week.


The total time from placing the order to arrival at my doorstep was a little over 7 weeks. Most of that time was the custom paint job. I was warned it would take a while, but it took a little longer than I was planning. After about 5 weeks, I emailed my contact at Miracle Bikes asking about the status. She sent me a photo of one of the completed frames, and a couple of days later sent me a shipping number. The shipping numbers can be tracked by the US postal service, but often there is a lag (in this case close to a week) between receiving the number and the USPS tracking system recognizing it. The time from receiving the shipping number to arrival was just over two weeks, so I imagine a buyer not wanting custom paint could receive a frame in less than three weeks.

The bikes look great, a nearly perfect rendering of the artwork I sent them, and the quality of the paint looks really good. The through axles I had added to the order were already installed in the dropouts. They seem to be specific to this frame design (which is also the consensus on this thread at mtbr.com), any prospective buyer is advised to order them with the frame. I didn't think to ask about it during the process of purchasing the frame, but headsets were included. I'm waiting for a few more parts and then will be ready to start assembling them.

Tuesday, March 17, 2015

MT-MC286 from Miracle Bikes

Last summer, I moved from central Illinois to west Texas. I've done some riding since then, but not as much as I'd like to because I just haven't found the riding very enjoyable here, the primary reasons being narrow roads with fast traffic and a surprising number of loose dogs. Like central Illinois, the area is crisscrossed with small farm roads, but the farm roads here are mostly unpaved. The dirt roads are readily accessible from where I live, and I've found them to be much more traffic and dog free, so I've concluded that riding the dirt roads is my future, and that I want a bike designed for such riding. That is the origin of my next project, a cyclocross bike, or rather two cyclocross bikes so Heather and I can ride together.

My first plan was to find some kind of inexpensive cyclocross bike from someone like bikesdirect.com, where aluminum frame cyclocross bikes with disc brakes start at about $900. We both like our carbon road bikes a lot, and since my last experience ordering a frame with custom paint job direct from China last year was relatively painless, we eventually decided to spend a bit more and go in the direction of carbon again.

I had three requirements for the frames: the size range needed to go as far as 48 cm and 58 cm (60 would be preferable, but I can make 58 work), disc brake compatibility, and through axle dropouts. Because I haven't owned a mountain bike made more recently than the mid 1990's, I really don't have much prior experience with disc brakes and through axles, but based on all of my research, this is the direction cyclocross bikes are going, with road bikes likely to follow soon. Some major brands, such as Giant, are already selling cyclocross bikes with through axles. My primary motivation for doing this is forward compatibility: through axles and disc brakes make it more likely that the wheels and frame will be interchangeable with future wheels and frames.

It took some time to find someone selling a frame that met all three criteria. Nearly everyone has a disc frame, and several manufacturers appear to have recently introduced through-axle compatible frames, but I could only find one that offered all of the sizes I wanted: the MT-MC286 from Miracle Bikes. The frame is also listed on Alibaba.com, which is how I contacted them. I got a reply pretty quickly, and I went back and forth for a few days with the person about what I wanted. The base price of the frame was quoted to be $480. I don't know whether this represents any kind of a discount over the price of only buying one frame. A custom two-color paint job was quoted at $70. Shipping is effectively two for the price of one because the frames will ship in a single box. (The frame I bought last year was in a box probably big enough for two.) They requested payment via PayPal, and add 4% to the cost to cover the fee that PayPal deducts. Total for the two frames came to $1300. I was told that they have a bit of a backlog of up to 20 days on their painting (apparently due in part to Chinese New Year). All of this is pretty consistent with my previous experience, so I wasn't too worried.

Before sending money, I thought I should read some more about them. I didn't know anything previously about Miracle Bikes, but after doing some research I did find at least one blog that discusses importing frames directly from Chinese manufacturers, and he lists Miracle Bikes as one of the ones he considers to be reputable. Given that and the built-in protections that come from using PayPal, I decided I was ready to give it a go.

We've decided to get matching frames, so we came up with a design, and sent the following image to Miracle Bikes:



I placed the order a little over a week ago, and I'm hoping that it will ship within about 2 weeks.

I'm in the process of finding components to go on the frames, but one persistent question in my mind has been what kind of through axle to use. It's my understanding that there are different types of through axle designs, and they need to match the dropouts of the frame, but there's very little information online about what is compatible with this frame. I eventually found this very helpful thread on the forums at mtbr.com. A number of commenters on that thread have already bought this frame from Miracle Bikes, and some of them bought through axles from Miracle Bikes with the frame. I contacted Miracle Bikes and was quoted a price of $29 for a set of axles, so I have added that to my order. Now, I just wait...

Thursday, February 19, 2015

Tire clearance on the VB-R-027

I've become a believer in riding on the widest possible tire for the application. After many years riding very skinny tires, I decided to try 25 mm road tires a few years ago after fixing one too many flat tires at the side of the road. The reduction in pinch flats since the change was quite dramatic, so when I bought my new frame from Velobuild, I hoped it would allow me to go one step further to 28 mm tires, given that their model VB-R-027 was a bit more relaxed in its geometry than some of their other frames.

I can now report that 28 mm tires work fine, as long as they aren't really 28 mm. I got a new pair of Continental Grand Prix 4 Season tires this winter in the 700x28C size.


The problem is, I don't think they are actually 28 mm wide. They seem to be about the same size as the old tires I removed, a less expensive pair of tires that were marked 700x26C. A relatively rough measurement using a ruler and eyeballs seems to confirm that they are about 26 mm wide. (This also appears to be confirmed on various forums I've read).

Here is what the Continental tires look like in the fork:



There are maybe 2-3 mm to spare all the way around. Clearance is similar behind the bottom bracket:


The worst clearance on the frame is the rear brake bridge, which in my opinion should have been 1-2 mm higher.


I forgot to photograph the seat tube clearance, but it's about 2-3 mm. The 28 mm tires that are really 26 wide work just fine on this frame. A true 28 mm tire might work, but it would be very, very close. For this reason, I'm perfectly OK with the tires being slightly smaller than advertised.

I have occasionally had problems getting the rear wheel in and out of the frame. The angle of the dropout combined with the size of the nut on the very old quick release skewer I'm using forces the wheel forward enough that the tire rubs a bit on the seat tube and chainstay bridge. I compared it to another carbon frame made by Giant and discovered that its dropout is angled differently and avoids this problem. This isn't a very big deal for me, but if someone were worried about quick wheel changes in a race, it could be a problem.

Tuesday, October 21, 2014

VB-R-027: the completed bike

I finished assembling the bike just a couple of weeks after my last posting about the frame's arrival, but I have been very busy (including moving to a new house) and didn't get to writing about it until now.

Assembly

Assembly of the new bike was pretty easy. I had read online about headset installation and expected to need special tools to get the headset bearings installed into the fork crown. I eventually figured out that the headset included with the frame (which did not come with any instructions) just snaps into place with no tools required.

The shift and rear brake cables are all internally routed, and have liners built into the frame. The shift cables were very easy to install, while the brake cable hit a bit of a snag (literally) because the liner didn't seem to line up perfectly with the exit tube. Eventually I discovered that I could get a cable into the liner from the reverse direction. Using a reverse inserted cable to hold the liner in place while I threaded the cable through in the forward direction finally got the cable in relatively easily.

As noted in a previous post, my old frame had a 59 cm top tube, while this one appears to be only 57 cm (despite VeloBuild's geometry chart claiming 58 cm), so I replaced my 110 mm stem with a 130 mm stem, and have been able to replicate my position on the bike pretty well.


At the moment, I've got quite a stack of spacers on the steerer tube. I'm still considering going 1 cm higher with the stem, and then I may trim about 1 cm from the top of the tube to reduce the number of spacers.

The components to build the bike were taken off my 2005 Fuji Roubaix Pro, which had a 9-speed Shimano 105 group. The old bike was an aluminum frame with clamp-on front derailleur, but this frame has a bolt-on derailleur mount, so I needed a compatible derailleur. Shimano Sora is now 9 speed (and probably made with the same machinery as the old 105 parts), and the derailleur can be bought for about $25 on Amazon, so that's what I bought.


Finished Product

Here's the completed bike.


I've taken it out for a few rides now. With careful measurements, I succeeded in replicating the position I had on the old bike pretty well, so I haven't really had to adjust anything. It's a very different feeling from my previous aluminum frame--the increased stiffness and responsiveness to pedaling is immediately apparent. I don't have many points for comparison in terms of ride comfort. It seems at least as good as my old bike (aluminum frame with carbon seat stays), but I don't doubt that more expensive frames could further improve on it. It's a fun bike to ride, and I have no regrets about buying it.

Saturday, June 21, 2014

Arrival of the new frame from Velobuild

My new frame arrived from China last week, about 4 weeks after placing the order. As far as I can tell, the shipping only took just over a week, and much of the remaining time was spent on the custom paint job. I suspect an order without custom paint might be quicker. After sending Chris at Velobuild a picture of the paint job I wanted, he contacted me about two weeks later to ask whether I wanted glossy or matte finish. I responded, and then heard back again about a week later with shipping confirmation and tracking information.

I had to go to the post office to pick up the box, though I think they would have delivered it to my door if anyone had been home when they came.


I got a large box that was taped shut very securely, but despite prominently displayed arrows pointing which way goes up, the side of the box was a bit dented, and featured several prominent foot prints.


Despite my occasional frustrations with the US Postal Service, I'm inclined to trust that they are more competent than that, so I'm blaming this one on China Post. The frame inside was wrapped with some foam padding, and as far as I can tell, did not suffer any damage from the mistreatment of the box.


Here's the finished frame. For the most part, the frame looks great. The colors look more or less like what I was expecting, and the paint looks like it should be durable. A comparison to the picture I sent them reveals that they made one small mistake: the blue region on the chain stays is a little too long compared to the blue sections on the other tubes, but I think it won't be too obvious when the complete bike is assembled.

The only other disappointment so far is that I don't think the frame perfectly matches the claimed geometry specifications. The specifications for the frame on Velobuild say the the top tube length on this frame is 58 cm, which is one centimeter shorter than my existing frame. After measuring the frame, I think it's closer to 57 cm. I think I can compensate for this by getting a stem that is 1 cm longer than I was planning, and still get the same position on the bike that I had before.

Aside from those two details, I don't have any other complaints about the frame or the process of buying it. I'm still awaiting a couple of parts I need to assemble the new bike. I've already got a new seatpost and stem for the new frame, as well as a new set of brake and shifter cables. I forgot until I'd already got everything else that I'll need a new front derailleur, because my old one is the clamp-on type, which is not compatible with this frame. When that arrives, assembly will begin.

Saturday, May 17, 2014

My next bike: a VB-R-027 from 梅 辉辉

Over the last couple of years Heather and I have been riding together more, and we've been doing more rides with the kids on the tandems. More riding inevitably makes me start thinking about how much fun it would be on the latest new bike. Last year Heather upgraded her old aluminum bike to a new one with a carbon fiber frame, and she thinks it's a substantial improvement in ride quality over the old one. I'm not going to be able to buy my dream bike any time soon, but I've become curious enough about carbon fiber frames to look around at some of the less expensive carbon frames. People who ride and write about the super expensive bikes are all convinced the extra cost buys a better quality ride, but carbon fiber frame construction has advanced so much that I think even the inexpensive ones may now be well ahead of where any type of frame was 10-15 years ago, including my current road bike, a 2004 Fuji Roubaix Pro.

At some point in the last few months I became aware of a whole new world I didn't even know existed: cyclists who buy bike frames direct from the manufacturers in China. I first stumbled into this when looking for tandem frames, thinking that if I could buy just a frame I could upgrade one or both of our tandems at a lower cost than buying the whole bike. It turns out that hardly anyone sells tandem frames except for expensive custom builders, and a few Chinese frame shops that will sell direct to consumers (in addition to the frames that get resold under other brand names). The process of buying a custom titanium frame from China is well documented by the Spanner Bikes blog, which is a fascinating read. I'd like to do that some day, but titanium is beyond what I can spend right now, so I started looking at carbon fiber frames from China.

Since I have a birthday coming up, I've decided that this year I'm going to get a carbon frame (thanks, family!). To keep costs down I'm going to (for now) put the aging Shimano 105 group off my Fuji on it. After doing a fair bit of research I concluded a few things. First, there are a few sellers that seem reputable and are even willing to offer warranties nowadays, but the process of sending a broken frame back to China is probably slow and expensive, so I'm still accepting a bit of risk doing this. Second, I decided I don't want a frame that tries to imitate a brand name frame. There are outright counterfeits and frames that are just similar looking to famous name frames, but I want to respect the R&D those companies put into their designs and I'm not doing this to pretend it's something it's not. Third, it appears the main benefits of ordering direct from China are selection and customization. You can now get a generic carbon frame from a US distributor like Bike Nashbar for as little as $500. I decided to buy from Velobuild Mall, which offers a dozen carbon fiber road frames in the range of $320 to over $500, but shipping from China is $80, so the cost is not that different, but with more frame options and custom paint jobs.

The majority of frames offered by Velobuild only go up to 58 cm, while my existing road bike is a 61 cm frame. However, some of the frames have top tube and head tube lengths that are similar to my existing frame, so I should be able to replicate my fit with the right length seatpost. I'm not interested in aero frames because they are generally considered to have a harsher ride. Those constraints left me with two or three frames that could work and I went with the "VB-R-027" model, currently selling for $349. In addition to being less expensive than the other frame I was considering, it had slightly longer chainstays, which will hopefully give me the biggest possible tire clearance. I'm happy with the 25 mm tires I'm using now, but I'd like the option of bigger tires if they will fit. Since I'm going to the trouble, I decided I might as well get a custom paint job. I went with 3 colors for $70 (1 or 2 colors cost less). I put the frame, seatpost collar, and custom paint in my cart, and proceeded to checkout, at which point the shipping and some tax (I'm not sure which government is getting that) were added. A few seconds later I got a confirmation email from PayPal saying:

You sent a payment of $517.96 USD to 梅 辉辉.

So there you have it. I just bought a bike frame from China. The checkout process didn't provide a way to specify what I wanted in my paint job, so I sent an email to chris@velobuild.com to ask. Chris advertises his email prominently on Velobuild.com, and he responded within minutes. He asked me to just email him a picture of the paint scheme I had in mind. I had already prepared artwork for my proposed paint scheme using Inkscape, so sent it off. The drawing includes a head tube logo I designed, but apparently doing that level of detail would have added extra cost, so I told him to skip that part. The finished product should look something like this, minus the head tube logo:

New shifters and derailleur on the Bike Friday tandem

Last year I switched the Bike Friday tandem to road-style drop handlebars. The Sachs (now SRAM) Dual Drive system has a 3 speed internally geared hub with 7 speed rear derailleur. The system came with Grip Shift shifters, which work great, but are for flat handlebars only. At the time, I had read a couple of sources that I consider to be reliable claiming that any 7-speed Shimano drop bar shifter is compatible, so I found a set of 1990s vintage Shimano RSX 3x7 shifters on eBay. The triple left shifter worked great on the internally geared hub, but the 7 speed right shift lever never seemed to work quite right despite several efforts to readjust it. It seems that the cable wasn't pulling the derailleur far enough to get all 7 gears, so it would work OK for 2-3 gears but not the rest.

Initially, I assumed that one possible reason for the poor shifting was that the RSX shifter mechanism was simply wearing out due to its age. At some point recently I discovered that in the last year or two, Shimano has started selling a 3x7 drop bar shift lever set for the first time in many years. The 7 speed Tourney group appears to have been available for a few years and is found on various low-priced bikes, but only last year was a drop bar shifter made available. So, my first solution was to try swapping out the RSX shifters for a brand new set of Shimano Tourney 3x7 shifters.



These shifters sell online for about $90. Amazingly, after buying these I sold off the old RSX shifters on eBay for $65, so this swap ultimately only cost me about $25. I'm constantly amazed how much some vintage bike parts will sell for. The Tourney shifters have the thumb lever like Shimano Sora did until about a year ago. I prefer the "behind the brake" location for the upshift lever, but this works fine. These also have the "indicator" that shows you what gear you're in, another feature I associate with lower end Shimano road groups, and which I always assumed I didn't need. As it turns out, it's actually been nice to have the gear indicator on a tandem because it's not as easy as it is on a single road bike to know how many gears you have left just by looking down.

The Tourney shifters didn't solve my shifting problems. At this point, I started measuring how far the shifter pulls the cable compared to the original shifter that came with this bike, when it finally dawned on me that the rear derailleur on this bike was expecting a different cable pull (known as "actuation ratio") than the shifter was pulling. I had assumed that because the spacing of the 7 rear cogs was identical to Shimano 7 speed systems, a 7 speed Shimano shifter would work with this, without giving any thought to the rear derailleur.

The original derailleur is labeled "Sachs Centera". I can't find any documentation on this old shifting system. Sachs was bought by SRAM in 1997, so I'm assuming this bike and Dual Drive system was made around that time, because I don't think it's much older than that.


Regardless of the technical details, I was pretty sure the derailleur was the problem, but didn't want to spend a lot of money on trial and error. All I needed was a derailleur that's compatible with Shimano road shifters. For $15 on Amazon, I got this "SunRace R80", which claims to be Shimano-compatible.


This is designed for an 8 speed system, but Shimano 7, 8, and 9 speed all use the same cable actuation ratio, just with the clicks spaced closer together, so in theory this derailleur should work with any of them as long as the shifter is compatible with the spacing of the cogs. With the new derailleur installed, I can now finaly reach all 7 gears! Shifting is still a little sluggish sometimes. The derailleur hanger is slightly misaligned, so I'm going to try fixing that, but it could also be that this is just how a $15 derailleur shifts. In any case, I'm happy enough with this setup that I'll stop messing with it for now.

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.