Saturday, November 3, 2012

A new tandem

As noted in my prior posting about tandem trailers, I've decided they aren't safe and have given up on the one we have. With my children currently at the ages of 8 and 6, we're still a few years away from the age where they can keep up on longer rides, and where I feel comfortable with them riding their own bikes on certain roads (such as the narrow bridges near our neighborhood). As I've already written, I'm a big fan of the Bike Friday tandem, but it's hard to find even a used one for less than $1000 on eBay, so I decided I would spend the winter looking for alternatives that might cost a little less. I've decided I'm less concerned about the portability offered by Bike Friday tandems, so I'm mainly concerned that the rear seat go low enough for a (relatively tall) 8-year-old.

A few weeks ago, I found a local Craigslist seller selling this Raleigh tandem for $200:

Amusingly, the seller listed the bike as a Schwinn, complete with a similar picture to this with the Raleigh logo plainly visible. Based on some internet research, I was able to determine that this model is from 2002, and is called the "SC Tandem". The frame is a blend of chromoly and high-tensile steel. It appears from Raleigh's web site that they have sold a similar tandem for the last 10 years or so, with varying model names, but more or less the same frame geometry. For a while there was an aluminum frame version that retailed for around $900, but the steel frame version has usually sold for about $650. The official specifications for the frame size are 19.5 and 16.5 inches. Based on my seat height measurements of the other tandem, I concluded that 16.5 inches might be low enough for my needs, so I took a risk and bought the bike.

This closeup of the rear triangle shows the somewhat odd design choice of what amounts to two sets of seat stays. The rear brake is mounted on the lower ones, making the top one more or less unnecessary (though it does have mounts for a luggage rack). The quick release seatpost collar is removable, so in theory it would be possible to cut off 1-2 cm of the top of the rear seat tube to get the seat lower, but it appears that will not be necessary for my 8 year old. If I were trying to get this tandem to fit a smaller child, it seems feasible to simply cut off the upper seat stays and more of the seat tube. This being a steel frame, some paint or rust protection for the affected areas would be necessary, but the result would be a frame with a geometry not much unlike some of the other common tandem frame designs out there.

There are a number of things I plan to modify on this bike. In particular, the rear seat has a suspension seat post, which does not appear to be functional, and will not allow me to get the seat all the way down to the frame where I need it. So, I will be replacing that and making other changes to bring the front seat and handlebars closer together to accommodate a 5'4" rider. I'll write more when I get that far.

Also, at some point I'll consult the owner's manual to learn why night riding is dangerous.