Thursday, May 5, 2011

Conversions, Measurements, and yet more Joining

My most recent project in prep for this latest frame build had to do with wheel sizing. Conventional road frames these days measure at a diameter of 622mm, or more commonly referred to as 700c. The problem that many of these frames have is lack of tire and fender clearance as a result of strides made by the U.S. bike market that treats bikes as either play things or work out equipment.

Traditional clearance for road bikes. 23mm wide tires (unusually skinny) with minimal, if any more room for fenders.

To make these bikes practical, it is worth investigating the style of French constrictors from the earlier half of the century. The wheel size they most often used for their cyclo-touring bikes and city load-carrying bikes was 584mm, a.k.a. 650b. Though more difficult to find rims and tires for this size, I found advantages to making the switch. There are many school's of thought regarding wheel sizing; a popular one that I have traditionally followed espouses that wheel size should grow with frame size. Another one that I'm experimenting with is that wheel size should be predicated on tire size. The wider the tire, the smaller the wheel (in a nutshell.) Since I have little interest in 23mm tires that many road bikes come equipped with these days, I figure I would try these theory out on my own racing machine by put 650b wheels on it equipped with 32mm tires.
From this...

To this!

The conversion was a success, leaving me room to fit 32mm tires. I also tossed on some fenders that were donated to the shop. Perhaps its a bit blasphemous to equip such a high end bicycle with freebie bent plastic fenders, but it is the wet season after all. The bike has a bit of a clownish element to it, but is otherwise extremely comfortable and zippy.

The wheels were a bit of a challenge to lace, as I had both used spoke washers at the flange as well as laced the drive side 3-cross and the non drive 2-cross. This was to help balance out the torsional loads the wheel experiences from the drive terrain. There is more thought into it than that, but that's the short and narrow of it...

I'm pretty proud of this Chris King free bin score...

Label facing the valve hole perfectly!!!

What this project has taught me is that A: 650b's still feel fine even on large frames B: A bit more clearance while building my frame can open up a world of possibilities on my frame and C: Grand Bois' are a superior tire... SO GOOD!

This past week, I also dropped by the Bike Stand in downtown Olympia for a sizing up for bike fit. Shawn Stevenson of Stevenson frames did the measuring as well as gave a few tips on frame building. I was surprised by the results, as he found that a 63cm top tube would be appropriate (quite long) and that a 62cm seat tube would be like-wise a good fit. The above frame pictured has a 65cm seat tube! I'm not sure what I'm going to do with this information, but it certainly complicates things for me.

I tried silver brazing rod this week. Here are the results:

Lug sample.

Fillet sample.

Everything is coming along nicely, though I am feeling a tad under the weather. Hopefully work rounds out by week 7 and frame construction can start.

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