wheel size rant

It's been a while since my last post. Here's a recap of 2009 - I rode the Orange bike as often as I could, it has become my favorite bicycle. I'm not getting many emails, so I don't think this blog is generating much interest. For now, I have no plans to build more prototypes, and this venture has resulted in two nice bicycles (mixte and 650B sportif) for me to ride. I thought of building a 559 road bike more or less like the Orange bike but have shelved that idea for now.

I have come to the conclusion that 700C wheels are not ideal for people who are shorter than average. I think a road bike with a shorter front center has a better front/rear weight distribution and handles better. To enable a large wheel (diameter) bike to fit shorter individuals, compromises are made to push out (forward) the front wheel (hence longer front-center distance) while keeping a shorter reach to the handlebars. My somewhat smaller wheeled Orange bike is a delight partly because it fits me better than my other bikes - I feel better balanced on it despite nearly identical contact points (seat, handlebar, and cranks) as my 700C bikes.

Some have argued for the benefits of wider road tires, in the range from 1 1/2" to about 1 3/4" width. Personally, I think that is too wide for a smaller/lighter rider who is riding mostly on paved roads, and would like to see more road tires in the width range from about 1" to 1 1/4". In the world of 700C road bikes, the common size for high performance tires is a nominal 23mm width - less than an inch. At least in 700C many lightweight performance road tires are available in 25 mm, and there are a few speciality tires (Grand Bois, Challenge) in about a 27-29 mm width that offer more comfort for bumpy roads and little if any performance penalty.

There is a family of "26 inch" wheel sizes (iso rim diameters 559, 650A, 650B, 650C) that I think make great road bikes, but there are few tires available in the 1 1/8" +/- range that I am advocating. The most common smaller wheel size is 559 (mountain bike), and roady tires for it tend to be wider and heavier and for commuters seeking flat-resistance. The common smaller wheel size for road bikes is 650C, and tires for it are almost exclusively 23mm width., and no mass market road bikes built for the alternative smaller wheel sizes, excepting various lower end comfort bikes, urban bikes, and some road bikes for women intended for 23 mm width 650C tires.

So - it's not going to happen anytime soon, but I feel confident stating that if lightweight, supple, 1 1/8" +/-width tires were made for the family of 26" wheels (pick one, I don't think the small difference in diameter among these sizes matters that much) and roadish bicycles designed for those wheels were easily available, most shorter than average road bikers would get a better fit, better handling, and be happier riding such a bike.

Somewhat related to the above, I have thought about ideas for mixing wheel sizes, and I worked out some equations for forks which I'll write up sometime. The idea is that using different front/rear wheel diameters and changing the front fork is a fairly easy way to modify one's bicycle.

Basically, I recognized that there are 3 separate/orthogonal transformations that can be combined to get any desired result. The 3 transformations are: i) changing the fork (length, rake) and diameter of the front wheel so as to maintain constant front center and trail, b) changing fork length and rake without changing front wheel diameter so as to increase/decrease trail (what someone else referred to as "frame neutral geometry"), and c) changing fork length and rake so as to cause a rotation of the bicycle about the rear axle.

That's all for now. If you're reading this, leave a comment!

Happy 2010,

Michael

The Furry Cub Specifications

The Furry Copper Bee, or Cub (Cu is the chemical symbol for copper), is a custom-sized, quick handling road bike intended for use with fenders, medium width tires, and a semi-upright to athletic riding position. It is fun to ride, with a lively, responsive feel. Unlike most road bikes, the Copper Bee is intended for "V" (linear-pull) brakes (or cantis). V brakes work well and are a good match for a bicycle with wider tires and fenders. When flat or swept back bars are used, the Cub has the appearance of what some call a "City Bike."



Whereas the standard road bike today uses 700C (622 mm diameter rims) wheels with narrow (23 - 25mm width) tires, the Cub uses a range of wheel sizes with medium width (30 - 35 mm) tires depending upon rider height and preference. For medium height riders, we suggest 650B (584 mm diameter rims) wheels for additional foot clearance with wider tires and fenders, or mountain bike 26" (559 mm diameter rims) wheels. The prototype is copperish orange and uses 650B wheels, hence the name Copper Bee.

Because it is a custom sized bicycle, there are no standard sizes, however, here are some guidelines to our thinking about geometry:

sizes 58 cm and above: 700C wheels, 73 head angle, 435 mm chainstays
sizes 53 cm - 58 cm: 650B wheels, 72.5 head angle, 430 mm chainstays
sizes < 53 cm: 26" wheels, 72 head angle, 425 mm chainstays
for all: bottom bracket height around 267 mm

Pricing:

custom frame, fork, 1 coat powder, Columbus Zona or equivalent tubing: $1,450.

Variations:

choice of wheelsize (700C, 650B, mountain 26")
standard or standard oversize diameter tubing
1" threaded or 1 1/8" threadless fork


Options:

extra light tubing: +$150
basic cromoly tubing: credit $115
wavy head rings: +$35
clear or tinted 2nd coat: +$70
premade fork: credit $75 (approximate)
other: ask

More: see FAQ at google group: http://groups.google.com/group/furrybluecycles

Riding with fenders

This past weekend I finished adjusting the rear fender and went for a test ride. There's not a lot of need for fenders around here in the spring, but they do look classy!

Tax Day!

It's been slow progress, but I'm still here. Between sickness, rainy weather, and visitors, well I haven't had a chance to take more pictures and ride the orange bike with rear fenders on. Plan to hit those goals within a week!

Fenders mounted

A quick progress report. With help from Eric Fetch, made a few changes to the orange bike: 1) front brakes working much better now, 2) cut down the steerer tube so there's not such a huge stack of spacers above the handlebar stem. I put on the rear fenders, need to get a washer so that the rear clamps are tight, but otherwise it's done. I hope to take some pictures soon.

I've worked out the specs and pricing for the orange bike, aka the Furry Cub (Copper Bee), and I hope to post those in the next week or so.

A Furry FAQ

I've written up a "Frequently Asked Questions" text file and posted it to the google group http://groups.google.com/group/furrybluecycles?hl=en

I'm duplicating a portion of the FAQ in this blog posting:


Who is Furry Blue Cycles?
Furry Blue Cycles is Sharon and Michael Gordon.

? What's Your Mission?
Our mission is to bring to market hand-made steel bicycles that are not commonly available, and that reflect our taste and the kind of bicycle riding we do. We live in bicycling paradise in the San Francisco Bay Area and go for recreational road rides around Stanford University.

? Where does the name come from?
Our son is an aspiring puppeteer, and in brainstorming ideas for the little company we suggested "puppet cycles" since the bicycle is an inanimate object controlled by the rider. Our son didn't like that name and instead suggested his favorite blue furry puppet.

? What kind of bicycles do you make?
Short answer: our bikes are closer to a road bike than a mountain bike, but are in-between in the following ways: they may use smaller wheels than the 700C wheels of a road bike, they are intended for medium width tires (say 1 1/4" to 1 1/2"), and they may be designed for flat or swept back handlebars and a less bent-over position.

? Isn't that a long winded way of saying Furry Blue makes hybrid bicycles?
The typical hybrid bicycle these days has a stiff aluminum frame, a heavy gauge steel fork, and comes with stiff/heavy 700C medium width tires, has a somewhat "slow" steering, and is built higher off the ground to avoid pedal strikes on uneven surfaces. The Furry Blue bicycle is more of a road bike in the frame design - it has a light gauge steel frame, lighter road fork, is built lower to the ground for stability, and has a quicker, more responsive feel to the steering. It is not necessary to have a wider tire be thick and heavy, and a Furry Blue bicycle is intended for supple, medium width tires that complement its lightweight construction and frame geometry.

Riding the Orange Bike

(Note: click on the picture of the bike to enlarge.)

I've had a few rides now on the orange bike, it's a lot of fun. I'm still fiddling around with the setup, and for now I've left the fork uncut because once it's cut, you can't go back.

The main thing bothering me at this point is that I am getting a bit of ghost shifting, probably due to using friction shifters with an 8 speed cassette.

The orange bike uses "650B" wheels which are somewhat smaller than a road bike (700C), yet about an inch larger (at the rim) in diameter than a mountain bike. As I explain below, I wanted slightly smaller wheels than the standard 700C, and it was a bit of a toss up for me to go with 650B versus mountain bike wheels. I think if I had a shorter torso, or liked wider tires (say 1.5" or even 1.75" in width), I might have picked the mountain bike wheel size. But I wanted to use narrower 1 1/4" width tires, and from what I've read narrower tires work better with slightly larger diameter wheels since they have a longer "contact patch" with the ground. Basically that says that 650B is a nice in-between size.

The 650B size was quite rare in the USA, although some similar sizes were common on the old "3 speeds" by Raleigh (650A), and yet another slightly different size was used on the 3 speed Schwinns of my youth. The 650B revival in the USA owes much to the efforts of Rivendell Bicycle Works to make rims and tires readily available, and they were the first to introduce non-custom bikes with the 650B wheelsize. The Riv 650B models (Saluki, Bleriot) are intended as "country bikes" that move easily from smooth roads to gravel or dirt.

I'm aware of two other small companies that have embraced the 650B wheelsize for production bikes: Kogswell and Rawland. While these production 650B models have their differences, they all have longer chainstays and different steering than a typical road bike. And while I only had a brief ride on a Rivendell Bleriot, my experience with 700C bikes leads me to generalize that a longer wheelbase and slower steering makes a bike feel more sedate, if not actually slower.

For the kind of riding I do (mostly smooth roads), 700C wheels with say 28 mm width tires work well. But for slightly wider tires and/or fenders, and if I want good clearance to avoid hitting the front wheel with my foot, then a smaller size wheel makes sense.

So I wanted to create a 650B bike that would use the relatively narrow Grand Bois tires and feel quick and agile like a sporty road bicycle. I'm going to continue test riding, but so far I think the orange bike has met its design goals. As I've noted, the idea of a "go-fast" 650B bike isn't an original idea, but to my knowledge no one has attempted to "standardize" the concept and make such a bike more widely available.

I plan to mount the fenders soon and get more pictures up in a few weeks.