While spending five months on the road in Europe, I had plenty of time to daydream. Most of my daydreams included the consumption of ice cream. But sometimes I’d think about bikes. In particular, touring bikes, and what I believed to be the ideal touring bike for me and Carrie. I was enjoying my touring bike, but Carrie often described her touring bike with four letter words.
But before we go any further, let’s first take a cruise down Memory Bike Lane:
A Brief History of Carrie’s touring bikes
After my visit to Doug Fattic’s framebuilding class in the winter of 2007 and before our summer 2008 bike tour in Iceland, I built Carrie a touring frame set. She took that bike to Iceland and used it afterwards for her daily commute and other shorter tours. It was powdercoated forest green and it was called Dilbert, Dilby for short.
In 2011, on her way to work, Carrie and Dilby collided with a sedan. Carrie suffered a few bruises but Dilby was dead. The top tube and down tube buckled near the head tube.
By that time I had sold most of my framebuilding equipment, a decision I still regret, so I couldn’t build a replacement. Carrie bought a royal blue Surly Long Haul Trucker and called it Indy. The name didn’t stick though because of Indy’s most annoying quirk: the severe handlebar flop factor. Indy became Floppy.
Floppy served its master well over the last five years. Despite the floppy front end, the toe overlap, and poor position of the seat tube water bottle bosses, Floppy dutifully carried Carrie and her stuff for roughly 25,000 miles. To top it off, Floppy joined us on our 5500-mile tour through Europe last summer. A more reliable bike cannot be found.
The idea for a new frame set is born
But during our trip, Carrie was getting sick of dealing with Floppy’s floppiness. The bike refused to stay upright leaned against any object. The front end flopped and the bike would topple. It was at this point that I promised to make her a new frame set.
Since we’ve continued to pack lighter on our trips, and since Carrie weighs a wee bit over 100 pounds, it was time to ditch Floppy for a lighter frame with skinnier tubes, a frame that fit her well, a frame with less flop factor and no toe overlap, a frame that would deserve the title Dilby II.
What’s in a frame?
The design parameters were straightforward. Here’s what was important:
- Reduce flop factor
- Eliminate toe overlap with fenders
- Ditch as much weight from the frame set as possible
The main problem with a high flop factor is a bike’s tendency to wonder at low to moderate speeds. Since Carrie never exceeds moderate speeds, she’s constantly fighting with the bike to go in a straight line. This is especially troubling while climbing during a tour. With the extra weight on the bike, tourists climb slowly. It’s always harrowing for Carrie when we’re climbing up a busy road. She has to concentrate to avoid swerving into traffic.The 42cm Long Haul Trucker Carrie rides has a head tube angle of 70 degrees with a 45mm fork offset for a flop factor of 22mm.
On the opposite end of the flop spectrum are French randonneuring bikes. They are known for their stability at low to moderate speeds. I built myself such a bike. It has a 73 degree head tube angle with a 63mm fork offset for a flop factor of 10mm.But I didn’t want to go full rando for Carrie’s bike. While these bikes are indeed stable at low to moderate speeds, they can get rather lively and sometimes even shimmy at higher speeds. These aren’t attributes I wanted to include in her bike. I wanted to build her something with the moderate-speed stability of a randonneuring bike and the higher-speed stability of her Long Haul Trucker. To do that I decided on a flop factor in the mid-teens, a happy compromise.
There are two ways to decrease flop factor: increase head tube angle and fork offset. While trying to decide on these magic numbers for Carrie’s new frame set, I scoured the Internet for ideas. The best example I could find was an Alex Singer city bike, described by none other than Jan Heine of Bicycle Quarterly fame. The frame set had a 71 degree head tube angle with 55mm fork offset for a 17mm flop factor. I used these numbers as a starting point.
Toe overlap isn’t an issue until it is. A few times during our recent tour, I heard Carrie curse as she almost fell over from clipping her toe on the front wheel while getting too caught up in sightseeing. Tourists do a lot of sightseeing at slow speeds. Since her bike flops so much while climbing, she will occasionally experience the annoying toe overlap during a moment of inattention.
At 5’2”, Carrie rides small bikes. Toe overlap is pretty much guaranteed with small production bikes. Since I was borrowing the head tube angle and fork offset dimensions from the Alex Singer, I only had two other options for getting the front wheel away from Carrie’s feet: wheel size and top tube length.Choosing the wheel size was simple. Twenty six inch wheels are perfect for touring. They’re not too big, like 650b and 700c, but they’re not too small, like 20 inch and 24 inch. Plus, there’s a wide array of medium-width tires to choose from.
The final piece of the puzzle was to choose top tube length. I used the longest top tube I thought Carrie could handle without resorting to a stem shorter than 80 millimeters. Even though it’s a custom bike, it’s always good to have a few different stem length options in either direction. I could have used an even longer top tube and shorter stem, but if she were too stretched out she couldn’t install a shorter stem to compensate.
There’s little talk of the importance of bike weight in the world of bike touring. And for good reason. Most tourists want a bike to be reliable while carrying themselves and usually 40 pounds of gear or more, or even way more. But for a lightweight tourist who travels with an ultralight load, Carrie doesn’t need the oversized, thick-walled tubes of a Long Haul Trucker. Floppy tops the scales at around 35 pounds. That’s almost a third of her body weight!
My goal is to remove at least 10 pounds of bike. Most of that will come from component selection, but some of that can come from tubing choices. I decided to use traditional tube sizes with thin walls to shed some weight:
- Top tube: 25.4mm diameter with .7/.4/.7 butted walls
- Down tube: 28.6mm diameter with .7/.4/.7 butted walls
- Seat tube: 28.6mm diameter with .8/.6 butted walls
- Head tube: 31.8mm diameter with .9mm wall
- Steerer tube: 25.4mm threadless
- Fork blades: 28×19 oval blades small tips and .9mm wall
- Chainstays: 22.2mm round-oval-round .7mm wall
- Seatstays: 14mm single taper with .6mm wall
While her frame will be more prone to denting, I’m betting that the compromise will be worth it. The frame should also be adequately stiff for someone her size. A larger version of this frame would feel too flexible to a big guy, but Carrie and her gear weigh less than the average guy, so it should prove a good match.