When presented the opportunity to build a bike start to finish, I elected to put my theory that cyclocross bikes are built with too little BB drop to the test. I had theorized for some time that a bike that handled more like a traditional stage racing bike would be easier to lean through the tight turns of a cyclocross course.
So the $64,000 question is: How does it handle? My experience in riding the bike I built under Stanton’s guidance has been that the greater-than-usual BB drop does help the bike corner better than other cyclocross bikes I have ridden. Cornering clearance has not been a problem. On broad, sweeping crit-style corners where I have seen other riders pedal through the whole of the corner, I have been able to pedal through as well. On the super-tight corners that I have only ever seen in cyclocross courses, corners where the course sometimes literally doubles back on itself is where my rig really excels. I have been able to corner much more aggressively than many other riders. Likewise, I’ve noticed in watching other categories race over the same course that the corners I coasted through were corners other racers coasted through as well.
While I expected the bike to corner well, there were two other, subtle, handling assets I didn’t anticipate. I noticed that in riding through frozen ruts, or any ruts for that matter, that I tended to be thrown off my line less than other riders around me. And on the opposite end of the spectrum (though I believe the handling issue to be related), on sandy stretches I was much more comfortable allowing the bike to slide and drift than I have been on any other ‘cross bike. Indeed, one of my favorite memories of riding this bike was in my district championship and and feeling the bike drift slightly while hammering under full power over sandy hardpack.
But don’t take my word for it. When Tim Rutledge, the former product manager for Redline first got the green light to introduce a Redline cyclocross frame and fork, he elected to design a bike that would handle like a traditional road bike when equipped with a 23mm clincher. He modeled the geometry after two bikes he saw reviewed in Bicycle Guide: an Eddy Merckx and Mario Cipollini’s custom Cannondale. Both were built around 7.5cm of BB drop. Rutledge has moved on to other pastures and Redline’s geometry has evolved to reflect that the company now offers complete road bikes, but Rutledge won a master’s national championship (as did several others) aboard the bike he designed.
The tragedy here is that no one truly understands the interplay of all aspects of bicycle geometry. By that I mean, there isn’t an engineer out there who can explain in objective terms how each dimension relates to the others. We know in broad strokes how they relate, but as the previous comments have shown, there is some disagreement about what one truly experiences as bottom bracket height changes. Our use of terminology confuses the issue: Is a bike with a low bottom bracket (7.5cm of drop or more) more stable or more maneuverable? It comes down to how you think about bicycle handling. And while the specific differences in physics between how two-wheel and four-wheel vehicles handle are substantial, I do believe the differences in handling between a Mini Cooper and an SUV do help to illustrate the difference in sensation, because what is at stake is a matter of perception–if the rider or driver perceives confident handling, greater speed seems possible and not unreasonable.
While it is true that I could have shortened the bike’s trail or wheelbase, both those approaches have liabilities related to tire clearance and toe overlap that must be worked around. I think most builders would say that less trail will make a bike more responsive, but that isn’t the same thing as cornering easily and what I was looking for was a bike that I could lean without fighting, a bike that increased my sense of confidence when in a corner. I found a design that I like, no more no less. Ultimately, the question is why the industry continues to follow a convention based on a piece of equipment no longer used, a convention which can be validly questioned.
Disabusing us of these ideas isn’t the business of the frame builder. Rather, we are left to our own devices and either we learn just how skilled the torch bearers are, or we decide to take up the craft ourselves. A few years ago, I was invited to take a middle road.
For those who follow the ranks of juniors, Toby Stanton is known for producing more national championship winning riders than any two coaches combined. Jonathan Page, Robby Dapice, Jesse Anthony, Larssyn Staley, Saul Raisin and Will Frischkorn all called him coach. He also builds and paints frames under the label Hot Tubes and in the late 1990s he began teaching frame building classes to the curious.
The class takes the uninitiated from un-mitered tube to painted frame. Choices along the way include lugs or TIG welding, not to mention the opportunity to design your own logo. Some in the industry have expressed some skepticism about Stanton’s ability to impart all that a frame builder needs to learn in a single 9-5 week. He is clear with everyone the workshop is not a trade school for future professionals, though that’s not to say builders haven’t apprenticed under him. Upon my arrival he stated repeatedly, “This is about your comfort level; you can do as much or as little as you want.” You could say it is frame builder fantasy camp—a guided tour, if you will.
For me, it was the perfect opportunity to test my theory that a ‘cross bike with a lower BB would corner more easily. What we settled on was a cyclocross frame with a 59-centimeter seat tube (measured center to center), a 58cm top tube, 42cm chainstays, 43 mm of fork rake, parallel 73-degree seat and head tube angles and the kicker: 7.5cm of bottom bracket drop—a full centimeter lower than most ‘cross frames. With a set of road clinchers this bike would have the bottom bracket height of a traditional Italian stage racing bike, about 26.5cm. Toby walked me through the steps for producing the drawing, which detailed the angle of each junction and each tube’s length down to the millimeter. We then mitered each tube and began fitting them together in the frame jig.
Most tubes received two cuts per end: one for the angle and one to conform to the round profile of the tube. I deburred each end on a belt sander, filed each edge square and Dremeled the inside of each lug smooth. Only then did we begin brazing.
By the time we brazed the fork my skill had improved dramatically, but I still waivered between so little heat that I bent the silver rod rather than feeding it in and heating the joint to the point that the silver was practically sucked into the joint like a chocolate bar into the maw of a five-year-old.
We checked both the frame and fork for alignment and I attempted to hide my amazement: They were as straight as a Nevada highway. Stanton handled the sandblasting and painting duties, though I understand he now guides students through these steps as well.
In 40 hours (maybe a bit more) we went from uncut tubes and a simple theory to a finished frame. After baking the paint overnight, I assembled it into a bike and raced it a day later at ‘cross nationals.
Given the long nature of this post, my riding experience will come in a subsequent post, an unexpected Part III, if you will.
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