So Emma, why choose Bond?
Emma Pooley: Bond.Bike is a bespoke frame builder. I will be racing on fully custom geometry (and colour) road and TT bikes. For me, as a smaller-than-average cyclist (1.57m “tall”), this means that I can finally ride a bike that fits my slightly unusual geometrical requirements. Size and fit are the most crucial determining factor of any bike frame for health, comfort, and performance. Being a "morphological exception" (the official jargon!) has its challenges.
Bond frames stand out for their beautiful simplicity of design, but more importantly they handle beautifully. Aluminium is light and stiff and the technology of this material has been quietly moving forwards for decades, so that it’s now a real competitor with carbon in terms of performance. I'm going to have a featherweight TT bike in a size to fit me, and I can’t wait!
Can you explain a little about the geometry of your bikes?
Emma Pooley: When setting about defining the frame geometry for my Bond road and TT bikes, I knew what I wanted but I wasn’t sure if it was possible. I’m hugely grateful to both the Bond.Bike engineer for his help, and a former colleague from a previous pro cycling team, whose expert advice was invaluable in coming to the final specification.
The first key decision was wheel size. For the reasons described above, 650c wheels simply make sense for a rider my size. However, because I plan to still do the occasional road race, 650c would be a risky choice for the road bike because it’s near impossible to get a spare wheel in a hurry mid-race (as hardly anyone uses them, neutral service do not carry them). So I have gone for 700c on the road bike, and 650c on the TT bike. Another key factor is crank length: Rotor make a 165mm crank which is shorter than “standard”, thus reducing toe crossover problems (as well as reducing the vertical range of motion of my feet and knees, which is useful for comfort of breathing when tucked down in an aero position). Thus I was able to specify a shorter reach than any of the mass-produced frames I’ve ever previously ridden, which means that the top tube length is short - this means I’ll be able to reach the handlebars! Also in order to reduce toe crossover, I specified a relatively low headtube angle, and relatively large fork rake. This together means the front wheel will be further in front of the handlebars than usual, but with a reasonable fork trail so that the bike is not too twitchy at the front end. These adjustments were more critical on the road bike (because of the larger wheels) but I also pushed reach and headtube angle right to the limit on the TT bike - because it’s always possible to put on a longer stem, or move the saddle backwards, but impossible to make a bike frame shorter than it is!
The second key measurement that is significantly different on my Bond.bike frames, to those you’ll find on the mass market, is the headtube height. I’ve reduced this to the absolute minimum possible, to get as low as possible at the front. This helps with aerodynamics, especially on the TT bike where I have traditionally had to use a very extreme step to drop enough height at the front to be in a good aero position. In reducing the headtube height, it’s helpful that the Bond.bike frames are made of aluminium since this will have sufficient stiffness and strength (whereas carbon would have to be layered more thickly in this part of the frame to be strong enough - which increases frame weight).
Road bike / TT bike
Crank length 165mm / Crank length 165mm
Headtube angle 71deg / Headtube angle 72deg
Reach 361mm / Reach 375mm
Headtube length 90mm / Headtube length 84mm
Seattube angle 76deg / Seattube angle 80deg
Rear centre 405mm / Rear centre 399mm
Regarding aero properties, I haven’t tested the Bond.Bike frames in a wind tunnel, so I can’t give you CD measurements for them. In any case the drag of the frame alone is pretty meaningless for real life situations, since it’s the aerodynamic properties of rider and bike and wheels together that affect one’s drag. And though the Bond.Bike frames won’t have aero tubing, this has far less of an effect on drag than body and head position - all too often neglected in favour of “aero-looking” frames! With the frame geometries I’ve specified, I will be able to reach a lower position than on any off-the-peg bike I’ve ever ridden previously, so I’ll be more aero than previously.