So far in this series Iíve introduced two theoretical bike fit problems, and then solved them. By problem I mean: What bike matches this set of fit coordinates? Solving means is a list of bikes that match those coordinates.
But Iíve started off at a lope instead of a gallop. I lobbed myself softballs. I havenít presented hard problems to solve. Letís make this a little tougher.
Iíve already written that the bike industry has coalesced around a single geometry for tri, just as they have diverged in geometries for road. The few outlier tri geometries favor the taller positions. Few are making tri bikes for lower positions. But thatís not entirely the case. There is hope for what I term Aliens and by these I mean the freaks of nature who contort into pretzels to ride long and low positions.
I have adopted as a motif naming my stereotypes after Game of Thrones characters. Who is the most space-bending, contortionist character able to morph into an superhuman position aboard a bike? I nominate Jaqen Híghar, the faceless shapeshifter.
In real life Iím talking about zachboring on our reader forum, with a Pad Y/X of 610mm/530mm, and knightly76, a one-size-down version with stats of 575mm/510mm. What bikes will fit these people?
In the old days, the classic Cervelo P3. Why arenít bikes like this made anymore? Two reasons. Positions aboard these bikes likely wonít be UCI legal (1.3.023, which don't matter to you and me but they matter to bike makers who're making one frame for all timed race uses. Second, when fitters err, they donít err in the long-and-low direction.
Still, there are options.
Orbea Ordu LTD This is the bike made today that, when built, as specíd, is ready for to fight the long/low battle. If you take a Size-L out of the box and build it up, change the factory specíd stem from a 90mm Ė6į pitch to a 100mm Ė17į (parallel to the horizon), keep aerobar pads in the native, neutral position, you have a bike that perfectly fits zachboring, that is, a bike with a Pad Y/X of 610mm/530mm +/-2mm. How can this be? This frame has a stack/reach of 540mm/430mm, and thatís only 5mm longer than the 540mm/525mm that is almost ubiquitous (Quintana Roo, Felt, Cervelo, Dimond, Trek). The difference is in the handlebars. The Vision TriMax bar has pads that sit only 45mm above the pursuitís centerline and, at their neutral, central pad position sit 12mm in front of the handlebar clamp (the pursuit bar center). Profile Designs with the J4 bracket that set 15mm behind the pursuit bar (although it is possible to flip these brackets and make them a set-forward set of aerobars). When you can add 27mm to the cockpit distance, and lower the armrests 15mm, simply with an aerobar change, thatís a major change to how the bike fits.
Now, what about knightly76? We have to work a little harder. If we do replace the factory spec stem with the stem we used for zachboring, no pedestals under the pads, the Pad Y/X on the Size-M frame is 588mm/510mm. We canít quite get there. With a Ė25į stem we can, and we even need to add a 5mm pad pedestal to get to the target Pad Y/X. The nice thing about the Ordu LTD series, it looks like a super bike, but it can take any stem. I built up a Shiv for myself last week, I resorted to a Ė25į stem to get the bike to fit me, itís not the ideal scenario but it got done and Aliens, like beggars, canít be choosers.
Slowtwitch resource cyclenutz (David Bowden) down in New Zealand is the best Iíve come across at solving the kinds of fit problems Iím tackling in this series. David not only has an encyclopedic knowledge of the sub-assemblies to meet any fit problem, heís turned it all into a terrific calculator: type in the problem, click the button Ė Help! Mr. Wizard! Ė presto, the calculator solves the problem and spits out the complete bike solutions. He turned me onto a great find, the SL-KĖ20į stem from FSA. It comes in 10mm increments from 50mm to 120mm.
Trek Speed Concept For zachboring itís a Size L in this bike, with a 15mm pedestal and that 5mm spacer between the mono-extension and the pad wing. That means weíre 5mm away from not being able to serve him up a Speed Concept. What about length? Trek offers 3 ranges for Pad X for this bike, this size, this stem: 484-502; 470-515; 401-584. The center of all those ranges is about 495mm, and each range is successively larger, meaning you have to do successively more to get the cockpit long enough. But it can be done!
Remember how we had to work a little harder to get the Ordu to work for knightly76? And even so, we could only get it to within 3mm of his proper ďlowness?Ē We can get to within 5mm of his lowness on a Speed Concept, in a Size-M, and like zachboring the center of the 3 length ranges almost catches the cockpit distance but not quite. For both these Slowtwitch readers a Speed Concept is a good choice.
TriRig What? Tririg is making bikes now? No. It makes a 1-piece stem/aerobar that is long and low, much like the Vision bar above. For zachboring any of these bikes with a stack/reach of 540mm/425mm will work with a TriRig Alpha X. Heís within 10mm of making it height wise without needing to resort to the undermount configuration, and the undermount is not a bad solution. The Alpha X set up undermount with 20mm of pedestals, and the pads in the center holes, gives him 610mm/525mm. What would I really do? Iíd raise the bars 10mm so I could enjoy the overmount. The undermount option is fine, but when you pedestal the Alpha aerobar in the undermount position the aerobars donít raise as the pads raise. zachboring is plenty low enough, he can afford a few millimeters of raise to get the ergonomics of this bar set up in an ideal way.
That freak of nature knightly76 rides the next size down (Size-54 in everything except QR, which is size-52, or a Size-S in Dimond) with the TriRig, undermount, only 5mm of pedestal, and heís dead on his Pad Y/X.
There are 4 Slowtwitchers out of 42 so far whoíve given me Pad Y/X numbers that are so long and low that I canít solve them or, if I can, itís going to be hard and itís going to be ugly. Everyone else is probably solvable, weíll see as the series progresses. but as you see the bar used makes more difference in the end than the bike geometry. As to all the options above theyíll all work great. The slight edge is given to the Orbea only because the bike itself is slightly longer, offering a longer front/center and therefore a slight bit better weight displacement for riders who will undoubtedly run into some handling challenges even if they solve the fit riddle.