650c Project Bike

The idea for this article came about some months back. In September of 2012, we interviewed triathlon legend, Ray Browning. You may or may not know, but Ray won Ironman New Zealand in 1989, aboard one of the first real triathlon bikes ever made. That bike was made by Quintana Roo, and owned by Dan Empfield (who is now the publisher of this website). Through the early and mid-1990’s, triathlon bikes had 650c wheels. As in – ALL triathlon bikes had 650c wheels, regardless of frame size.

Wheel size aside, the story continues. Ray Browning is a physiologist by trade, and overall biomechanics expert. The guy knows his stuff, and continues his work today as a professor at Colorado State University. Somewhere along the lines during his transition from racer back to academic, Ray worked with intimately with Serotta, as director of their Serotta International Cycling Institute. My mind starts putting pieces together. Ray knows Dan Empfield. Dan Empfield knows Ben Serotta. All of the men involved are bike guys, triathlon guys, and bike fit guys. They’re also very good guys, and each contain the right mix of common sense and curmudgeonly-hard-edged-wit (no, I don’t know what that really means, either). All of this old-school bike geek love got the gears creaking in my brain.

What this story boils down to is a phone call to Ben Serotta:

“Hi Ben, Greg Kopecky here with Slowtwitch. I’d like to pitch a project bike idea at you…”

The rest? History. Before we go any further, I must extend our deepest gratitude to the folks at Serotta for participating in a decidedly off-the-wall project. Without their understanding and dedication to triathlon, none of this would have happened.

Bring on the Small Wheels

We’ve written a lot about various wheel sizes. Not a week and a half ago, we wrote THIS.

This editor has ridden road and triathlon bikes with 700c wheels, mountain bikes with 26-inch wheels, and mountain bikes with 29-inch (700c) wheels. However, this editor has never – not once – ridden a properly-fitted triathlon bike with 650c wheels. All of the old-school guys rode 650c wheels… quickly. Why not me? Rather than continuing to write about 650c based on others’ experience, I decided that it was time to try it for myself. Also, from a selfish point of view, I want to do what no other triathlon publication seems to do, which is make a serious effort to review 650c products. Yes, 2013 is the Year of 650 here at Slowtwitch.

Because I’m really bad about letting the cat out of the bag, here it is:

This bike has been a wonderful learning experience, so let’s talk details.


Do I need 650c wheels? Far from it – I’m 6’ 1” tall. More than anything, I wanted to see ‘how they ride’. Could I really feel the difference, assuming the rest of the bike’s geometry mimicked my 700c bike? At the beginning of the design process, I had a few key things in mind:

1. Retain the exact saddle relationship of pedals-saddle-bars as my normal 700c bike.

2. Dial in the front-end geometry to match my 700c bike. I didn’t want any big handling differences to be caused by this, so I could more accurately evaluate the wheel size.

3. Find out if there is anything to the new aerobar designs that allow the rider to ‘pedestal-up’ their arm pads.

The bulk of the geometry was easy to figure out. I knew my desired stack, reach, seat tube angle, bottom bracket drop, and so on. We dialed the trail to just over 60mm, matching my 700c bike. The real question mark was #3 (above). The new thinking in aerobars is that, while you cannot fit someone on a bike with a head tube that is too tall, you can always fit someone on a bike with a too-short head tube. All you do is raise the aerobar pads and extensions up with very tall risers. In an email, Dan told me, ‘Don’t build the bike too tall. If you’re going to start with a head tube bottom, keep it low, and raise up the pads with pedestals.’

Some people who argue against 650c say that they result in too-tall head tubes for taller riders, because the wheel is so short. They say that the tall head tube is less aerodynamic and, well… it looks ugly. Fine then – we’ll go short.

In order to try out this theory, I chose to use Zipp’s Vuka Alumina Clip.

Above, you see the 10mm riser option; they also have 25mm and 50mm risers. This would leave me with plenty of upward movement available, so we kept the head tube to a reasonable 160mm. If that still seems tall, that’s because I have a long inseam for my height, and corresponding high saddle height of 81cm. My saddle is way up in the air, and I need to get my bars up to reality.

Everything should work out just fine, right? I signed off on the geometry chart, and waited patiently for my frame.


In the meantime, I attended Zipp’s 2013 press launch in Tucson, AZ. This included a ride aboard their new Vuka Stealth bar. They went so far as to fit a bike exactly to each editor’s specifications, so we could make a true evaluation of the product.

At this event, my bike had a Vuka Stealth with the 25mm risers. It also had no bar tape – likely for aesthetic reasons. Those familiar with Tucson know how poor the roads are; I soon found myself riding with a death grip on the base bar. It was cold and we were all wearing full-finger gloves. Combine that with a base bar that was narrower than I’m used to, MUCH lower than I’m used to, and without bar tape, and my hands literally started cramping halfway through the ride. Thankfully, we found a roll of bar tape in the SRAM NRS support car, and wrapped the bars at a rest stop. Their wonderfully-grippy Service Course CX tape made the remainder of my ride much more enjoyable.

This experience did leave me worried, however. I really didn’t like having the base bar that low – even with the bar tape. If I was only riding 40km-or-shorter time trials, I could see getting away with it, but for everyday training and Ironman racing, it just wasn’t going to fly. Part of this likely has to do with a serious neck and shoulder injury that I sustained several years ago, but the point stands – my plan wasn’t going to work. The biggest ‘problem’ was that Serotta was ahead of schedule, and my frame arrived early – before I could change anything.

What to do?! I’m being dramatic, so don’t fret. I wasn’t really that worried. Before the process began, I thought of this potential problem. If for some reason I didn’t like the pedestals, I could - gasp - flip the stem up. Isn’t that one of the Slowtwitch Deadly Sins? Yeah, well… whatever. Call it a sacrifice in the name of experimentation. To combat this horrible fashion problem, I chose Zipp’s 6-degree stem option, rather than the sharper 17-degree. In fact, I’m quite pleased with how this all worked out. I’m among the few who go to the trouble to really disassemble my bikes for travel, so I can avoid oversize baggage fees. This also means that space is at a premium, and the key constraint is the long axis of the bike – the tip of the rear dropouts to the top of the head tube. The longer this distance is, the tougher it is to fit into a bag (I remove the fork, stem, seatpost, and cranks completely). Having a short head tube meant that my future travels would be easier.

Before we move on, I want this bike to serve as an example for those who have not tried a high-pedestal bar setup. Some people seem to be fine with it, even for long course triathlon. I advise that you not commit to that $10,000 bike purchase with an integrated, non-adjustable front end and just assume that you’ll jack up the arm pads if need be. Talk to your fitter first, and if possible, test ride a bike with this configuration.

The take-home for me is a big one:

There is no substitute for a properly fitted bike. Read that three more times if you have to. Now that I’ve tried it for myself, I personally do not believe that these stackable aerobars – versatile as they are – solve all the problems with an ill-fitting frame. You might like a high-stack bar, and you might not. ‘Nuff said, so let’s move on.

Mechanical Details

My opinion is that the bike is elegant in its simplicity. No aero tubes or internal cables? Not for this bike. Serotta certainly has the ability to make aerodynamic options, but I wasn’t about to ask them to double their material and labor cost for my project bike. Also, it just wouldn’t fit the theme. A classic look felt more appropriate.

The frame is a custom version of their Legend Ti.

Did I mention that it’s custom? How about this – does your bike have the official Slowtwitch logo? Mine does:

One very standard feature is the good ol’ threaded bottom bracket shell. To date, this is my favorite system for reliability, ease-of-service, and crankset options.

With round tube bikes, I always spec a third set of bottle cage mounts on the bottom of the down tube. The weight penalty is insignificant, and it greatly increases my fluid-carrying capacity.

The fork is a Serotta-made carbon model. It has a 1 1/8” steerer tube and custom rake specification. Oh, and some killer gold paint that matches the rest of the bike’s logos:

Material has been machined out of the dropouts to save weight:

Even the rear brake bridge has the trademark ‘S’:

No electronic shifting for this bike. It wouldn’t fit the theme, and I’m quite happy with the performance of mechanical shifting. This build has a mixed 10-speed drivetrain of Shimano Ultegra and Dura Ace:

In addition to the Hed Jet 6 race wheels pictured above, I built up a pair of training wheels – Mavic Open Pro 650c rims, DT Aerolite spokes, and CycleOps Powertap hubs.

This was one area of the build that proved to be very challenging. There simply are not many 650c rims these days. I had to search high and low, and finally found that Mavic still makes a 32-hole version of their wonderful Open Pro. While I would have preferred fewer spokes (32 is a lot for such a small wheel), it worked just fine. Because of the high spoke count, I went with a lighter spoke in DT’s line – to retain ride quality. The Aerolite is one of my favorite spokes of all-time, and bladed spokes always make wheel truing easy.

Another big challenge was finding a proper chainring for this bike. Going from a 700c to a 650c wheel means that my overall gearing is reduced. In order to match a the gearing of a 53/39 crankset on 700c wheels, you need a 57/42 crank on 650c. Interestingly enough, as chainring technology has improved by leaps and bounds in recent years, the number of size options has greatly diminished. The cost to manufacture high-tech rings is very high, so I can’t say the SKU reduction comes as a surprise. The problem is that it’s becoming very difficult to find anything over 55 teeth.

I called up the good people at Rotor USA, to see if they had any stock of the 56 tooth Q-Ring. I was in luck.

That’s a 165mm 3D crank, TT spider, and 56/42 time trial Q-Rings. While the gearing is slightly lower than my 700c bike, I consider it ‘close enough’. This also gave me an opportunity to try a non-round chainring, which is something new to me.

We’ll offer one more article on this bike, with some more photos of the build process, along with my impression after putting some hard miles on the bike. Are 650c wheels the best thing ever? Are they outdated technology?

Also, over the next several months, we will test and review as many 650c-specific products as we can get our paws on. So far, our list includes two sets of race wheels, a rear clincher disc, and a handful of tires. Who said that small wheels were dead?