This week’s Bikes of the Bunch belongs to framebuilder Rob English of English Cycles. English, a former winner of the Best In Show award at the North American Handmade Bike Show (NAHBS), is perhaps best known for his fresh look at systems most people just accept as the norm and turning them completely on their head. Examples include the way his stems preload the headset bearings, his one-sided bikes, and his rethinking of steel as a performance material.
Now it’s English’s turn to share his latest build, a bike he squeezed into the build queue in order to test a few new ideas. Enjoy.
Integrated disc rotors
Road disc brakes are pretty great, in terms of stopping power, modulation and consistency. However, the very tight tolerances between pads and disc can be frustrating to set up without rub, and it only takes a slight ding to the rotor to have a constant noise that can be tricky to remedy.
So, a thought experiment. Why are the pads so close to the rotor? In order to get the most mechanical leverage – a big movement at the lever equals a small movement at the pads. But why do we need that much leverage? Because the rotors are very small, so to be able to slow the much larger rotating mass of the wheel, we have to squeeze the rotor tightly. Therefore if the rotor was bigger, we could have a caliper with the pads further away, and this would be fine as we wouldn’t need as much mechanical advantage.
To take this to the extreme example, what if the rotor was the size of the rim? Like 622 mm in diameter. In looking at this problem, it became apparent that it would be possible to dispense with a separate rotor and use the rim of the wheel as the braking surface. Testing of different materials for the braking surface and the pads concluded that a machined aluminium surface and standard pads provides fantastic dry weather braking. They’re not awesome in the wet — for those conditions having the braking surface further away from the wet tire/rim in the form of a separate, smaller rotor makes the best sense. But I digress.
With the rotor being almost five times bigger than normal, the brake pads can be several millimetres clear of the braking surface without sacrificing power. This would make brake rub nonexistent even if the wheel goes a little out of true. It also turns out that a well designed mechanical caliper can provide all the power and modulation required – no need for the usual hydraulics. It turns out a steel cable will do this job admirably! Testing also showed that a 32 mm tire can fit comfortably under the caliper.
So I decided to build a bike around this concept. And I discovered another advantage to this radical braking system – by moving the caliper mounting from the end of the fork leg to the fork crown, the fork legs do not receive any asymmetrical loading, and can be built to have compliance for comfort that will not be activated under braking forces.
There was also no need for the regular oversized through-axle – instead the wheel can be mounted totally securely with open dropouts and a cam-actuated quick-release lever that allows for the wheel to be removed in seconds without tools. And better yet, with no hydraulics, there are no concerns about needing to block the pads from excessive movement whilst the rotor is removed. And it is even easy to add cable splitters or other forms of cable quick release if the bars need to be removed for travel.
I am very excited about this revolutionary bicycle, and look forward to testing it. Look at all the gains – the same braking power, modulation and control, but with less weight, easier-to-remove wheels, no hydraulics, more compliant fork and no rotor-rubbing noises! Yes, there are a couple of downsides – it’s not ideal in the wet, and it can’t use the best shaped aerodynamic (carbon) rims. Still, could this oversized rotor concept be the next big thing in cycling?
The finer details of this steel steed
The bike I built around this concept allowed me to try a few other ideas out too. I wanted to try undersizing the tubing a little from what I usually use, to see how that felt for ride quality. For my personal bikes — as a 140 lb, 5’9″ (64 kg, 175 cm) rider — I have generally been using a 35 mm down tube, ovalised 28.6 mm top tube, 28.6 mm seat tube, ovalised 24 mm chainstays and 9.5 mm seatstays. For this one, everything went down one size, so the down tube is 31.8 mm (bi-ovalised at the BB), ovalised 25.4 mm top tube, 25.4 mm seat mast, ovalised 22 mm chainstays and 8 mm seatstays.
I continued my gradual adjustment with my personal bikes of lengthening the top tube and shortening the stem. Funnily enough, I had the bike fully designed when Open released its new road bike, which implemented many of the same ideas, albeit in carbon with disc brakes. This includes a 25.4 mm seatmast, offset seat tube, and a 72.5º head tube.
I have built with an ‘upside down’ headset setup for many years and having a one-piece stem/steerer makes for a very clean appearance. On this bike I machined the fork crown to include the pinch bolts so there was nothing to braze on, and the extra thickness of the crown spaces the legs for the 32 mm tire clearance.
Keeping with the undersized theme, I had an old 26 mm handlebar so built the stem to match. There is a 1” steerer, but with the headset shimmed to fit into a 1-1/8” headtube – this just gives room for the gear cable stops to be inset into the head tube for the internal routing. At the rear, the offset seat tube with a subtle bit of shaping in the middle clears the 32 mm tires with a chainstay length of 404 mm.
I have grown used to having extra bottle capacity and so added bosses on the rear of the seatmast. However, I brazed them internally so it maintains clean lines when the cage isn’t installed. The seatmast cap uses the same pinch bolt system as the fork crown, allowing for fine tuning of the saddle height.
Built up with (really nice) spares
The parts are a mixture of mostly used components I had in the shop. I always admired the original Sweet Wings cranks back in the ‘90s. They were so far ahead of their time with a two-piece construction, oversize spindle, and external bearing. So I jumped on the chance when I came across a used set for sale. I revamped an old set of EE brakes with new bushings, and cleaned up the used Campy Record 11-speed shifters and derailleurs. I had a set of DT 240 hubs that had been unlaced, so I picked up a locally made set of Astral rims to go with them.
A side part of this project was curiosity about the weight of a bicycle mostly made of metal, with exception to the carbon handlebar, saddle rails and some carbon in the shifters and derailleurs. With a steel frame, fork, stem and crank, and aluminium wheels with those big tires, complete with bottle cages and pedals, the bike comes in at 15.5 lbs (7.03 kg). I’m pretty happy with that.
I haven’t had a chance to ride it extensively yet, but an initial couple of rides tell me it feels plenty stiff enough, and rides, well, like a bike. Once I get to really push it hard on some descents I’ll get a better sense of the characteristics.
Frame: English Cycles custom, integrated seatmast
Fork: English Cycles custom
Headset: Cane Creek 40, 1″ shimmed to 1-1/8″ headtube
Wheelset: DT240 straight pull hubs, Sapim CX-Ray spokes, Astral Solstice rims
Shifters: Campagnolo Record 11
Crankset: Sweet Wings (original), 170 mm, 53/39 Shimano chainrings
Bottom bracket: Sweet Wings
Front derailleur: Campagnolo Record 11
Rear derailleur: Campagnolo Record 11
Cassette: Campagnolo Record 12-27
Chain: KMC X11SL
Brakes: Cane Creek EE brakes
Tyres: Rene Herse Stampede Pass 700×32 mm
Handlebar: WR Compositi
Stem: English custom stem/steerer
Seatpost: English custom seatmast cap
Cages: Silca Sicuro Ti
Bar tape: Pro
Saddle: Selle Italia SLR
Pedals: Speedplay X2
See more of Rob English’s bikes at englishcycles.com.