With the UCI allowing teams to test disc brake road bikes in two races this fall, Cervelo needed something for Team MTN Qubeka to ride.
The all-new Cervelo R3 Disc is that bike, and it’s both very similar and completely different than the standard rim brake model bearing the same name.
They wanted to keep the race geometry and handling since it’s going to be tested at the highest level under MTN Qubeka. The problem was, they had to widen the chainstays to fit the 135mm rear hub spacing that disc brake hubs use. And that can throw off the chainline. Most other brands simply extend their chainstays to accommodate the wider axle spacing, which is usually necessary to maintain proper shifting. There are specific recommendations from Shimano regarding the amount of chain deflection from chainring to cog. If it’s too much, the chain can start to pick up the chainring ramps too early, potentially limiting the number of usable gears or negatively impacting drivetrain performance.
Cervelo found a way to keep the chainstay length exactly the same…
The 5mm extra hub width was split evenly from left to right. Where Cannondale has shifted the extra width to the driveside on some bikes, that requires a specially dished or offset wheel lacing. Cervelo wanted to keep the bike compatible with high end wheels you may already own, though.
The solution was simple – move the crank arm outboard by 2.5mm on the driveside, lining everything up perfectly. They had plenty of room to work. The bike uses their 79mm wide BBright standard, which splits the difference between BB30 and BB90 (no, the numbers don’t all refer to the same thing, but BBright’s spindle width is exactly in the middle of those two. That kept the chainline correct without lengthening the stays, but to get the rear brake caliper inside the rear triangle, they had to loop the left seatstay further out a bit and use flat mount brake calipers.
Note how the non-drive seatstay sticks further back than the driveside? That’s what opens up the dropout area so the brake caliper can fit inside. This official pic also shows the correct graphics color for the FSA SL-K crankset that’ll come stock…no red graphics like what’s on the display bike. SL-K bar, stem and seatpost are also used.
The R3 Disc makes the move to 12mm thru axles front and rear. For now, they’re using a standard threaded design with QR lever, but they may switch to their sister company Focus’ thru axle system in the future.
Not content with simply drilling dropout holes from one side of the frame to the other, Cervelo came up with a semi-floating design to ensure perfect alignment. Thru axles require very tight concentric tolerances, which they say is very hard to do in mass manufacturing. So, the rear derailleur hanger is floating in the frame, given a few millimeters to wander when placed there on it’s own.
To line everything up and install it with perfect precision, you’d then slide the wheel in, thread in the thru-axle and then thread the nut on the outside of the driveside dropout. By putting the axle in while the hanger is a little loose, it can be perfectly aligned from side to side. Then by tightening the bolt on the driveside, everything is locked into place. That removes any binding from the thru axle and ensures perfect alignment and shifting.
Claimed clearance for 700×25 tires, but depending on the rim and tire combo, you may be able to get a slim 27 in there. The chainstay clearance is the limiter. BB stiffness increases at least 25%, mainly thanks to different layup, the seatstay’s wider stance and switching to thru axles.
Frame weight is claimed around 950g depending on size. On sale in October. It’s their first disc brake bike, but it won’t be their last…
The rest of the bike’s spec is Shimano BR-RS805 hydraulic disc brakes, 140mm rotors, Ultegra mechanical group, Fizik Antares saddle, HED Ardennes GP+ Disc and Continental Grand Prix Race (700×25).
In addition to the R3, they have a few team replica colorways available to first come, first served. There are only a few of the Tour de France MTN Qubeka team bikes left, and each one purchased sends a Buffalo Bike to Africa to help keep that economy moving along.
They also have a Bigla pro women’s team frameset (left) and Velocio team replica in an R5.
The P3 gets a mostly white with aqua blue color hits throughout. It also gets a Di2 Shimano group rather than mechanical, which meant they left off the hydraulic Magura TT brakes. They did this because the customer for the P3 wants/needs the additional shift buttons by the brake levers, and Magura’s hydraulic TT levers make no concessions for Di2 button shifters.
