Urban Legends: The S3 and Campy 11
The power of the internet never stops amazing us. Combine a thread about the new Cervélo S3 on the influential Weight Weenies forum with one misinterpreted reply by Cervélo to a consumer and you end up with the hottest rumor on the web since Biggie killed Tupac: Word on the web is that the S3 isn’t compatible with Super Record 11.
Is it true? No, it is not true. The purpose of this missive is simple and clear: To clear the air and to explain how and why the Cervélo S3 is indisputably compatible with all Campagnolo 11-speed componentry.
The thrust of the Weight Weenies thread is this: A potential Cervélo S3 customer heard of troubles related to the installation of a Campagnolo Super Record 11-speed crankset on an S3 frame. Apparently the 39t chainring can come close to the outside of the right chainstay. He was concerned that, under flex, the chainring would rub.
Ask any experienced bike mechanic if they’ve seen this issue before, and they’ll tell you ‘of course.’ Regardless of frame brand. Regardless of component manufacturer. Regardless of 9, 10, or 11 speeds. It happens sometimes. And it’s an easier fix than patching an inner tube. It’s not a ‘rig’ job -- it’s simply good bike mechanicking.
For starters, install your Campy 11 BB according to Campy specs, then insert your left crankarm. Feel that springiness as you push the crankarm against the BB? It’s there by design, and it’s caused by the wavy washer that sits between the outside of the non-driveside BB cup and the inside of the bearing on the left crankarm. The main purpose of the wavy washer is that it allows the bottom bracket to work within a small range of bottom bracket width variability. According to Campy literature, their Ultra Torque crank/BB will work within a 1.6mm range. For Italian bottom brackets, that range is from 69.2mm – 70.8mm, and for English bottom brackets the range is from 67.2mm – 68.8mm.
Install your right crankarm and torque the fixing bolt to spec. Is the small chainring closer than you’d like to the outside of the right chainstay? If so, then do what we’ve done for time immemorial: Remove the crankarm and right BB cup, place a spacer behind it, then reinstall it in the frame. The key is this: The size of the spacer can’t be so thick that it puts the total bottom bracket shell/spacer width beyond the factory specification. An easy <1.0mm spacer to find around a bike shop is the one that comes for the back side of Shimano cassettes. Once you face the S3 BB shell, this 1mm spacer should put you at right around 68.8mm. And if you want to play it safe, you can buy a Wheels Manufacturing 0.7mm alloy BB spacer made for this very purpose (QBP # CR1237. It costs less than a cup of coffee).
Given the cushion of the non-driveside wavy washer plus the fully-locked-together Hirth Joint design of a Campagnolo Ultra-Torque crankset, you have a perfectly operational unit with no additional drag to the BB or imperfection in any way, shape, or form. Our modification is barely worth mentioning because it’s one that bike shops have been doing to all varieties of bikes and bottom brackets forever. No product can be mass produced without some minor variability. That’s why good bike mechanics exist. Never has there been such a shitstorm about something so easy to resolve.