Remodelling a Cervelo P3

This autumn/winter, I planned to refurbish my 2010 Cervelo P3. Over the last year or two, I’d gone from 9 speed to 11 speed Dura-Ace, so that I could swap wheels with my main time trial bike, a Cervelo P5, which is presently equipped with SRAM eTap kit and concealed Magura RT8 hydraulic brakes.

The main intention of the remodelling was to reduce the amount of cabling exposed to airflow on the P3, and generally make the bike a bit sleeker. The P3 is quite a bit bit lighter than my P5 bike, so I have the intention of using it on rather more undulating courses where its monstrous top gear is rather useful on long descents.

I intend to ride the P3 for my club's New Year's Day '10' - this would use a pair of H3 trispoke clinchers I have - the front H3 is usually mounted on the P5, and was last used at the Duo Normand in September.

Buying the parts

I’d hoped to find an aero brake similar to the Tri-Rig Omega X (which I’d have liked, but I thought the pricing of those brakes as an import to the UK to be excessive). Unfortunately there wasn’t much else that wasn’t aimed at direct mounting. And to switch to direct mount brakes would have opened an entire can of worms, and probably a new frame. I thought of using a set of Magura rim brakes and promptly searched eBay. Two sets were being auctioned. I missed out on the first, but the second set was won for a very reasonable price. As I have RT8s on the P5, I have some experience of maintaining the Maguras, but none of the actual installation. Links to web pages about the RT6 are hard to find now the brakes are discontinued, but this is what the RT8 version look like (The RT6 look similar but are all black).

I then set about seeing how affordable eTap would be for this bike. eBay was again my first port of call. I found a NIB rear mech at around half price and a similar front mech for a good price and ordered these - the BlipBox came from Wiggle. Ultimately I bought a pair of Clics (the extension end mounting eTap gear switches).

The Magura levers weren't compatible with the USE Tula handlebars, so I resurrected a set of Vuka base bars and some Deda GCB extensions from my parts bin. These had been tried on the P3 back in 2014 for the Duo Normand, with rather unfortunate consequences that involved contravening Team Grumpy Rule #2, and having to obtain a hacksaw from the local supermarket in order to rescue the situation. At the time of writing, I still need a full road test to be confident of the extensions (but they are well-torqued).

Rule #2. Don't tinker with your bike the evening before the event. It will break, either then or, worse still, during the event.

TeamGrumpy.org

Installing the Magura brakes

There’s a useful description of the installation process over at Slowtwitch. Actually, the hardest part was persuading the brake hosing to pass through (a) the handlebars and (b) the top tube. For the former, this just required some patience and the use of a bent spoke and a small size allen key. For the latter, I needed ingenuity, the bent spoke, the allen key and a spot more ingenuity. Plus, I had to Dremel out the alloy cable stop at the front entry point for the brake cable in the top tube.

Connecting the hose to the brake lever required considerable patience. First, this involves inserting a barbed nut (see left) into the hose, which is made of a rather rigid plastic. It looks pretty easy in this video from Magura. In practice, tapping the barbed end into the hose proved difficult, possibly because the hose was rather brittle at low temperatures - for the first couple of attempts, the hose split rather than accept the barbed end. However, once this was sorted, the barbed end screws directly into the rear of the brake lever.

At the caliper end, one uses a screw-on fitting with a disposable olive. Again, this is notionally quite straightforward - you first pass the sleeve nut over the hose, followed by the olive. Then the sleeve nut is passed over the olive and screwed into the brake caliper, compressing the olive to make a tight seal. The olive is a single-use item. I don't off-hand know why the caliper end of the hose can't attach in the same way as to the lever (maybe that would introduce unwanted twisting to the hose). Of course, this didn't turn out so straightforward for the rear brake, despite following the instructions as best I could. And so, at this point, all seemed well.

When I came to secure the brake levers to the Zipp base bars, it seemed as though they just would not secure via the two allen key screws that were supposed to achieve this feat. With some irritation, I delved into the internet and found an exploded parts diagram of the RT6/RT8 levers, and discovered that there were a few parts missing - parts that worked as an expansion plug to fasten the levers into the base bar.

I contacted the eBay seller, but to no avail: the brakes had been removed by a bike shop, and the missing parts lost. To be honest, these parts are small, and fly off at the slightest nudge, so I’m not surprised. I then emailed Magura UK to ask if I could buy the parts by mail order. The reply came back quickly, no, they weren’t offered for sale. But…I was invited to send through my address and phone number, and they’d send out a set. Well, what stars! The day was saved.

A couple of days later, the parts arrived. While fiddly, the installation is (at least in principle) simple. That done, I filled the system with oil and adjusted the caliper bite point to match the wheels (as per this Magura video). All was great…until it seemed as though oil was slowly seeping out from the rear brake system. It took a fair bit of poking to see where this slow leak was - ultimately it appeared to have been the junction between the hose and the rear caliper, and once that was addressed, the brake was fine.

Installing and setting up the SRAM eTap gears

This rebuild involved the installation of the eTap aero system for TT/Triathlon bikes, in which there’s no combined brake/gear lever as in the road bike system. Instead, there’s a ‘BlipBox’ to which up to two pairs of gear change switches are attached by wires - the BlipBox transmits the wifi signal to the gear mech. Because the BlipBox is itself a controller, it’s possible to use that alone to control gear changes, and this was my original plan. Initially, therefore, I merely mounted the blipbox near the end of the extensions. In execution I found that the switches on the BlipBox are really too small for my fat fingers, plus the location of those switches were a little inconvenient, so I reverted to using a pair of ‘Clics’, switches that mount in the end of the tri-bar extensions.

Installing SRAM eTap is stupidly easy. No wires or cables to the gear mechs, so no fiddling around passing cables through the handlebars or frame. I plonked the Clics in the ends of the extensions after drilling out the extension tubes to allow the wires to exit near the base bar, where they neatly route out to the BlipBox which I’ve mounted on a mount that screws to the stem front plate. The wires from the Clics are not really exposed, and the whole setup looks very neat. I haven’t set up a second set of switches on the base bars.

Shifting is a little clunky, but that probably reflects the non-standard cassette - an EDCO monocoque steel 11-speed affair used to convert a Corima disc wheel to 11-speed - as much as inaccuracy in setting up indexing. Gearing is 57/46 up front, with an 11-23 cassette.

Wheels

The wheels currently on the P3 are a Hed Stinger 90 (front) and an old Corima disc wheel. These are both tubular, and I'm reluctant to use them to ride out to club events - I've had too much hassle with punctured tubs over the years. The likely wheels to be used on its first outing, probably the New Year's Day '10', will be a pair of Hed H3 clinchers - the rear also converted from 9 speed to 11-speed using an EDCO monocoque cassette.