My road disc project, CX frame + Campag + TRP HY/DR brakes

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by Miller


(full resolution:

Building this bike started with this forum. I don’t have an off-road background, I don’t think fashionable equals good, but I was intrigued by discussions about disc-braked road bikes and the emotions evoked by the idea. I do lean towards Campagnolo for drivetrain so when ‘mjduct’ of this forum mentioned he had a Novatec D712SB disc hub in 135mm width with Campag spline lying around I hesitated... then took the plunge and bought it from him. The hesitation because it was a commitment to dispense with the perfectly nice Principia alloy bike I’ve been using for the past few winters. I found a matching front D711SB hub on Ebay.


What disc frame to go for? I settled on the Planet-X “Dirty Disco” but the day before I was finally going to buy it they went out of stock in 56cm. This forum helped again as through it I learned that the P-X frame is a Chinese open-mould design known as the AC024. There are tons of them on Personal import from China? This project would feature new processes as well as new technologies.

Crystal at could hardly have been more helpful and in July the below arrived sporting huge clearances, matte finish, my choice of paint colour, BSA BB, a matching seatpost and no logos. Acres of carbon, wow.


I’ve had exposure to disc brakes through my commuter bike and maintaining children’s bikes and I knew I definitely preferred hydraulics, who wouldn’t, but there’d be no easy marriage of those with legacy Campag ergos. That is, until TRP announced their HY/DR cable-actuated hydraulics. A review suggested a concern about Campag levers having enough cable pull but nevertheless I ordered them from my LBS, and a few weeks later these arrived, very pretty if somewhat over-packaged. Rotors are included.


Wheels next. I wanted something with a wide rim and a non-machined sidewall so that pointed at the H-plus Son Archetype. For spokes I wanted to try Sapim D-light however they’re only imported to UK in a limited range of lengths that didn’t play nicely with the hubs and that rim. Then on I saw that they’d stock of Velocity A23 with a dark sidewall and an ERD that fitted the available D-light spokes in a 3-cross build on the Novatec hubs. A bit lighter and cheaper too than the Archetypes. They built up nicely. There was an issue to be dealt with though: from using Novatec hubs in a wheelbuild earlier this year I knew the RHS cap clashed with the Campag cassette lockring. It did in 11-speed anyway, would it also clash in 10-speed? Oh yes, tightening the lockring locked the hub bearings. The inner edge of the lockring bears down on a flange on the cap. Five minutes with a flat file reduced the diameter of the troublesome flange. Below shows a modified cap on the left, and as supplied on the right:


One final piece of the puzzle to sort out before I could build the bike. The frame puts the front mech cablestop just below the seat cluster and above the derailleur hanger. A road front der expects bottom pull. What to do? Someone on this forum pointed me at" onclick=";return false;" onclick=";return false; and their ‘umlenker’, a small piece of machined steel that switches the cable pinch point to outboard of the derailleur pivot and thus converts it to top pull. You can see it here installed on the Athena mech:


With parts in place I could get to work and build the bike. This weekend I’ve ridden on it for the first time. I did a photo session today at the Reading CC cyclo-cross race in a brief intermission between monsoon-level rain showers. Tried not to let it get muddy. Good tyre clearance:


3T bar and stem combo, from this forum, and 09 Centaur carbon 10v ultashift ergos, Campag’s best-ever 10v ergo in my opinion.


Michelin Pro4SC tyres in 25c inflate quite wide on the A23 rims. Pedals were an indulgence, Ribble are offloading Look Keo2 Max in limited edition colours for just £63 at the moment. I liked the fluo yellow and black ones which sort of match the green theme you might be detecting.


Close-up of the beefy fork and TRP brake. I wanted a secure quick release and found a pair of Deore XT on ebay. A disk bike is not the place for lightweight skewers.


Another view of the brakes. The rear brake routing precludes putting a Garmin sensor on top of the chainstay but it mounted neatly beneath.


Yeah, this bike should really be used in a CX race but I hate mud and I can’t do running mounts.


Having amassed a grand total of 2 hours aboard this machine at time of writing I can already say I am loving it. The brakes are great, the handling is sharp, the bike is responsive and the wheels are damping out the bumps. It’s a blast. Oh yeah, this being weight-weenies after all: about 8.3kg as pictured.
Last edited by Miller on Tue Oct 22, 2013 11:02 am, edited 1 time in total.

by Weenie

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by Fixie82

I like! Nice fixes, especially with the 'umlenker', nothing like finding a great workaround solution. I am just wondering if the cable routing could be changed to give a slightly less aggressive bend at the headtube? Could you cross the cables over at the front right to left, left to right and then cross back again behind the seatpost? Looks good as is but it's going to give some hella cable rub.

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by Valbrona

Ain't got time to hang around waiting for those pictures to download.

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by prendrefeu

I like the build a lot, and thank you for documenting the components a bit, that's always nice to see.

Happy riding!
Exp001 || Other projects in the works.

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by Deev

Excellent, well thought out and specced build. Unusual to see discs and Campag. Gutsy choice with the Chinese carbon disc frame - let us know how it goes long term.

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giant man
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by giant man

Yup. looks great now it's built up, nice ...

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by Miller

Fixie82 wrote:I am just wondering if the cable routing could be changed to give a slightly less aggressive bend at the headtube? Could you cross the cables over at the front right to left, left to right and then cross back again behind the seatpost? Looks good as is but it's going to give some hella cable rub.

That's a suggestion I may take up, thanks. CN has been looking at CX bikes lately and mentioned a team mechanic doing as you suggest although didn't say why, presumably for better routing.

Re Valbrona, the pix are from Flickr. If they're slow to you, you need better broadband.

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by astranoc

Looks great. If I may add, you can use the lizardskins bartape to completely match the color, this one looks a bit faded for the color of the bike.

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by ross

Like this but not too keen on the different shades of green, also your front valve is open ;)

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by ultyguy

Nice ride! Not my choice of colours, but hey, to each his own. Totally agreed on the 09 era Centaur kit, great stuff.

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by Miller

Here's an update two months in.

The Speen Umlenker didn't work out well. A week ago I did a front upshift and... nothing happened. The Umlenker had broken the front mech. A tab on the Umlenker braces the device against the gear cable guiding tab on the Campag mech and it exerts enough leverage that the routing tab on the mech broke off, as per photo below.

I've replaced the assembly with a Shimano CX70 top-pull derailleur and that feels like a much better solution, it's an efficient light-feeling derailleur that has the benefit of making the bike look less busy.

Full mudguards do make the bike look busy but on damp British winter roads they allow for a more pleasant riding experience. They're held on with multiple zipties, I'm still tuning the exact configuration but it's stable enough.

The HY/DR brakes are good with excellent modulation and quietness... unless it's wet in which case the front brake squeals like a pig. I could wish for less lever travel, I may experiment with different brake casing to see if that offers an improvement.

Teething troubles aside, this is turning out to be a big confident bike which is a pleasure to use.

Athena front mech, broken tab circled, culprit in the background

Shimano CX70 top-pull mech works well with Campag ultrashift ergo

Bike in full winter garb

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by Dennis

Great looking bike. Should be a great ride. Only thing I would change is that I would remove the red stripe on the stem. It's a easy job with some aceton. Anyway great job!

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by Quinn039

getting rid of that red stripe and then finding a better matching green for the bartape would clean this bike up a great deal. Nice build and I liked the play by play.

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Samuel Sanchez Gonzalez
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by Samuel Sanchez Gonzalez

That's a great winter bike indeed. Makes you want to ride in bad weather.

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by mihai


by Weenie

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