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Internal rear brake cabling on 2018 Cervelo P2 / P3
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Hi all, so I finally got annoyed enough at the cable sticking out of the side of my otherwise awesomely sleek bike to want to change it. I'm using a TriRig Alpha One cockpit and eTap, hiding the Blip Box in a Torhans Bento X box.

So now I've taken the whole thing apart ... I have no idea what I'm doing but figured I'd give it a go anyways :) The top tube has this 3 hole box built into it but it looks like running the rear brake down through one of those would then make it difficult to get back up to run along inside the top tube ... so how is this supposed to work? Or is the P2 not actually designed to allow this and is a hack required? If so ... what? Drill a hole (for a cable stop?) into the rear side of the 3 hole cavity to allow a straighter cable back towards the rear of the bike?

Photos attached of that little 3 hole box/cavity thing on top tube, annoying side-cable, full bike as it was a few weeks back.

Thanks!

Edit for anyone finding this in future:


I ran all the cabling housed (Jagwire compressionless) front to back, through the 3 port box, as recommended below but this ended up being slightly too much friction for the bake/levers to release. SO ... I broke out a power drill and carved a slot 'up' from the center hole in that internal box, about half the height, (image attached of completed cut) to give the housing a smoother path and ... it worked! Never been so happy to see a brake work in my life.

Took several hours of my weekend but was kinda fun to do, having done it once I'll do it again ... but it was a hassle, getting a LBS to do it seems entirely sensible as well.
Last edited by: Aurigan: Oct 8, 18 9:11
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Re: Internal rear brake cabling on 2018 Cervelo P2 [Aurigan] [ In reply to ]
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You have to remove the fork, then you can route the cable down through the hole behind the stem and out the bottom of the headtube. Next, loop it back in and up towards the rear of the top tube. Pull the housing out the hole by the seatpost, and be careful not to kink the cable housing as the loop is pulled back in at the lower headtube bearing hole.
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Re: Internal rear brake cabling on 2018 Cervelo P2 [Aurigan] [ In reply to ]
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Vacuum cleaner and a piece of string will get anywhere you need to go.
One the string is in, pull an inner cable through, thread an outer over that.
Once the outer is in, remove the inner and cut outer to required length, dress ends and fit an inner.
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Re: Internal rear brake cabling on 2018 Cervelo P2 [Aurigan] [ In reply to ]
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There’s an image somewhere floating around that shows the route the cabling should take; if you use the search function I thinks it’s either P 2 or P3 internal cabling) and look through the thread I think you should be able to find it; I sent that image to my LBS who then did it for me.
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Re: Internal rear brake cabling on 2018 Cervelo P2 [DFW_Tri] [ In reply to ]
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Hrm, couldn't find anything after 20 mins or so of searching ... any chance you can dig it out of your old emails?
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Re: Internal rear brake cabling on 2018 Cervelo P2 [quadlt250] [ In reply to ]
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Thanks for the reply ... so ... it ends up looking like the green line on the attached? Where do you put cable stops ... seems like bare cable wouldn't work well running through that 3 hold plastic box internally.
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Re: Internal rear brake cabling on 2018 Cervelo P2 [Aurigan] [ In reply to ]
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The bike looks awesome! Make sure you use the updated alloy Monopost we sent along, it improves stiffness dramatically. Or if you didn't get one, please shoot an email to support@tririg.com - we sent them out to all Alpha One owners.

Regarding your question, quadlt250 has the most correct answer. The answer by lyrrad is usually true, but because of the odd path the housing needs to take, you'll get the best braking performance by following quadlt250's advice. That's how we did it on our build at http://www.tririg.com/...ervelo_New_P2_Review

Thanks!

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TriRig.com
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Re: Internal rear brake cabling on 2018 Cervelo P2 [Aurigan] [ In reply to ]
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You’ll need a bigger “S” loop that goes deeper into the headset or else it’ll bind up and kink over time. I did the same mod on my (P2 size61) i went with Jagwire’s top of the lline line cable housing that is the most flexible


What size frame is that? 58?
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Re: Internal rear brake cabling on 2018 Cervelo P2 [Tall_Coffee] [ In reply to ]
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61 ... I'm 'only' 6'2" so really wasn't sure I needed/wanted such a big frame even though the size guide said that was the one for me ... 1k miles in and I'm happy with it though.
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Re: Internal rear brake cabling on 2018 Cervelo P2 [Aurigan] [ In reply to ]
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Your diagram is pretty accurate. As to your question - no cable stops. You remove the stop from the rear port, and just run full housing from your brake lever all the way to the brake.

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TriRig.com
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Re: Internal rear brake cabling on 2018 Cervelo P2 [TriRig] [ In reply to ]
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TriRig wrote:
The bike looks awesome! Make sure you use the updated alloy Monopost we sent along, it improves stiffness dramatically. Or if you didn't get one, please shoot an email to support@tririg.com - we sent them out to all Alpha One owners.

Ha, yes, that's an 'old' photo ... I got it and have been happily using it for the last hundreds of miles ... was really impressed how TriRig dealt with the original post having issues!
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Re: Internal rear brake cabling on 2018 Cervelo P2 [TriRig] [ In reply to ]
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TriRig wrote:
Your diagram is pretty accurate. As to your question - no cable stops. You remove the stop from the rear port, and just run full housing from your brake lever all the way to the brake.

Ah interesting ... guess I could enlarge the hole in the plastic widget things (what are those called?) that fit in the frame to let the housing run right through them to keep it all looking tidy ... awesome, thanks for the pointers!
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Re: Internal rear brake cabling on 2018 Cervelo P2 [Aurigan] [ In reply to ]
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Yeah, there is plenty room for a long S loop. I ran mine through the middle hole behind the stem
Last edited by: Tall_Coffee: Oct 6, 18 11:44
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Re: Internal rear brake cabling on 2018 Cervelo P2 [Aurigan] [ In reply to ]
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You shouldn't need to enlarge anything - there's already a hole at the back of the cable stop behind the steerer tube, which is ordinarily meant for electronic connectors. But it's more than enough room for the housing to slot in.

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TriRig.com
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Re: Internal rear brake cabling on 2018 Cervelo P2 [TriRig] [ In reply to ]
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Right! The two piece clamp on the top tube looks like it works perfectly for housing ... the little stop/plastic thing that goes at the rear of the bike on the top tube to fit in that exit hole will need to have a slightly bigger hole in it to route housing through though.
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