Crossed vs. Uncrossed shift cables?

Discuss light weight issues concerning road bikes & parts.
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loudtiger
Posts: 107
Joined: Sat Apr 30, 2011 3:37 am

by loudtiger

Lately i've been seeing more and more people with their shift cables routed so that they don't touch the headtube with the cables crossing underneath the downtube. This provides a cleaner look up front and prevents the housing from rubbing on the headtube. What are the downsides of this approach? Is there any added friction with the cables crossing underneath?

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wheelbuilder
Posts: 431
Joined: Wed Feb 08, 2017 2:10 am

by wheelbuilder

Its perfectly fine for externally routed cables. It can be tough to not cross them twice though if internal. Can totally be done, but you have to take your time with a little trial and error.

kode54
Posts: 1184
Joined: Tue May 23, 2006 9:39 pm

by kode54

i have mine crossed. it makes for a smoother transition on my Indy Fab bike with mechanical shifting.
- AX Lightness Vial EVO D + DA9150 + Enve SES 3.4 carbon hubs
- Parlee Altum + DA9150 + Enve SES 4.5 carbon hubs
- Parlee ESX + DA9150 + THM SRM PM + Enve SES 6.7 CK hubs
- Independent Fabrication Ti FLW + DA9100 + Enve 3.4 CK hubs

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Calnago
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Joined: Sun Nov 07, 2010 9:14 pm

by Calnago

There is actually less friction using this method as the bends are smoother. Plus, no cable housing touches your frame. The only downside is making sure the cables don't get twisted in the downtube during installation, since you can't see them and generally have to ensure this by "feel". But lately, with some manufacturers putting the cable insertion points dab smack in the middle of the downtube (rather than off to the sides), it can actually make for harsher bends again, so you have to just evaluate each situation as it comes up and use your better judgement.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

topflightpro
Posts: 812
Joined: Tue Jan 13, 2009 2:35 am

by topflightpro

Calnago wrote:
Sun Jan 21, 2018 8:23 pm
The only downside is making sure the cables don't get twisted in the downtube during installation, since you can't see them and generally have to ensure this by "feel".
I had this happen to me once. It was driving me nuts. Got the RD shifting perfectly. Then I started working on the FD, and every time I'd shift up, the RD would shift too. Could not figure out what was going on. Took it to my shop, and the first mechanic was a bit mystified until the second one told him the cables were twisted around each other - he had had it happen to him once before.

spud
Posts: 642
Joined: Sat Feb 07, 2009 5:52 am

by spud

I've run them both ways. No downsides to doing the cable cross, just have to be more careful in running cables, ensuring they are not crossed by keeping tension on one while increasing tension on the other and seeing if there is an effect. As said above, evaluate based on the geometry of the ports.

Fiery
Posts: 412
Joined: Sat Mar 16, 2013 9:21 am

by Fiery

It can be impossible to achieve with external cables without having them rub the downtube - at least I've yet to own a bike where it is doable.

mattr
Posts: 3501
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

Fiery wrote:
Mon Jan 22, 2018 3:51 pm
It can be impossible to achieve with external cables without having them rub the downtube - at least I've yet to own a bike where it is doable.
Depends where the stops are, the shape of the downtube and the type of bottom bracket guide.

We've only got one bike where it's possible. The others all have too deep a downtube/end stops mounted too high.

wilwil
Posts: 162
Joined: Thu Sep 23, 2010 5:47 pm

by wilwil

I don't like how crossed can make the cables stick out in between the bars and the frame entry. It depends on where the the cable stops or frame entry holes are positioned. I like the the cables to stay in front of the head tube as much as possible.

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Calnago
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Joined: Sun Nov 07, 2010 9:14 pm

by Calnago

wilwil wrote:I don't like how crossed can make the cables stick out in between the bars and the frame entry.
Fair point, and if your frame is large enough the S-bends required probably don’t add too much cable friction, but every curve in a cable housing does add “some”. This is why in the old days with skinny steel tubes and cable stops on the lower side of the downtube, it was often the preferred method of routing for many, particularly when it came to the smaller frames. This went out of favor for quite awhile as tubes became bigger and cable bosses were more and more installed on the side of the downtube making it impossible to do the cross underneath the downtube with externally run cables. Then, as tubes became “superfat” it was apparent that you could do the cross cabling method again, except it was internally routed and you don’t even see it. I’m obsessive about having a perfectly shifting mechanical drivetrain, and so at some point I switched over and began routing the cables crossed internally. I cut the cable housing as short as possible to minimize the flaring out of cables from the downtube while maintaining as smooth a line as possible and being able to turn the bars fully either side without ripping out cables in the event of a crash or even just transporting the bike in a contorted position in the back of a car or something. The only reason I didn’t do it on my C59 earlier was because I knew there was sort of an “I-beam” sheet of thin carbon running lengthwise down the center of the downtube. I initially thought that piece ran the length of the downtube which would have prevented crossing of cables internally. But it doesn’t, it only goes a little ways down the downtube, probably to stiffen things up a bit up front. This was one of the key changes with the C60, in that they could do away with that internal piece of carbon. Anyway, the point is that piece didn’t run the length of the downtube and therefore allowed me to cross the cables internally in my C59 as well. It took a little while for me to get used to the “new look” having always taken pride to kind of “frame” the headtube badge in a perfect elipse of cable housing up front. But now, with the way I do it, I think it looks even cleaner than before and there’s no denying the cable runs are smoother, which is significantly more critical these days with 11 speed drivetrains than it was back in the days of 8 or even fewer cigs in the back. My C50 still has the double cross in front of the head tube routing due to the fact it’s externally routed and the cable bosses and downtube thickness prevent an “under the downtube” cross.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

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themidge
Posts: 527
Joined: Fri Jan 13, 2017 4:19 pm
Location: Auld Reekie

by themidge

Calnago wrote:
Tue Jan 23, 2018 9:13 pm
My C50
What have I not heard of/seen this doubtlessly magnificent bike before now :?:
:hello:
Cannondale Supersix 2008 (weight: 7.3kg)
B'twin Triban 540 (in bits)
Vitus "Benotto" 979 (weight: :? )

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Calnago
Posts: 6004
Joined: Sun Nov 07, 2010 9:14 pm

by Calnago

I had it long before I even started being a contributing member to Weight Weenies... and after a C40 which I sold to a friend so I could get the new C50 when it came out. That first C50 was blue and suffered an untimely fate as it crashed into the roof of my garage, and this one replaced it...

Ha... I just noticed you can see my tubular wrapped up (sort of) in saran wrap under my saddle. I joked about this in my Koppenberg thread as someone asked about my current little "dry bag" which I used to carry my spare tubular these days...
Image

Image

Probably a couple better photos for this thread would be frontal views showing the aesthetics of the different cable crossings.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

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