# Crossing derailleur cables on downtube?



## RJP Diver (Jul 2, 2010)

So I got my bike back from its free spring tune up from the LBS. In addition to typically lubing/adjusting/etc I had them shorten the brake and gear cable housing on my 2011 105 group. (Where both the brakes and the shifter cables route under the bar tape.) When I first got the bike it was set up with the stem in an upright position, so they hadn't trimmed the housings. Now that I've dropped the stem, the housings were too long.

So when I get the bike home tonight I notice that the cables for the FD and RD cross each other as they run along the downtube. The proper shifters still control the FD/RD, but it appears in order to optimally route the housings from the bars, they ran them into opposite sides on the top of the downtube (by head tube) and then crossed them on the way down.

Is this normal/acceptable? Never seen it before.

Thanks


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## PlatyPius (Feb 1, 2009)

RJP Diver said:


> So I got my bike back from its free spring tune up from the LBS. In addition to typically lubing/adjusting/etc I had them shorten the brake and gear cable housing on my 2011 105 group. (Where both the brakes and the shifter cables route under the bar tape.) When I first got the bike it was set up with the stem in an upright position, so they hadn't trimmed the housings. Now that I've dropped the stem, the housings were too long.
> 
> So when I get the bike home tonight I notice that the cables for the FD and RD cross each other as they run along the downtube. The proper shifters still control the FD/RD, but it appears in order to optimally route the housings from the bars, they ran them into opposite sides on the top of the downtube (by head tube) and then crossed them on the way down.
> 
> ...


Cannondale was one of the big ones that did the crossed cable thing. In some cases, it does make for a better transition for for the cable from the bar to the frame. Me, I don't like it much.


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## MisterMike (Aug 12, 2004)

I've heard of it but never done it. The idea as I understand it is to get less bend in the cable housings. I'd say it should be fine.

From the late, great, Sheldon Brown (RIP):
http://www.sheldonbrown.com/cables.html


> *"Criss-Cross" Cables*
> Most bicycles with handlebar-mounted shifters run the rear cable on the right, the front on the left. This causes some awkwardness in routing the length of housing from the shift lever to the frame stops. Due to the need to allow these housings to be long enough to permit the bars to be turned all the way back and forth, the housings often wind up making a reverse bend--for instance, the rear will go from the shifter, which is on the right, swing forward and cross over past the centerline of the bicycle, then back over to the right side of the top tube, before heading down the down tube. These extra bends increase friction, and the fairly forcible contact between the housing and the side of the top tube can damage the finish.
> 
> A neat solution to this is to run the cables "criss-cross" style: The rear runs from the lever, (on the right) around the top tube, and to the cable stop on the left side of the downtube! The front cable crosses over similarly from the left side of the handlebar to the right side of the down tube.
> ...


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## RJP Diver (Jul 2, 2010)

PlatyPius said:


> Cannondale was one of the big ones that did the crossed cable thing. In some cases, it does make for a better transition for for the cable from the bar to the frame. Me, I don't like it much.


Cool - just wanted to make sure it wasn't just a screw-up. Will ride it a while and see if I notice anything to not "like it much" myself. The housing routing does seem much cleaner up front anyway.


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## looigi (Nov 24, 2010)

Trek Madone 6s come this way. The cables cross inside the downtube.


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## Kerry Irons (Feb 25, 2002)

*Experience*



RJP Diver said:


> So when I get the bike home tonight I notice that the cables for the FD and RD cross each other as they run along the downtube. The proper shifters still control the FD/RD, but it appears in order to optimally route the housings from the bars, they ran them into opposite sides on the top of the downtube (by head tube) and then crossed them on the way down.
> 
> Is this normal/acceptable? Never seen it before.



As others have noted, it is to reduce the amount of bend in the cables as they come off the bars. I've been doing this for 13 seasons with no issues, but maybe PlatyPius is aware of something that will yet jump out and grab me.


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## reptilezs (Aug 21, 2007)

i like criss cross routing when it makes sense. for me its just another thing in the "tool box"


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## RK250 (Nov 16, 2007)

The other day I was with a buddy and we were looking at the new Scott bikes. I said to him, "Who's the jackass who built this thing?", referring to the criss cross. Looking at it a bit closer, the housing bends looked really clean. When I got home and looked at my Orbea Orca, I thought it actually made for a more sensible cable path. I un-did the wires, stuffed the housing in the opposite stops, criss crossed the wires and I'm stunned at how much cleaner it all looks. You, my man, are now in good company!


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## RJP Diver (Jul 2, 2010)

RK250 said:


> You, my man, are now in good company!


:thumbsup:


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## Ventruck (Mar 9, 2009)

I decided to do this when swapping cables and housings a week ago. Noticeable difference where now my half-***ed internal routing setup at the bars is just as smooth as when the housings were hanging out. Before crossing, shifting worked out, but not as smooth.


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## PlatyPius (Feb 1, 2009)

Kerry Irons said:


> As others have noted, it is to reduce the amount of bend in the cables as they come off the bars. I've been doing this for 13 seasons with no issues, but maybe PlatyPius is aware of something that will yet jump out and grab me.


It depends on the frame. On some frames, it can lead to the housings rubbing on the headtube. Also, it doesn't seem like much, but the extra drag from the cables rubbing on each other at the cross point can cause some Shitmano shifting problems with newer 105/Ultegra/DuraAce.

Don't forget that the cable, since it's exiting at an angle from the stop, will also be rubbing the cable stop/barrel adjuster. This can lead to grooves in the stop, a groove in the barrel adjuster, and/or fraying of the cable.


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## dysfunction (Apr 2, 2010)

I do it too, it does clean up routing on my frame (it's also reduced rubbing on the head tube, go figure). I also actually like the adjusters in the location it puts them on.


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## looigi (Nov 24, 2010)

The only slight reservation I have about doing it is that the cables need to make sharp bends at the beginning of the channels in the guide under the BB, which has parallel channels. It's a small angle, but a sharp bend. IMO, if you have the correct length housing for how you have the cables routed, the differences between crossed and not are purely cosmetic.


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## RJP Diver (Jul 2, 2010)

looigi said:


> The only slight reservation I have about doing it is that the cables need to make sharp bends at the beginning of the channels in the guide under the BB, which has parallel channels. It's a small angle, but a sharp bend. IMO, if you have the correct length housing for how you have the cables routed, the differences between crossed and not are purely cosmetic.


Maybe it's the way the Specialized is set up, but the cables don't have to make any sort of sharp bend as they enter the guide beneath the bottom bracket. They cross each other about midway along the downtube. Neither do they rub on the cable stop/barrel adjusted atop the down tube.

Ray


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## matanza (Jun 9, 2004)

RJP Diver said:


> Maybe it's the way the Specialized is set up, but the cables don't have to make any sort of sharp bend as they enter the guide beneath the bottom bracket. They cross each other about midway along the downtube. Neither do they rub on the cable stop/barrel adjusted atop the down tube.
> 
> Ray


My two Specialized bikes are routed that way and it makes a all around cleaner installation and there is no binding or rubbing the headtube. I prefer this set up.


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## Mel Erickson (Feb 3, 2004)

Yes, it makes sense. I do it on all my bikes that have the downtube style cable routing. Makes for better functioning because the housing from the bar to the stop is a smoother bend. It's a pretty minor benefit. I also like the appearance better at the bar end. Looks cleaner and neater. I wouldn't go out of my way to change an existing setup but I would do it when changing housing or, in your case, shortening the housing. Either way is fine, personal preference.


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## carveitup (Oct 25, 2008)

I do this on most of my bikes and also my wife's. I originally did it back in the 90's when I had almost 1st generation grip shift (SRT 500R?) shifters on my mtb. The sram rep suggested it since those shifters were very sensitive to friction in the system. I find it gives a cleaner line from the shifters/bar to the stops on the frame. Works fine with Force, Ultegra and DA.


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## acidzerocool (Aug 1, 2007)

My BH G5 is routed this way. The cable crosses on the guide located on the BB. This bike was designed for it and recommended.


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## Mel Erickson (Feb 3, 2004)

PlatyPius said:


> It depends on the frame. On some frames, it can lead to the housings rubbing on the headtube. Also, it doesn't seem like much, but the extra drag from the cables rubbing on each other at the cross point can cause some Shitmano shifting problems with newer 105/Ultegra/DuraAce.
> 
> Don't forget that the cable, since it's exiting at an angle from the stop, will also be rubbing the cable stop/barrel adjuster. This can lead to grooves in the stop, a groove in the barrel adjuster, and/or fraying of the cable.


If a shifting system is so sensitive to the friction of two cables touching each other on the underside of the downtube then the much greater friction of the cable passing through the housing would be more than it could take. Sorry, I don't buy it and have never experienced this problem in nearly 40 years of routing cables this way.

Same can be said for the exit angle. Never had a problem, never had a groove, none of mine even touch the barrel or stop. The angle of deflection is way too small for this to be a problem. I am tall and my frames are in th 58-61cm range and maybe if you've got a very small 47cm frame this could happen. Even then I don't see an issue. Heck, many older frames didn't have a cable guide under the BB. The cable just rode right on the BB shell. Yeah, eventually they formed a groove but it didn't hurt a thing.


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## Kerry Irons (Feb 25, 2002)

*Alternatives*



PlatyPius said:


> It depends on the frame. On some frames, it can lead to the housings rubbing on the headtube. Also, it doesn't seem like much, but the extra drag from the cables rubbing on each other at the cross point can cause some Shitmano shifting problems with newer 105/Ultegra/DuraAce.
> 
> Don't forget that the cable, since it's exiting at an angle from the stop, will also be rubbing the cable stop/barrel adjuster. This can lead to grooves in the stop, a groove in the barrel adjuster, and/or fraying of the cable.


Then you wouldn't want to do it on that frame. The general reason to cross cables is so that the housings DON'T rub on the head tube.

My current bike has over 120,000 miles on it with crossed cables and no sign whatsoever of the cables wearing groves in the barrel adjusters. Maybe I just haven't given it enough time?

As to friction at the cable cross, I'm with Mel on that one - there is essentially zero friction there, especially compared with the friction of the cable going through the housings.


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## PlatyPius (Feb 1, 2009)

Kerry Irons said:


> Then you wouldn't want to do it on that frame. The general reason to cross cables is so that the housings DON'T rub on the head tube.
> 
> My current bike has over 120,000 miles on it with crossed cables and no sign whatsoever of the cables wearing groves in the barrel adjusters. Maybe I just haven't given it enough time?
> 
> As to friction at the cable cross, I'm with Mel on that one - *there is essentially zero friction there, especially compared with the friction of the cable going through the housings.*


There is. However, that can be all it takes for some newer Shimano shifters to not work properly. Do a search for Shimano shifting issues here on the forum. The housings (wrong brand) can cause the shifting to go wonky. They need to put a stronger spring in the RD or something... I've already run into a couple that didn't want to shift down to the 11/12 because of housing friction.

I worded my reply poorly yesterday, I think. The issues I listed are the issues that happen to *some* bikes that would make you not want to cross the cables on them. I didn't mean that all bikes have that problem.

Me, I just don't like the look of it. I have Campy, so it isn't going to affect the shifting; I just don't like it.


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## Kerry Irons (Feb 25, 2002)

*Confusion*



PlatyPius said:


> There is. However, that can be all it takes for some newer Shimano shifters to not work properly. Do a search for Shimano shifting issues here on the forum. The housings (wrong brand) can cause the shifting to go wonky. They need to put a stronger spring in the RD or something... I've already run into a couple that didn't want to shift down to the 11/12 because of housing friction.
> 
> I worded my reply poorly yesterday, I think. The issues I listed are the issues that happen to *some* bikes that would make you not want to cross the cables on them. I didn't mean that all bikes have that problem.
> 
> Me, I just don't like the look of it. I have Campy, so it isn't going to affect the shifting; I just don't like it.


Mel and I thought you were talking about friction where the exposed cables touch under the downtube, but here you are talking about housing friction. I'm confused.


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## PlatyPius (Feb 1, 2009)

Kerry Irons said:


> Mel and I thought you were talking about friction where the exposed cables touch under the downtube, but here you are talking about housing friction. I'm confused.


I'm saying that new Shimano is crap. A slight amount of housing friction can make it stop working. Take the housing friction - right at the threshold - and then add a slight amount of friction at the cable cross/barrel adjusters/etc from crossing the cables, and it could be just over the line enough to make 105/Ultegra/DA stop working (not shifting down to 11/12). I'm not sure what the difference is, but some new Shimano is incredibly sensitive to drag, and some seems to be less sensitive to it.


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## hazilim (Jan 17, 2012)

*Criss-cross cable routing*

My Trek 7.5FX originally came with straight/parallel cable routing. It had Deore MTB-type components (3 X 9) & was heavy, but shifted fine. I upgraded the bike to all 105 & changed to Ksyrium Elite wheels. The bike lost 5 pounds, BTW. When I brought it home from the LBS, I saw that the shift cables had been installed "criss-cross" under the downtube. The cables entered & exited the guides under the BB very smoothly. Shifting was crisp & accurate.
Several months ago, I re-routed the cables to the "uncrossed" state. The cables seemed to both enter/exit the plastic guides under the BB at a more acute angle. Everything worked, but shifting was problematic, especially upshifts at the RD.
I just re-did the cables "criss-cross"; the mech at the LBS was right. Shifting is smoother, probably due to less cable friction.
A source of different under-BB cable guides would be fantastic, but I don't know where to look for different ones.


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## metoou2 (Mar 18, 2009)

will have to try this


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