New bike - gear cables advice please

jontymo

my wife and i recently bought 2 new bikes, mine is a trek 1.2 and is running sweet, my wifes is a specialized vita 2010 model purchased about 2 weeks ago from Evans.

My wife was struggling to change through the front gears, i have managed to get it better by adjusting the nut on the gear lever half a turn, as i was messing about i noticed the gear cables for the front and rear derailieurs crossed over about half way down under the main tube and are actually rubbing against each other, i checked my bike and they are parrallel, i presume this is wrong but before returning the bike i just want to check if anyone else knows if this is ok or not?

Hope you can understand.

Cheers, Jon

softlad

it's not 'wrong' as such - I have seen some bikes set up this way, although I prefer the conventional way myself. The theory is that it gives a better routing into the frame bosses from the shifters themselves.

So long as the bike has been set up correctly, it shouldn't affect how the bike shifts gear....

nicklouse

crossing the cable is normal.

better routing around the head tube less friction and rubbing on the frame.

jontymo

Thanks guys, looks like i got it wrong.

Lakesman

never crossed cables on my bikes and it doesn't sound right to me.
why would they even need to cross ? right hand cable runs down the right side of the bike to the rear; left hand cable runs down the left side, under the bottom brack and up to the front mech. if it's shimano they'll emerge from the levers towards each other in front of the bars and cross there; that's normal.
the guys are correct though ; cables inside their outers which cross shouldn't affect the shifting unless they were really forced into an odd angle.
sounds more like the initial set up. with the front it can be the height and angling of the front mech which takes a lot of experimenting with to get right. get evans to put one of their more experienced technicians on it.

John.T

They cross under the down tube. This is normal on some Specialized bikes. I run my Madone the same way for the reasons that nicklouse gives. Better cable runs and no scuffed laquer.

alfablue

Sheldon Brown says:

"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 down tube! The front cable crosses over similarly from the left side of the handlebar to the right side of the down tube.

The bare cables then cross one another under the middle of the down tube, making an "X". The cables may touch where they cross, but they will do so very lightly, since they are both straight...the tiny bit of friction at this crossing is more than offset by the reduction in friction in the smoother-flowing cable housings.

This technique does not work with over-the-bottom-bracket cable routing, but is doable with most newer bikes that have under-the-bottom-bracket cable routing and cable stops mounted toward the bottom side of the down tube.

John.T

The important bit is that the down tube cable stops must be low on the tube so the cables stay clear of the tube. It works well and I no longer need any protective tape on my head tube.

maddog 2

like John says, crossed is fine if they clear the downtube.

better cable routing from bars to frame leads to slicker/smoother shifting. I certainly cross all my bikes, if the cable-stops suit it.