Jonathan Kaplan said:I'm new to bike mechanics and I'm attempting to install Ultegra STI brifters. I know that the left
brake cable (facing the front) is supposed to cross in front of the stem to the top tube. The
right would then go down straight in side the loop from the left.
Do the shift cables go left to left downtube stop and right to right downtube stop or does the
left cross to the right downtube stop and right to the left downtube stop?
If you did the crossover at the handlebar, wouldn't it have to be crossed back before the bottom
bracket?
My on line article on cable prep and installation covers this. Here's an excerpt:
"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."
The whole article is at sheldonbrown.comcables.htmlOpen ↗
Sheldon "Criss-Cross" Brown +-------------------------------------------+
| It's easier to be original and foolish | than original and wise. | --Gottfried Wilhelm Leibniz |
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