njorange

I am converting my old Cannondale SR600 to STI. The original down tube shifters were standard orientation of front derailleur on left side of bike and rear derailleur on right side of bike. When I add STI shifters and cross the cables coming off the handlebars the orientation will be reversed. The front derailleur has to go down the left side of the bike due to cable routing under the bottom bracket. I don't really like this as I will inevitably use shift the wrong derailleur when using this back up bike. If the rear derailleur is on left of handle bar should rear brake be on left of handlebar too? I see 4 options I have to route my cables and curious what other folks have done.

1) Don't cross the cables coming off the handlebars. I don't think this will give enough slack to move the handlebars plus the cable will be bend at a steeper angle.
2) Just live with the reversed orientation and would have to adapt when riding this bike. But keep the brakes oriented with right of handlebar being rear brake.
3) Live with both reversed brakes and gears so that the rear derailleur is also the rear brake.
4) Change cable routing piece under bottom bracket. This does not seem feasible since frame is formed to allow front derailleur on left side of bike.

I will probably go with option 2 since brakes are more important to keep oriented the same. If I change the wrong derailleur it has less downside then hitting the wrong brake.

curbtender

Why are you crossing the cables? STI will be left/front, right/rear.

Andrew R Stewart 

What? Drop bar STI controls only have the rear in the right lever and front in the left. The brake levers don't care which brake (front or rear) they pull. Gear cables can be crossed while traveling from the down tube stops to the BB guide, done all the time and on many of my own (and small) bikes.

So to review. The rear der has to be controlled by the RH STI lever but that side's brake lever could control either brake. The rear cable could attach to the DT stop on either side of the DT, crossing back over if attaching on the left side. Andy

fietsbob

Yea AFAIK, its Running the right shift cable to the left head tube side housing stop to let the cable line take a smoother curve to reduce friction ,

then under the downtube it crosses over the left shift cable that cable in the right stop goes to the left side cable guide to the FD

the other crossing from left to right and on to the Rear D

its a choice..

Side of the Big C'dale Downtube housing stops may not seem as attractive to you..







....

njorange

Andrew R Stewart 

Inner cable contact as they cross under the DT has never been an issue for the many who do this. Maybe it will be for you though More likely the "problem" will be the really fat diameter DT that your Cannondale has and where around the DT the cable stops are located and whether the inners will clear the DT or rub against the paint (if you do try crossing the cables along the DT). Andy

rccardr 

Andrew R Stewart 

rccardr- What size bike do you ride? Do you do your own wrenching on your bikes?

One challenge with smaller sized bikes and with shift cables that are under the bar tape is that the open sections of casing running from the bars to the down tube can get very short. So short as to affect the steering, the cables act as springs on the handlebars. Add to that is that to allow enough open casing to not snag/pull or kink when the bars are fully rotated (like when crashing or placing a bike in the car) can result in rather curvy casing paths, the casing no longer flows with little or no "over bending". With taller frames of longer stems there's more distance between the casing leaving the bars and it entering the DT stops so this tightly curved or too short for complete bar swing situation is far less a problem.

By looping the rear shift cable/casing around the headtube and along the LH side of the DT (and the reverse with the front cable) the openness of the loop increases, the tightness of the curve relaxes and everything works better and stays that way longer. This is much the same with the way rear brake cable/casing gets routed too. (Although the brake casing is less stiff and more forgiving to tighter curves in general).

Until one experiences the problem on their own and is the one responsible for that problem the amount one will seek solutions is likely less. Andy

TireLever-07

I was going to say, cross them where they run under the down tube too, or use bar ends. Even stem shifters, Check the down tube braze-ons too. They had a least 2 different styles. Modern compressionless Derailer Cable housing, even improves friction shift bikes. The other housing is for brakes only.

dabac

I don't know how all bikes are configured.
Maybe there are some where the placement of the cable stops make this an issue.
But I've crossed cables both along the top tubes and along the down tube more times than I can remember and never had any issues.
Even when the angle at entry/exit has seemed a bit sharp, the cable has still eventually failed where it "always" does, at the clamp.
Sure, the cables will cross and touch. But the force bringing them together is really, really tiny.
No force = no friction, no abrasion, no problem.

nfmisso

One addition; if you are worried about it, you can put the cables in liners in the regions of the crossover.

This what I use: https://www.amazon.com/Jagwire-Black.../dp/B0029LF1XO

I use it primarily on the exposed cables on top of the top tube on my bikes so equipped to prevent rubbing on the straps of my triangle bag and trousers when stopped.

veganbikes

You shouldn't have issues with any routing unless you are currently having issues. Basically you will need some downtube cable stops like those made by Shimano or Problem Solvers and the cables will go through the same place as the downtube ones because they will replace the downtube shifters.

If you didn't want STI levers Gevenalle is a great option. They allow you to use your down tube or bar-end shifters (or their own shifters) mounted to the front of drop bar brake levers so you can shift as many gears as you want and keep a friction front derailleur. I have them on my touring bike and love them.

Ironfish653

Make sure you use cable liner or those little tiny rubber 'donuts' on the cable if it looks like it might contact the frame.
Also, if it's really tight clearance, route the FD cable under the RD cable under the downtube. You shift the FD far less often than the RD, so it'll rub the frame less, and put less wear on the paint.

Prowler 

Retro Grouch 

I cross the cables in front of the head tube and again under the down tube if I have clearance. If the cables are going to rub on the bottom of the down tube, I don't cross them and keep them all on the same side. I'm guessing your Cannondale would be a same side bike for me.

FWIW, I don't worry about the cables rubbing against each other. Try rubbing them together by hand and see how long it takes to wear them out. Then remember they only rub a tiny bit and at that only when you shift.

curbtender

Just for reference, which sti group is njorange using?

njorange

I am using Shimano Dura Ace/Ultegra 2013 vintage. I think it is called 7700 series or something like that. It came with my Trek Madone.

I did get it routed by crossing the cables under the DT. They rub each other and the frame but I put heat shrink tubing where they rub so the frame should be fine.