Cable routing Question

r3hxn

Hopefully on the home stretch now with my bike build! dont get very many hours a week to work on it so its been a long term project!


I am now at the stage I need to install some new cables for the Derailleurs and rear brake. I've tried to read up as much as I can before attempting it I just had 1 particular question.
With most cable set ups I started to take note of (to be fair, is not a lot of bikes) there is always a straight, area ( under top tube or under downtube) where the cable is bare from 1 cable stop to the next. I could not find much information on why this was, whether it was a technical/scientific reason or as Sheldon Brown very briefly mentions, just to save weight?

I just wanted to understand whether it is something I absolutely should incorporate, or if its just a weight thing it will probably be an easier install to have the cable run with an outer all the way from start to end.


thanks in advance.

cooldad

Depends on the cable stops on the frame. If it's designed like that, and most are, there's not much you can do. You can run full outers, but will need to use cable ties.

The Rookie

As CD says, you are pretty much stuck with the cable layout designed for the frame.

The frame is stiffer than the cables so you get better quality of shifting by using the frame and not outer cables (where you can), also it is cheaper and lighter.

r3hxn

I guess that leads onto my follow up question..

Below are photos of my frame, to me this looks like something that would run with full outers only. Is that right?

Is there a name for this type of routing(?) so that I can look it up in more detail.

thanks again.

The Rookie

That is for full length outers (making good quality outers a must), there should be a stop on the seat tube for the front mech.

r3hxn

that's right there is.

thanks I think I have it mentally sorted.

Will go at it tonight.

r3hxn

just 1 final question, I got home and opened my package for a Clarks S/S cable set, there are just 2 items in it I am not sure what they are exactly. Pic below..




There is the red tube, I am not sure what this is for?

The 2 clear 'barrels(?)' : I'm guessing this is for certain frame types and is where the outer would stop and let the wire run bare? ( please correct me).


thanks

The Rookie

Not a clue, you just need cables and end caps, maybe the clear bits are to aid cutting?

stubs

Clear things look like do nuts you slide them on the exposed cable (If your frame has it) to stop the cable rattling against frame. Red tube not sure might be to help with installing cable on frames that have internal runs.

r3hxn

cheers

as long as they are not something completely obvious I had missed.

JBA

The clear pieces are donuts and need to be separated in to two lots of three.

The Rookie

Argh yes, I can see that now, most mine are black, designed for use on open sections to stop the cable rattling which the OP won't have.

r3hxn

you know what they say about, measure twice, cut once.

They should of said measure thrice !

live and learn.

stubs

If your building up a bike with no old cables to measure, measure them against frame and add at least 4 inches/10cm.

Another tip is to buy the crappest cheapest outer you can find fit that get it right then use it as a template to cut the good stuff.

njee20

Another tip is to buy the crappest cheapest outer you can find fit that get it right then use it as a template to cut the good stuff.

Or just do it right first time, seems unnecessarily difficult. Do you buy cheap forks to check you get your steerer length right too!?

r3hxn

yea, I doubt its a mistake someone would make twice. I just didn't allow enough outer for rear derailleur to move. and with the front derraileur cable, I cut it after measuring it up, but it frayed before I put a cap on it, meaning a follow up cut would of been too short. But thankfully I had spares.

stubs

njee20 wrote:

Another tip is to buy the crappest cheapest outer you can find fit that get it right then use it as a template to cut the good stuff.

Or just do it right first time, seems unnecessarily difficult. Do you buy cheap forks to check you get your steerer length right too!?

Aah but your awesome and have never made a mistake. If your cabling up a new bike and have never done it before then its a trick to avoid buying two sets of expensive cable.

Chunkers1980

But SP41 is £2 a metre and less. Rubbish stuff I can find is about £1/m so you're just wasting a £/m whatever. Wing it with the more expensive stuff and get it right and you're onto a winner as you'll have saved the rubbish.

Short answer - stupid idea.

Also, if you fukk up the long bits, they can be used on the shorter bits.

njee20

Aye, that was my thought.

It's a sound principle if the expensive stuff was 10 times the price of the cheap stuff, but it's not. I also wouldn't add 4" to each cut, perhaps an inch more than you think, but if you can't get to within 4" then you shouldn't be fixing your own bike, in fact you probably shouldn't be allowed out on your own. You'll just end up with loads of useless off cuts.

stubs

It must be awesome to get everything right first time. Pity no one on here knows what it feels like.

njee20

So you've now said twice, I'd rather fuck the odd thing up, than buy 'contingency products' any time I did something!

cooldad

This^^^^^^^^

If you're really worried, dry fit one end, run it to the next stop, and cut.

The Rookie

I thought that was what everyone did....... certainly how I always do it, measuring is much more likely to create an error.