cbslc

I'm working on a Specialized Dolce Elite size 48. The brake cable routing is under the top tube. Then it goes to the dual pivot brake. The problem is the housing length is so short that it goes outward instead of inward and rubs against the riders back leg. I tried shortening the length of the housing, but that resulted in really bad brake release, I have a zip tie holding the housing to the seat tube and that sort of works, but its pretty ugly. Anyone tackled this issue?
I noticed the adjusting barrel on the Ultegra 6700 brakes seems less tall than others, this could potentially increase the length between the frame lug and the brake bolt, but I can't tell if the arm is just longer and it ends up making no difference...

sch

Hard to imagine a few inches of housing interfering with brake release unless the angles were really off. I assume you flattened (grinder) the
brake housing ends and used ferrules? I see no problem, even esthetic, preventing use of a strategically placed zip tie. Did the same on
my latest build with internal routing for the rear brake cable where it entered the frame near the headtube so the brake cable would not
develop an angled entry after a lot of L turns. Can't see the L side of the bike on the web site, is brake housing full length brifter to brake
or do they break it on the top tube with bare cable, and this is internally routed?

dwmckee

Can you post a picture?

CliffordK

Take some photos.

What kind of brake levers are you using?

Are you talking of the releasing of the wheel when doing maintenance, or typical opening/return of the brakes during use?

Campy puts their brake release at the brake levers. Several of the generics (aero, non-brifters) such as Tektro have an option of brake lever release too. Finding a good place for barrel adjusters could be tight, but there may be alternative positioning.

I would think that after a few weeks of zip tying the cable housing to the seattube, it would naturally take that shape, and one might be able to dispense with the zip tie.

Thinking a bit outside of the box. Some of the old Mixte frames would use a bottom routed brake cable.
https://www.bikeforums.net/bicycle-me...xte-frame.html


Sheldon Brown shows a similar "hack".
Installing and Adjusting Caliper Brakes


Anyway, perhaps a radical change in your cable routing would be worth considering.

Oh, keep in mind, a downward loop of cable housing can trap moisture and lead to a premature demise of cables and cable housing.

dabac

(Some) Travel Agents can be run in pulley mode(no change of ratio).https://problemsolversbike.com/products/travel_agents/
These lets you do a nice and tight 90 deg change of pull direction.
Or use a v-brake noodle.
They're available in several degrees of bend and even flexible ones:Amazon.com : Jagwire Flexible Brake Noodle, Bag of 10 : Bike Brake Mounts And Adapters : Sports & Outdoors

You may need to trim the diameter at the insertion end on the v-brake stuff to get it to sit nice in the barrel adjuster.

And/or bottom out the barrel adjuster on the brake, and add an in-line one somewhere else.

Andrew R Stewart 

The brake is a dual pivot caliper, not a V brake. So no noodle.

I share the frustration when bikes have poorly located "braze ons". It's a common issue on the smallest sizes (and sometimes on the largest) because the locations of stops and such is often determined by the common sizes then just applied to the small sizes to save the time it takes to reset the jigs or fixtures. People who design and build but don't assemble, service or ride the bikes shouldn't be allowed to, IMO.

In my hobby frame building I spend a lot of time with braze ons. I make my own in some cases. I locate them based on both my years of LBS service work, the rider's needs and the components intended to be used. I take pride in this. More then once I've had a painter contact me and ask if I know that a cable stop is off center ot off line and crooked. I do these tiny positioning aspects to best line up the casing with the inner cable.

As mentioned the OP could try to grind/file the end of the casing at a small angle to better direct the casing in the direction wanted. A tie can be used to pull the casing over a little. I've even made a full loop (like a roller coaster has) to allow the best casing movement or route and been pleased with the results, even though it goes against common practice. I don't know if these are made any longer but if the top tube is round a clamp on stop (which were common back when ATBs with canti brakes were being converted to V brakes) might be used to relocate the rear cable stop.

fietsbob

Buy a New cable and enough housing to make the next installation Long enough.

dabac

I noticed that.
The fact that there wasn't one doesn't mean one can't be used.

Think beyond what a noodle is and focus on what a noodle does - it provides a tight 90 degree bend.

One end takes brake cable housing just fine. Doesn't take much skill to trim the other end to fit into a barrel adjuster. A neat and useful trick If you need a tight bend IMO.

Andrew R Stewart 

I agree that noodles have other then V brake applications (like routing STI cables down along a handle bar bag's sides). But in this case the noodle would need significant bending to produce a replacement of the casing which still routed from the top tube stop. Then there's the issue of the now reduced length of casing, what with the noodle taking up some of that function. But you're right in thinking that I thought you had miss read the OP. Sorry about that. Andy.

cbslc

Sorry I've have the flu for a few weeks and am just getting back in the swing of things.
When I made it shorter, it seemed to make the angle to the barrel adjuster too severe (not shooting straight down enough??) and kinda kinked it.

FBinNY 

First, your cable is too long. Trim it so the run to the brake fitting is aligned with the ferrule, instead of over shooting and coming back. The right length will leave the brake parallel to the seat stay and rise no higher than the top of the top tube before dropping back to the braze on. That alone may solve the problem, maybe still using a tie to keep it against the frame.

Otherwise a fancier solution may lie in using a rigid noodle cut and curved to fit for some or all of the run.

gsa103

The correct length is somewhere between the two. The picture is too long, the other is too short, you need the middle ground.

CliffordK

The Tektro R725 REAR comes with a noodle that you might be able to direct in the general right direction.

https://www.rosebikes.co.uk/article/...25r/aid:506056



Here is a set that crank_addict installed on his bike.
https://www.bikeforums.net/classic-vi...l#post18571929

cbslc

So I shortened the housing by about 3/4". And tried again. Still have to tie the cable to the seatpost. But now, what is happening is the housing is slightly more forward and the back of the riders thigh hits the housing. So, back to the drawing board.
Still wondering if the shimano BR-6800 brake has a shorter left arm (when looking from behind) and if that may solve the problem.

woodcraft

I have a bike with that kind of issue.

fietsbob

Brompton gets both brakes that come up from Below , to work with their folding scheme .

In the shop I regularly got Mixte bikes in like those when the brakes stopped working
the up turned housing U had filled with water and rusted in to Non functionality..

Brompton solution was a V brake Boot In between the side pull Arms ..

Also consider generously greasing the cable and using Teflon Lined Housing that helps too.

https://www.bikeforums.net/attachment...5&d=1457643057,
that seems OK the housing pushes down from one side as the cable pulls Up from the other side .

how side Pulls work, essentially.. cannot be too short or the housing no longer pushes the upper arm down.

You Might go buy some Nokon housing , it is a segmented Bead and barrel design that accepts shorter bends Better .. https://www.nokonusa.com/NokonUSA_Products%20(black).htm
https://www.wiggle.com/nokon-nokon-un...cable-set-15m/

I expect you only Need 6inches for right at that spot..
[TABLE="width: 100%"]
[TR]
[TD="width: 15%"]KON05050 (Silver) KON01050 (Black)[/TD]
[TD="width: 57%"]Extension set (42 pieces) for gear or brake cables, length 15.75" with 78.75" liner, available in black or silver finish.[/TD]
[/TR]
[/TABLE]

Tunnelrat81

I had the exact same issue with my father in law's specialized allez bike this last year. It's either a 48 or 50cm frame also. I fought with it for an hour or two, tried different things, different housing, different cable...and finally took it to my LBS. They proceeded to try the exact things that I had already tried. I did consider nokon, but couldn't justify the cost simply for 6 inches of housing, so I had them sell me full length brake housing and i simply zip-tied the housing in three places....the rear most zip tie was only 2 inches forward of the frame's housing stop, which points to a pure functional design failure on specialized's part. They could have moved that stop forward a tiny amount and solved this problem, but someone was asleep at the wheel that day. Shame on you Specialized.

My wife has a Ruby frame in size 54cm, and although the condition exists, the slightly larger frame allows for somewhat decent (not great) function. My father in law's brake caliper simply didn't have enough strength to pull cable back through after using the brake. I tried all lengths between too short and too long, all with unworkable results.

I may eventually revisit the nokon idea as a christmas gift for him so he can get those zip-ties off of his bike, but the improvement in braking action they allow compared to standard cable is like night and day.

-Jeremy