alexk_il

Currently running 1x with gear with all the cable routed nicely through cable holding guides on the top tube. See the photo attached.

Planning to change to 2x, I suspect the grey brake cable should be moved to the bottom cable holding guide to free the middle cable holder for the front gear cable. Unfortunately the bottom guide is too wide and can't really hold the brake cable.

What do I miss? What are my options?

FBinNY 

You missed a few possibilities. For example the frame may have been designed for hydraulic brakes, in which the 3rd position would be a support for the brake line.

There are options involving using a full housing for either the brake or a gear cable.

Looking at the mating cable bridge will provide some insights.

Feel free (encouraged) to post a 2nd photo and text description of what's there now for more specific help.

base2 

https://duckduckgo.com/?q=stepped+ferrule&iax=images&ia=images&pn=1
It looks like your frame was designed for full length housing. Though, depending on the particulars of your bike specifically, a stepped ferrule as shown in the DuckDuckGo sort engine link above may allow for a break in the housing...If that is what your goal is.

If it were me, I'd just run full length housing (simpler) or use hydraulic brakes if capable.

alexk_il

It was originally sold with V-brakes and 3x, the frame supports disks. The previous owner has modified the bike for 1x with V brakes, I'm building 2x with TRP Spyres.

Here is another photo of the front cable guides. The one closer to the rear looks identical, just reversed.
​​​​​​


Not sure if this helps, but

alexk_il

Thanks, I guess that's what I am missing. 😁

alexk_il

Is it "one size fits all" solution or are there variants? I can see ferulles in the search window to be visually different.

SalsaShark

Frame appears to be designed for a full housing run on the unused housing guide on the cable stop cluster. You will likely have to run a full housing on whatever will be using that free spot. If it is too large to secure shift housing, I would replace the rear brake cable and housing with a full housing utilizing the spot that is currently free, and then use the free cable stop for the front mech.

base2 

There are indeed various types and styles. The one I was thinking of was (but took me a few extra minutes to find):
https://www.amazon.com/Jagwire-Alloy.../dp/B0025UGY7Q
It is supposed to adapt from full housing to broken/open housing. I have a pill bottle of them but, sadly I do not have firsthand experience. Though, I see no reason why it would not be the proper product.

alexk_il

This is the bike Trek 6500 SLR. Was definitely sold with V-brakes.

The guides are about 7mm wide, the break cable is 5mm, how do I make sure the fully housed cable doesn't pop out of the guides when I rotate the handle bar? Or accidentally touch the cable?

alexk_il

Might work, the 7.3mm diameter seem to match my guides. Thank you.

SalsaShark

Found a photo of a 6500, and looks to be a step ferrule of sorts designed for the rear brake. The one in the picture looks to have a flange to keep the bushing and housing secured.
Looks like Base2 linked to the correct product.

alexk_il

Thank you, I just needed the term "Cable stops" to find what's required.

Here is a quick video that explains how it works, perhaps it will be helpful for someone in the future.

FBinNY 

Keep in mind that there MAY be a safety (or legal liability) issue here.

Depending on the structure, the stops may not be strong enough (not the stops, but the mount to the frame) for the relatively high loads of brake cables. A stop (glue) failure will disable the brake, possibly causing a crash, but definitely inconvenience, plus an annoying repair. So it's possible that the manufacturer, knowing the legalities in the event of failure opted to save the grief by routing a full housing brake cable.

This was never a problem BITD, when "braze ons" were acrually brazed to steel frames. When the design was translated to aluminum or carbon frames and stops were either glued or riveted on, all sorts of unanticipated issues happened.

If you don't KNOW how well the stop was affixed, I suggest you use a full housing brake cable.

alexk_il

Good point, thank you. How do I prevent the full housing from popping out of the cable guides which are too wide to keep the cable inside?

FBinNY 

You can find a ferrule of the right ID and OD and drill out the bottom, then slide them onto the housing, and maneuver them into place when the installation is complete. Keep them home with a light adhesive if necessary.

Alternately, fit the cable, mark the place where the guides are, pop out the cable, wrap in tape to build it up, then pop back in and slide back into position.

alexk_il

Good idea of using the tape, thanks.

I think I will take my chances though and will trust Trek to know what they are doing. The bike was designed to use mech brakes, the risks of them doing it wrong aren't that high. I would assume that a dangerous frame design would have prompted Trek to issue a recall, like they did with front rotors and QR levers a decade ago.

I'll check the cable stoppers idea first, hope it will.

Thanks anyway.

Ironfish653

Common practice in the “transition era” was mfgrs making a frame with both rim and disk mounts and using it on a couple-three different models at different price points, especially mid-range MTBs.

Since your TREK has disk mounts, it makes sense that the cable guides are intended for hyd lines, since the buyer of the less expensive v-brake model would be more likely to be ok with adapter ferrules than someone paying for the higher-line disk brake version.

cyccommute 

A step ferrule won’t work. They “step” from 5mm to 4mm (usually) and the opening on your cable guide is larger than 5mm. You need a guide stop. It goes into the oversized cable guide and the 5mm brake cable ferrule goes into the guide stop. See pictures below

Untitled by Stuart Black, on Flickr

Untitled by Stuart Black, on Flickr

Here’s how much larger the cable stop is than a 5mm ferrule

Untitled by Stuart Black, on Flickr

Normally, the oversized ferrule allows for the bike to use hydraulic lines if desired.

base2 

You mean like the one I linked to in post number 8 & was subsequently confirmed as correct by SalsaShark & RJ The Bike Guy via the OP's linked video?

FBinNY 

No problem, and didn't want to scare you which is why I full capped and bolded "MAY". In any case, there seems to be rust, meaning that you have a steel frame (you can check with a magnet), implying the boss is brazed on. If this were an aluminum frame, the absence of a visible weld would imply a bonded (glued) boss.

In any case, a valuable mental exercise is to put yourself in the role of the maker and try to figure out what they might have been thinking. So here you have a boss with 3 positions, 2 gear + 1 brake. It would have been easy to have all three identical, so you have to ask yourself, WHY is one different? Also, the third position lacks a fulcrum (housing stop), again ---- WHY? Not knowing anything more, you need to consider the possibility that it was not intended to bear much load, and therefore allowed for a lower strength attachment.

I'm not saying this is the case here, and others have offered a good answer, but the mental exercise is critical to making good decisions when modifying ANYTHING. Failure to consider what the guy before me was thinking, and/or what could possibly go wrong, has lead to many engineering disasters, from bridge collapses to booster rockets.