Forum home Road cycling forum Workshop

Help changing an internal (infernal?) rear gear cable

mr.b-campagmr.b-campag Posts: 203
As per the title. This is one of the few jobs I leave to the lbs but that doesn't seem to be an option atm. I think the last time they did this they threaded a gear cable outer through it and then put the cable through. I guess I wasn't paying too much attention as when I've tried this myself I've realised the cable port on the down tube is far too small for this. It looks like it can be taken out and I've removed the small bolt that holds it in, but it's flush to the frame and doesn't seem to want to budge. Any ideas on how to get this out?

Thanks in advance for any help.

B

Posts

  • I've done this. Might be a different bike to yours, but the principle is the same.

    You should be able to remove the cable port. It may have some sort of springy plastic piece to hold it in place. You will just have to explore carefully and use a small screwdriver/pliers to remove it.

    Then drill or dremel a hole in the base of this big enough to allow the outer through. Then get some lagging. Wiggle and others sell it. It is foam type stuff that will go into the frame and stop the outer bashing the frame and driving you nuts!

    Then look at the rear. The stop on the chain stay may also be removable. Mine was held on with 2mm Allen boltsThat all depends how the rear is threaded. Take care not to loose them! Drill/dremel this as well.

    How does the inner exit the frame under the chain stay? There may be another grommet type thing that will also need drilling out.

    Then run the outer all the way to the mech. Job done.

    Not a difficult job to do....once you've got your head round it.
  • david37david37 Posts: 143
    drilling out bits?????????? If you cant work it out, take it to a competent local bike shop. if you see one with teenagers working un supervised it's unlikely to be one where competent repairs are made.
  • paulbnixpaulbnix Posts: 466
    I recently changed the rear derailleur inner on my Synapse.
    After I had struggled and finished I realised how I should have done it.
    1) cut off the old inner at the derailleur
    2) pull it out of the chainstay
    3) remove both cable ports on the downtube - yes you will have to be able to do this
    4) push some outer over the old inner up the downtube out of the top cable port
    5) remove and replace the inner and feed it down the outer in the downtube
    6) pull the outer from the downtube and feed the new inner down the chainstay
  • whyamiherewhyamihere Posts: 7,246
    If you're ever likely to work with internal cables again, buy this: https://www.amazon.co.uk/Park-Tool-IR-1-2-Internal-Routing/dp/B01LZDE1UY

    Yes, it's expensive, but the amount of time I've saved doing internal cable routing with it makes it worth its weight in gold.

    If this is the only time you're ever likely to do it, get a strong magnet (this is one of the parts of the kit). It will attract the gear cable through the frame and allow you to guide it to the exit hole.
  • lesfirthlesfirth Posts: 999
    Before you get your drill out look on Youtube. There is lots of info there.
  • mr.b-campagmr.b-campag Posts: 203
    Thanks everyone. I'm definitely not drilling anything! As suggested I've managed to lever out the cable port. The hole at the end of the chainstay is plenty big enough and I've tried to run some cable outer over the existing cable (from both ends) but can't seem to get past the bb shell judging by the length that will go in.

    I'm wondering if this might partly be because the outer isn't running smoothly over the existing inner, but simply bending it? The solution would be to take the existing cable out (which is how the mechanic had to do it as I'd already removed the existing cable that time). But I'm nervous that then leaves me having to deal with magnets. vacuum cleaners etc. as per youtube/gcn.

    What do people think?
  • paulbnixpaulbnix Posts: 466
    In my case with the Synapse I removed the chainset before I started.
  • mr.b-campagmr.b-campag Posts: 203
    Thanks Paul,

    I've just moved house so don't have any space or my full toolkit to do much in the way of heavier maintenance. And the mechanic in Decathlon (the bike is a B'Twin Ultra 720AF) definetly didn't remove the chainset - I think I would have noticed that at least! :D

    If I can't do this does anyone recommend any bike shops in the Crystal Palace area that are both trustrworthy and open (obv. for lots of reasons I'd prefer to do this myself atm)? Cadence is closed. Anyone had any dealings with Blue Door Bicycles or can recommend others?

    B
  • photonic69photonic69 Posts: 994
    Hi. I re-cabled my son's Synapse recently. No drilling. No magnets. No removing cable ports or stops. Still a lot of faff though.

    Get yourself some Jagwire Slick Lube Liner - it's a thin white tube that it just slightly bigger than the inner cables (gear and brake).

    Disconnect inner from the rear derailleur. Cut cable crimp off. Remove short outer. Slide Lube Liner over the inner (still in place) and push all the way through to the Bottom Bracket, then feed up the Down Tube to the Head Tube and out the cable stop. Now pull the inner all the way through and out. Put new inner in the shifter and then thread through the Lube Liner all the way to the rear.

    You can trim the Lube Liner carefully and leave in place or extract it completely. If you leave it in place then make sure you don't cut or snag the inner with a blade and don't leave it too long else the outer won't sit snug in the cable stops.
    As per pic - I did all cables (brake/gears) inner and outer. Still took 3x longer than it would take me to do a traditionally cabled bike.



  • mr.b-campagmr.b-campag Posts: 203
    Thanks for the tip. I've just ordered some off the bay - hopefully it will arrive when they say it will (back end of next week). Still up for any other bright ideas in the meantime tho!
  • alihisgreatalihisgreat Posts: 3,872
    Agree with the above. This is the cable liner that i ordered and used to re-cable my Orbea Orca (complete re-cable inc. outers):

    https://amazon.co.uk/gp/product/B07JL9HFTD/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

    I ran it through the chainstay and the downtube in two different lengths (unlike photonic69 who seems to have used one length) as i found there can be a surprising amount of resistance through the liner tube, especially if you get any kinks or tight turns. I also found i needed to remove the BB cable guide which gives a little more space to play with.

    Took me ages the first time, as wanted to be careful with the BB guide, frame inserts etc. but was 10x quicker second time round once its clear how it all works.

    When i snapped a rear gear cable in the shifter, and only replaced the inner cable (not the outers), I also used the thread method with some success:

    - Tie a thread to the end of the current cable (if you google this method there is a specific knot that works well.. but the name escapes me)
    - Pull current cable out of bike (bringing thread through the internal routing)
    - Tape thread to make sure it doesn't fall out
    - Tie thread to new cable (using the fancy knot again)
    - Pull new cable through frame with thread

    Be careful to not pull the thread off the cable, and can be quite fiddly to get the cable through all the holes even though it is being guided by the thread. If you haven't left the old cable in, then you can pull a thread up through the frame with a vacuum cleaner.

  • mrdsgsmrdsgs Posts: 330
    the "lube liner" is just like the inner liner in gear or brake cable outer . If you have any spare/old gear cable outer it is an easy job with a stanley knife to salvage the outer cable inner liner, then you use that to slide over the end of your old gear inner cable working from derailleur forwards and leave this liner inside the frame to then guide the new gear inner back through starting at downtube. Quite easy to do once you have the knack.


    Colnago Addict!
  • mr.b-campagmr.b-campag Posts: 203
    Thanks mrdsgs,

    Unfortunately I just moved house and most of my stuff is in storage. Have ordered that liner and just hoping it arrives quickly and that this is as easy as you say!

    B
  • StillGoingStillGoing Posts: 5,153

    If you're ever likely to work with internal cables again, buy this: https://www.amazon.co.uk/Park-Tool-IR-1-2-Internal-Routing/dp/B01LZDE1UY

    Yes, it's expensive, but the amount of time I've saved doing internal cable routing with it makes it worth its weight in gold.

    If this is the only time you're ever likely to do it, get a strong magnet (this is one of the parts of the kit). It will attract the gear cable through the frame and allow you to guide it to the exit hole.

    Personally, I wouldn't bother with it. I had trouble routing cable inners for a customer in a Specialized Venge. Tried the Park Tool kit, but although it could pick the cables up from outside the downtime, it couldn't navigate the over the lumps inside and kept dropping connection. Couldn't tell if the cables when working from inside had been picked up and the odd time I did, it again couldn't navigate over the lumps and bumps inside. Eventually I used the magnet for the spoke nuts on Fulcrum wheels attached to a cable inner which did work.

    In your case though, you need the Jagwire internal housing or similar. Thread it over the old inner before removing the inner. You can then just insert the new inner without issue.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • whyamiherewhyamihere Posts: 7,246

    If you're ever likely to work with internal cables again, buy this: https://www.amazon.co.uk/Park-Tool-IR-1-2-Internal-Routing/dp/B01LZDE1UY

    Yes, it's expensive, but the amount of time I've saved doing internal cable routing with it makes it worth its weight in gold.

    If this is the only time you're ever likely to do it, get a strong magnet (this is one of the parts of the kit). It will attract the gear cable through the frame and allow you to guide it to the exit hole.

    Personally, I wouldn't bother with it. I had trouble routing cable inners for a customer in a Specialized Venge. Tried the Park Tool kit, but although it could pick the cables up from outside the downtime, it couldn't navigate the over the lumps inside and kept dropping connection. Couldn't tell if the cables when working from inside had been picked up and the odd time I did, it again couldn't navigate over the lumps and bumps inside. Eventually I used the magnet for the spoke nuts on Fulcrum wheels attached to a cable inner which did work.

    In your case though, you need the Jagwire internal housing or similar. Thread it over the old inner before removing the inner. You can then just insert the new inner without issue.
    Not intending to derail the thread, but that's where the included cables come in. You could in this situation use one with a magnet on it to go backwards through the routing path, with the stronger attraction to the larger magnet helping it keep connected, then pull the cable through on the cable's magnet rather than from the outside. Having said that, I've never cabled a Venge, so can't say for sure if the kit would help or not.
  • photonic69photonic69 Posts: 994
    I’ve used strong magnets to fish the end of a brake cable out of the top tube port on the Synapse. Useful things to have especially when doing loose ball bearings on hubs etc. Put it directly below the hub and when you drop a ball it will just stick to the magnets. Easy

    https://www.first4magnets.com/square-c36/12-x-12-x-12mm-thick-n42-neodymium-magnet-7-4kg-pull-p3489#ps_0_3588|ps_1_781
  • photonic69photonic69 Posts: 994
    I’ve used strong magnets to fish the end of a brake cable out of the top tube port on the Synapse. Useful things to have especially when doing loose ball bearings on hubs etc. Put it directly below the hub and when you drop a ball it will just stick to the magnets. Easy

    https://www.first4magnets.com/square-c36/12-x-12-x-12mm-thick-n42-neodymium-magnet-7-4kg-pull-p3489#ps_0_3588|ps_1_781
  • StillGoingStillGoing Posts: 5,153

    If you're ever likely to work with internal cables again, buy this: https://www.amazon.co.uk/Park-Tool-IR-1-2-Internal-Routing/dp/B01LZDE1UY

    Yes, it's expensive, but the amount of time I've saved doing internal cable routing with it makes it worth its weight in gold.

    If this is the only time you're ever likely to do it, get a strong magnet (this is one of the parts of the kit). It will attract the gear cable through the frame and allow you to guide it to the exit hole.

    Personally, I wouldn't bother with it. I had trouble routing cable inners for a customer in a Specialized Venge. Tried the Park Tool kit, but although it could pick the cables up from outside the downtime, it couldn't navigate the over the lumps inside and kept dropping connection. Couldn't tell if the cables when working from inside had been picked up and the odd time I did, it again couldn't navigate over the lumps and bumps inside. Eventually I used the magnet for the spoke nuts on Fulcrum wheels attached to a cable inner which did work.

    In your case though, you need the Jagwire internal housing or similar. Thread it over the old inner before removing the inner. You can then just insert the new inner without issue.
    Not intending to derail the thread, but that's where the included cables come in. You could in this situation use one with a magnet on it to go backwards through the routing path, with the stronger attraction to the larger magnet helping it keep connected, then pull the cable through on the cable's magnet rather than from the outside. Having said that, I've never cabled a Venge, so can't say for sure if the kit would help or not.
    As I said, I tried them having borrowed a set from someone and they didn't work no matter how I used them. Personally, I wouldn't waste my money on them.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • StillGoingStillGoing Posts: 5,153
    As an alternative, you can try the vacuum trick with a thread of cotton. Suck one end through the port using a vacuum and carefully tie the other end to your cable inner. With a combination of gentle push and pull, you can get the inner to feed through.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • mr.b-campagmr.b-campag Posts: 203
    edited 3 April
    Got the cable through, so thanks everyone for that. But more problems now (see other thread) :-(
  • kevin_stephenskevin_stephens Posts: 183
    For my bike I find it easier to cut off a small section of Bic biro refil and use it to joint the end of the new gear cable to the cut end of the old cable. The refill is only slightly wider than the inner cables and when the two ends overlap inside the refil are tight enough to use the old cable to pull the new cable through and small enough to fit through the ports
    I want to climb hills so badly;
    and I climb hills so badly
Sign In or Register to comment.