Ribble/Ultegra front mech difficulties

[StefE]

I have a Ribble New Sportive Racing and I've never been happy with the front mech change, ie it's difficult to change up and snaps back violently on changing down because the cable is so, so tight.

I've checked the lever, cables, outer cables, mech etc. and all move fine and free and easy., but the tension seems to be coming from where the cable goes through the plastic guide under the BB and then through the hole in the frame. The angle seems extreme, something close to 90 degrees and the cable is developing a kink after around 30 mins use. I changed the cable but the same thing happened.

Ribble say it's not a normal problem and are sending me a plastic straw insert for the section through the BB shell which they think/say will help but I'm not so sure as it won't change the angle that the cable has to try and bend round. Hopefully it'll arrive today and the problem will magically disappear but I don't think so.

Does anyone have any ideas? It's driving me insane.....

 

[dabac]

There are pulley clamps available, for those who want to use bottom pull derailers with frames intended for top pull routing. If all else fails you might be able to get one of those and bypass the BB shell. With a pulley, a 90 deg change isn't much to worry about.

 

[StefE]

Thanks for the response but I'm not sure I follow as both the frame and the front mech are both designed for bottom pull, but I'll have a look to see if I can find a pulley clamp and see if that helps.

 

[alienator]

Go to Ribble and show them the problem. You could also try posting picture here. How long have you had the bike?

 

[StefE]

Hi Alienator and thanks for the response. Ribble are sending me a straw insert which they say will cure it but I'm not sure. If you look at the photo where the cable goes into the frame, the angle is very abrupt and close to 90 degrees which MUST add immeasurable friction but they say it's normal and they also say the cable guide is the correct length. i thought of geting a longer one which ends closer to the hole to lessen the angle but wouldn't know where to start. I would take it to Ribble as it's only 6 months old but it's a 4 hour roundtrip sadly. Any suggestions to this tedious problem would be welcomed and very much appreciated!

 

[alienator]

Hi Alienator and thanks for the response. Ribble are sending me a straw insert which they say will cure it but I'm not sure. If you look at the photo where the cable goes into the frame, the angle is very abrupt and close to 90 degrees which MUST add immeasurable friction but they say it's normal and they also say the cable guide is the correct length. i thought of geting a longer one which ends closer to the hole to lessen the angle but wouldn't know where to start. I would take it to Ribble as it's only 6 months old but it's a 4 hour roundtrip sadly. Any suggestions to this tedious problem would be welcomed and very much appreciated!

Your cable guide looks like it has seen better days. The straw, as they call it, is common. The image below shows something similar. If you follow the cable on the right you'll notice that shortly after the cable guide, the plastic inner cable liner (a specific feature of the bike in the picture) makes a sharp turn into the BB shell. That inner cable liner is akin to the "straw" you'll get. No matter, the straw will help once everything else is sorted. By everything, I mean the cable itself. If the cable is kinked, it needs replaced, otherwise the kink will just cause more drag in that "straw". It's possible perhaps likely that it was kinked on the initial installation. It happens if the person doing the install doesn't pay attention.

 

[StefE]

Thanks, that's helpful. The kink in the cable was caused by the abrupt angle and I've replaced it and the same's happened with the new one. Will try another when the straw arrives. The cable guide shouldn't have seen better days as it's only done about 900km and is less than 6 months old. I might look at replacing it anyway. If it doesn't work, i guess it's a 4 hour round-trip to Ribble. Oh joy....

 

[alienator]

If the bend is causing the cable to kink, you might want to re-do the front derailleur setup to insure that the cable is not too tight. When on the small chain ring, the front derailleur cable should have very little--in fact, almost none--tension on it.

 

[StefE]

ok thanks, that's very useful. I'll give it a go.....all advice very much appreciated.

 

[dabac]

Originally Posted by StefE .

Thanks for the response but I'm not sure I follow as both the frame and the front mech are both designed for bottom pull, but I'll have a look to see if I can find a pulley clamp and see if that helps.

Fitting a bottom pull adapter - although your bike is set up for bottom pull - means that you can route the cable above the bb, around a nice, round pulley instead of running it over that sharp corner that you suspect is causing your problem.

Here's a nice pic:http://problemsolversbike.com/products/cross_clamps_pulleys/

 

[alienator]

Fitting a bottom pull adapter - although your bike is set up for bottom pull - means that you can route the cable above the bb, around a nice, round pulley instead of running it over that sharp corner that you suspect is causing your problem. Here's a nice pic:http://problemsolversbike.com/products/cross_clamps_pulleys/

....IF his bike's design is amenable to such a modification.

 

[dhk2]

That cable routing isn't right on your frame. The cable guide needs to ends right at the hole, so the cable is "lead into" the hole and not subject to a hard bend
like you've got. I think the problem is that the cable guide is too short, or the hole in the stay is drilled in the wrong place. Either way, Ribble needs
to fix this problem by furnishing the correct guide, or drilling another hole. You paid good money for a quality frame and shouldn't have to accept this obvious mistake.
This is a "manufacturing defect" that is covered by your lifetime warranty. Don't know anything about Ribble bikes, or your LBS, but IMO both should be doing better than this.

Take a look at some other bikes to see how it should be done. When you go back to your dealer, ask them to look at other bikes they have in stock to illustrate correct
cable routing. On a new Trek Madone 5.2 I looked at today, the cable guide is "built in" to the bottom of the frame, so the guide channel actually provides a full-radius bend for the cable.

Here's a photo of my bike to illustrate:

 

[alienator]

That cable routing isn't right on your frame.  The cable guide needs to ends right at the hole, so the cable is "lead into" the hole and not subject to a hard bend like you've got.  I think the problem is that the cable guide is too short, or the hole in the stay is drilled in the wrong place.   Either way, Ribble needs to fix this problem by furnishing the correct guide, or drilling another hole.   You paid good money for a quality frame and shouldn't have to accept this obvious mistake.    This is a "manufacturing defect" that is covered by your lifetime warranty.  Don't know anything about Ribble bikes, or your LBS, but IMO both should be doing better than this.     Take a look at some other bikes to see how it should be done.   When you go back to your dealer, ask them to look at other bikes they have in stock to illustrate correct cable routing.  On a new Trek Madone 5.2 I looked at today, the cable guide is "built in" to the bottom of the frame, so the guide channel actually provides a full-radius bend for the cable.  Here's a photo of my bike to illustrate: 

Good call. I didn't notice that.

 

[dhk2]

Wonder if StefE has seen my reply. Always a disappointment when I think I've posted something helpful (which addmittely isn't all that often) and then the OP doesn't bother to read or reply.

 

[James Donovan]

Thanks for the response but I'm not sure I follow as both the frame and the front mech are both designed for bottom pull, but I'll have a look to see if I can find a pulley clamp and see if that helps.

 

[dabac]

Originally Posted by James Donovan .

Thanks for the response but I'm not sure I follow as both the frame and the front mech are both designed for bottom pull, but I'll have a look to see if I can find a pulley clamp and see if that helps.

Well, there's the plan, and then there's the execution of the plan. Sometimes they're not the same.
As suggested by DHK, maybe your frame got drilled wrong.
Anyhow, you've tried replacing the cable, and the new one kinks/fails at the same spot. It'd be amazingly unlikely that the cable is to blame.
So something's off with your bike. No matter what it was designed for, it's apparently not doing its job.
If you want to get it working, it'll have to be fixed. The fact that it's supposed to work as-is when reality tells you that it doesn't isn't much help.
Either keep pursuing it as a warranty issue, or start tinkering.
A pulley clamp, if it fits your seat tube, will do away with the sharp bend that's fraying your cable.

 

[alfeng]

Quote:Originally Posted by StefE .

Any suggestions to this tedious problem would be welcomed and very much appreciated!


DARN!?!

Well, this may-or-may-not be stating the obvious, but by MY reckoning (without seeing the complete frame), YOU may be using the frame holes which are intended for routing Di2-or-EPS wiring ...

And so, you may want to explore the option of routing your FRONT (and, ¿REAR?) cable(s) on the outside of the downtube instead of internally ...

Or, not!?!

THE dodgy alternative would be to drill a NEW hole about an inch further away from the under-BB cable guide for the Front derailleur cable.

 

[dabac]

Originally Posted by StefE .



Hi Alienator and thanks for the response. Ribble are sending me a straw insert which they say will cure it but I'm not sure. If you look at the photo where the cable goes into the frame, the angle is very abrupt and close to 90 degrees which MUST add immeasurable friction but they say it's normal and they also say the cable guide is the correct length. i thought of geting a longer one which ends closer to the hole to lessen the angle but wouldn't know where to start. I would take it to Ribble as it's only 6 months old but it's a 4 hour roundtrip sadly. Any suggestions to this tedious problem would be welcomed and very much appreciated!

Looking at that pic again, prompted by alfeng's post - I can't really tell with the shadow and the glare - but isn't there another hole, right at the end of the cable guide? Something like 8-10 mm forward of where the cable is routed in the pic. Would explain it all rather nicely.

 

[dhk2]

I can't really see the hole you're talking about, but that's where it needs to be. Again, the buyer shouldn't have to worry about how to fix it. The product as delivered is defective, so either the LBS or the manufacturer needs to correct the cable routing. As I said, it's sad that a new bike is delivered like this. Didn't the LBS even bother to test ride the bike?