Chain won't shift to large chainring (Tiagra)...

[Mazz]

My bike's just come back from repair after an accident (rear wheel and brakes replacement). They've made some adjustments to the gear cables - now it's practically impossible to change from the small chainring to big by single hand strength alone (Shimano Tiagra groupset) -I need to dismount then use 2 hands , which (not surprisingly) is very inconvenient. Honestly thought I was going to snap the gear cable I had to use so much force.

Is it a case of slackening off the cable at the front derailleur gripping bolt and retightening? Looks like the barrel adjuster is fully wound in so I can't use that?

Alternatively it's back to the shop, let them sort it.

Thanks

 

[Paulus]

It could be that the adjuster stop needs a tweak to allow the mech to go over far enough.

 

[figbat]

It could be that the adjuster stop needs a tweak to allow the mech to go over far enough.

This would be my first port of call - the upper limit screw. Gently does it, little tweaks at a time with a test ride in between. I find that a ride is required to see if it all works - a bike that changes perfectly on the workshop stand can sometimes be off when under power.

 

[Mazz]

Cheers for the replies...this is the bit I am bound to get wrong. Which of the screws is it and in which direction should it be turned? I'll try find a diagram I think.

 

[roubaixtuesday]

The High stop is the one you want, marked with an H.

Undo it half a turn at a time.

If uncertain, you can always undo them both a couple of turns, to see if it makes a difference at all, then wind back to base position before making sure you've got the right one.

 

[Vapin' Joe]

Front mech adjuster stops are not generally marked. If yours isn't, upend the bike and you will see the screw which is butting against the stop when you try to shift, this being the one to tweak.

 

[Mazz]

The High stop is the one you want, marked with an H.

Undo it half a turn at a time.

If uncertain, you can always undo them both a couple of turns, to see if it makes a difference at all, then wind back to base position before making sure you've got the right one.

Yes mate thanks. No H or L marks on mine but a quick video showed me it's the screw furthest from the bike's Centreline. Some short turns anticlockwise seems to have done the job but I'll find out when riding tomorrow.

 

[Once a Wheeler]

I once had this problem and it turned out to be caused by an obstruction in the cable feed. Take out the inner cable and give it a good oiling. Pull through a bit of old cable with a twist of fabric in the frayed end and make sure it passes smoothly. Doing this, I found a short section of a single strand of wire had become jammed in the outer cable. I was able to get a pair of pliars on to it, pulled it out and after that all was sweet and smooth. Good luck.

 

[Ming the Merciless]

It could be because your front derailleur is filthy. A clean and a couple of drops of oil wouldn‘t do any harm in easing the force needed.

 

[Mazz]

Seemed to working fine on the ride this morning.
I was a bit surprised that by them replacing the rear wheel, that the front derailleur mech was affected - although that might be down to the impact with the car/road as the bike fell onto the drivetrain. Maybe that messed up the front derailleur settings. No idea.

 

[Ajax Bay]

The main resistance (not including the hard stop of a limit screw) is friction in particular underneath the bottom bracket shell (for external cable routing). A frequent clean and push some grease on the cable there is recommended - any more than that requires unclamping: to be avoided if everything's adjusted OK.

 

[cyberknight]

what version of tiagra ? the newer models route the cable differently to way you have it in the picture .

 

[Mazz]

what version of tiagra ? the newer models route the cable differently to way you have it in the picture .

Not sure what version of Tiagra, but bike frame is Specialized Allez Elite from 2013, I think.

 

[Mazz]

The main resistance (not including the hard stop of a limit screw) is friction in particular underneath the bottom bracket shell (for external cable routing). A frequent clean and push some grease on the cable there is recommended - any more than that requires unclamping: to be avoided if everything's adjusted OK.

Yes mate, I flipped the bike over to look at the cable runs under the BB. It was a mess, but I've cleaned and greased it now. Bang on, smoothness of shifting has improved significantly, cheers.

 

[Webbo2]

Not sure what version of Tiagra, but bike frame is Specialized Allez Elite from 2013, I think.

Looking at the picture it looks like no one’s cleaned it since 2013.😉