Rear mech shifting trouble

cdaly_

I'm running a sora 8-sp rear mech with tiagra 9-sp shifter and cassette but lately I'm having a bit of trouble with gear shifts. (bike was a sora 8-sp hybrid until I did a drops conversion using 9-sp tiagra shifters).

Having set the limit screws correctly, set the shifter to the second sprocket position and adjusted the cable I end up with one of two options:

1. I can shift down with a single push of the lever but shifting up needs two clicks and a push.
2. I can shift up with a single click but shifting down requires 1.5 pushes of the lever

I've done a bunch of fiddling around with the cable adjuster but cannot get it to the correct one push / one click change. It's almost there but not quite.

Possibilities I can think of are

1. Bent hanger (I did crash off the bike at speed about a year ago but not since then and I would have thought I would have seen the issue back then)
2. Worn jockey wheels. Bike has about 20,000km on it at this stage

Thoughts?

07Lapierre

cdaly_ wrote: »

I'm running a sora 8-sp rear mech with tiagra 9-sp shifter and cassette but lately I'm having a bit of trouble with gear shifts. (bike was a sora 8-sp hybrid until I did a drops conversion using 9-sp tiagra shifters).

Having set the limit screws correctly, set the shifter to the second sprocket position and adjusted the cable I end up with one of two options:

1. I can shift down with a single push of the lever but shifting up needs two clicks and a push.
2. I can shift up with a single click but shifting down requires 1.5 pushes of the lever

I've done a bunch of fiddling around with the cable adjuster but cannot get it to the correct one push / one click change. It's almost there but not quite.

Possibilities I can think of are

1. Bent hanger (I did crash off the bike at speed about a year ago but not since then and I would have thought I would have seen the issue back then)
2. Worn jockey wheels. Bike has about 20,000km on it at this stage

Thoughts?

I imagine you need a new rear mech ( 20,000km??)

Is there much "free play" in the rear mech? To work correctly, there shouldn't be any sideways movement. e.g. the jockey wheel cage should only move up and down, it should not have any sideways movement.

ednwireland

having just benrt and straightened a hanger, i can shift but am not getting rattle free gears looks like the jockey are out of true to the mech (waiting on new mech from CRC)

cdaly_

So, looking at the tiagra mech, I have to consider a GS (medium) or SS (short) cage and I'm confused...

• Pulley Cage: SS/GS
• Max Front Difference 16T (SS)/22T(GS)
• Total Capacity 31T (SS)/37T(GS)
• Max Rear Sprocket: 27T

So, I'm running a 52/42/30 triple so is that a front difference of 22T and therefore requires a GS?
Max rear sprocket 27T but I'm running a 28T (and used to run a 30T).
What does the Total capacity mean?

07Lapierre

You'll need the Long Cage (GS). the chain on your bike is longer than a "standard" ( Double chainset 52/39 and 25/12 cassette).

I've a triple chainset and a long cage is what you need.

cdaly_

Only free play I can see / feel is the upper jockey wheel moves side to side when I wiggle it. I presume that would be sufficient...

07Lapierre

cdaly_ wrote: »

Only free play I can see / feel is the upper jockey wheel moves side to side when I wiggle it. I presume that would be sufficient...

It could be yes. Especially with triple chainsets. I had a similar problem before and I changed the rear mech and fitted a new chain. Problem solved.

cdaly_

So, new tiagra mech ordered. Chain and cassette are pretty recent...

DirkVoodoo

cdaly_ wrote: »

Only free play I can see / feel is the upper jockey wheel moves side to side when I wiggle it. I presume that would be sufficient...

Perfectly normal, the guide pulley is designed to move from side to side on it's bushing to allow better shifting.

cdaly_

Ah bother! Gonna have to review...

cdaly_

So, new mech arrived today.

I took off the old mech (sora 8-sp) and wiggled it about. A lot of play in the parallelogram pivots.

Fitted the new mech and adjusted but I still have shifting issues. Now I start to wonder am I shifting wrongly? If I push the lever over until it just clicks, I sometimes don't get a shift down unless I push the lever over a bit more. OTOH, a click of the change up lever responds instantly.

I took off the hanger for inspection but it looks straight and has no cracks or such.

Only other thing is the shifter itself. A second-hand tiagra shifter, not sure how old and I've no idea how these shifters fail...

lescol

I would open the quick release of the front brake, pull the lever and spray the insides of the shifter with WD40, click up and down the range quickly. Also turn the cable tension screw on the derailleur a quarter turn anticlockwise. Then ride to check the shifting again.

You're not doing anything wrong with the gear shifting, each click should produce a gear change.

Also, are the cables running freely?

cdaly_

Hmm. Will try WD40 suggestion, sounds good. Cables seem to be running free. Oiled them up a week ago while servicing. I have a new cable but I'm not fitting that today with the Tour of Louth tomorrow. How long does a gear cable take to stretch anyhow?

07Lapierre

cdaly_ wrote: »

So, new mech arrived today.

I took off the old mech (sora 8-sp) and wiggled it about. A lot of play in the parallelogram pivots.

Fitted the new mech and adjusted but I still have shifting issues. Now I start to wonder am I shifting wrongly? If I push the lever over until it just clicks, I sometimes don't get a shift down unless I push the lever over a bit more. OTOH, a click of the change up lever responds instantly.

I took off the hanger for inspection but it looks straight and has no cracks or such.

Only other thing is the shifter itself. A second-hand tiagra shifter, not sure how old and I've no idea how these shifters fail...

U sure you've adjusted it correctly?

when the chain is on the smallest sprocket..when you push the (one click)lever, does the chain move to the next sprocket without clicking/skipping?

cdaly_

So, all through the Tour of Louth it was a bit iffy. I'd have to trim to get a gear change.

Fitted the new cable last night and replaced the rear sleeve and it seems to be behaving a bit better now. Maybe sticking cable was at fault.

Will keep an eye.

I noticed a screw in the top of the shifter and I'm wondering what that does. If you pull the brake and look down you see the screw head. Maybe that adjusts the per index distance. Couldn't find anything in the shimano docs though.

07Lapierre

cdaly_ wrote: »

So, all through the Tour of Louth it was a bit iffy. I'd have to trim to get a gear change.

Fitted the new cable last night and replaced the rear sleeve and it seems to be behaving a bit better now. Maybe sticking cable was at fault.

Will keep an eye.

I noticed a screw in the top of the shifter and I'm wondering what that does. If you pull the brake and look down you see the screw head. Maybe that adjusts the per index distance. Couldn't find anything in the shimano docs though.

The screw in the lever hood adjusts the "reach" for the lever. If you've small hands, turning the screw moves the brake lever closer to the handlebars.

sorry this refers to Sora shifters...apologies for the confusion..

bcmf

As far as I remember the screw head you see is only for a cover. If you changed your cable and its slightly better then change your housing as well. It can make a big difference.

07Lapierre

bcmf wrote: »

As far as I remember the screw head you see is only for a cover. If you changed your cable and its slightly better then change your housing as well. It can make a big difference.

This Might Help...

http://techdocs.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/ST/EV-ST-4400-1885_v1_m56577569830612343.pdf

bcmf

It was screw that is marked 3 on that linky I was reffering to.

cdaly_

Screw is pointing straight down and doesn't seem to hold a cover. It exists on both left and right hand levers.

When I fitted the new cable I changed the housing at the derailleur and things are improved today. Might change the housing at the levers also.

I notice (after mistakenly fitting a brake cable that gear cable is thinner than brake cable. Should I be using thinner housing too? Would that account for any of this issue? I would suspect not as the cable is pretty much permanently under tension.

Gavin

Gear outer cable is different to brake outer cable.
http://www.sheldonbrown.com/cables.html

ednwireland

20 mins with one of these

http://www.wiggle.co.uk/p/cycle/7/Cyclus_Gear_Hanger_Alignment_Tool/5300003490/



and my shifting is pretty close to perfect