Swapping wheels - gear problems

Herbsman

Anybody know anything about this? I have one pair of wheels for racing and one for training. I have been swapping each pair in and out every week without any problems until recently when I put a new inner cable in.

I adjusted the cable tension so the gears shift perfectly on the racing wheels, but then when I put the training wheels in the gears are all over the place.

Both wheels have exactly the same cassette, both cassettes are the same age (about 2 months old, same age as the chain) but obviously the one on the training wheels gets used more often.

Never had this problem before... What could be causing this? Is it just a case of more wear on the training wheels' cassette?

ugo.santalucia

I fear you have not done a good job... check again. When indexing, always start from the middle sprocket... the jockey wheels need to be perfectly aligned under the sprocket

smidsy

Also it is unlikely that both sets of wheels are aligned exactly the same, even if they are running the same cassette.

The spacings on the hub and freewheel may not match exactly so it is not unusual to have to tinker when swapping between sets.

A few turns of the barrell adjuster should sort it assuming everything else is set up/installed properly.

Herbsman

ugo.santalucia wrote:

When indexing, always start from the middle sprocket...

Never heard this before... will give it a go ta.

ugo.santalucia

Herbsman wrote:

ugo.santalucia wrote:

When indexing, always start from the middle sprocket...

Never heard this before... will give it a go ta.

It is written in any Campagnolo derailleur manual... in this respect Shimano is no different... it makes a lot of sense if you think about it

smidsy

The idea being that if you put the chain on the middle of the cassette it puts it in a neutral position.

i.e pretty straight and with a decent amount of tension in the chain but not overly stressed. This provides the best base from which to set things up.

Herbsman

WHat if I had 10 speed? No 'middle' sprocket ;-)

declan1

Try this from Park Tool - it's the best method I've ever tried.

Index Setting
Set limit screws (if not already done).
Shift chain to outermost rear sprocket (smallest). Shift chain to outermost (largest) chainring in front.
Test initial inner wire tension. Pedal a normal cadence and shift rear derailleur with one click on lever. Use care to only move lever one position. If derailleur moves one sprocket, tension is adequate.
If derailleur fails to shift one sprocket, inner wire may be too slack. Turn barrel adjuster fully into derailleur body (or shift lever) then turn counter clockwise two turns to allow for index adjustments. Loosen inner wire pinch bolt and gently pull on inner wire with fourth hand tool or pliers to remove slack. Tighten inner wire pinch bolt.
If derailleur will not shift one sprocket after removing slack in "d", return lever back to outermost sprocket position and increase inner wire tension by turning barrel adjuster counter-clockwise 1/4 turn and attempt shift again.
Shift to second sprocket in rear. Pedal and increase inner wire tension by continuing to turn adjusting barrel counter-clockwise until a definite rattling is heard. Rattle is from chain scrapping against next sprocket.
Once a too-tight rattle is achieved, turn barrel adjuster 1/4 turn clockwise, to release inner wire tension, and pedal again. Listen and look for signs of scraping or rattling. Continue turning barrel adjuster 1/4 turn clockwise at a time until rattle disappears.
Shift derailleur one sprocket inward at a time, listening for signs of rattle, indicating a too tight inner wire. Turn adjusting barrel 1/4 turn clockwise to eliminate rattle. Note: Do not attempt shift to largest rear sprocket while in largest front sprocket. This gear is normally not used and adjusting tension to this shift may compromise other commonly used gears.
Shift to innermost (smallest) chainring and check gears again. If no rattling is present, index adjustment is done.

Herbsman

Already use that guide, ta.