My bike is haunted!

On Tuesday, September 3, 2013 11:08:28 AM UTC-4, Ian Field wrote:
After all the weird goings on with the brakes, I now have something odd

going on with the gear twistgrip.



The old SRAM grip broke so I bought a new one (same make - later model). The

grip came complete with a length of cable inner, it was too much trouble to

unthread it all so I could re-use the recently replaced inner already there,

so I fitted the cable with the new inner.



After setting up the adjustment I now find if I'm going along in 7th - I

have to shift down 3 clicks before the chain shifts.



It takes at least 2 clicks at once to change into top - so the cable isn't

too slack.



Thanks for any help.

If the cable is in the right position on the rear gear changer then it has to be something else.

Just some ideas that might help.

Is the derailleur hanger bent? Has the bike fallen over on that side recently?

My understanding is that you only replaced the inner cable. Correct?

Is the inner cable the same diameter as the one you removed?

Does the cable move freely both ways when not attached to the rear gear changer/derailleur?

Is the housing SIS housing - that is with longitudinal strands of wire? NOT spiral wound like bake housing.

Are the ferrules at the ends of the housing metal?

Are the openings of the ferrules smooth and not worn?

I's try attaching the gear cable to the derailleur and then shift the it to the 4th rear sprocket. Adjust up and down so that each shift to the net cog is precise = no chatter when in gear. That way any accumulated error is reduced more than if the adjustment/setting is done on the smallest rar cog.

After adjusting everything use your thumb against the derailleur to make sure it can't overshift into the spokes or off the smallest cog.

You might try reading this for a better understanding of how to adjust the derailleur:

http://sheldonbrown.com/derailer-adjustment.html

Hope something helps. Let us know if you need more help.

Cheers

On 9/4/2013 12:14 PM, Ian Field wrote:
The label on the rear shifter is "xxx Megaranger" - the xxx could
possibly be SIS.

"MegaRange" is the name Shimano uses for cassettes with a 34T large cog
and compatible components.

--
T0m $herm@n

"Sir Ridesalot" wrote in message
...
On Tuesday, September 3, 2013 11:08:28 AM UTC-4, Ian Field wrote:
After all the weird goings on with the brakes, I now have something odd

going on with the gear twistgrip.



The old SRAM grip broke so I bought a new one (same make - later model).
The

grip came complete with a length of cable inner, it was too much trouble
to

unthread it all so I could re-use the recently replaced inner already
there,

so I fitted the cable with the new inner.



After setting up the adjustment I now find if I'm going along in 7th - I

have to shift down 3 clicks before the chain shifts.



It takes at least 2 clicks at once to change into top - so the cable
isn't

too slack.



Thanks for any help.

If the cable is in the right position on the rear gear changer then it has
to be something else.

Just some ideas that might help.

Is the derailleur hanger bent? Has the bike fallen over on that side
recently?

My understanding is that you only replaced the inner cable. Correct?

Is the inner cable the same diameter as the one you removed?

Does the cable move freely both ways when not attached to the rear gear
changer/derailleur?

Is the housing SIS housing - that is with longitudinal strands of wire?
NOT spiral wound like bake housing.

Are the ferrules at the ends of the housing metal?

Are the openings of the ferrules smooth and not worn?

I's try attaching the gear cable to the derailleur and then shift the it
to the 4th rear sprocket. Adjust up and down so that each shift to the net
cog is precise = no chatter when in gear. That way any accumulated error
is reduced more than if the adjustment/setting is done on the smallest rar
cog.

After adjusting everything use your thumb against the derailleur to make
sure it can't overshift into the spokes or off the smallest cog.

The 1st gear problem is sorted, I pushed it against the stop and adjusted so
the chain was centered on the sprocket - apparently pushing it by hand is
easier than pulling it with the cable, once I backed off the screw a single
turn it gets 1st no problem.

When I replaced the inner (yet again!) I noticed that the final loop of
outer to the gear was fraying at one end - all of the outer has now been
replaced.

The bike was scrounged on Freecycle over a year ago and was pretty tatty
when I got it, I'm thinking general wear problems - maybe the spring has
gotten weak with age, Is this something I can actually get at to replace?

On Thursday, September 5, 2013 10:35:44 AM UTC-4, Ian Field wrote:


The bike was scrounged on Freecycle over a year ago and was pretty tatty
when I got it, I'm thinking general wear problems - maybe the spring has
gotten weak with age, Is this something I can actually get at to replace?

I think it's highly unlikely that a derailleur spring would get noticeably weak with age on any bike seeing normal use. I'd look first for friction in all the various pivots and sliding surfaces.

- Frank Krygowski

"Frank Krygowski" wrote in message
...
On Thursday, September 5, 2013 10:35:44 AM UTC-4, Ian Field wrote:


The bike was scrounged on Freecycle over a year ago and was pretty tatty
when I got it, I'm thinking general wear problems - maybe the spring has
gotten weak with age, Is this something I can actually get at to replace?

I think it's highly unlikely that a derailleur spring would get noticeably
weak with age on any bike seeing normal use. I'd look first for friction
in all the various pivots and sliding surfaces.

It seems to move freely enough, when I clean it I don't use solvent - I use
a stiff brush soaked in new engine oil to dilute the grime.

DETACH N REATTACH CABLE PULLING CABLE TIGHT WITH SMALL VISE GRIPS, CLEAN HOLD SCREW FLOWED WITH RED LOCTITE. LET CURE. THEN GO BACK TO THE LEVERS, ROTATE WHEEL N SHIFT. WATCH THE CABLE END. DOES THE CABLE END MOVE WITH THE LEVER ?

IF THE CABLE HAS EVEN A SMALL KINK IN AREAS WHERE CABLE CURVES THEN PROB IS THERE.
IF YOU FIND A KINKED CURVE, WOEKING IT OUT BENDING BACKWARDS, MIDDLE TO EITER SIDE MAY CURE THE PROB BUT BUYING A NEW CABLE IS BEST.

CHECK CABLE TENSION AFTER FIRST PARAGRAPH, INCREASE THEN DECREASE TENSION WHILE SHIFTING TO CHECK EFFECTS.

CLEAN CABLE AGAIN WITH THNNER THEN ISOPROPYL. COAT WITH FINISH LINE DRY LUBE SHAKEN WELL.

CLEAN HOUSING WITH THINNER. CURVE HOUSING, DRIP IN THNNER DOWN A BROKEN SPOKE WITH CURVE AS RESERVOIR. LET SOAK OVERNIGHT. PT CABLE IN N PULL BACKN FORTH FOR 2-3 HOURS. FLUSH HOUSING WITH THINNNER. RECLEAN CABLE N LUBE. LUBE HOUSING WIT FL.

INSERT CABLE N GO BACK TO PARAGRAPH ONE.

"T0m $herman" wrote in message
...
On 9/4/2013 12:14 PM, Ian Field wrote:
The label on the rear shifter is "xxx Megaranger" - the xxx could
possibly be SIS.

"MegaRange" is the name Shimano uses for cassettes with a 34T large cog
and compatible components.

Can the sprocket stack be stripped down so I can replace only the worst worn
sprockets?

Getting the smallest 7th gear sprocket that will fit that freewheel hub
might be an option, and maybe an extra tooth or 2 on the 1st gear sprocket.