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Gear cable problem at Mens Shed.

Posted: Mon Feb 18, 2013 12:26 pm
by master6
The blokes at our mens shed think that I know everything about bicycles. How wrong they are. Road bikes are my thing, and I usually have no problem sorting out the village clunkers. There is no LBS in town, so people come to the shed for repairs.
Today we have a Repco clunker with broken gear cables. It is 7 speed, and has a twist type gear changer on the handlebars . It is labelled "Falcon Dyna Grip MLG 271"
My question is, can this shifter be dismantled to fit a new cable?

Re: Gear cable problem at Mens Shed.

Posted: Mon Feb 18, 2013 8:06 pm
by master6
umm...must be a tough one :(

Re: Gear cable problem at Mens Shed.

Posted: Mon Feb 18, 2013 8:29 pm
by barefoot
Grip-shifters (ie the twisty shiters that were very popular on ~'00s MTBs) come apart in a couple of different ways.

They are made up of two nested cylinders - the inner one clamps on to the bar, the outer one is a sleeve that rotates on the inner one. For the cheaper grip shifters in particular, you need to slide the outer sleeve off the inner sleeve - along the handlebar. There will probably be a ridge and groove arrangement so the assembly snaps together, and thus, will need to be snapped apart with some force and/or leverage.

The functional guts of the shifter are in the fat housing bit at the inner end of the shifter - make sure you take note of how the cable is looped around there when you disassemble it, because you'll have to re-assemble it the same way. It can be tricky getting the cable to sit in the right place while you stuff it into the housing and snap it together.

The higher-end grip-shifters usually had an access cover screwed on to the housing so you could get in and change a cable without separating the cylinders... but I reckon if it was one of these, you'd have figured that out ;-)

Good luck!

tim

Re: Gear cable problem at Mens Shed.

Posted: Mon Feb 18, 2013 10:29 pm
by drubie
The grip shifters are of a surprisingly diverse set of designs. One set I was handed (kids bike, broken cable) you didn't have to remove the shifter completely to access the cable but it did help.

I ended up removing them (just a grub screw), then winding the cable backwards until the slack bit poked out on the inner side of the grip shifter. Once you've got enough cable to grab on this particular set of Falcon shifters, you could maneuver the cable stop out of the shifter, but still had to wind the cable out bit by bit backwards. Replacement was just as painful. It's not exactly a difficult job but it is time consuming - look to the inside surface of the shifter (i.e. the opposite side of the grip) to see where the cable stop is captured and work backwards from there.

I did fix the shifter, but we ended up buying a set of cheap Microshift 7 speed units from ebay, which transformed that particular bike.

Re: Gear cable problem at Mens Shed.

Posted: Mon Feb 18, 2013 11:22 pm
by ironhanglider
barefoot wrote:Grip-shifters (ie the twisty shiters that were very popular on ~'00s MTBs) come apart in a couple of different ways.

They are made up of two nested cylinders - the inner one clamps on to the bar, the outer one is a sleeve that rotates on the inner one. For the cheaper grip shifters in particular, you need to slide the outer sleeve off the inner sleeve - along the handlebar. There will probably be a ridge and groove arrangement so the assembly snaps together, and thus, will need to be snapped apart with some force and/or leverage.
I haven't got much to add but frequently they only come apart at one end of the shifter travel. From memory it was in the small cog position. The 'Gripshift (tm)' design was very simple, a couple of bits of moulded plastic with an odd shaped spring for the ratcheting. Hopefully what you've got is a copy of that.
barefoot wrote:The functional guts of the shifter are in the fat housing bit at the inner end of the shifter - make sure you take note of how the cable is looped around there when you disassemble it, because you'll have to re-assemble it the same way. It can be tricky getting the cable to sit in the right place while you stuff it into the housing and snap it together.

The higher-end grip-shifters usually had an access cover screwed on to the housing so you could get in and change a cable without separating the cylinders... but I reckon if it was one of these, you'd have figured that out ;-)

Good luck!

tim
Cheers,

Cameron

Re: Gear cable problem at Mens Shed.

Posted: Tue Feb 19, 2013 8:24 am
by Mulger bill
Dunno if this is worth anything...
Somewhere in my mountain of old MTB magazines is an article on GripShift maintenance. I could dig it out, scan and email if you like.

Re: Gear cable problem at Mens Shed.

Posted: Tue Feb 19, 2013 8:55 am
by master6
Mulger bill wrote:Dunno if this is worth anything...
Somewhere in my mountain of old MTB magazines is an article on GripShift maintenance. I could dig it out, scan and email if you like.
Thanks Bill. I am going to the shed today, and will try the ideas suggested by barefoot. If still in trouble, I will get back to you.
Thanks,
Jeff