We just purchased a used eight speed specialized mountain bike, 24 inch wheels, for our kid. I’m no professional bike mechanic, but I have adjusted rear derailers for many years successfully by myself. I don’t know what’s wrong with this one though. Check out the videos and tell me if this is fixable or if the shifter simply needs to be replaced.
The derailleur moves freely by hand, and the cable appears to be in good condition, but maybe it is not moving freely in the housing? The shifter does not click seven times in each direction as one would expect for an eight speed shifter. Sometimes it is six sometimes it is five, hard to tell. There is a lot of resistance to turning it. I’m working at it with no back wheel on the bicycle so it’s not getting resistance from actual shifting. It also doesn’t work when I have somebody else hold the derailleur in the position that it would be in for the largest cog.
How can I tell if the internal mechanisms of the shifter itself are working correctly?
Issues with shimano shifter – kids bike
byu/neilweiler inbikewrench
by neilweiler
16 Comments
Honestly those generally aren’t worth tearing apart. Cheap and easy to replace the whole thing. Chances are something is broken internally that you can’t buy a replacement for.
I would replace cable and housing and fill the shifter full of a one step cleaner and lube
I would bet that cable and housing just needs to be replaced. From the video it looks a bit old. Probably a lot of galvanization going on keeping the cable from moving freely.
Should only do that whilst pedalling unless shifter is not connected
The whole shifter with cable costs 15 bucks and it’s easy to replace.
Stop shifting without pedalling!
My friend’s kid’s bike just had the same problem. Replacing the whole shifter is cheap and easier than replacing the cable on the twist shifters. I think it was $23 for the pair (front and rear shifter plus all cables and housing) for Shimano parts on Amazon
The cable stop inside these shifters is made of flexible plastic, they are notoriously shit. If I was you I’d replace this with an 8 speed Shimano trigger shifter, dream boat shifting afaic
Change the gear cable – both inner and outer. Adjust as necessary afterwards.
Replace the frayed cable and spray all moving parts with lubricant of your choice… not water based lol
My gfs old Shimano Altus(?) shifter had the same issue. Bike was sitting for a long time and not being used. Sprayed some WD40 all up in the shifter mech to wash out the old crud and grease, and let it sit for a couple hours. Worked flawlessly after. Give that a try first.
Just before we go all technical etc is the adjustment stop on the derailleur wound out enough to allow it to shift, just wondered if it had a knock
The barrel adjuster is all the way in. You could have tried that, before you replaced the cable.
Take the cable off the derailleur by unscrewing the nut. Now that the cable is loose, try shifting. If it still doesn’t shift, the problem is in the shifter. Spray some lubricant and it will work again. I like to use a solvent like wd40 then silicone spray to leave a lasting lubrication. If it shifts, the problem is in the cable. Run the cable through the housing to check for friction. Then replace the cable. If there’s still friction you also need to replace the housing. Note that you need a housing cutter and a pick (to open the housing), you can’t just use a cable cutter (you can use it on the cable, though.
Replace the shifter with a compatible trigger shifter. Your kid will love you for that. Cable and housing have to go too.
Cable isuue