Shifter problems

[jaykoo511]

OK. So my nephews gave me two identical bikes for my kids. They were in bad shape and I had to do some major clean up/parts replacements.

One of the things that I replaced were the cables and the housing for the shifters. These are 21 speed grip twist shifters. I watched the videos about 20 times and seem to have gotten most of the shifting to work. The bike has no issues shifting - the chain does not touch the cage or anything (except for the normally not used chainring-cog combo) Here is the problem. Once the bike is on the ground, it takes much more strengths than what a kid would have to shift to the biggest chainring. If I turn the grip shifters, I can get it to go into the largest chainring but it seems that it would be very difficult for a kid to do the same. I am having the identical problem on two identical models of bikes leading me to believe that I am doing something wrong.

BTW, I did clean and lube the inside of the shifters and did put white lightening dry lube on the derailleur springs. I am a newbie when it comes to bike servicing and any help would be greatly appreciated.

[cyclerUK]

Some "twist grip" shifters are renowned for being hard to turn.
Beyond making sure everything is free and lubed there's not much else you can do.
The obvious answer is to change them, perhaps for thumb shifters. (or Rapidfire type).
I have seen a mod where some one increased the diameter of the twist bit but maybe to much for small hands??

[jaykoo511]

Thanks cyclerUK for your input. I asked my nephews and they said that they could shift to largest chain-ring when they had the bikes. I have no way of knowing since I took it apart without first trying the shifters. Also, since these are kid's bikes I have hard time believing that they would have been difficult to shift into the highest gear when they were new. It's not that they will not shift... It's just that they need a lot of force to "twist into "3" for the largest chain-ring... If it helps, the twist-shifters are Shimano and so are the front (and rear) derailleur.

[Bill]

I can tell that some of the twist grip shifters are more or less lower end cheap made for department store bikes. Yes even shimano made cheap shifters. The idea for them is while the bike is in motion they are easier to shift when pedaling. After a while the spring (actually it is a piece of bent metal) loses its correct bend and makes it hard to shift over time. The other thing I can thing of is the grip being butted up against to close to the shifter which causes some friction. As cycleruk said above the only real way to fix it other then what I said is to upgrade them to a nicer shifter. Sorry I can't give any better advice but as with anything they breakdown over a period of time.

Good luck ,
Bill

[jaykoo511]

Thanks Bill. I'll probably change the shifters as you both recommend. Hopefully the new cables will still[/align] be long enough with the click shifters.

[Bill]

(05-01-2010, 12:05 AM)jaykoo511 Wrote:  Thanks Bill. I'll probably change the shifters as you both recommend. Hopefully the new cables will still[/align] be long enough with the click shifters.

Depending on what kind you get you "should" (key word lol) have a little extra left over, because with grip/twist shifters the cable is looped once around shown in alex's vid tutorial. If you do have more then enough always trim it at the derailler end of the cable .


Bill