Switching shifters and maybe rear derailers

[RatRodDad]

My wife's Columbia bike (not sure how old it is) has a thumb lever type shifter on it for shifting the rear derailer. You have to push on the lever until the chain finally decides to move - and hopefully it only moves to the next gear and not over 2 or more. So it makes it tough to change gears easily or accurately while you are riding along.

Here's what her shifter looks like now ...

Later model bikes come with twist grip shifters for their rear derailers, so I was thinking about trying to put one of those on her bike. I'm not sure, though if that can be easily done or if there is anything special about the derailer on those bikes versus the one that is on her's.

Here's the twist shifter on my "donor" bike.

It also seems like the bikes that have the twist shift on them seem to have the cables for the shifters running under the frame - through guides along the way. So I don't know if there is some reason they have to be done that way or if that is just how they decided to mount the cables at some point.

Here's the bottom of the donor bike with the cables running through a plastic guide mounted to the bottom of the crank housing.

So if any of you have done that type of switch before, let me know if it's doable and also what issues you ran into doing it. I hate to pull her bike apart if the other type of shifter won't work. I would appreciate any help or advice you can give me.

 

[tartosuc]

to help you i will need to know how many gears are in the back of each bike and a pic of each derailleur ...from there i will help you figure it out.

twist shifter like the one on your pics are indexed(clicks for each shift)
depending on how many gears at the back and the brand/model of the derailleur it might or might not be compatible. also the shifter on the first pics in not indexed, so i'm 90% sure that you will not be able to use the same derailleur... indexed derailleur have an adjusting nut to adjust the tension of the cable and fine tune the shifting.

from you picture, the first shifter is pretty rusted and I'm sure the cable is rusted too..you can start by swapping the cable for a new one put grease on the cable and grease the shifter, it will help a lot and you will probably be able to move more than on gear at the time...

 

[RatRodDad]

Tartosuc, thanks for getting back to me so quickly.

I guess I should have included some shots of the derailers in question and some more details on the gears.

Here is the derailer that's on the bike right now ...

And here is the one that was on the donor bike ...

Both bikes had 5 rear gears, which is why I chose this bike as a donor bike. So the twist shifter has 1 through 5 on it, which is what it would need.

My feeling, without knowing much about one derailer versus another, is that I should use the one that was on the donor bike, since I know that one matched the twist shifter.

What I am most unsure about is whether something special is needed on the cables, since the ones on the donor bike ran through that guard under
the bike rather then being old style cables. So I don't know if they have to do that or if a regular cable in a housing running down along the frame - like it currently does on the bike - will work okay. It seems like either way would work, but maybe there is something special about the way cables have to be run on a twist shift.

Thanks again for your help.

 

[tartosuc]

Ok,

so first you will need to use the derailleur maked SIS with the grip shifter, gears will be compatible.
you will also need a new cable with sis housing, thats the most important point(the housing on the bike right now does not look like sis housing and it make the whole diffference in the world for smooth shifting), you can run a full housing from front to back without a problem, housing are sold by the foot at any bike store, dont forget to put the metal ends on the housing...like i said in the other post put grease on the cable, it will help a lot the shifting.

1 setup the derailleur on the bike ajuste the 'L' and 'H' screws to limit where the derailleur will go. then place you cabel and housing with metal ends from the shifter to the derailleur make sure your shifter is at the position where there's no cable pull. tighten the cable to the derailleur.

from there when you shift you use the ajustable screw(the one that the cable goes trough at the derailleur) and ajust the tension of the cable to achieve the smootest shift in between the gears...if you turn clock wise you release tension on the housing therefore on the cable...counter clockwise is pushing on the housing therfore putting tension on the cable...always make your ajustement by 1/4turn and try shifting all the gears after every ajustement..if one gear try to .... upward and not suposed to, release tension if it try to go downward put more tension...

you might have to re set your cable on the pinch bolt of the derailleur a few time beacause the cable will stretch a little and the housing metal ends will set into the housing...

hope its not too complicated...

have fun...

 

[RatRodDad]

Thanks, Tortusuc. It doesn't sound too complicated.

Will the bike shops have replacement cable that is specific for a SIS shifter?

The only cable I've purchased before is the stiff that comes in a kit that you can buy at WalMart - and it comes with several cables in it for the shifters and the brakes.

 

[TexasXXX]

Holy crap, someone from the Houston area! :shock: I'm trying to get some folks together in the area sometime to hangout and ride. I've got a few other folksthat I've met thru Craigslist.......and one other person who's a member here (or a lurker) who lives in Tomball.

Drop me an email sometime if you might like to ride or meet some other folks.

Brian Wilbanks
[email protected]

 

[ricksterr1221]

This is why i dont own a bike with gears.. I own 1 and its unridable. :mrgreen: Props to those of you who have the patients and knowhow ability to work with them.

 

[mastershake916]

Special cable housing? Never heard of that.

 

[-=RaTb0y=-]

I had a mid 80's MTB bike with those shifters and
it had index/friction option.

 

[ricksterr1221]

My moms old mountain bike had gears just like that.. I took all the gears off and put on a set of cruiser rims ape hangers and a fat cruiser seat. She liked it better. So did i...

 

[tartosuc]

Special cable housing? Never heard of that.

there's 2 types of gear cable housing. ss type(for index shifting) and regular type for friction shifting. the housing of the sis one is made from multiple strait (along the lenght of the cable) lines and the friction one are a twisted line that wrap around the cable(same as a brake cable housing)...the twisted one got flex and you dont want that for index shifting. a lot of '80 bikes that were setup with the 5-6-7 speed index shifting, were setup with the regular cable housing and its mainly why they were not working good..I was a bike mechanic back then and when the sis hosng came out we were just swaping the housing and all the ghost shifting problem went out.

Now most of the cable sold on the market for shifting are sis, you just need to double check, but sometimes you get some regular ones at big stores like wallmart.

see the link below for another explanation

http://sheldonbrown.com/brandt/sis-cable.html

in my opinion a good derailleur system gives better performance than a internally geared hub exept maybe for a rollhoff speedhub but tha one is worth around 1500$ for the hub alone...

@ratboy.: nowadays the option of friction/index is not there beacause the systems are beter quality. the cheaper one we fin now is equivalent to the best one in the 80'

@rickster.: it's really not complicated tp make theses work properly,you just need to do it 1 or 2 times to understand and you are good to go... like any bike, if you keep it clean and oiled properly it will run good, the most important thing is to have good cables not rusted in the housing.
on my mountain bike, I usually put new cables once a year to keep it running trouble free.

@all, I Have good knoledge of pretty much all the mechanical systems in the bike industry except the internal hubs, so dont hesitate to ask me questions.

 

[RatRodDad]

Tartosuc, thanks for the great explanation. That does make sense about the cables being different so that there is no stretch in the cable itself when you pull on it. :idea:

I haven't really paid any attention to the cables in the past, thinking they were all the same, but I will now know to check them - or to be sure to get the correct kind for what I am doing.

Thanks again.

 

[new_dharma]

friction shifters are better...IMHO...but I like the vintage AND classic stuff

 

[RatRodDad]

Well, today - despite the heat and humidity - I finally decided to try switching the shifter and rear deralier on my wife's Columbia bike.

I bought the new shifter cable and cable housing at my LBS quite a while ago and just hadn't gotten around to making the switch.

Tartosuc was right on about the cable housing being a specific kind for indexed shifters. I heard his story almost word for word from the LBS folks - and didn't have the heart to stop them in the middle of their explanation or say "yes, I knew that already". :lol:

Now for a good laugh. When I walked into the LBS I told them I needed a cable and cable housing for a Shimano "sis" sinfter. Both guys at the counter gave me a funny look and said "what kind of shifter?". So I said "the kind that says SIS on the shifter". They started laughing and said "That stands for Shimano Indexed Shifting" "We've never heard it called a "sis" shifter before though. I thought about the other Shimano shifter types and I wondered if an SRAM shifter is pronounced "S" ram, or if it's pronounced S R A M?

Anyway, back to my update. I got the shifter and derailer installed and it seems to be working pretty well. Unfortunately the rains came before I was done so I did a minimal amount of test riding due to the water on the street and no fenders on the bike.

Here's a couple of shots of the finished product. My only issue now is whether my wife will be comfortable using the full grip and the shifter and brake next to it - or if I will eventually need to cut the grip shorter and move the shifter and brake over some. It seems to be working fairly well, though, and it's much easier to use than the old friction shifter that was on the bike. So I think she's really going to enjoy it compared to the old one.