3 speed ladies triumph- I want to change the chainring!

[medel]

Hi all!

I purchased an old triumph with a Sturmey Archer 3 speed to fix up for my girlfriend. The SA is working well, but the overall setup is geared too high for my liking. This confirms several articles I have read on the gearing issue. I can locate a SA sprocket to put on the hub (I want to increase to 21 or so teeth). I do not know where to start when it comes to replacing the chainring. Can anyone please refer me to a good article or a good parts seller?


Thanks!

 

[deorman]

The hub sprocket is retained with a simple snap-ring. The front ring on older bikes is dealt with in these 2 articles.
http://sheldonbrown.com/opc.html
http://sheldonbrown.com/cotters.html
If you have a cotter crank, you might want to change to a modern type, which is held by nut or bolt that threads onto the end of the crank shaft. In the unlikely event that it already has a modern crank, you need a crank arm puller which you can buy at most bike shops. Pedal and bearing race threads on the left side are left handed.

 

[Tater]

You can pick up the rear cog from your local bike shop or on the Web. Amazon.com has one that will fit your hub. 21 Tooth Cog

Like Deorman said, it a simple clip. Have a look at this Youtube video for a visual on how to change it: Youtube Cog Video

Good luck.

 

[Bicycle808]

I'd start with the cog; you can get some really big ones...

http://bikesmithdesign.com/cogs/index.html

Try a big'n, and see where that leaves the gearing. Changing a sprocket on a Raleigh-threaded cottered crank is not worth the hassle imo, and will also cheapen the look of the thing.

 

[deorman]

I despise cotter cranks. :|

 

[medel]

Wow thanks all!

I had read that cottered crank article a day before I posted this question. I have been unsuccessful so far in removing the cotters, and therefore the cranks and the chain ring. I like the link to Bikesmith and their various cogs.

I think I will try a 22T cog. That is a move up from 19T. If I go any bigger, I think I might have clearance issues (as it is all so close already).


Any thoughts anyone?

Again... Thank you!

 

[Wildcat]

I did some different combinations on a 3 speed I put on a 26" BMX style cruiser. I started with a 22 tooth cog, but was always hunting for that extra gear between 2nd and 3rd. There's a pretty good jump between 2nd and 3rd, so either one has to be where you like to cruise along on a regular basis. If the bike came with an 18, probably a 20 would put it at the right spot. If not, more speeds will be needed, but so will more money.

 

[Bicycle808]

Wow thanks all!

I had read that cottered crank article a day before I posted this question. I have been unsuccessful so far in removing the cotters, and therefore the cranks and the chain ring. I like the link to Bikesmith and their various cogs.

I think I will try a 22T cog. That is a move up from 19T. If I go any bigger, I think I might have clearance issues (as it is all so close already).


Any thoughts anyone?

Again... Thank you!

You can get a Sturmey or Shimano 22t really easy, just about anywhere. 23t Shimanos are commonplace, too.

As far as clearance: what is tight? Clearance at the chainguard, or clearance at the seatstay? Or something else?

 

[medel]

Clearance is tight where the seat stays and chain stays meet at the dropouts. I figure that if I have more teeth on the cog, its diameter will increase. At some point, the cog will be too big for that combined area and rub on either the chain stay or the seat stay.

But... I realize that a 22T cog will be minimally bigger in diameter than a 19T, right?

I think that is what I am going with.