Sprocket

[ConnoisseurEquator]

Hi
I swapped the sprocket of my Raleigh 3 speeds with a 17 from a 21.
The problem is the chain is now either too long or too short.
Anything that can be done?
Thanks

 

[iluvmybike]

Too long - remove a link or two.
Why would it be too short if you've gone down from 21 to 17?

 

[ColinJ]

Too long - remove a link or two.
Why would it be too short if you've gone down from 21 to 17?

Too long so remove a pair of links, but then it would be too short?

 

[Big John]

I've got the same issue and am currently toying with getting a chain tensioner but reluctant to part with money. Think I'll have to bite the bullet and let the moths out of my wallet.

 

[Chris S]

Can you reposition the wheel in the dropouts to compensate for the new sprocket size? If not you will have to shorten the chain if the new sprocket is smaller than the original or lengthen it if the new sprocket is bigger. 4 teeth on a Sturmey Archer cog corresponds to one complete chain link (i.e. an inner and an outer).

 

[rogerzilla]

A bike designed for a 3 speed hub should have horizontal dropouts (they're actually perpendicular to the seatstays, but that's what they're called).

So find a chain length that allows the chain to be tight when the wheel is slid back along the dropouts. If they are very long, there may be a choice of wheel position if you remove or add an inch of chain. Generally the position toward the front of the slot is preferred in this case. Avoid the wheel being right at the back of the slot anyway, as you won't be able to take up chain wear.

 

[ConnoisseurEquator]

The reason I fitted a 17 was to go faster on flat ground.
There aren't any compromises in this case. Although they tell you one can, you can't.
I suppose I will have to fit back the 21 or maybe get a 19. Between the 2 sizes.

 

[ColinJ]

I thought that we had mentioned half-links, but that must have been another such thread...

So, half-links... Like THIS ONE! (Assuming that you have a 3/32 chain - if not, buy one to suit yours.)

If you chain is just too long or too short, then add one half link to the shorter chain. Hopefully, that will be near enough perfect.

 

[ConnoisseurEquator]

So, half-links... Like THIS ONE! (Assuming that you have a 3/32 chain - if not, buy one to suit yours.)
If you chain is just too long or too short, then add one half link to the shorter chain. Hopefully, that will be near enough perfect.

Hi
The problem with the Raleigh chain or old ones is that they don't do half link as far as I know

 

[Chris S]

Raleigh 3-speeds use 1/2 x 1/8 inch chains. You can get half links for these off ebay.
https://www.ebay.co.uk/itm/144039238740

 

[T4tomo]

ConnoisseurEquator does it not have either horizontal drop outs or (less likely on an older bike) eccentric bottom bracket to provide some adjustment. pop up a photo of the drop-outs...

 

[fossyant]

The answer is pedal faster

 

[Proto]

New bike.

 

[ConnoisseurEquator]

A pic says it better

 

[ConnoisseurEquator]

I will have to find a half link for a chain with a 1/8" pitch

Chain size is specified by pitch and width. The pitch is the distance between rollers (1/2" on all modern bicycle chain). The width is the internal width where the sprocket teeth fit in. Bicycle chain comes in four basic widths:

• 3/16" (.1875", 4.76 mm), used until the middle of the 20th century on many bicycles; this was inch-pitch chain.
• 1/8" (0.125", 3.18 mm) chain is used on most single-speed bicycles, and bicycles with internal gearing.
• 3/32" (0.094", 2.30 mm) chain is used on derailer equipped bicycles that have more than 3 cogs at the rear.
• Even somewhat narrower chain, typically .090" or 2.29 mm between the inner plates, is used for derailer-equipped bicycles with 10 or more sprockets at the rear.