Sprocket size for sturmey archer 3 speed

[Tonee62]

Hi, I'm about to have a rear 28" wheel built with 3 speed dyno-hub for my restored Raleigh Roadster, the original sprocket was 18 tooth with a 46 tooth chainset. I've been reading interesting comments about having a larger sprocket. Whats the thinking on here, what do people think the best size sprocket would be? Thanks

 

[Trent Tourist]

You can get larger sprockets if you google for suppliers, they're still available. If your roadster is post 1950 they're dead easy to change, just ping off a circlip. Older hubs are screw on, can still be changed, if not stuck, but may be harder to get sprockets. Makes the hills easier !

 

[Tonee62]

You can get larger sprockets if you google for suppliers, they're still available. If your roadster is post 1950 they're dead easy to change, just ping off a circlip. Older hubs are screw on, can still be changed, if not stuck, but may be harder to get sprockets. Makes the hills easier !

Hi Trent Tourist, Thanks for the information my roadster is a mid 60s DL1. I was wondering if there was much difference between say using an 18 tooth sprocket and a 20 tooth.

 

[tyred]

For a 28" wheeled roadster, I would go for a 22 tooth sprocket. You would have a middle gear somewhere around 60" , a 45" climbing gear and an 80" "tailwind gear" (these gear sizes are educated guesses - you can find the gear tables and calculators online if you really want to know)

This should work fine for most circumstances but they are heavy bikes so if you live in a hilly area, Sachs/Sram 24t sprockets are available and will fit the hub (but won't fit inside a full chaincase if you have one).

 

[Tonee62]

For a 28" wheeled roadster, I would go for a 22 tooth sprocket. You would have a middle gear somewhere around 60" , a 45" climbing gear and an 80" "tailwind gear" (these gear sizes are educated guesses - you can find the gear tables and calculators online if you really want to know)

This should work fine for most circumstances but they are heavy bikes so if you live in a hilly area, Sachs/Sram 24t sprockets are available and will fit the hub (but won't fit inside a full chaincase if you have one).

Thanks Tyred, the 22 tooth sounds a good option, just need to get my hands on one.

 

[Sterba]

Am I dreaming here? I seem to recall a long time ago when confronted with this problem, I found a cog that had been removed from a set of sprockets (cassette that can be disassembled) and it, amazingly, had just the right hole diameter and indents to fit straight on the SA hub. This meant that I could choose any size cog I liked and gear down to my heart's content. Because the bike was used for hauling four year olds around, I fitted a 28tooth cog. Top gear became the equivalent of normal, and the two lower gears allowed me to ride up the steepest hills.The only issue was that these cogs are designed for thinner chains, although I don't think it matters much, so I fitted a chain from a seven speed derailleur and a better chainset to match. I think the cog needed a thin washer before refitting the circlip back on the hub so it didn't waggle around. I am sure someone will be able to confirm this idea.

 

[tyred]

I've read that before a

Am I dreaming here? I seem to recall a long time ago when confronted with this problem, I found a cog that had been removed from a set of sprockets (cassette that can be disassembled) and it, amazingly, had just the right hole diameter and indents to fit straight on the SA hub. This meant that I could choose any size cog I liked and gear down to my heart's content. Because the bike was used for hauling four year olds around, I fitted a 28tooth cog. Top gear became the equivalent of normal, and the two lower gears allowed me to ride up the steepest hills.The only issue was that these cogs are designed for thinner chains, although I don't think it matters much, so I fitted a chain from a seven speed derailleur and a better chainset to match. I think the cog needed a thin washer before refitting the circlip back on the hub so it didn't waggle around. I am sure someone will be able to confirm this idea.

I've read that before but don't own any cassette hub bikes so have never been able to explore that particular avenue.

 

[Brand X]

Threadomancy..

Can anyone tell me where I can find the correct cogs? I've got a 3-speed Raleigh with 26" wheels and I'd like to have lower gearing. I've never changed cogs/sprockets before so I'm not sure which are the correct ones for an old Raleigh or how many teeth the front and rear cogs need.

 

[Hugh Manatee]

I got one from a well known auction site. The gear was simplicity itself to remove. As someone has already said it was just a big circlip. The tricky bit was getting the chain length right afterwards. It fell right between links as it were.

 

[Brand X]

I found a handy guide on YouTube. Sorted. :-)

View: https://www.youtube.com/watch?v=I1bIEvJmE1o

 

[billiobob]

Very useful. I have an old Pashley Mailstar and I wanted to replace the rear sprocket to lower the gearing.

 

[biggs682]

Very useful. I have an old Pashley Mailstar and I wanted to replace the rear sprocket to lower the gearing.

easy enough to do as said earlier in thread

 

[FrankCrank]

Worth noting that SA, Shimano and SRAM sprockets are all interchangeable, but SA ones seem to be the most readily available.

Sprockets with higher tooth count are dished, so you have 2 options for your chainline. Some sprockets only work with one speed chains, some work for speed chains and one speed chains, if that makes sense.

 

[davidphilips]

Ebay?https://www.ebay.co.uk/itm/Sturmey-...hash=item566bf3f5a3:m:m5U_3Ktp6XSeCSYsBX25U4A