Hello all...My first post...I have a late 70's early 80's one speed 26" bike that I am converting to a 3 speed...the number of teeth on the pedal sprocket is 44 and the rear is 19 teeth...with the 3 speed hub installed it will have 44 teeth in front and 18 teeth in the rear...will this work or do I need to add more teeth to the rear...There is a slight hill to go up to get to town...any suggestion would be helpful...thanks, 1.75

I assume you've been riding it a while as is and so have a basis for comparisson.

Typical 3 speed hubs have ratios of .75:1, 1:1, and 1.333:1, so with the 18t rear sprocket it's be as if you had a 24t, 18t and 13.5t on the rear. If you feel that'll be enough you're good to go. Otherwise you can enlarge the rear sprocket and offset the entire range lower.

thank you...the trip up this hill into town should be a whole lot easier than just the one speed...will three more teeth make the peddling easier yet?

If you add them to the rear. It would be more difficult if you add it to the front.

Yes, going to a larger sprocket will push the entire range lower. If you use a 24t rear sprocket, your high gear will be close to what you're riding now, giving you 2 lower gears. That might be too much, but the 21t might make lots of sense.

Thanks again...I just hope that there is a notable difference going from single speed to 3 speeds...is there any good reading this that you know of? have a good evening...1.75

There's no way to tell for sure whether the 44/18 will work for you and your needs, but my guess is that the 18 tooth is not going to be sufficient for much of a hill. It is very easy to acquire and install a larger rear cog if necessary, as both Sturmey and Shimano cogs are available up to 22 teeth.

If you can find a friend with a multi-speed bike you can ride, see what front/rear combination is low enough for you to make it up that hill. Divide the front teeth by the rear teeth and then divide that into 33. The result is the number of teeth you will need on the three speed that give you the equivalent gear. Keep in mind that the lower gear to go up the hill means your high gear will be lower also. Whether that will be a problem depends on how fast you tend to turn the cranks. My guess is that 20 teeth might be a good compromise.

There's plenty of reading about gearing, just search the net. Here's a gear chart you can use. Your chainring is 44t so follow down and see the ratio with the 19 = to 62. As I said the high gear will be 1.3333x62, and the low = .75x 62.

Now with the help of a calculator (or grade school kid) you can easily calculate the 3 gears for any size sprocket and compare.

But that's still abstract, so you might want to borrow a geared bike (internal or external) climb the hill and find out what you need for a low gear, then select a sprocket that gives you the same low.

Thanks again for all the good info...I am going to see how much the cogs are and maybe get a 20 and 22...have a good one 1.75

Don't forget that you might need to buy a new chain.

It might make sense to start with the larger sprocket -- the 22t -- that way if you need to shorten the chain when changing to the smaller one it'll be easier than having to lengthen it.

OTOH, it's possible that the chain will belong enough as is. The rear wheel moves forward or back 1/8" for every tooth change in the rear sprocket. So if you have room in the dropout to move the rear wheel forward 3/8" you can use a 22t sprocket with your existing chain.

I have always found that the planned starting point for IGH gearing is just that: a place to start. As you ride it you will probably want to tweak it a bit so that you normal cruising gear is exactly where you want it. Most ppl want 2nd gear as the cruising gear but some use the highest gear to have 2 lower gears. Rear cogs are not expensive and easy to replace.

3 spline AW3 cogs are made from 13 to 21t, most are 3mm/ 1/8" thick.

44: 18 x 26" is like a 63.5" wheel.

No, AW cogs are made at least to 22 teeth.

And Shimano makes a 23t that works with SA (3/16" though)

Enlarge a sprocket? That's an amazing trick.

Exactly what I did when I was commuting on a 3 speed. Rather than just use the high gear for downhills I set it up so that I could comfortabley maintain cruising speed on level ground, allowing for higher rpm to handle tailwind conditions. That gave me two other gears to handle hills, headwinds, etc.

+1 to this, it's how I've got the 3-speed on my folding bike set up and how I did run the other 3-speed bike I used to have. The extra low gear is much more useful much more of the time than having another high gear would be.

Is that what the kids are calling it these days?

Hello again.. I originally started this post back on 5-6-13...Well anyway an update, I have converted my bike to a 3 speed (Shimano hub) 44 teeth on crank and 20 on the hub...it felt like second gear was the same as when it was a single speed...so I put a 40 tooth on the crank and it is just what I wanted...now third gear is like the single speed was and have two lower gears for the hills or lite cruising...thanks again to all. 1.75

Makes sense - that is the same as if you had put a 22 tooth cog with the 44 chainwheel.

cny bikeman...are you saying you have to take away more teeth in front and add less in back to get the same ratio? confused

Yes, that's exactly what he's saying. When people speak of gear ratios, they're talking about the ratio between the driven and driven gear. 44:22 = 2:1 = 40:20. BTW it also equals 42:21, or 38:19. 2:1 means the wheel turns twice as fast as the crank so, in a typical 3 speed hub, with direct drive in the middle gear it would have the wheel making 2 revolutions per turn of the crank in 2nd.

Earlier I gave you the multipliers for the other gears. So for the same 2:1 sprockets, in 1st the wheel would turn 1-1/2 turns (.75 x 2) per crank rev, and 2rd would turn 2-2/3rds per rev (1.3333 x 2).

ok, looked at the chart again and I see the same # coming up no mater which way I went 44-22 or 40-20...is one way better to go then the other? thanks for being patient with me...all new to me but enjoying the learning...thanks 1.75

In a theoretical sense, bigger sprockets are better, ie 44:22 vs. 36:18. But the difference is very small, so the smart approach is to go the way that requires the least expense, and hopefully replacing only one item. If rear sprockets big enough are available, than that's usually cheaper, but whatever works is fine.

[QUOTE=FBinNY;15612648]In a theoretical sense, bigger sprockets are better, ie 44:22 vs. 36:18. But the difference is very small, so the smart approach is to go the way that requires the least expense, and hopefully replacing only one item. If rear sprockets big enough are available, than that's usually cheaper, but whatever works is fine.[ /QUOTE]

Ok, got ya now, actually I have a 22 tooth cog for the rear, just thought it was easier to do with the crank...thanks again

I did the same with my three-speed. It came as a three-speed, and I figured if I was going to climb hills or haul cargo with it, it needed lower gears. I have the standard 48T chainwheel and 18T sprocket. I changed the rear first to a 22T and later to a 24T. Now my 2nd gear is lower than my first gear used to be. I'm tempted to label my shifter 0, 1, and 2.

My top gear is pretty low now, so when going down hill and reaching a certain speed, I can't pedal any more, so I just coast. I think this is a great way to put a three-speed to use.