Folding Bikes - Dahon Piccolo gears upgrade

Hi,
I have Dahon Piccolo folding bike.
There is 3 rear gears inside the hub.
The gear are very hard to ride when going up a hill.
I just now got the blink that I can just change the front crank ring to a lower count.
I would like to get a recommendation for the size of the ring and the type.
We have steep hill before home that we need to do before reaching home. I have trouble doing it with Trek 1200 road bike with 39 front and 25 rear cogs. So we'll need something that is a better ratio then this.
Thanks

[QUOTE=kipibenkipod;5104431]Hi,

Hi,
I have Dahon Piccolo folding bike.
There is 3 rear gears inside the hub.
The gear are very hard to ride when going up a hill.
I just now got the blink that I can just change the front crank ring to a lower count.
I would like to get a recommendation for the size of the ring and the type.
We have steep hill before home that we need to do before reaching home. I have trouble doing it with Trek 1200 road bike with 39 front and 25 rear cogs. So we'll need something that is a better ratio then this.
Thanks

Good question.

I have the Presto which has the same gears as the Piccolo. I happen to find 2nd gear perfect because it's low enough to allow you to ride all day long.

48T chain ring
13T cog

Gives you the following 66 inches high gear

49 Direct drive
37 Low gear

You're only hope is to lower 3rd gear to 49 inches but that will eliminate your high gear. If you don't mind coasting down hill, this just might work. You don't have to change the front chainring but just change to a 17 tooth sprocket. This is about as low as you want to get with a 3 speed hub.

48T chain ring
17T cog

50 inches High gear
38 Direct drive
28 Low gear

Good question.

I have the Presto which has the same gears as the Piccolo. I happen to find 2nd gear perfect because it's low enough to allow you to ride all day long.

48T chain ring
13T cog

Gives you the following 66 inches high gear

49 Direct drive
37 Low gear

You're only hope is to lower 3rd gear to 49 inches but that will eliminate your high gear. If you don't mind coasting down hill, this just might work. You don't have to change the front chainring but just change to a 17 tooth sprocket. This is about as low as you want to get with a 3 speed hub.

48T chain ring
17T cog

50 inches High gear
38 Direct drive
28 Low gear

I agree with Dahon Steve. I own 4 different 3 speed bikes, 3 folding and 1 regular bikes. If I were to change my gearing ratio, I would always change the rear cog first to a larger diameter. But the tradeoff is a loss of speed at the flat terrain. So I keep all of the bikes using the stock chainring and cog combination they all came with. I seem to have little trouble with 99% of the rolling hills surrounding my house. These hills morph into completely flat terrain at a moment's notice.

Good question.

I have the Presto which has the same gears as the Piccolo. I happen to find 2nd gear perfect because it's low enough to allow you to ride all day long.

48T chain ring
13T cog

Gives you the following 66 inches high gear

49 Direct drive
37 Low gear

You're only hope is to lower 3rd gear to 49 inches but that will eliminate your high gear. If you don't mind coasting down hill, this just might work. You don't have to change the front chainring but just change to a 17 tooth sprocket. This is about as low as you want to get with a 3 speed hub.

48T chain ring
17T cog

50 inches High gear
38 Direct drive
28 Low gear

Sorry for the late response.
The first gear is very hard just to start riding, even for me. My girlfriend uses the bike and she goes up hills but with a very lower rate of pedals, which creeping me out. I want her to be able to do ~70rpm uphill.
I have moved my Trek 1200 from 42 to 39 front ring and the difference is very low.
Going from 13 to 17 at the back, I think will not make such a difference uphill.
I don't care of flat terrain. She don't get to 3rd gear.
Why 28 Low gear is the lower I want to get?
Will I have to change the chain to accommodate bigger rear sprocket ?
Thanks for the help.

Heh, sorry no offense, but that reads like a babelfish output... :)

Today I went to the LBS that sold those bike, and he told me that he don't have the rear sprocket, because it has something that related to the gearing. He told me that he can find front ring that is smaller. What size of ring should I go with?

Today I went to the LBS that sold those bike, and he told me that he don't have the rear sprocket, because it has something that related to the gearing. He told me that he can find front ring that is smaller. What size of ring should I go with?

The front chainring will require you to purchase a new crank. Very expensive. The least expensive way to reduce your gears is to buy the rear cog off the internet.

You can buy the larger cog here.

http://sheldonbrown.com/harris/sturmey-archer-parts.html

Kikibenkipod, contact coatropheus, he's in Israel too, very knowledgable and has a bike shop. He will be able to advise you where to get a rear sprocket to reduce your gearing.

Going from 13T to 17T in the back will make a big 30% difference, unlike going from 42T to 39T in the front which is only a 9% difference.

Kikibenkipod, contact coatropheus, he's in Israel too, very knowledgable and has a bike shop. He will be able to advise you where to get a rear sprocket to reduce your gearing.

Going from 13T to 17T in the back will make a big 30% difference, unlike going from 42T to 39T in the front which is only a 9% difference.

I don't find the user coatropheus in this forum. Can you check if the name is correct?
Thanks

The front chainring will require you to purchase a new crank. Very expensive. The least expensive way to reduce your gears is to buy the rear cog off the internet.

You can buy the larger cog here.

http://sheldonbrown.com/harris/sturmey-archer-parts.html

What I have been told is, it will cost about 10$, and it is very easy to switch the front ring.
Other store told me that all the crank should be replaced.
Maybe I will drop by again and ask if he was talking about a full crank or just a ring.

Sorry, caotropheus (http://www.bikeforums.net/member.php?u=27177).

here on ebay is a rear cog for you:
http://cgi.ebay.com.au/STURMEY-ARCHER-NOS-3-Spd-COG-1-8th-18T_W0QQitemZ170142581836QQihZ007QQcategoryZ42328QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Or here:
http://cgi.ebay.com.au/OLD-STOCK-18T-BIKE-SPROCKET-STURMEY-ARCHER-REPLACEMENT_W0QQitemZ180154111229QQihZ008QQcategoryZ420QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Jur,
Thank you very much.

UPDATE!
Hi all,
We have upgraded the rear sprocket to 18 tooth. We tested it on a long ride with hills. It sure improved the revs my girlfriend do when pedaling.
We actually didn't test it on the big hill near our home, but I feel that now she would take it to the top in one go.
Thank you all for the help.

Changing the rear sprocket:
---------------------------------------
Very very easy!
1. Take out the back wheel.
2. There is a big C clip that hold the sprocket in place. Take it out with a screwdriver.
3. Replace the cog and put the C clip back.

Oh, the chain was small, so I had to put a new chain. Take that in consideration.