Folding Bikes - Getting more gear inches...

Hi,

I have a locally made folder with sixteen inch wheels, with a 55 teeth front crankwheel and a rear six-speed freewheel with the smallest teeth at 14T. This makes for a gear-inch of 60 or so, which is quite pathetic considering the high cadence in order to reach 30km/h.

I was wondering, how I could get more gear inches, so I can ride quickly and more efficiently? The truth is that I have gone searching for a six speed freewheel with less teeth (11T, 12T) to no avail. Does anyone have any ideas on how I can get more gear inches? So far I have not seen a bigger front crankwheel, but I have thought of getting shorter cranks, and I was wondering if that would help me get more speed?

Thanks!

You have summed it up accurately. Getting another freewheel will be almost impossible.

The only viable option is another chainwheel. I am assuming (in the absence of a pic) that the crankset is one piece with the chainwheel. The easiest option is likely to be to get another crankset with the biggest chainwheel you can find. That will probably be 56T, although 60T ones can be found without too much trouble. A cheap used cranset from ebay is the way to go; or take it to the LBS for them to pull of the crankset to advise you; they may even have an old used set for you.

This is a problem with smaller wheels. I have a 56 X 15 single speed setup on my 20" wheel Swift. That gives a nice 75 inch gear. How does Moulton get their high gears - well over 100 inches I believe - with their 17" tires?

AFAIK, Moultons have some really expensive proprietary freewheels with 9,10 and 11 T as their smaller 3 gears. It's just what every small wheel bike needs...

Alright, sounds good, I'll ask around for a 60T or bigger crankwheel, since there's no other option. Though I did see a 12T six speed free wheel on ebay going at $25USD. Not bad, but not sure it would fit either, there's something like 120 and 126mm versions, am I right?

Thanks.

Without knowing anything about your "locally built" folder's general configuration, folding regimen, frame material, OLD, chainstay length, handlebars, drop-outs, bottom bracket, which 16" tire size you have, etc., it's hard to make a specific recomendation.

General comment: A Sturmey-Archer AW hub could give you a 91 gear inch top with your existing 55T chainwheel (assuming ISO35-349 tires). A Sturmey 8-speed hub could give you a 142 gear inch top.

HTH,
tcs

I'm much less mechanically-minded than the other guys here, so this may be a nonsensical post in the context of your particular bike--but I do know that my 20"-wheel Swift with a Sram Dual Drive internal gear hub has a range of about 21-120 gear inches.

Best option is the Sturmey Archer 8-speed hub. Other solutions, in no particular order:

1. Loosescrews.com has 60T chain rings for like $40, which will help a little. Keep looking on ebay and you will occasionally find larger chain rings still. You can have custom rings made, but that gets very expensive indeed.

2. You can get a 7-speed freewheel with a 13T smallest cog.

3. You can switch your rear hub to a cassette; that will give you the option of a 11T.

4. Shimano Capreo group gives you an even smaller one-- 9T.

5. Shimano Nexus 4-speed, Sturmey Archer 3 speed, 5-speed, or 4-speed --if you can find one-- are also pretty good options.

6. Sram dual drive sounds interesting, but I don't know the details.

6. A similar solution, a bit exotic but much cheaper, would be a Sturmey Archer AW hub (available used cheap cheap cheap) with two cogs, spaced 2 or 3 apart, such as 13T and 15T if you want the highest gears possible; this will give you six speeds, rather evenly spaced, topping out around 76 gear inches with your 55T ring.

Thanks a lot for the suggestions. I don't really mind going down to 5,4 or 3 gears, neither do I mind going up to 7 gears, but the problem with more gears lies in the fact that my bike might not have enough clearance. I'll check with my bike store and see what they can do.

As mentioned previously, the following options would be best.

1. Sturmey XRF-8 internal gear hub (28 hole, 116mm OLN)
2. Shimano Nexus 4 internal gear hub
3. Shimano Capreo hub/sprockets
4. SRAM Dual Drive (Internal 3+external sprockets, make sure dropouts wide enough)

Shimano make 7sp freewheels starting at 11t, possibly the cheapest option.