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Iief 07-31-11 03:59 AM

Curious about gearing on bikes
 
I love my Boardwalk S1 but not when it comes to very steep grades. I'm thinking about getting a 6 speed bike to help me manage the hills and perhaps speed me along the flats a bit quicker. For downhill however, I do not wish to go any faster.


Does this mean I want a bike with tall gearing or short?

How do I tell which is which, and is changing the gearing relatively simple to accomplish?

Thanks

bendembroski 07-31-11 09:42 AM

http://www.sheldonbrown.com/gearing/index.html

snafu21 07-31-11 10:02 AM

Ya Sheldon Brown - he's da man. Is the Boardwalk the single speed model? Your options, to get up hills easily are:

1) Sell it and buy something else
2) Fit a smaller front chainwheel (take links out of chain)
3) Fit a larger rear cog (put links in chain)
4) Both 2) &3)
5) Fit hub gears ( wheel rebuild etc)
6) Fit deraillers and rear cassette if the frame and wheel will take it.


Adding gears to bikes which don't have them starts to get expensive, when you have a bike with gears the RANGE of them is important - easy gears for hills, tougher gears for the flats. As an example (there are others) a Dahon Speed D7 will work well on most urban hills, have plenty of speed for the flats or descents. The top gear maxes out at about 20-22mph, enough for me, but slow for some. Hilly towns and luggage tends to need gear ranges to suit. On hills I want to spin along slowly, not stand up on the pedals.

The D7 range, as an example is 34 inches - 92 inches spread over the seven gears.

My Brompton has only three speeds. The (wide) range of them is not enough for me in hilly country, and if I make them any lower, there won't be enough oomph on the flat. So rather than spend money on it - it's on Ebay.

Test ride all bike purchases if possible - there's a trend amongst manufacturers to over-gear single speed bikes slightly, believing we're all muscle-bound mashers.

If you want to see what's available in 20" wheel bikes, the Downtube 9FS squeezes in 9 speeds to a folding bike, and the range of them is pretty good for the hilly area I live in, by way of an example. Think 7 speed derailleur, really, or at least 5 speed rear hub.

http://www.downtube.com/Full_Suspens...ding_Bike.html

The only reason I mention these bike is because I've owned all of them. There are plenty of other models to choose from.

fietsbob 07-31-11 10:50 AM

I resolved snafu's situation with a Swiss mountain drive crankset,
made by Schlumpf, in Switzerland, I bought mine thru CM Wasson in Palo Alto Cal

another solution, My first purchase from him, was a FD adapter, [ala SP in UK]
to shift 2 chainrings, from the handlebars..
[i'm about to return it for credit to my card, unused, if any one wants it,

Thor has a FD kit for Dahon's too. instead.. ]

Schlumpf developed the mountain drive crank,
to turn utilitarian 3 speed bikes into 6 speed mountain pass hunters.
with another planetary gear .. instant shift at any speed even zero.

torque transfer is via a knob laid on the Brompton BB
between the Rear pivot and the BB, ...
quite tidy..


Oh, and I read, Brompton dealer in Scotland , Kinetics, does SA 8 speed hub kits ,
installed in the bikes if you wish..


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