Two speeds or three?
10-19-10, 07:25 AM
#1
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Two speeds or three?
I currently commute on a single speed at roughly 70 gear inches. I'm planning to look at a Brompton, but I'm not sure whether the two-speed model or the three-speed model would be better for me. I suspect I'd use it for commuting and to ride when I travel, but I don't know that I'd be touring on it. Thoughts?
10-19-10, 08:10 AM
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Two if (carrying) weight is an issue (you can easily save ~800g), otherwise a 3 speed SA hub will bring you MANY miles of troublefree cycling. I currently have a 3-speed. I do not have a lot of hills here and i am a spinner not a masher, i rarely get to use the top gear, so every once and a while I wonder if a 2 speed might not have suited me better, though it is nice to have the top end for those few moments. I commute on my Brompton daily (~14km), I've taken it with me on various trips on trains, etc. with or without luggage and it had worked out fine.
-Carcinogent
P.S. If you are mechanically inclined you can replace the internals of the 3-speed with old medium ratio ones (Sturmey Archer AM), found on ebay, etc. and get 3 very nicely spaced gears. (Roughly 2 tooth difference (~15.5%) in each gear step) Also with a 3 speed you can change the rear cog if you are not happy with the gear ratios you have; with a 2 speed i think you have to change the crankset.
-Carcinogent
P.S. If you are mechanically inclined you can replace the internals of the 3-speed with old medium ratio ones (Sturmey Archer AM), found on ebay, etc. and get 3 very nicely spaced gears. (Roughly 2 tooth difference (~15.5%) in each gear step) Also with a 3 speed you can change the rear cog if you are not happy with the gear ratios you have; with a 2 speed i think you have to change the crankset.
Last edited by Carcinogent; 10-19-10 at 08:15 AM. Reason: P.S.
10-19-10, 08:29 AM
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Brompton offers optional higher and lower gearing for the 3-speed, and optional lower gearing for the 2-speed. See https://www.brompton.co.uk/page.asp?p=3069. Personally, I would choose the 3-speed, since I like IGHs.
Last edited by GeorgePaul; 10-19-10 at 08:33 AM.
10-19-10, 09:14 AM
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if you think that you will be using it on some hilly route in the future, it would be smart to save some more and get the 6 speed instead. wouldn't hurt to have that extra gearings in case you need it.
10-19-10, 10:55 AM
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If you're already happy riding single speed then you should be happy with either.
If you're looking to gear up cause your sick of riding ss then you'll prolly really appreciate the 3 speed.
If you're looking to gear up cause your sick of riding ss then you'll prolly really appreciate the 3 speed.
10-19-10, 12:14 PM
#6
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I live where its quite hilly, so I bought a different crankset, made for Bromptons,
by Schlumpf innovations, a Swiss manufacturing biz.
it is a planetary 2 speed , made so it uses the 3 speed twice,
shifting into low range on the crank and high gear in the hub,
and thats the next lowest ratio.
works well .. Mountain drive, for Brommys it's a 54t, 130 bcd.
[planetary low is an equivalent to a 21.6t chainring]
I have a SRAM made 15t cog on my AW3, so the direct middle gear is a 58",
you can fit a 13t or 14t on, to raise the range.
By both being planetary gears the shifting is quick on each,
tap the heel button in the center of the crank,
and flick the trigger shifter on the handlebar.
by Schlumpf innovations, a Swiss manufacturing biz.
it is a planetary 2 speed , made so it uses the 3 speed twice,
shifting into low range on the crank and high gear in the hub,
and thats the next lowest ratio.
works well .. Mountain drive, for Brommys it's a 54t, 130 bcd.
[planetary low is an equivalent to a 21.6t chainring]
I have a SRAM made 15t cog on my AW3, so the direct middle gear is a 58",
you can fit a 13t or 14t on, to raise the range.
By both being planetary gears the shifting is quick on each,
tap the heel button in the center of the crank,
and flick the trigger shifter on the handlebar.
Last edited by fietsbob; 10-19-10 at 01:36 PM.
10-19-10, 12:48 PM
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Well i suggest keep it simple. 3 or 2 speed. The 6 speed and other additions/ modifications make things too complicated imho. Igh>derailleur when it comes to commuting and as i said earlier get the 2 speed if carrying weight of the bike is of importance.
-Carcinogent
-Carcinogent
10-19-10, 01:46 PM
#8
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Now they use the shimano spline type on the 2 cog cassette, so you can pick either 12/16 and 13/15 combos to use.
crank options , 44, 50 and 54 t chainring options .. from the factory ..
crank options , 44, 50 and 54 t chainring options .. from the factory ..
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