bikertrash

Hello,
Has anyone checked out the Schwinn site and seen their World Adventure model? Anyway it has that new Alfine group. 8 speed internal hub, two chainring crank. Never seen that before. I figure this must be shimanos answer to the Rohloff. Not as pricey, but still have to deal with a derailer. I'm not sure if still running a front derailer is a good idea. I liked SRAM's concept of the 3X8 duodrive, but I guess that tends to break.Anyhow, as soon as someone gets this ride, let us know whatyou think. I'd offer a link, but don't knkow how to do that.

nashcommguy

A friend of mine and I were talking about this very thing the other day. Single speed hub w/a tensioner and a front der w/2 chainrings, maybe a 50t and 40tx16. Also, in the same conversation we talked about a 3 sp bottom bracket/crank assembly w/a 7 or 8 speed internally geared hub. Seems we're a little late.

ax0n

Sheldon beat you to it (in a way, with an old Sturmey Archer 3 speed instead of an Alfine 8) and then some.

http://sheldonbrown.org/otb.html

nashcommguy

What I should've said was a three speed 'internally geared' bb w/a single chainwheel coupled with a 7 or 8 speed hub w/a single cog. Thanks for having me clarify. Read the link to the SB article and though it's very innovative and funny he doesn't mention a bb w/ig. Everything is based on a triple chainring, 7 sp fw and a 3 sp SA hub. There must be something limiting about the type of torque/motion one applies at the cranks for what my friend and I came up with not to have been developed. Apologies to the OP for the thread drift.

climbhoser

I've thought about the 3spd. BB and IGH option for some time. Not enough to really dig, but I agree that there must be some incompatability for us to not have seen it yet. Though I actually got the idea from someone else's thread drift many moons ago.

uprightbent

Check out the new Jamis 08' Commuter. I have last year's 3.0 model with the Alfine group and love it. I think the new model is the 4.0?

It has 2 rings with a derailer and chain tensioner plus they added disk brakes. Sheldons shop gave the original bike last year great remarks and they stocked it as well. At $539 (for the 3.0) you'll have plenty leftover to add quality accessories and still remain under $1,000 for a nice, simple all weather ride.

grolby

A more likely reason that such a system hasn't been developed on a production bicycle is, as Sheldon Brown says, "nothing exceeds like excess." The technology exists (SRAM DualDrive 3x9, quad front rings, Schlumpf dual drive bottom bracket) to create a bicycle with 216 gears. But such a thing is outside the bounds of usefulness, as is Sheldon's tame-by-comparison 63-speed OTB. I think that we reached the level of covering the ground we needed with triple cranks and 7-speed cassettes and freewheels. More than that is certainly nice, but I think that, beyond 21 speeds, everything else is just gravy.

tcs

The Shimano Nexus/Alfine 8 has goofy ratio steps between the gears. To half step this hub, one would have to use three chainwheels.

Starting with - arbitarily - a 700x32 and 23T cog. The three chainwheels could then be a 42T, 45T and 47T.

Gear progression would be:
1st ratio, 42/23 = 26"
1st ratio, 47/23 = 29"
2nd ratio, 42/23 = 32"
2nd ratio, 45/23 = 34"
3rd ratio, 42/23 = 37"
3rd ratio, 45/23 = 39.5"
4th ratio, 42/23 = 42"
4th ratio, 45/23 = 45"
5th ratio, 42/23 = 49"
5th ratio, 47/23 = 55"
6th ratio, 42/23 = 60"
6th ratio, 45/23 = 64.5"
7th ratio, 42/23 = 70"
7th ratio, 45/23 = 75"
8th ratio, 42/23 = 79"
8th ratio, 45/23 = 85"

TCS

JoebikerLa

I upgraded to a red band nexus 8 from derailure gears with a close ratio cassette. It was a bit difficult getting used to some of the big jumps of the nexus, but I've adjusted. I live in a flat area, so finding one chain ring up front that gives me a comfortable cruse in 6th gear, or whatever gear you are happy with. I have plenty of speed range for the riding that I do.

I wrote all that to say that I don't need two chain rings, I just deal with the hub like it is. I do wish I had closer spacing though.