hss one swb homebuilt

Hi

I really fancy building a swb bent, and am impressed with the plans of the
hss one, but have a couple of questions if anyone has experience of this
model:

What gear combinations are needed for the 20/20 configuration

Has anyone built a 26/20 version, i am reluctant to play with the design in
case i cause problems with the handling.

regards

Gary

--
visit our website at www.justjents.co.uk

Gary Teale wrote:

Hi

I really fancy building a swb bent, and am impressed with the plans of the
hss one, but have a couple of questions if anyone has experience of this
model:

What gear combinations are needed for the 20/20 configuration...

Using an ISO 406-mm (or other sized in the range of ISO 305-mm to ISO
451-mm) drivewheel presents a few challenges, since the overall gearing
range will be smaller for a given tooth differential between the front
chainrings compared to using a larger diameter drivewheel.

Large chainrings have the disadvantage of slower/poorer front shifting
and greater cost, but are commonly used by some manufacturers, e.g. RANS
Rocket and Tailwind.

If you do not mind a bit of extra weight, a tiny bit of extra drivetrain
friction, and no quick release, the SRAM 3x7/8/9 DualDrive hub will
provide a wider gearing range than any triple crank that can be handled
with a stock front derailleur.

A mid-drive jackshaft allows for a very wide gearing range with normal
road or MTB cranks and the overall gearing range can be altered by
changing a single cog, e.g. Earth Cycles Sunset Lowracer [TM]. The
disadvantages are that the jackshaft and front chain tensioner will
custom parts, overall weight will be slightly greater, and drivetrain
friction will be slighter greater than some single chain set-ups.

A mid-drive using a single chainring, two cassettes, and two rear
derailleurs can also provide a wide gearing range. Parts should be
available from Rotator, which uses this arrangement on most versions of
the Tiger and Pursuit.

The Rohloff hub will provide a wide gearing range, with drivetrain
friction and overall weight not to different from a derailleur system
[1]. Its main drawback is the ca. $900 US MSRP.

The Schlumpf series of two-speed bottom brackets/cranks will provide a
very wide gearing range, however, the jump in gearing will be very large
when shifting between ranges, which requires correct double shifting on
the part of the rider to end up in a reasonable combination. The
disadvantage is cost [2], weight, and drivetrain friction.

[1] Especially if you have Rohloff compatible rear dropouts to eliminate
the torque arm and use an eccentric BB to eliminate the chain tensioner.
[2] Especially for US residents, with the recent drop in the exchange
value of the dollar.

--
Tom Sherman - Earth (Downstate Illinois, North of Forgottonia)

Gary Teale wrote:
Hi

I really fancy building a swb bent, and am impressed with the plans
of the hss one, but have a couple of questions if anyone has
experience of this model:

What gear combinations are needed for the 20/20 configuration

Depends what cadence you tend to use and whether you favour a high top end
for pedalling down hills over a low bottom for draggin up 'em. My Trice XXL
has a 24-42-52 chainset, 11-34 cassette and 406 rear wheel, giving a gear
range of 13-86". This is entirely adequate for me, but others look on in
horror and/or amazement.

The ICE-modified Shimano Capreo hub/cassette combination allows a 9-33 or
9-34 rear end, which may be preferable and doesn't add weight, complication
or that much financial outlay.

--

Dave Larrington - http://www.legslarry.beerdrinkers.co.uk/
World Domination?
Just find a world that's into that kind of thing, then chain to the
floor and walk up and down on it in high heels. (Mr. Sunshine)