Update on 2011 Soma Buena Vista 650B build
somervillebikes
frameset around a 650B IGH wheelset for my wife. I thought I'd
provide an update and a couple of refresher pics. This bike was built
up as a city bike with a lot of comfort-cruiser elements incorporated
for the type of riding my wife does-- almost exclusively short errands
around the city, with the occasional recreational ride of 10 miles or
less-- sometimes on gravel paths. My wife originally wanted a vintage
mixte, but finding one in her size (58cm) proved impossible. So we
settled on a new build with mostly new parts. I was intrigued by the
Soma mixte frameset because it seemed to have all the right
ingredients for a 650B build-- gobs of clearance at the fork crown and
rear triangle, 59mm brake reach with 650B wheels, and an okay (not
ideal) BB height. I was so impressed with Hetres on my previous 650B
project that I wanted to fit her bike with them as well. The Hetres
fit with plenty of room to spare!
After a few months of use, my wife reported knee pain and numbness in
her foot. Admittedly, the original Brooks B17 was never the
appropriate saddle given the relative height of the handlebars, but at
the last phase of the build I ended up going into "budget" mode and
started pulling parts out of my bins. So eventually we swapped it out
for a B67. I also swapped out the MKS touring pedals for cruiser
pedals with a flatter platform, and a narrower bottom bracket to
reduce the tread (again, I skimped in the original build and used an
unnecessarily wide 124mm BB that I had in my parts bin). The trio of
mods seems to have done the trick.
My wife also complained of a lack of a basket, so I added a locally
made basket (Peterborough baskets, made in Peterborough, NH). I used
a decaleur to support the basket from above, and an additional fender
stay with P-clamp to prop it from below (taking advantage of the mid-
fork threaded bosses as attachment points for the stays). This keeps
the basket well below the handlebars and also triangulates the front
fender attachment. It's worked out well so far and obviates the need
for a front rack to properly support the basket.
http://farm8.staticflickr.com/7070/6905908251_bec3c7bbff_b.jpg
http://farm8.staticflickr.com/7189/6910108905_1c0551377f_b.jpg
Complete flickr set here: http://www.flickr.com/photos/7516215@N03/sets/72157626542404830/with/6905908251/
Anton Tutter
Somerville, MA
somervillebikes
with 700C.
Alex Wetmore
I like the basket setup, it seems like a nice solution for light loads.
It looks like you are running it with a Shimano Nexus or Alfine rear hub. If you ever have shifting problems (especially into 1st gear under load) try moving the cable housing clamp forward as far as you can. The short run of housing with two bends like that doesn't work so well with the Shimano IGHs. Bike manufacturers who build bikes for IGHs should do a better job of this, they just need to move the stop forward about 4" from it's normal location, but they don't. On my wife's Soma Mixte the stop was farther forward than where it is on your bike, it did work in the original location.
alex
________________________________________
From: 65...@googlegroups.com [65...@googlegroups.com] on behalf of somervillebikes [atu...@gmail.com]
Sent: Monday, February 20, 2012 8:13 AM
To: 650b
Subject: [650B] Update on 2011 Soma Buena Vista 650B build
http://farm8.staticflickr.com/7070/6905908251_bec3c7bbff_b.jpg
http://farm8.staticflickr.com/7189/6910108905_1c0551377f_b.jpg
Anton Tutter
Somerville, MA
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somervillebikes
The IGH is a Nexus "red band" 8. I'm not thrilled with it, as the
gear spacing is really odd and 4th seems so inefficient compared to
the direct drive 5th that it never makes sense to use 4th-- it always
makes pedaling even harder. But Mrs. S likes it just fine and enjoys
its integration and outward simplicity. We live on the tallest peak of
a very hilly town, and Mrs S is also commonly pulling a Burley
Piccolo, so the ability to change gears when at rest is also quite
nice.
As for the geometry, the 58cm frame has 73 degree parallel geometry.
I considered that reasonable given the long virtual TT (58.2cm).
That cable stop is indeed a problem. I have the clamp placed as far
forward as is permitted by the diameter of the chain stay, and in fact
I have the clamp stretched quite a bit where it is. The cable housing
between that clamp and the IGH does have a mild sigmoidal kink, but
I've confirmed many times that it doesn't ever restrict the cable
movement. The return spring on the IGH is plenty strong to instantly
take up any slack. That said, the hub does occasionally skip within
about seconds after downshifting from 4th to 3rd. It happens more in
cooler weather, but I've concluded that the cause must be internal to
the hub; even in the coldest weather the shifter cable does not get
hung up at that kink, not even for a second.
Is there any reason you can think of not to eliminate the short run of
housing and cable stop clamp, and just run housing-less cable all the
way from the downtube cable stop to the hub? I can't, except for the
theoretical possibility of frame flex.
Anton Tutter
Somerville, MA
Fred Blasdel
>
> Is there any reason you can think of not to eliminate the short run of
> housing and cable stop clamp, and just run housing-less cable all the
> way from the downtube cable stop to the hub? I can't, except for the
> theoretical possibility of frame flex.
I had exactly this setup on my old Kogswell for its last 8-9000 miles,
be prepared to fiddle with the cable tension Every Single Time the
wheel is removed from the frame. You also need to be mindful of the
loose cable, it's fairly easy to end up kinking it or pulling it out
of the bb guide.
After enough use in poor weather the little window on top of the
"cassette joint" will eventually be too fouled to see through, but it
can be removed so you can still see the tick marks to get the tension
right. Also be careful when overhauling the hub, good solvents will
dissolve the yellow and red paint used for the alignment markings.