SF Cyclotouring

Ride reports and other ramblings from a San Francisco cyclist.

8/29/2006

Fuji CX goes to 8 speed!

Last night I finally finished up some bike-tweaking that I've been
trying to get to for quite a while...

When I built the Fuji CX up I used some scrounged wheels I had in the
shop, consisting of some old Wolber rims, early 105 freewheel hubs,
and a 7-spd Sachs FW I've been hording in my parts drawer for at least
10 years. I manged to coax the 9-spd barcon to index on the 7-spd FW
using an extreme version of the "alternate cable routing" trick
described at sheldonbrown.com. At any rate, the rear wheel was
problematic at first, and gave me some dishing/truing problems, making
me think that the rim itself is warped. It's actually held up much
better than I expected, but the FW hub makes me nervous (even though
I'm lightweight, I've bent FW-hub axels before on both road bikes and
MTBs) and I really want 8 or 9 speed compatability to better index
with the 9-spd barcon shifter.

So, I kept looking for a good used cheap wheelset on the local
Craigslist, and I found one a few weeks ago -- a guy who lived 1 block
from me was selling a set of Mavic CXP-21s laced to current-gen/9-spd
105 hubs...and he sold 'em to me for $65, which I thought was a darn
good deal. I'm not too sure about the CXP-21 rims...they don't have
eyelets, and I'm a big fan of those (an aside: the CXP-22s DO have
eyelets). They're also about 1mm narrower than the tried-n-true Open
Pro or MA-2 rims, making me wonder about their capability for wider CX
tires. Finally, the oddest thing about them is that, presumably due
to their semi-aero profile, the sidewall braking surface is only about
7.3mm tall, compared to the 10-12mm found on Open Pros and other rims.
V-brake pads are actually TALLER than the rim sidewall, making pad
adjustment a more precise task.

Some poking around on the web made me realize that lots of CX bikes
come with these rims as OEM (e.g., Cannondale) so I figured that
they'd work well enough. I've spent random evenings over the past few
weeks adjusting the hubs (the grease is still fresh-n-clean!) and
truing the wheels, trying to achieve balanced spoke tension. I
initially thought these wheels were reasonably true, but after getting
them home and in the wheelstand I saw differently. Nothing horrible,
but certainly worse than I'd ride. The front rim also had a minor
sidewall ding that I didn't catch when I was buying them, either --
looks like somebody hit a curb or a big pothole or something with an
underinflated tire.

Finally, I spend some more time truing the wheels last night, and
finally got them "good enough". I'm reasonably happy with the
spoke-tension-balance in both wheels, but the front could be a little
straighter. I got some tires mounted (700x35mm foldable Specialized
TriCross -- thought I'd try 'em since they're "Yet Another Set of CX
Tires Kicking Around the Shop") and I also installed the
filth-n-grunge-caked-on XTR 12-32 8spd cassette I picked up for $5 at
last year's Veloswap (I thought it was 9spd when I bought it, DOH).
It cleaned up nicely with lots of elbow grease, an old toothbrush, and
some degreaser. It actually doesn't look too worn and I think it'll
work, which is great because it's LIGHT.

I mounted the wheels, adjusted the v-brakes to suit, and then
re-routed the rear derailleur cable to use the "standard" alternate
cable routing which is supposed to make 9-spd shifters index on an
8-spd cogset. I'm happy to report that works great (at least in the
workstand). Although I don't have a scale to weigh it, the bike feels
quite a bit lighter now, due to the freehub, XTR cassette, and lighter
tires. Looking foward to a quick test ride tonight after work!

On a tangential note, there's a Fuji CX just like mine up on Ebay
right now: http://tinyurl.com/qvjvx I'm curious to see what it sells
for...

1 Comments:

Blogger cyclofiend said...

Oh man! If that bike gets lighter, we're going to have to hide more rocks in your backpack...

Can't wait to see it on the trails!

-- Jim

12:56 PM  

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