Problem with Sora crank replacement for 105

"Boris Foelsch" <[email hidden]> wrote in message
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I've seen people say that a good option for a replacement

square taper crank

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these days is a Sora or Tiagra.

So I have an old Bridgestone on which I replaced the old

105 (87vintage)

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cranks (model FC-1050) with a new Sora. I'm using a SRAM

PC-89 chain and

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figured I might have to swap the stainless rings (8 speed)

for Aluminum. I

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stuck a set of 9 speed Dura Ace wheels into the 126 mm

rear end.

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I noticed that it seemed like there was a lot of spindle

showing on both

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sides when I installed the cranks. I even tried twice to

mount the left

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crank because it's so obvious.

I went to check out the shifting and sure enough, I can't

even get into my

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big ring in the front. It's too far off to the side. I've

tourqued the crank

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bolts down pretty hard.

BB Type: Shimano, not sure of the model. Can read BC 1.37

48 VIA UB on the

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ring on the drive side.

Any clues here, please?

This BB worked fine with the 105 cranks. I bent them in

one of several

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crashes years ago, but other than that they worked.

You don't state whether it's double or triple ring, or the length of the current BB spindle.

See Sheldon Brown's pages - sheldonbrown.combottombrackets.htmlOpen ↗ for the correct
bottom bracket length........

105-SC 1055 - Double - 113 (115) - Square 43.5 chainline 130 7-speed 1990-92 105-SC 1056 - Double -
107 - Square 43.5 chainline 130 8-speed 1993- 105-SC 1057 - Triple - 118 - Square 45 chainline

Sora 3300 - Double - 110 - Square 43.5 chainline 130 8-speed 2001-02 Sora 3303 - Triple - 113 -
Square 45 chainline

From the above, looks like you need a shorter BB spindle

The steel rings should work OK with nine speed - the RSX seven speed crank does on my wife's nine
speed setup

Did you readjust the front derailleur (inner and outer stops)? You will definitely have to do this
with a chainline that is farther to the right. But even if you can fix the shifting there may be a
chainline problem.

See sheldonbrown.comchainlineOpen ↗.

You may well need to replace your BB with one with a shorter spindle. There are two ways to do this.
One is to find your crank in a database that lists the proper BB length. Another is to measure your
chainline with the new crank installed and figure out how far you want to move it inward -- say, 4
mm. Now remove your crank and measure your current BB spindle -- say, 118 mm. Subtract twice the
discrepancy (to move the crankarms inward by 4 mm on BOTH the left and right sides) to get the
correct length. In this example, 118 - 2 x 4 = 110
mm.

Mike Yankee

(Address is munged to thwart spammers. To reply, delete everything after "com".)

Boris-<< So I have an old Bridgestone on which I replaced the old 105 (87 vintage) cranks
(model FC-1050) with a new Sora. I'm using a SRAM PC-89 chain and figured I might have to swap
the stainless rings (8 speed) for Aluminum. I stuck a set of 9 speed Dura Ace wheels into the
126 mm rear end.

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<BR><BR>

<< BB Type: Shimano, not sure of the model. Can read BC 1.37 48 VIA UB on the ring on the
drive side.

Any clues here, please? >><BR><BR>

Yep, BB is too long....BB spindle length are matched to crank model, not frameset...

Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
(303)440-3535 vecchios.comvecchios.comOpen ↗ "Ruote convenzionali costruite eccezionalmente bene"

"Qui si parla Campagnolo" <[email hidden]> wrote in message
"]news:[email hidden]...

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Boris-<< So I have an old Bridgestone on which I replaced the old 105 (87 vintage) cranks (model
FC-1050) with a new Sora. I'm using a SRAM PC-89 chain and figured I might have to swap the
stainless rings (8 speed) for Aluminum. I stuck a set of 9 speed Dura Ace wheels into the 126 mm
rear end.

Quoted message said:

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<BR><BR>

<< BB Type: Shimano, not sure of the model. Can read BC 1.37 48 VIA UB on

the

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ring on the drive side.

Any clues here, please? >><BR><BR>

Yep, BB is too long....BB spindle length are matched to crank model, not frameset...

Too bad - the whole point was not to spend the money and time it takes to replace both cranks and a
BB. If I knew I needed to, I probably would have gone to Octalink.

Thanks for the help, Boris

[email hidden] (Qui si parla Campagnolo) wrote in message
news:<[email hidden]>...

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Boris-<< Too bad - the whole point was not to spend the money and time it takes to replace both
cranks and a BB. If I knew I needed to, I probably would have gone to Octalink. >><BR><BR>

Be careful of Octalink, essentially on the way out by shimano. In 2 or so years, may be gone
entirely. If ya gotta have spline-get ISIS...

Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
(303)440-3535 vecchios.comvecchios.comOpen ↗ "Ruote convenzionali costruite eccezionalmente bene"

Why not just find a similar vintage shimano crank on ebay?

"Evan Evans" <[email hidden]> wrote in message
"]news:[email hidden]...

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[email hidden] (Qui si parla Campagnolo) wrote in message

news:<[email hidden]>...

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Boris-<< Too bad - the whole point was not to spend the money and time

it takes

Quoted message said:

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to replace both cranks and a BB. If I knew I needed to, I probably would

have

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gone to Octalink. >><BR><BR>

Be careful of Octalink, essentially on the way out by shimano. In 2 or

so

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years, may be gone entirely. If ya gotta have spline-get ISIS...

Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
(303)440-3535 vecchios.comvecchios.comOpen ↗ "Ruote convenzionali costruite eccezionalmente bene"

Why not just find a similar vintage shimano crank on ebay?

It turns out that with some adjustment of derailleur screws and the cable, it does work. Of course,
my feet are now too far apart, but for what I'll use this bike for, it may be okay. It's my rain
bike and I live in Cali. I'll have to take it on a longer ride and see.

Good point about Octalink going away. The bike industry (well, Shimano anyway) is such a pain about
that sort of thing. I knew square taper wasn't about to disappear.

I haven't had much luck finding bike stuff on ebay.

If the additional spindle length isn't a problem, I've achieved my aim. Crank replacement for under
$50. They look nice too.

Boris