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Old 03-11-11, 08:55 PM   #1
rustybucket
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Ultegra Open Pro spoke question

I have a pair of Open Pros that were taco'd in an accident with a car, I want to buy new open pro rims and spokes and build up some new wheels with the old Ultegra hubs.
I bought the wheels new and they were already built. I have removed some spokes from the damaged wheels and measured them and they are different sizes to what the online spoke length calculators recommend.
Can someone please tell if I am measuring from the correct part of the spoke?
The spoke sizes I have when measuring from here are front 294mm, rear left 293 and rear right 291mm.
Online calculators recommend Front 296mm, rear left 296mm and rear right 294mm.
What size should I get?
Open Pro rims on Ultegra 6600 hubs.
Thanks

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Old 03-11-11, 09:47 PM   #2
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Not enough info. Number of spokes? lacing pattern?
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Old 03-11-11, 10:56 PM   #3
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ERD = 602 (Screwdriver flat of nipple)
32H
3X

295.42 @ 295.00

294.63 @ 294.00
292.86 @ 292.00

Will result after final tension and dish with spokes coming to just a hair under the screwdriver flat of standard nipples.

=8-)

The calculators you are using are aiming for the top of the nipple - that's why you are seeing longer lengths.

http://www.mrrabbit.net/wheelsbyflemingapplications.php

Is where mine is...grab the spreadsheet after scrolling part way down...

=8-)
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2. I like anyone will comment in other areas.
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Old 03-12-11, 12:41 AM   #4
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These folks will send you the correct length after telling
them what hub and rim you'll be using. They only sell
double butted Wheelsmith spokes.

http://peterwhitecycles.com/spokes.asp

Model
Weight of 32, 262mm spokes w/o nipples
Price per spoke with nipples
Wheelsmith DB14, 14-16 gauge
172 grams
$1.05 each
Wheelsmith DB14, 14-16 gauge (black)
172 grams
$1.36 each
Wheelsmith XL14, 14-17 gauge
137 grams
$1.30 each
Wheelsmith DH13, 13-14 gauge
220 grams
$1.25 each
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Old 03-12-11, 05:45 AM   #5
rustybucket
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Thank you mrrabbit that spreadsheet is awesome. Must have taken a lot of time. I feel confident in buying the same size spokes that were in my original wheels.
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Old 03-12-11, 12:33 PM   #6
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Yes, you measured correctly from the inside of the elbow (not on-center) to the end.

IMO an actual built wheel trumps a calculated spoke length. Since you're using the same rims, measure the spokes as per your picture, and adjust if you wish according to how high the spokes reach into the nipples. Ideal is between the bottom of the screwdriver slot, and the you of the nipple, so add or subtract from the existing spokes to achieve that.
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Old 03-12-11, 01:10 PM   #7
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If they are not kinked you can reuse the spokes. Make note of which way they were installed and use that on the new rims.
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Old 03-12-11, 04:57 PM   #8
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I was not sure if I could re-use them or not. There are some on the rear that are bent from where the car bumper hit me. The rear wheel is really bent, but I think I could use a lot of the spokes from the front wheel.
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Old 03-12-11, 06:00 PM   #9
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Spokes can handle bending, it's just kinking that they don't like. I expect you can re-use most of your spokes.
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Old 03-12-11, 06:11 PM   #10
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You have to bend them to lace a wheel. A kink on the other hand is a stress riser and the point where a spoke will break.
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Old 03-12-11, 07:23 PM   #11
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If a rim is really bent in an accident, doesn't that put a lot of stress on the spokes, pulling them to one side? Making them weaker?
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Old 03-12-11, 07:31 PM   #12
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Quote:
Originally Posted by rustybucket View Post
If a rim is really bent in an accident, doesn't that put a lot of stress on the spokes, pulling them to one side? Making them weaker?
Spokes tension-wise are rated way beyond what most rims and hubs can handle. It's excessive flex at a given point allowed due to under tensioning, nasty single point kinking, and nasty cutting scrapes that typically do 'em in.

I'd worry more about your rim in this case...it's a very lightweight racing clincher to begin with. Drop by a shop and get a second opinion if you are concerned, and/or post a pic here.

=8-)
__________________
4000+ wheels built since 1984...

Disclaimer:

1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:

Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
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