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Open Pro Rim / Wheel rebuild(10 posts)

Open Pro Rim / Wheel rebuildGeekRoadie
Jan 19, 2004 10:43 AM
I recently got tangled up in a crit wreck and suffered a damaged frame and out of true rear wheel. A question for you experienced wheel builders. Would it be worthwhile to rebuild with a new rim or can I use my old one. With the wheel completely disassembled, the rim has 1/2" variance around the circumference (tested by laying the rim on its side on a flat surface). Would it be reasonable to think that I can get this rim straight during the wheel build? Or, will this result in too much variance in spoke tension? The sidewalls and eyelets seem fine. I'm thinking I should buy a new one but wanted to see what you guys have done.. New spokes will be used either way.
Don't even think about it.Spoke Wrench
Jan 19, 2004 11:14 AM
That rim is trashed.
Depends on if is a small section or gradual changebimini
Jan 19, 2004 11:21 AM
If it is a gradual change, you should be able to pull it in easily. If the change is over a small section then you need a new rim. Also, check the radial trueness (remove the tire and watch the up and down motion of the rim when the wheel is turned. If there is an inward dip or flat spot the rim is toast.

Unless the spokes are damaged I would not replace them. Stainless work hardens, which means it gets stronger under cyclic load. Your spokes are just broken in. The pro's like to change out spokes just because it is the way it is the professional way (and allows them to sell a few spokes). Aluminum nipples I would change out, they fatigue with cyclic loads.

PS: I'm just a hobbiest who has been dinking with wheels for 30 years, not a pro.
Only for an emergency sparespluti
Jan 19, 2004 11:59 AM
I might try pushing the rim around with some careful vise work and a couple of blocks of wood. Anything you can use for leverage that won't cause more damage. If you can tweak more than half that damage out of it before relacing with new spokes and nipples it might make a good spare wheel.
You need a new rim.DaveLobster
Jan 19, 2004 2:16 PM
You can relace the old rim and make it round and true, but only at the expense of having completely out of whack tension. There was a discussion on the 'components' board, saying that if the ideal is even spoke tension, but truing out rim issues makes for uneven spoke tension, then the ideal wheel would start with a perfectly round rim.

As far as 'straightening' the rim first, I especially wouldn't do it on a rear wheel, which is the wheel which takes the most weight (look at how your tires wear), and is most likely to go untrue in the first place (which has a lot to do with the design of modern 9/10-speed freehubs, but that's another post).

If you don't want to shell out what the OP's cost, since you are getting new spokes anyhow you can get a different rim. Velocity Aerohead OC's are cheaper, lighter, and have an offset design that makes for a stronger rear wheel.
Don't be so cheap!Dave_Stohler
Jan 19, 2004 4:32 PM
that rim is toast. Bring it down to the recycling center, because all it's worth is $.2/lb for scrap aluminum.
New Rim time...GeekRoadie
Jan 19, 2004 6:59 PM
Got it, I am going to rebuild with new rim(s). I'm intrigued with the idea of Velocity Aerohead or IRD Cadence rims. They both seem comparable to my trusty OP's. I know that the Aeroheads have a good following here. By chance do any of you know what the spoke lengths are for the Aerohead OC version w/Ultegra?
Google time!pitt83
Jan 20, 2004 7:26 AM
Google "spoke length calculator" and find the .XLS spreadsheet. Gives lengths for most any hub / rim / cross pattern combo. DT website has precious few.

I was gun shy about it, so went to the LBS to order spokes instead of on-line. They use the exact same XLS.
Spoke Lengths....DaveLobster
Jan 20, 2004 1:02 PM
For the Aerohead OC, use 292mm for non-drive side and 291mm for the drive-side.

If you do use the spoke calc, remember that to compensate for the off-set rim, you need adjust the hub dimensions by adding the offset (3mm) to the drive side flange to center dimension, and subtract it from the non-drive side flange to center dimension.

-Dave
Shade tree mechanic trickKerry Irons
Jan 19, 2004 8:45 PM
Per others' comments, if the 1/2" is a "wow" rather than a dent, you might have a chance. To improve your odds, remove the wow by bracing the rim against a door frame and trying to straighten it with by leaning on it with your arms locked. Repeated pushes with increasing intensity are typically required. If you start with a rim that far out of true, you will not get a good wheel from the build.