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Old 05-15-12, 11:16 AM   #1
Puget Pounder
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Should I use my normal rim or try to find an off-center?

So I ordered a set of 650B synergy rims form QBP at cost, but the O/C version was not available, so I ordered 2 normal ones. Should I go through the trouble of finding an OC rim or just build up the normal version? 32 spokes, only 150lbs, and on an Ultegra hub that requires less drastic dishing anyways. Should I even bother?
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Old 05-15-12, 12:33 PM   #2
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10+ years of experience with millions of riders has proven that well built 32h wheels are more than adequate to the task and hold up fine to normal use. At 150#s you're easily within the range where you shouldn't expect wheel problems with normal (center drilled) rims.

Yes, an offset rim would reduce the L/R tension difference, but won't make a practical difference in your case. If you weighed 200+ pounds my answer might be different, But even there it's only might since I weigh 190#s and have never had any wheel issues with very light (305gr) rims, in over 100,000 miles of riding.
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Old 05-15-12, 01:56 PM   #3
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An o/c rim would be technically "better", but you won't notice "better" as long as "average" is good enough.

Of course, unless you're limited by time, going for "Better" can be strangely fulfilling.
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Old 05-15-12, 03:22 PM   #4
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OC rims have their own issues. Since your weight will not be a concern, I would stay with the standard drilling. If you were heavy or used Campy, there might be a reason for the OC. IMHO
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Old 05-15-12, 05:05 PM   #5
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Whether you should use an OC rim just comes down to whether you can find one in the spec you desire, IMO. If I had to wait a few weeks, I would.

Also, smaller rims like 650b will accentuate the tension difference a bit due to the greater proximity to the hub. I think... been up a bit too long to reliably intuit Pythagoras.

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OC rims have their own issues.
What are those, then? I'd be amazed if there's a single intrinsic downside.
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Old 05-16-12, 11:37 AM   #6
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Perhaps I will try to trade for one. I know that there probably won't be a noticeable difference for me since I'm a pretty light rider, but it'd just be cool to have. Thanks for the input. More input is welcome of course
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Old 05-16-12, 11:44 AM   #7
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Quote:
Originally Posted by Puget Pounder View Post
Perhaps I will try to trade for one. I know that there probably won't be a noticeable difference for me since I'm a pretty light rider, but it'd just be cool to have. Thanks for the input. More input is welcome of course
FYI- there's been bit of history of offset rims stress cracking at the holes sooner than they're symmetrical counterparts. I don't follow this stuff closely, so it may be old news and now resolved. But otherwise consider that you may be trading up for an improvement that won't make a difference to you, at the expense of something that will.

Possibly someone like mrrabbit who has more current experience with offset rims can chime in and confirm either way.
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Old 05-16-12, 01:02 PM   #8
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It comes down to how the vendor applies the feature...

Use the OCR profile in a lightweight racing clincher - it usually means a very thin wall. The likelihood increases that a circumferential stress line w/separation will develop on the drive side between the profile center and the sidewall.

Several manufacturers have run the gamut with this feature...but then again...lightweight racing clinchers when used regularly aren't expected to last anywhere near middleweights and heavyweights to begin with.

I've tossed quite a few lightweight OCR Ritchey's and Bontragers in the past that had this crack develop - with the Bontragers also being of the paired spoke type (bleah!).

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Old 05-17-12, 02:16 AM   #9
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Anyone have any info about the OC Aerohead's durability? Those are light.
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Old 05-17-12, 08:36 AM   #10
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I have 4 setups with Aerohead OCs and have seen zero problems with any (although less than 2K miles on most of them). I've heard of problems with Bontrager Race Lite OCs but my two Race X Lite OCs were acquired used with (supposedly > 6K miles on one) and show no problems.

I've gotten so used to building OC rears that I find the variable tension of a symmetric rear to be a harder build (I build and rebuild a lot. It's strangely theraputic)
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Old 05-17-12, 11:53 AM   #11
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Narrow rims the offset is rather small, is it not?
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Old 05-19-12, 06:26 AM   #12
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Doesn't matter; it has to be at least 4mm, which is worth an increase of 8mm OLD.

That's nothing to sneeze at.

Actually, looking at this, it seems like 3.5mm.


That's easily enough to make quite a difference, if my experience increasing OLD by 5mm is any guide.

Last edited by Kimmo; 05-19-12 at 06:33 AM.
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