Replacing OCR Rim

[mike]

Can I rebuild a wheel (using the same spokes and hub) that currently
has a Ritchey OCR rim with one that is not OCR? My OCR rim has a crack
in it (on the brake surface) and I need to replace it. I have a non-OCR
rim that has close to the same ERD (545 vs. 548), but I'm thinking the
offset is not going to allow this to work. I'm new to wheel building
and I figure this is as good a time as any to start learning.

 

[Mike Jacoubowsky]

> Can I rebuild a wheel (using the same spokes and hub) that currently
> has a Ritchey OCR rim with one that is not OCR? My OCR rim has a crack
> in it (on the brake surface) and I need to replace it. I have a non-OCR
> rim that has close to the same ERD (545 vs. 548), but I'm thinking the
> offset is not going to allow this to work. I'm new to wheel building
> and I figure this is as good a time as any to start learning.

The offset rims typically result in substantially less dish, which equalizes
spoke length for each side. A non-OCR rim typically requires 1 to 2mm
difference in spoke length. Add that to the difference in ERD, and I suspect
you've got a non-workable situation if trying to re-use the spokes.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com

 

[daveornee]

Can I rebuild a wheel (using the same spokes and hub) that currently
has a Ritchey OCR rim with one that is not OCR? My OCR rim has a crack
in it (on the brake surface) and I need to replace it. I have a non-OCR
rim that has close to the same ERD (545 vs. 548), but I'm thinking the
offset is not going to allow this to work. I'm new to wheel building
and I figure this is as good a time as any to start learning.

I think they would be off by enough that you might have some threads showing.
Why not get another OCR as they make a positive difference in the strength and reliability of the rear wheel.
What model Ritchey?
I may have one to sell.
dave at ornee dot net

 

[Qui si parla Campagnolo]

mike wrote:
> Can I rebuild a wheel (using the same spokes and hub) that currently
> has a Ritchey OCR rim with one that is not OCR? My OCR rim has a crack
> in it (on the brake surface) and I need to replace it. I have a non-OCR
> rim that has close to the same ERD (545 vs. 548), but I'm thinking the
> offset is not going to allow this to work. I'm new to wheel building
> and I figure this is as good a time as any to start learning.

Could use a another OCR rim, bought from a genuine retailer...not a
garage wrench...

 

[Paul Kopit]

On 12 Dec 2006 20:14:48 -0800, "mike" <[email protected]> wrote:

>Can I rebuild a wheel (using the same spokes and hub) that currently
>has a Ritchey OCR rim with one that is not OCR? My OCR rim has a crack
>in it (on the brake surface) and I need to replace it. I have a non-OCR
>rim that has close to the same ERD (545 vs. 548), but I'm thinking the
>offset is not going to allow this to work. I'm new to wheel building
>and I figure this is as good a time as any to start learning.

I built wheels on non offset rims for a while and they worked fine.
I'd guess what you propose will work too. I am faced with a similar
decision with a Velocity Aerohead rim. I have a non OCR that I would
use for a rear. I hesitate because when riding, I'll constantly know
I could have built up a better wheel.

 

[mike]

I don't know if I can find the same exact one. The rim is about 7 or 8
years old but has less than 500 miles on it. I believe the model is:
Ritchey SCX/OCR 32H. I might try a newer model, but I would probably
bring it in to a bike shop to compare the difference.

 

[mike]

Yeah, I think I'm going to buy an OCR rim, even if the other one might
work. I'll probably bring it into a LBS so that I can compare the new
rim to the old one.

 

[mike]

Sounds like it. Looks like I'm better buying an OCR rim. Thanks for the
help!

 

[mike]

I hear ya. From the advice I've received from everyone here, it sounds
like I'm better off buying a new OCR rim.

 

[daveornee]

I don't know if I can find the same exact one. The rim is about 7 or 8
years old but has less than 500 miles on it. I believe the model is:
Ritchey SCX/OCR 32H. I might try a newer model, but I would probably
bring it in to a bike shop to compare the difference.

I agree with your plan.
Most bicycle shops work with "garage mechanics" to help with good solutions.
I refer potential customers to them when I can. They may be able to tell why you had the crack with such low milage. They should be able to find a suitable replacement with the same ERD so you can reuse your existing spokes.

 

[mike]

Yeah, I'd like to know why the rim cracked. It looks more like a defect
than damage to me. I guess it doesn't matter much...either way I have
to get it replaced.

Thanks for the help!

 

[Victor Kan]

mike wrote:
> I hear ya. From the advice I've received from everyone here, it sounds
> like I'm better off buying a new OCR rim.

I'm kinda in the same boat as you, with a Ritchey OCR rear wheel that
isn't doing too hot (I can't get it true AND round) with my attempts to
rebuild it after some spoke/nipple threads failed.

When I looked at Damon Rinard's spocalc database, I think I saw that the
Velocity Aerohead OCR rim is different enough from the Ritchey OCR rims
that the spoke lengths wouldn't quite match up, but it might have been
"close enough".

If I recall, Ritchey's OCR system has both the offset rim and offset
hub, so the rim is less offset to the left than Velocity's is.

--
I do not accept unsolicited commercial e-mail. Remove NO_UCE for
legitimate replies.

 

[Qui si parla Campagnolo]

Paul Kopit wrote:
> On 12 Dec 2006 20:14:48 -0800, "mike" <[email protected]> wrote:
>
> >Can I rebuild a wheel (using the same spokes and hub) that currently
> >has a Ritchey OCR rim with one that is not OCR? My OCR rim has a crack
> >in it (on the brake surface) and I need to replace it. I have a non-OCR
> >rim that has close to the same ERD (545 vs. 548), but I'm thinking the
> >offset is not going to allow this to work. I'm new to wheel building
> >and I figure this is as good a time as any to start learning.
>
> I built wheels on non offset rims for a while and they worked fine.
> I'd guess what you propose will work too. I am faced with a similar
> decision with a Velocity Aerohead rim. I have a non OCR that I would
> use for a rear. I hesitate because when riding, I'll constantly know
> I could have built up a better wheel.

hmmm..'better' implies that there is something wrong with the non-OCR
one and gee for a few(10?) decades, OCR rims didn't exist and more than
a few wheels were made(Even today!!) w/o this thing and they are fine
and reliable.

 

[Qui si parla Campagnolo]

daveornee wrote:
> mike Wrote:
> > I don't know if I can find the same exact one. The rim is about 7 or 8
> > years old but has less than 500 miles on it. I believe the model is:
> > Ritchey SCX/OCR 32H. I might try a newer model, but I would probably
> > bring it in to a bike shop to compare the difference.
> I agree with your plan.
> Most bicycle shops work with "garage mechanics" to help with good
> solutions.

They do?

> I refer potential customers to them when I can.

How can you have 'customers' if you don't have a business and do this
for 'fun'?

They may be able to
> tell why you had the crack with such low milage. They should be able
> to find a suitable replacement with the same ERD so you can reuse your
> existing spokes.
>
>
> --
> daveornee