Simple wheel building question - new rim, old spokes

[Sweep]

Be gentle with me as maybe a very daft question indeed.

Brought on by the references on here to the demise of the CXP22 rim.

and my plans to start wheel building eventually.

My CXP22 rims are 32 hole.

If I buy another 32 hole rim and copy the same lacing pattern, how likely is it that I can use the same spokes?

I will be using the same hubs of course - rather nice XT ones that I am maintaining rather well.

[fatboy]

All depends on the rim erd. Plenty of on line calculators and sources of rim erd (not always consistent).

Assuming you find time with similar erd re-riminng does not need the wheel to be dismantled. Tape the new rim in line with the old one (noting spoke hole direction and valve hole), loosen the spokes on the wheel so tension is very loose and then transfer each spoke over 1 at a time. Remove the old rim and wind in some tension. I try to get all spokes to the same loose tension (I sometimes just go for the same amount of thread showing from each spoke) before I start adding tension.

Good luck

[Brucey]

CXP22 rim ERD is about 599mm +/- a bit depending on exact model and tolerances.

You can go a bit larger or a bit smaller depending on how the spokes sit in the nipples at present.

cheers

[andrew_s]

Assuming you find time with similar erd re-riminng does not need the wheel to be dismantled. Tape the new rim in line with the old one (noting spoke hole direction and valve hole),

As well as ERD, there's rim handedness to consider.

Most rims have the spoke holes slightly offset, so that spokes to the right-hand hub flange are slightly to the right side of the rim centreline. Rims come in mirror image versions, so that the right-hand spoke next to the valve hole can be either the hole just before the valve hole, or the hole just after the valve hole.

Unfortunately, it's very difficult to find out which handedness any particular model of rim uses, short of actually looking at one in person.
If asking someone else to look at their rim, take care to also specify, or get them to tell you, whether before/after the valve hole is viewed from inside the rim or outside.

Should you end up with a rim of opposite handedness to the old one, the set of spokes in the hub can best be maintained by lining up the valve hole in the new rim one spoke away from that in the old rim.

[fatboy]

Assuming you find time with similar erd re-riminng does not need the wheel to be dismantled. Tape the new rim in line with the old one (noting spoke hole direction and valve hole),

As well as ERD, there's rim handedness to consider.

Most rims have the spoke holes slightly offset, so that spokes to the right-hand hub flange are slightly to the right side of the rim centreline. Rims come in mirror image versions, so that the right-hand spoke next to the valve hole can be either the hole just before the valve hole, or the hole just after the valve hole.

Unfortunately, it's very difficult to find out which handedness any particular model of rim uses, short of actually looking at one in person.
If asking someone else to look at their rim, take care to also specify, or get them to tell you, whether before/after the valve hole is viewed from inside the rim or outside.

Should you end up with a rim of opposite handedness to the old one, the set of spokes in the hub can best be maintained by lining up the valve hole in the new rim one spoke away from that in the old rim.

I've never had the issue and (I confess after a glass of wine!) I can't see how you can't just flip the rim to solve this?

[Brucey]

you can't just flip the rim and solve it. If the rim handedness is different in the new rim your choices are

a) having the valve in the wrong place
b) drilling another valve hole in the rim
c) Ignoring the stagger in the rim drilling
d) relacing one side of the wheel so that the spokes are in different orientations in the hub

the path of least resistance is a), and c) is probably the worst option.

FWIW a CXP22 will have a right-handed stagger, which is the most common sort.

cheers

[fatboy]

you can't just flip the rim and solve it. If the rim handedness is different in the new rim your choices are

a) having the valve in the wrong place
b) drilling another valve hole in the rim
c) Ignoring the stagger in the rim drilling
d) relacing one side of the wheel so that the spokes are in different orientations in the hub

the path of least resistance is a), and c) is probably the worst option.

FWIW a CXP22 will have a right-handed stagger, which is the most common sort.

cheers

Realised how the rim symmetry means that turning makes no difference...

[nigelnightmare]

QUESTION?

What is the reason for the spoke offset being "left" handed if most are "Right" handed?

[Brucey]

In the vast majority of wheels it makes no difference until you come to replace the rim; a very few hubs have the spoke pattern implicit in the flange design but this is incredibly rare.

Some rim manufacturers always make them one way, some the other. Some manufacturers vary it apparently randomly; I have seen versions of the same rim that were all one way and in another size/batch they were all the other. It might be that bike manufacturers prefer one type over the other for some reason (like how their wheelbuilding machines/folks work best).

In truth it is one of these things that ought to be standardised (e.g. like right handed screw threads) because there is no fundamental advantage one way or the other; it is not as if there is any dispute about where best to have the valve in the spoke pattern.

cheers

[mattsccm]

But right handed screw threads have a very good justification. It confuses women!