Aloha Matt !
Sorry , sorry , sorry , for long delay . Just not enough time !
O.K. , here is what you should check :
1.) Wheel dishing , meaning how is the rim centered over the lock-nuts of the axle . This is easy to check . This is commonly talked about . No big deal .
2.) Where the actual hub-shell is located on the axle . This is less commonly talked about . This is changed by changing the spacers on EITHER side , or on BOTH sides !
This is easily done . But I don't remember the exact number , of exactly which size spacers you're supposed to have on each side , for each width of rear-end .
3.) Rear cogs versus rear-end width ( between the rear drop-outs ) .
120 mm = 5 speed
126 mm = 6 speed
130 mm = 9 speed or 10 speed
Of course , we are ignoring the "Ultra" "narrow" freewheels , and also 7 & 8 speeds !
And of course , you can always use FEWER cogs . I've never seen a 3 speed freewheel on a hub & axle set up for a 130 mm rear end . . . but . . . You can always use fewer , such as 5 speeds on a 126 axle-spacing .
4.) With a "bolt-on" rear hub , track style ( or bargain bicycle style ) , you can use an axle that's longer than it needs to be .
With a quick release skewer , if your axle were too long , you might end up having to use washers between the drop-outs and the ends of the skewer .
So , if you change widths , you almost always need to change axles .
5.) Everybody argues over how much damage it causes when somebody "re-spaces" their rear-triangle by "cold-setting" ( bending ) it .
But everybody pretty much agrees that forcing a 126 mm hub into a 120mm frame , or forcing a 130 mm hub into a 130 mm frame - causes no damage .
6.) So , back to your problem , your wheel expert may not have looked at all the details .
a.) FIRST make sure the hub-shell is where it's supposed to be , correctly spaced between the axle lock-nuts . This can be changed by adding or removing spacers , of different sizes , from either side ( or both sides ) . So first make sure the hub flanges and the axle lock-nuts have the right relationship going !
b.) THEN worry about where the rim is , by adding or subtracting "dish" . If the dish is too far off , and you can't fix it by simply loosening all the spokes on one side and tightening all the spokes on the other side . . . well . . . ya hafta buy some new spokes . If it comes to that , try to keep the spokes all coming out of the hub in the same directions as the original spokes . Spokes make dents in hub flanges . There is usually no need to make new dents . Just fill up the old ones with new spokes . There is another side to this argument . Note that I said "usually" . And when building a wheel , if you care about this at all , then look at where the label is , and which side it's facing , BEFORE you lace up the wheel . And the spokes should try to squeeze the seam together , not try to pull it apart . And the valve hole should not have spokes crowding it too closely . Take a look at a well built wheel . You'll see .
c.) Or , you could do things the less-than-perfect way . You could live with poor "dish" . Your tire would not be centered between the chainstays , but , you COULD live with that . The rear brake might not like it too much , but , you COULD live with that . When your bicycle was traveling in a straight line , after going through a puddle , it would leave two ( 2 ) separate little tracks behind it . But you COULD live with that .
AND , people have gotten away with doing things backwards . It is possible to try to center your rim by moving your hub with different spacers on the axle . Again , this is NOT the way your supposed to do it . But , as long as your smallest cog is not actually grinding on your right chainstay . . . and as long as your rear derailleur can deal with things . . . you can mess around somewhat . . .
7.) I'm posting this to the list , in hopes that some nice person will tell you EXACTLY what your spacer-washer count should be , and which sizes they should be , on each side , with a Campagnolo Record 120 mm 5-speed rear hub .
> Hey Raoul!
> Replying off list because I think this question is slightly off topic.
> I'd like to at least pick your brain on this a bit, and I LOVE your
> Anyway, here's the deal:
> My Masi came with a pair of old specialized hubs laced to mavic rims (to
> digress a bit, I totally hear ya on the rim color. Gunmetal rims are
> lame!). Anywho, the original owner had a 126mm 5-spd hub jammed up into
> the frame which is spaced at 120mm. So I got the hub respaced to 120,
> for ease of changing out the rim.
> Now I stick the wheel back in, and all is dandy, and decide to check the
> shifting. On the largest rear cog, the rear derailleur starts whacking
> the spokes, even though it shifted perfectly before!
> What gives?
> Here's what I'm figuring, and you may know the real answer to all of
> In changing the spacing you somehow also change the alignment of the rim
> as it centers up on the frame. Perhaps the wheel needs to be redished?
> HELP! :-)