I have a Dura Ace rear hub. It measures 133.2mm on the digital caliper. Was zerod before using. What the heck? I don't know what width to call this.

Someone engraved "Dura Ace" on your Campagnolo hub, probably when they respaced it.

Show a picture of the Campagnolo hub.

I believe Trek 520's had 132.5mm drop out spacing in the 90's.
It is rather unusual to see a Dura Ace freewheel hub spaced that far out though.

and that far off center too...
it appears to be a homespun "i'll change this to 135mm!" hack job.

the 132mm width dropouts were intended to fit either a 130 or 135mm O.L.D. hub... and didn't work well with either option.

i had a project road bike a few years ago that came to me with a 132-ish dropout width... i reset it to 130.

*that must be the ultra-rare Campy Super DA group's hub...

Sorry. Sorry. It is a Dura Ace. I would consider removing that large spacer in there and recentering but then I am concerned the axle would be too long.

just checked a spare DA freewheel hub... 36mm from FW thread shoulder to outside of locknut... 25mm from seal face to outside of locknut.
plenty of room for a 7sp. freewheel on it... overall axle length is 137mm, overall... 126mm OLD.
add any width remaining to achieve your desired OLD to the NDS end of the axle

stack... axle cone/1mm washer/inner 3mm locknut/10mm spacer, outer 6mm locknut with serrated flange out.
this is an old slotted style axle set.. 1mm washer is tabbed to the slot.

the idea is to make the drive side spokes angle in as much as possible, and also maintain the chainline of the freewheel, yet provide clearance for the chain while it's on the small sprocket of the freewheel.
a properly set up rear axle/hub will allow swapping to another wheel with minimal, or NO readjustments, to the rear derailleur.
i did such swaps fairly often with my DB Ascent bike... literally zero adjustments needed.

QR bare axle protrusion beyond the outer locknut is typically 4.5 to 5.5mm.

All the axle has to do is not hit the inside of the QR nut and head when fully tightened. (And not destroy the springs.) With many QRs the axle can be very close to protruding from the dropout and still have everything work. And if it doesn't, "adjusting" the length downward with a file or hacksaw is perfectly OK. Just keep the steel and abrasives dust out of the hub internals.

Hacksaw

Right. But if I am going to sell this on Ebay, which was the plan, I have the matching front hub, I can't say "Use a hacksaw...."

Edited.

Buy a used axle.

Q: could the engraving process cause the metal to stretch?

Your other option is to make you caliper disappear, list the hubs on ebay and play dumb after the buyer notices. Anyone buying these for a decent price is just going to fix them and move on.

Looks like somebody added a couple washers to a 126.5 mm 7400 hub, perhaps to make it work on a frame with 135 mm dropouts, and gave up on it. Your caliper is hiding the axle ends, so I can only guess that the axle is the standard length for this kind of hub, ~137 mm.

what the heck; you said "Campagnolo."

if people wanted to pay full price, they wouldn't be scouring the 'Bay.

that spacer on the Drive Side is too long, by 6 or more mm... and the proper DA spacer is 10mm.

measure the spacer using the caliper's mm scale, and a toothpick, and your thumbnail as a "mark". it's 16-17mm.
that spacer is the big issue.
any additional spacers/washers should be placed on the non drive side to obtain the desired OLD.
the drive side needs to be the dimensions i posted above.

note the grooved spacer, at a 10mm width.. this is the proper setup.
it's a 130mm OLD hub, btw...

https://i.ebayimg.com/images/g/yqcAA...U9H/s-l960.jpg

https://i.ebayimg.com/images/g/I4EAA...U9R/s-l960.jpg

Here is the length of the remaining axle. I do have as spacer a shown in the link above. I'll just substitute that one, even the sides out and call it good.

Total axle length is 141mm. With the change is spacers and a couple tiny washers am now at 129.5mm. Thanks to all.

Correct procedure is as follows:

It's called Dimension A

Freewheel Stop to End of Locknut

Make sure that comes out to 37.00mm.

Then, use remaining spacers and locknut on the NON-DRIVE side to establish the 126mm or 130mm spacing that the hub should be.

If you measure Dimension A now on your current setup and already have 37.00mm, then you got lucky and are already done.

Meanwhile I have to ask all the other posters...

Why do you guys keep going into these extended discussions after I have posted here many times over the following chart that is available for all to bookmark AND print out?

https://www.mrrabbit.net/docs/freewhe...OLD_sizing.pdf

This is already finished. Thank you.

If the other side of the hub has the same amount of axle showing, you did a fine job.