I would like to upgrade my wheelset to something newer. Specifically I was thinking about Mavic Aksium (although it remains to be seen what becomes of the current issues with the company). I have an old 80s frame and the dropout spacing is 126mm. I've heard that one can simply cut 2mm from each end of the axle and re-dish the wheel to have it fit the frame. Is this true, and would I be able to usey current drivetrain. It's set up as indexed downtube shifters for 6 speeds. Suntour groupset if it matters. I also saw a couple options of building a wheel from the hub. Velo Orange makes a 126mm hub and there is a complete wheel available from Harris cycles. I don't know to much about either of those options as far as weight, reliability, strength etc... Which route do you recommend? Thanks as always!
Don't cut hubs or respace hubs for this purpose. People who say to do that don't understand how compromised the left to right side tension disparity becomes. And it's not possible with a nonstandard axle set like the one you propose.
Which way to go really depends on whether you're talking about modernizing the drivetrain. You can just respace the frame to 130 with near total impunity if you want a modern group or some aspects of one. The spacing and rear triangle alignment requires string and a 2x4. You'll need dropout alignment tools to do the job right and don't let anyone say otherwise.
Respacing rather than slamming it in is better at preventing fatigue failure over time. There are many questions here about this. Dropout alignment is critical to preventing fatigue failures after a rear end has been respaced.
If you were going to half-convert the drivetrain, ie keep most of the existing parts but make it 7 or 8 speed friction with a cassette hub, Mavic wheels are somewhat of a uniquely poor choice because they've essentially always been 11-speed compatible with the extreme tension disparity and poor drive side bracing angle to boot. Not to say it'd be the end of the world, but you give up something for nothing there I feel. Better to get a common 8/9/10 hub in that case.
If you wanted to keep it 126 freewheel and get a new classic type wheelset, you could go either VO as you say, or the cheaper Origin8 RD-2100, a Quando hub that probably exists by other names as well. If you're US, the wheelsets that J&B does with that hub and which any shop can sell you are a good value for doing this sort of project for pretty cheap. They come paired with a Sun M13II, which is basically perfect if you want something that looks vintage. The equivalent VO set would be nice too, but pricier. Both of these hubs have the drawback of being 126mm freewheel hubs with axles that aren't particularly any more resistant to getting bent than other freewheel hubs but are proprietary shouldered units that would be trickier to replace if needed. The only workaround for that problem in a 126 freewheel cartridge hub is Phil.