I’ve only ever seen non-symmetrical lacing applied on rim braked wheels and factory disc wheels with minimal spoke count. On everything else for MTB it’s been either 28 or 32h using a symmetrical, but obviously offset pattern. On road/CX bikes, it tends to be either 24/28 or 28/28 in a 2x or 3x lacing pattern as above.

This is the same technique demonstrated in Roger Musson’s wheel building guide.

I’ve built everything from aluminium and scandium rims upto carbon and from 16h rim braked wheels upto 36h Alfine wheels, everything with discs has been symmetrical, everything with rims was radial front, radial NDS rear and 2x DS rear.

I’m probably over 60 wheels now. No failures, no broken spokes, and always using lightweight DTRev/Sapim D-Light or aero spokes.

No, you should change when you’ve weighed up the arguments for and against change and are convinced.

I’ve already repeated the arguments for lacing the disc side that way above, which to be honest are not mine, they are from Shimano, Sapim, Magura, DT Swiss, Leonard Zinn, Gerd Schraner and others, collated at Peter Verdone’s page.

Very simply it is that when torque is transmitted from hub to rim these spokes should be in tension and supported by the flange. The same logic applies to the driving forces on the other side of a rear, although since braking forces are higher than drive forces they’re more important.

On the other side of the argument you have Jobst Brandt and Ric Hjertberg suggesting that neither drive nor braking forces are significant overall, so you can do it whichever way you like, and the caliper clearance idea is an argument for staying symmetric per Chris King.

I guess I’m coming round to the arguable either way position. Personally, I find it easy to lace either way now, and I think there’s more merit to the arguments for asymmetric and know that it’s a minor issue in building a strong wheel.

The wheel building guides I’ve seen didn’t seem to think a disc wheel needed to be built particularly different. The one I used is Sheldon Brown –
I’m not sure what the Roger Musson one says.

I’ve only built 3 sets of wheels so far, all mtb disc wheels, and I built them all with 32 spokes and a standard 3 cross pattern. Can’t see any issues so far – does having a disc brake put particularlu more stress through a wheel structure than either the torque from pedalling or rim brakes?

Not looked in here since I decided to build the wheels, good to see some healthy debate but you lost me on asym…

Thought I’d follow up in case anyone cares or should stumble upon this in the future…

I decided to get a regular rim with the same ERD as the one I was taking from the lefty. I taped these together and shifted the spokes over. That was easy. Anyone want to buy a lefty??

I then got the right length spokes from that sdeals site (cheers to whoever sent us that link) for 30p/spoke (DT Swiss) about £13 total – they were silver not black as would have been preferred but they actually look OK and I don’t care much about spoke colour anyway – at least not on this bike.
(getting the right spokes is probably the most nerve wrecking step. Trust the online calculators, I used three or so and measured everything myself for a sanity check and all came out about the same size within 1 or 2 mm).

Laced up the wheel and hub using a youtube video and Rogers guide. Made a couple of erros along the way as wasn’t paying attention but it was obvious when something was wrong and easily rectified after taking a closer look. In short, lacing the wheel was easy too.

Next, truing… not so easy. I probably spent about 2 evenings (6 hours?) truing and tweaking both wheels, at one point each wheel was untensioned and started again and I had to walk away at a couple of points too. But I then started to get a feel for it. Initially my changes were too much, once the wheel is under tension small changes make quite a difference and it took me a while to get my head around the impact. I tried various methods for gauging the wobble but found that a combination square taped to the fork worked best for me, and a guitar plectrum for finding the spoke that loose/tight and a DIY nipple driver from an angle grinded Philips screwdriver to get everything kicked off. Heard folks say that they can tune a guitar by ear but not hear a difference in the spokes – I don’t get that, it seemed very obvious to me. The wheels weren’t perfect but they were within 1mm and just as true as the wheels I tested off my other bikes that were recently serviced.

In summary, my advice to anyone thinking about giving it a shot would be to go for it. It’s easy to lace the wheel and if it all goes tits up after that it’s just a truing job down at the LBS.