I am planing to build two 26" wheels. I want to lace the right side (freehub side) of the rear wheel with cross 4 pattern? Or maybe both wheels, both sides with cross 4 pattern? What do you think?

How many spokes per wheel?You need 36 or more.
No real advantage over 3X.

Not really sure if those are questions or statements?

Why cross 4?

There is nothing magical about the number of crosses, it has to do with the spoke angles at the hub flange and at the rim. What do you hope to gain by doing one side 3X and the other side 4X?

And isn't cross-4 weaker laterally? I always thought the only advantage was torsional strength.

Pretty much, that and it puts a tangential rather than radial stress on hub flanges, some of which may tend to fail in the latter case. Downside is it's less laterally stiff and a very teensy bit heavier. Structurally, radial is best if there's no torque to transfer between the hub and rim and the hub is designed to take it.

On small flange hubs, the difference between 4x and 3x is negligeable, since the spoke length and line of action is only slightly different. It does make more difference on larger flanges, but again, nothing earth shaking.

As, noted, you need 36 or more spokes to build 4x, otherwist, your spokes will be passing beyond the hubs centerline.

Back in the day when 36h was king, 4x was a popular pattern especially for OEMs because the same spokes could be used regardless of flange size, reducing the inventory by builders.

You need pretty large flanges and a high spoke count for x4 to make sense. Otherwise your spokes go past the 90° mark, which is a bad thing not just because you have spokes going over the heads of others, but mainly because torsion on the wheel will actually cause the spoke tension to decrease.

36 spokes, high flange (disc brake) hub. And first I will calculate spoke length with this spoke calculator https://www.machinehead-software.co.u...alculator.html and determine if the spokes touch the other spoke head on the flange.
So, do you think that 4x on the right and 3x od the left will be a good choice?

I don't rely on calculations myself, since you don't know if you've made a mistake until you go to lace it up.

I just do a test lace with some old spokes I know are more than long enough, only takes 15 minutes.

with 36h 4x is a no problem pattern, with the spokes going to the hub's centerline. There's no reason not to, and either 4x or 3x will work fine, with 4x maybe having a marginal advantage in wheel longevity, especially with a disc brake.

In any case whatever logic you use to decide on 3x or 4x would apply to both sides so pick one and go with it on both flanges. You're building a bike wheel, not mediating a union dispute so there's no reason to try to compromise with a half and half build.

Mavic E2 rim, laced a 36* Campag Hi-low flange (freewheel) hub DS 3X, NDS 4X
15ga plain spokes. it's been fine for decades.. NDS was just a bit longer than if 3X.


48 hole 5x, 40 , 4X touring wheels covered a lot of miles, 3 tours, before I sold them
& went 48 4x, 40 3x on the next set..

Actually, on the MachineHead Spoke Calculator there's a very cool Spoke Pattern Explorer https://www.machinehead-software.co.u..._explorer.html that shows if the spokes will touch the heads of the neighboring spokes.

36 hole 4 cross is the least likely to crack out the spoke hole,

as 1st cross is compressing the flange between the 2 neighboring spokes, as they pass each other,

going to the rim in opposing directions.