I have several rim and hub pairs that need to be built-up. They are all 36 hole and either 27" or 700c. Each pair will serve a different purpose, either commuting, touring or speeding along a smooth bike path.

What are the advantages and disadvantages of 3X and 4X spoke patterns in road bike wheels?

It's all about the angles: Ideally you'd like for the spokes to b e tangent at the hub and radial at the rim but you can't have both at the same time. Too many crosses will cause the spokes to overlap the adjacent spoke at the hub flange and, in an extreme case, can lead to spokes breaking at the nipple due to the angle they enter the rim. Too few crosses pull at the hub flange where it's weakest. Radial spoked hubs used to pull apart often enough that Shimano, for one, reinforced at least some of their front hubs.

Having said all that, unless you are using uncommonly large diameter hubs, I can't imagine having any issues with either 3 cross or 4 cross on 27" or 700c wheels. I've personally always built 36 spoke wheels 3 cross and 40 spoke wheels 4 cross.

Got it, thanks for clarifying that. I have only built a few pair of 3X wheels on old Normandy high flange hubs, they are slightly smaller in diameter than Campy Record high flange.

The reason I was curious about 3X vs 4X is because i just picked up a pair of wheels with 27" rims, Normandy HF hubs and 4X spoke pattern and was wondering why someone would build them that way. Would it have been for durability or comfort?

Raleigh, and other English bike people, used to do that--36h, 4X, high flange. My wag was that they did it because with 36 hole and 4X spoke length doesn't vary as much with changes in dish and hub flange diameter. It's almost completely determined by rim ERD. You can use the same spokes for front, rear, right and left. Then, just hire a teenager with a BA grinder. At least, that's what a lot of raleigh wheels looked like. For example, calculated spoke length difference for 4X (ERD 620mm) changes only about 1mm with either 40mm or 60 mm flange diameter. With 3X the variation is about 4 1/2 mm. Also, supposedly 4X wheels are more durable, but I don't think anybody makes that claim anymore.

One thing about 4X and 630mm rims (ERD about 620, or so) is that you end up with spokes about 307 or 308 mm and it seems uncommon to find spoke longer than about 300 mm listed as stocked, though I've seen some. That seems to indicate to me that not many people are building 622mm and 630 mm rims with 4X anymore. Not everybody can be wrong, can they?

Personally, I rarely build 4X except with 40h Sturmey Archer hubs. Built with some Normandy HF hubs for a Raleigh and used 3X and no singularity occurred.

4 cross, the spokes compress the hub flange aluminum between them ,
as 1st cross is the spoke on the opposite side of the hub flange,
going to the opposite edge of the rim..

3 cross and less the spoke force is pulling in Shear..
Spoke tension , pulling the hole in the aluminum outward towards it's edge..




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If the hub is a little 40mm/ hole circle 38mm, then likely use 4 cross.
I recently changed my rim on an old bike, reusing an old but nice front hub. Went from 590 to 584 rim. I goofed and went to 3 cross, thinking the heads would be less overlapped.
So the spoke crossover point moved about 20mm closer to the hub. This resulted in a 1 or 2 mm more bow along the spoke. This is both uglier and more unnecessary stress. And the spoke length would have been the same, darn it. But anyway, I will leave it, likely will be OK. I think 2 cross on really big IGH hubs is best.

Divide the number of spokes by 9. The largest whole number (without the .xxx - what's the English word? ) is the max theoretical number of crosses that a wheel can be built with. Generally, for most 26" and greater size rims.

Depending on rim diameter and hub flange diameter, this can vary. Spokecalc I use does warn if, based on effective rim diameter and flange diameter etc, there is a situation that a spoke will overlap the head of adjacent spoke - something that should generally be avoided.

The more crosses, the more the spokes are tangent, which is better (stronger wheel, pluss less stress on the flanges), as the other posters have nicely explained. Up to a point where spokes cross over the heads of adjacent spokes (sober, and still repeating myself, sorry ).

3X seems to be the way to go. Thanks for the response

Thanks for the reply and especially the spoke calculator. Nice website by the way!

I think I follow what you are saying. In 4X, the compressive force lies between two adjacent spokes...

So generally speaking, smaller diameter hubs can have more crossover points.

Here's the same hub and rim with 3X pattern...

For reference in the 1960s through the '80s Schwinn used 4x lacing on all high-end bikes and 3x on everything else. They must have thought there was a difference.

More crosses braces a wheel more against torsional forces between hub and rim. But excessive crossing can create issues like the spokes entering the rim at too-oblique angles if the hub flange is too big or rim ERD is too small, and the longer spokes also result in a slightly heavier wheel.

For 36-hole wheels... if these are 700c wheels where the rim is shallow box-section and the hub is low-flange, then you're starting to get into the territory where you can get away with 4-cross, but 3-cross will work too. If you've got a smaller ERD or a high-flange hub, I think you should stick with 3-cross.

I like wheels with the max number of crosses and have built many 4X 36 spoke wheels. Low flange racing wheels, high flange Campy Tipos; probably the biggest common flange diameter out there. My wheels went (and go) a long ways without spoke issues. Several have talked here of the interference between spokes and adjacent heads being an issue. It hasn't been for me and some of my hubs with interference have gone very long distances. I consider it an old wives tale as it matches my experience so poorly. (I build my wheels 4X, note the interference and wonder how long it will be before it gets pointed out I built it "wrong". I still have 2 Tipo front hubs that I still lace up 4X. They are winter wheels so the rims get replaced fairly regularly but I reuse the spokes and pattern.

Edit: One place the extra cross really helps is comfort on chip seal. Riding rural Oregon 4X is a real plus.

Ben

Not sure I understand the "comfort" thing reffered to.

As for spoke head overlap - similar experience, had no problems, when all done properly. All with 36 spoked 4X wheels. It should be noted that it's not perfect - makes changing a spoke (if needed later) a little bit more complicated and one needst to and can often place an extra bend (over the adjacent spoke head) on the already pretty stressed part of the spoke.

Though, if I'm the one building a wheel (choosing spoke length etc.), I opt for no spoke head overlap.

I have built a 5 cross 48 hole rear , was my touring wheel for 10 years.






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