Looking to get some opinions on lacing pattern for my road disc build. It's:
* Tune hubs (tall 55.5mm flanges front and rear)
* Enve SES 3.4 rims
* DT Aerolight spokes
I have already bought spokes for 2x lacing all around, but just unpacked the rims and found there's a sticker on them that suggests 3x lacing. Both front and rear wheel are 24 hole, and on a 24 hole standard rear wheel I'd always do 2x lacing since the spokes are shorter (lighter,stiffer) than with 3x and the bracing angle is a bit better... and there's still plenty of torsional strength. With the large Tune flanges, I'm inclined to think that 2x will be fine... maybe even better (adequate torsional stiffness, and improved lateral stiffness which would be good on a dished front wheel). But wanted to see what others think....? Should I go with the 2x, or get new spokes for 3x? The aim is to make these wheels as good as they can be, so I'm open to getting new spokes if that will improve them.
What lacing for 24 Hole Road Disc Build (Enve SES / Tune)?
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I've been meaning to call them about that. I'm not in the shop so I don't have a hub in front of me, but 3X for 24 would lead to the spokes overlapping adjacent heads. I can't see how 2X isn't the recommended pattern for 24 spoke wheels.
Thanks for your response Eric. In the limiting case where the hub flange is negligibly small compared to the ERD, then I think 3x with 24 holes leads to perfectly tangential spokes, and while I imagine the spoke would pass really close to the head of the adjacent spoke, I don't think it would interfere. Here's a page I found where Enve explain their wheelbuilding decisions:
https://enve.zendesk.com/hc/en-us/articles/203255049-Wheelbuilding-The-ENVE-Way
But as the hub flange gets bigger relative to ERD, the spoke pulling angle increases and I think will in reality be > 90 degrees... the larger the hub flange, the larger the excess. Therefore, I think the best lacing ought to depend on the choice of hub. I think their most common build is with the DT 240 centerlock hubs which have pretty small 44/42mm flanges on the front, and 44/47.5mm on the rear (measurements for NDS/DS). Those are pretty small flanges and I can see that the 3x might work well there. I think the limiting pulling angle (in case of small flange) for 2x / 24 holes is 60 degrees, but again goes up as the flange gets bigger relative to ERD. With the Tune hubs and 55.5mm flanges... even assuming 60 degrees, the spokes would create the same moment of force as for a 48mm flange with tangential lacing (55.5 * cos(30 degrees)). That suggests to me that the Tune hub laced 2x should have equal or better torsional stiffness (for the front particularly), and better lateral stiffness (because of the 2x vs 3x) than their standard DT 3x suggested build... Do you agree?
Here's some photos from wheelbuilder.com of a few 3x builds on these rims (spokes are definitely close to interfering, but it does seem like they clear):
And here's one that Rich laced 2x:
https://enve.zendesk.com/hc/en-us/articles/203255049-Wheelbuilding-The-ENVE-Way
But as the hub flange gets bigger relative to ERD, the spoke pulling angle increases and I think will in reality be > 90 degrees... the larger the hub flange, the larger the excess. Therefore, I think the best lacing ought to depend on the choice of hub. I think their most common build is with the DT 240 centerlock hubs which have pretty small 44/42mm flanges on the front, and 44/47.5mm on the rear (measurements for NDS/DS). Those are pretty small flanges and I can see that the 3x might work well there. I think the limiting pulling angle (in case of small flange) for 2x / 24 holes is 60 degrees, but again goes up as the flange gets bigger relative to ERD. With the Tune hubs and 55.5mm flanges... even assuming 60 degrees, the spokes would create the same moment of force as for a 48mm flange with tangential lacing (55.5 * cos(30 degrees)). That suggests to me that the Tune hub laced 2x should have equal or better torsional stiffness (for the front particularly), and better lateral stiffness (because of the 2x vs 3x) than their standard DT 3x suggested build... Do you agree?
Here's some photos from wheelbuilder.com of a few 3x builds on these rims (spokes are definitely close to interfering, but it does seem like they clear):
And here's one that Rich laced 2x:
I think 2X is what I'd do.
Their explanation isn't exactly right. For one thing, they say radial lacing is laterally stiffer and that's not the case the way they do it. Radial with heads out is the least laterally stiff pattern since the bracing angle is the smallest. A cross patter is actually laterally stiffer. The stiffest is radial with the heads facing in giving you the highest bracing angle. The only problem is that some hub shells don't handle that stress well and sometimes it can warp the bearing bores giving you a loose fit. The gets worse with higher profile rims.
24 2X isn't a balance between lateral and torque loads, it favors torque loads. A balance is actually 2X where you have a slightly more laterally stiff pattern and still have excellent resistance to torque loads.
Their explanation isn't exactly right. For one thing, they say radial lacing is laterally stiffer and that's not the case the way they do it. Radial with heads out is the least laterally stiff pattern since the bracing angle is the smallest. A cross patter is actually laterally stiffer. The stiffest is radial with the heads facing in giving you the highest bracing angle. The only problem is that some hub shells don't handle that stress well and sometimes it can warp the bearing bores giving you a loose fit. The gets worse with higher profile rims.
24 2X isn't a balance between lateral and torque loads, it favors torque loads. A balance is actually 2X where you have a slightly more laterally stiff pattern and still have excellent resistance to torque loads.
I called and talked to Enve to get their take. Apparently their reasoning has some other factors, and additionally, when they build these wheels with the Chris King R45 disc hubs, they lace them 2x and NOT 3x because the flanges are tall (57mm). If the hub flange is 55mm or more (so Tune fall in this category), they recommend the 2x.
The reason they do 3x on smaller flanged hubs is because they apparently did some tests of impact under braking load (simulating hard braking at speed an getting a side impact), and wanted the failure mechanism for the wheel to be the rim cracking but maintaining the integrity of the wheel. With the smaller flanged hubs and 2x lacing they were finding that 2 or 3 of the spokes spokes would tear out of the rim, whereas with 3x lacing on these hubs, they got the failure mechanism they wanted.
Either way, in my situation, they suggested to go ahead with 2x.
The reason they do 3x on smaller flanged hubs is because they apparently did some tests of impact under braking load (simulating hard braking at speed an getting a side impact), and wanted the failure mechanism for the wheel to be the rim cracking but maintaining the integrity of the wheel. With the smaller flanged hubs and 2x lacing they were finding that 2 or 3 of the spokes spokes would tear out of the rim, whereas with 3x lacing on these hubs, they got the failure mechanism they wanted.
Either way, in my situation, they suggested to go ahead with 2x.
dwaharvey wrote:
The reason they do 3x on smaller flanged hubs is because they apparently did some tests of impact under braking load (simulating hard braking at speed an getting a side impact), and wanted the failure mechanism for the wheel to be the rim cracking but maintaining the integrity of the wheel. With the smaller flanged hubs and 2x lacing they were finding that 2 or 3 of the spokes spokes would tear out of the rim, whereas with 3x lacing on these hubs, they got the failure mechanism they wanted.
This is interesting. Makes for much better reasoning than their ad copy.
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Agreed. Having said that, it doesn't make a lot of sense to me why the lacing would affect spokes tearing through the rim with a side impact under braking load. The guy I spoke to said he thought the 3x was more "absorbant", but that sounds pretty hand-wavy and not convincing. I just don't see how that really affects the rim connection. I do see how it could affect the hub connection and lead to flange failure (or not). Anyway, I feel good that even they are a proponent of 2x in my case.
Another interesting piece of info from them, in case anyone was tempted to run a standard set of 3.4s on a disc hub, or a pair of standard rears, or even a pair of the disc specific rears.... The front disc specific rim has reinforced spoke holes and bed to counteract the large forces that a front disc wheel gets. So using one of their other rims up there is a bad idea.
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Another interesting piece of info from them, in case anyone was tempted to run a standard set of 3.4s on a disc hub, or a pair of standard rears, or even a pair of the disc specific rears.... The front disc specific rim has reinforced spoke holes and bed to counteract the large forces that a front disc wheel gets. So using one of their other rims up there is a bad idea.
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